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  Subjects -> ENGINEERING (Total: 2298 journals)
    - CHEMICAL ENGINEERING (192 journals)
    - CIVIL ENGINEERING (192 journals)
    - ELECTRICAL ENGINEERING (104 journals)
    - ENGINEERING (1209 journals)
    - ENGINEERING MECHANICS AND MATERIALS (385 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (69 journals)
    - MECHANICAL ENGINEERING (92 journals)

CIVIL ENGINEERING (192 journals)                     

Showing 1 - 192 of 192 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 17)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 36)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 28)
Agregat     Open Access  
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 31)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 1)
Archives of Civil Engineering     Open Access   (Followers: 10)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 16)
Building & Management     Open Access  
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 6)
Canadian Journal of Civil Engineering     Hybrid Journal   (Followers: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 17)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 2)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 6)
Civil and Environmental Research     Open Access   (Followers: 19)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 18)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 10)
Civil Engineering Dimension     Open Access   (Followers: 8)
Civil Engineering Infrastructures Journal     Open Access  
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 269)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 36)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 2)
Construction Engineering     Open Access   (Followers: 9)
Construction Management and Economics     Hybrid Journal   (Followers: 22)
Construction Science     Open Access   (Followers: 4)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 2)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 17)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 14)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 9)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 16)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 4)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 3)
Géotechnique Letters     Hybrid Journal   (Followers: 7)
GISAP : Technical Sciences, Construction and Architecture     Open Access  
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indonesian Journal of Urban and Environmental Technology     Open Access  
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 2)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 22)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 16)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 1)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 14)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 9)
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 6)
International Journal of Protective Structures     Hybrid Journal   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 10)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Built Environment     Open Access   (Followers: 4)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 7)
International Journal Sustainable Construction & Design     Open Access  
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal   (Followers: 1)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 12)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 8)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Engineering, Science and Technology     Open Access  
Journal of Civil Society     Hybrid Journal   (Followers: 4)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 24)
Journal of Construction Engineering     Open Access   (Followers: 7)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 8)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 14)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 21)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 5)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 11)
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 3)
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 40)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 3)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the Civil Engineering Forum     Open Access  
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Journal of Water and Environmental Nanotechnology     Open Access  
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 17)
npj Materials Degradation     Open Access  
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 7)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 12)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 11)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 6)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 61)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 5)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 10)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 12)
Structural Mechanics of Engineering Constructions and Buildings     Open Access  
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 23)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 13)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 9)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 6)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 6)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 2)
Thin-Walled Structures     Hybrid Journal   (Followers: 4)
Transactions of the VŠB - Technical University of Ostrava. Construction Series     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Underground Space     Open Access  
Water Science & Technology     Partially Free   (Followers: 25)
Water Science and Technology : Water Supply     Partially Free   (Followers: 22)

           

Journal Cover Structural Concrete
  [SJR: 0.874]   [H-I: 14]   [11 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1464-4177 - ISSN (Online) 1751-7648
   Published by John Wiley and Sons Homepage  [1589 journals]
  • Behavior and failure modes of reinforced concrete beams strengthened with
           NSM GFRP or aluminum alloy bars
    • Authors: Guohua Xing; Zhaoqun Chang, Osman E. Ozbulut
      Abstract: Although the use of near-surface mounted (NSM) fiber reinforced polymer (FRP) reinforcement satisfactorily enhances the flexural capacity of deficient reinforced concrete beams, the concrete beams strengthened with NSM FRPs typically exhibit brittle behavior. Aluminum alloy (AA) bars possess non-corrosive characteristics like FRPs but also exhibit a nonlinear tensile response with a clear yield point. This paper investigates the failure modes of reinforced concrete beams strengthened with either NSM glass FRP (GFRP) bars or AA bars. A total of six concrete beams including one control beam were tested under four-point bending. The effects of NSM reinforcement type, internal steel reinforcement ratio, and NSM reinforcement ratio on the failure behavior of the strengthened beams were examined. The ultimate flexural load capacity, ductility index, energy absorption capacity, strains in steel reinforcement and in concrete, and cracking behavior for each tested beam were determined and analyzed. The results indicated that for the same NSM reinforcement ratio, the NSM GFRP bars provided considerably higher increases in the flexural strength of reinforced concrete beams compared to the AA bars. However, the beams strengthened with AA bars showed more ductile response compared to the beams strengthened with NSM GFRP bars.
      PubDate: 2018-01-08T00:51:25.038166-05:
      DOI: 10.1002/suco.201700099
       
  • Strength of steel fiber reinforced concrete beams in pure torsion
    • Authors: Ali Amin; Evan C. Bentz
      Abstract: This paper presents a simple yet accurate technique for determining the strength of steel fiber reinforced concrete beams loaded in pure torsion. The results of the model are compared with 21 beams found in the literature as well as two new beams tested by the authors and reported herein. The model considers the beneficial effect of the fibers in resisting tension after the concrete matrix has cracked, and it is implemented into the widely accepted space truss analogy for reinforced concrete members subjected to pure torsion. The proposed model provides good correlations to the collected test data with a test to predicted ratio of 1.10 and COV of 0.19. A simplified method of the aforementioned model, suitable for design, is also presented and is shown to provide good predictions to the test data.
      PubDate: 2018-01-04T23:21:25.616116-05:
      DOI: 10.1002/suco.201700183
       
  • Response of reinforced concrete beams to high-velocity fluid impact. Part
           I: Experiments
    • Authors: Hasan Korucu; Ayhan Irfanoglu
      Abstract: Thirty-two reinforced concrete beams were tested under static and fluid impact loads. Hoop (rectangular) and spiral transverse reinforcement of various configurations were used to confine the specimens. The objectives were to observe the effect of shape of beams and configuration of confinement reinforcement on the impact resistance, and to estimate the limiting fluid velocity that causes total failure.
      PubDate: 2018-01-03T07:35:08.199358-05:
      DOI: 10.1002/suco.201600163
       
  • Response of reinforced concrete beams to high-velocity fluid impact. Part
           II: Numerical modeling and simulation
    • Authors: Hasan Korucu; Ayhan Irfanoglu
      Abstract: Fluid impact tests on reinforced concrete beams with rectangular or circular transverse reinforcement were modeled and simulated using explicit finite element analysis software, LS-DYNA. The mid-span displacements were measured and compared with the results of simulations. The objective was to test the accuracy and fidelity of the numerical modeling and simulation approach and to confirm that damage caused by fluid impact on the beams can be estimated with a reasonable accuracy over a wide range of impact velocity.
      PubDate: 2017-12-27T22:52:07.558501-05:
      DOI: 10.1002/suco.201600164
       
  • Stage of construction: An essential consideration in designing reinforced
           concrete building structures
    • Authors: Yezid A. Alvarado; Manuel Buitrago, Isabel Gasch, Camilo A. Prieto, Yesenia A. Ardila
      Abstract: This paper analyzes the potential influence of the construction process on the serviceability stage of the structure of reinforced concrete (RC) buildings. For this, a number of cases of buildings erected by habitual construction processes were simulated by a finite elements model, including and excluding the construction process. The shoring–clearing–striking method was seen the least harmful to the long-term behavior, but even so maximum loads during construction exceeded the design loads. On the other hand, shoring–reshoring–striking procedure had construction loads similar to the design loads but worse long-term behavior. In view of the results obtained, it is of the utmost importance to consider the construction phase when designing building structures. Some practical recommendations are given to improve the consideration of the construction process in the design as well as to take into account the long-term behavior of structures due to load history during construction.
      PubDate: 2017-12-26T00:31:15.339997-05:
      DOI: 10.1002/suco.201700128
       
  • Cover Picture: Structural Concrete 6/2017
    • PubDate: 2017-12-22T01:24:59.010424-05:
      DOI: 10.1002/suco.201770062
       
  • Structural behavior of cast-in C-channel anchors in precast concrete under
           uniaxial tension
    • Authors: Islam S. AbouHamdah; Mohammed A. Al-Osta, Mohammed H. Baluch, Muhammad K. Rahman, Ahmed Ibrahim
      Abstract: The cast-in C-channel is a small anchoring steel piece used to post-connect different types of elements in precast concrete members. The objective of this study was to investigate the ultimate capacity of cast-in C-channels under uniaxial tension and to compare its ultimate load capacity and failure modes with a three-dimensional finite element (FE) simulation, and to develop a mechanistic solution for cast-in C-channels. Five samples were cast and tested in varying configurations to induce the different failure modes of the channels, focusing on the influence of the confinement of the host concrete as well as the effect of the studs. The results showed that flexure of the channel governed the capacity in both the experimental work as well as in FE. In addition, the results of having local lip yielding as another dominant failure mechanism were similar to that observed in the experimental work and the finite element method (FEM). The FEM predicted not only the failure modes as addressed in mechanistic formulations but also captured the diagonal cracking in the host concrete and relative slip of the embedded channel, both phenomena observed in the experimental work but not accounted explicitly in the current design formulations.
      PubDate: 2017-12-18T22:18:12.883072-05:
      DOI: 10.1002/suco.201700163
       
  • A coupled thermo-mechanical inelastic analysis approach for reinforced
           concrete flexural members during fire
    • Authors: Hitesh Lakhani; Akanshu Sharma, Jan Hofmann
      Abstract: A practical approach to evaluate the complete load–deflection–time response of reinforced concrete (RC) flexural members under fire is presented. The proposed approach is extendable for performance evaluation of RC structures at all three levels of complexity, namely member level, sub-assembly level, and the structural level. The approach involves three main steps: (a) transient heat transfer analysis to evaluate the temperature distribution across the critical section; (b) determination of moment–curvature characteristics for the critical sections using temperature-dependent constitutive laws for concrete and steel; and (c) nonlinear static analysis to obtain load–deflection plots of the member at regular intervals of the fire exposure. The series of load–deflection plots for different exposure durations are then used to obtain the deflection–time plots for the applied load level. The important issue of considering the initial stiffness of fire-affected beams taking into account the material degradation and thermal damage has been addressed in a simple yet rational manner. The presented approach does not consider the phenomenon of thermal spalling (explosive) and is applicable for cases where thermal spalling can be neglected. The approach is straightforward and easy to implement as only simple tools available to structural design engineers/design offices are required.
      PubDate: 2017-12-15T00:37:21.705307-05:
      DOI: 10.1002/suco.201700071
       
  • Deformation-based method for the analysis of reinforced concrete- and
           fiber reinforced polymer-jacketed columns subjected to axial compression
    • Authors: Attila Várdai
      Abstract: This paper introduces a generalized approach for the sectional analysis of jacketing, based on the compatibility of lateral deformation of a jacketed column and jacket wall. The method is suitable to determine the magnitude and distribution of confining stresses provided by reinforced concrete or fiber reinforced polymer jackets at any stress level, and to estimate the ultimate resistance of strengthened columns subjected to axial compression. After the discussion of the theoretical bases of the proposed method, a simplified application is introduced. For validation of applicability and accuracy to predict ultimate capacity, comparison with a large number of experimental results with square- and circular-shaped columns is presented. According to the comparisons, the average of the absolute values of relative errors of the proposed method is 8.34%. The calculation results are evaluated qualitatively as well to highlight relevant issues for jacket detailing and to point out possible future directions of developing adequate design methods.
      PubDate: 2017-12-14T23:38:37.231537-05:
      DOI: 10.1002/suco.201700019
       
  • The cyclic performance of reinforced concrete columns using the
           lap-spliced crosstie and lap-spliced inner hoop
    • Authors: Tai-Kuang Lee; Cheng-Cheng Chen, Kai-Shen Zhan
      Abstract: A lap-spliced crosstie consists of two J-shaped steel bars (rebars) that have a straight end and an end featuring a 180° hook. A lap-spliced inner hoop is the lap splice of two U-bars. In this study, cyclic load test was conducted on four large-sized reinforced concrete (RC) columns to investigate the cyclic performance of RC columns comprising lap-spliced crossties and lap-spliced inner hoops. The research results are presented as follows: (a) The ductility of the specimens that adopted the lap-spliced crossties and lap-spliced inner hoops was significantly superior to that of the specimens using conventional crossties and crossties featuring a 180° hook on the two ends. (b) The use of the lap-spliced crossties and lap-spliced inner hoops may significantly improve the constructability of crossties over the conventional crossties; however, the amount of transverse reinforcement used is most likely to increase. (c) The lap-spliced crosstie and lap-spliced inner hoop were formed on the basis of the tension lap splice of rebars. Therefore, column size has to be large enough to meet the minimum requirement for tension lap splice of rebars when lap-spliced crosstie or lap-spliced inner hoop is to be used.
      PubDate: 2017-12-11T22:47:19.735232-05:
      DOI: 10.1002/suco.201700098
       
  • Optimizing the ultimate strength of precast reinforced concrete pipes in
           three-edge bearing tests
    • Authors: Li-Chung Chao; Chiang-Pin Kuo
      Abstract: By utilizing Taguchi method, this paper presents a simplified approach that aims at developing technical recommendations of control factors of reinforcement and concrete for steel wire reinforced concrete pipes (SWRCP). For this purpose, the structural behaviors of full scale of 400 and 600 mm inside diameter SWRCPs were analyzed. Three control factors, namely wire diameter (dw), wire winding pitch (pw), and water/cement ratio of concrete (w/c of concrete) were designed in an L9 orthogonal array. The best possible levels were determined for maximization of crushing load (Fcr) and ultimate load (Fu) in three-edge bearing tests and minimization of crack width (Wcr). Based on the results, the economical and optimal control factors of dw, pw, and w/c of concrete for SWRCPs with inside diameter of 400 mm are 6.5 mm, 100 mm, and 33.5%, respectively. For SWRCPs with inside diameter of 600 mm, the optimal control factors of dw, pw, and w/c of concrete are 6.5 mm, 33 mm, and 33.5%, respectively. In addition, by the use of analysis of variance, the contribution percentages of control factors were obtained and were used as the most effective factors on the Fcr, Fu, and Wcr for SWRCPs. Through the implementation of the study, this paper concludes a practical and significant overall idea of designing SWRCPs for pipe manufacturing industry.
      PubDate: 2017-11-30T21:37:08.784292-05:
      DOI: 10.1002/suco.201700143
       
  • An analysis of the shear-transfer actions in reinforced concrete members
           without transverse reinforcement based on refined experimental
           measurements
    • Authors: Francesco Cavagnis; Miguel Fernández Ruiz, Aurelio Muttoni
      Abstract: A traditional difficulty in the understanding of the role of the various shear-transfer actions in members without transverse reinforcement has been a lack of detailed measurements on the development of shear cracking and their associated kinematics during the process of failure. In this paper, this issue is addressed on the basis of an experimental program on 20 beams investigated by means of digital image correlation. The measurements are shown to allow a clear understanding of the mechanisms leading to shear failure and their evolution (transfer of forces between the various potential shear-carrying actions) during the loading process. The amount of shear carried by the various potential shear-transfer actions is estimated for varying levels of load accounting for the cracking pattern and actual kinematics on the basis of fundamental constitutive laws for concrete and steel. The results are shown to be consistent and provide a rational basis for the understanding of the phenomenon of shear transfer in reinforced concrete members without transverse reinforcement.
      PubDate: 2017-11-30T21:32:24.820532-05:
      DOI: 10.1002/suco.201700145
       
  • Flexural strengthening of structural concrete with iron-based shape memory
           alloy strips
    • Authors: Julien Michels; Moslem Shahverdi, Christoph Czaderski
      Abstract: This paper presents a study on structural concrete retrofitting with iron-based shape memory alloys (Fe-SMA). Initially, the Fe-SMA strip is prestrained at ambient temperature with a remaining deformation. Subsequently, it is applied on the structure as an end-anchored strip. The shape memory effect, characterized by the material’s back transformation to its initial shape, is created upon heating at an elevated temperature of about 160°C. In this case, a mechanical end anchorage refrains the alloy to develop its recovery in strain and hence transforms it to a recovery stress, which results in a prestress in the concrete substrate. The ease of installation of the strip itself combined with an efficient and rapid direct fastening method render this strengthening technique highly competitive for the market. In this paper, material characteristics such as the ductile behavior of the alloy in tension as well as its activation by means of fast resistive heating are presented. The application on reinforced concrete beams is described and static loading tests are shown in order to demonstrate the efficiency of the technique. An improved structural behavior at service state proves that Fe-SMA strips are an efficient and innovative method for structural strengthening. Finally, a site application is presented. It demonstrates that Fe-SMA strips are a competitive solution for replacing existing, more pricy, and technically more complicated methods.
      PubDate: 2017-11-27T21:02:32.017826-05:
      DOI: 10.1002/suco.201700120
       
  • Predictive strength of ready-mixed concrete: Exemplified using data from
           the Norwegian market
    • Authors: Morten Engen; Max A. N. Hendriks, Jochen Köhler, Jan Arve Øverli, Erik Åldstedt, Ernst Mørtsell, Øyvind Sæter, Roar Vigre
      Abstract: A hierarchical model for the variability of material properties in ready-mixed concrete is formulated. The model distinguishes between variation on the batch, recipe, plant, producer, durability class, strength class, and regional standard level. By considering Bayesian inference and maximum likelihood estimators, the contributions from the different hierarchical levels to the variability can be estimated. The methodology is demonstrated by considering more than 14,000 compressive strength recordings from Norwegian ready-mixed concrete plants. The results suggest that the compressive cube strength of lab-cured specimens can be represented by a log-normally distributed variable with mean 1.28fck,cube and coefficient of variation Vc,cube=0.13. Prior parameters for Bayesian updating are given for a range of strength and durability classes. The application of the results is demonstrated in two examples. Since the durability class gives a required maximum water–binder ratio, and the strength of the concrete is governed by the water–binder ratio, the durability class introduces a strength potential if the concrete is subject to strict durability requirements and low-strength requirements. It is suggested that the designer should specify a strength class that utilizes this strength potential, and it is expected that a closer collaboration between the designer, contractor, and producer will result in improved concrete specifications.
      PubDate: 2017-11-27T20:50:35.046787-05:
      DOI: 10.1002/suco.201700950
       
  • Numerical investigation of the shear behavior of reinforced
           ultra-high-performance concrete beams
    • Authors: Sifatullah Bahij; Saheed K. Adekunle, Mohammed Al-Osta, Shamsad Ahmad, Salah U. Al-Dulaijan, Muhammad K. Rahman
      Abstract: This computational investigation focused on numerical modeling of the shear behavior of ultra-high-performance concrete (UHPC) beams reinforced longitudinally with high-strength rebars and ordinary-strength steel (stirrups). Nonlinear three-dimensional finite element model, using the concrete damaged plasticity model and material properties obtained from uniaxial compressive and tensile laboratory tests, was conducted to simulate UHPC concrete beams within a commercial finite element software package ABAQUS 6.13. This investigation included the effects of various parameters; shear span-to-effective depth ratio (a/d), volume fraction of steel fibers, Vf, longitudinal reinforcement ratio, ρ, and stirrups spacing, s, on shear behavior of UHPC beams. Numerical results compared with previously obtained experimental results in terms of shear force–midspan deflection and cracking-propagation behaviors. The results showed that finite element analysis predicted the shear behavior of UHPC beams in good agreement with the experimental data and predicted the response of the beam with variation in various parameters with a good accuracy.
      PubDate: 2017-11-27T20:41:16.230172-05:
      DOI: 10.1002/suco.201700062
       
  • Thermo-mechanical response of concrete sandwich panels reinforced with
           glass fiber reinforced polymer bars
    • Authors: Andreas Schmitt; Valter Carvelli, Marcin M. Haffke, Matthias Pahn
      Abstract: The thermo-mechanical behavior of sandwich panels was experimentally investigated. The panels featured two external concrete layers reinforced with glass fiber reinforced polymer rebars (GFRP) and an internal expanded polystyrene insulation layer. These are typical for low load bearing and thermally insulated panels in façade claddings. To assess the suitability of the internal GFRP reinforcement, the heating condition was such that rebars in one concrete layer were exposed to temperatures higher than the glass transition temperature of the resins. Such extreme condition allowed verifying the retention of the mechanical behavior, in terms of deformability and load-carrying capacity, with bending tests of unheated and heated panels. As main outcome, the elevated temperature produced significant modification of the insulation layer, considerable reduction of global stiffness and load-carrying capacity, while GFRP bars were not apparently modified.
      PubDate: 2017-11-27T02:23:30.735024-05:
      DOI: 10.1002/suco.201700048
       
  • Innovative design concepts: Application of textile reinforced concrete to
           shell structures
    • Authors: Josef Hegger; Manfred Curbach, Alexander Stark, Sebastian Wilhelm, Kristina Farwig
      Abstract: Today's challenges comprise climate change, urbanization, and demographic change. The building industry is of major technical and economic importance for these subjects. Due to the versatility, structural concrete is the major applied material in building industry. The associated cement production contributes significantly to the CO2 emissions. Hence, new technologies and planning methods as well as production and recycling techniques have to be developed to account for a fast changing world and to reduce the carbon footprint. High-performance materials, such as textile reinforced concrete, in combination with new construction methods and conceptual designs, can reduce the material usage significantly. In this paper, new construction methods as well as conceptual designs are proposed, which result in economic structural members.
      PubDate: 2017-11-23T17:46:55.656875-05:
      DOI: 10.1002/suco.201700157
       
  • Study on the deterioration process of cement-based materials under sulfate
           attack and drying–wetting cycles
    • Authors: Huaicheng Chen; Haoliang Huang, Chunxiang Qian
      Abstract: In this paper, the deterioration process of mortars degraded by sulfate under the restricted and unconstrained condition was investigated, respectively. Sodium sulfate (5 wt%) and dry–wet circulation method was adopted to accelerate the deterioration process. The deformation, damage rate, and porosity were measured by linear variable differential transducers (LVDTs), ultrasonic velocity measuring technology, and X-ray computed tomography (XCT), respectively. Mass loss and loss rates of flexural strength and compressive strength were also measured to evaluate the deterioration results. Scanning electron microscope (SEM), energy-dispersive Spectrometer (EDS), and X-ray diffraction (XRD) were used to analyze the degradation mechanisms. The experimental results indicate that the greater the water–cement (w/c) ratio of mortars, the more serious the deterioration. XCT images and analysis results of porosities show that, among the mortars after being degraded by sulfate solution for 360 drying–wetting cycles, the M30-SR sample under restricted condition is deteriorated most seriously. SEM/EDS and XRD analysis results indicate that the microstructure of hydration products changed obviously. Sodium sulfate and gypsum are observed after being degraded by sodium sulfate.
      PubDate: 2017-11-23T17:42:17.846828-05:
      DOI: 10.1002/suco.201700038
       
  • Variations of in situ concrete strength by European Standard and American
           Code
    • Authors: Sergio Gavilan; Luiz Carlos Pinto Da S. Filho
      Abstract: Europe and United States exert a worldwide influence in the field of concrete control, proof of this is that many countries adopt their regulations, due to lack of own regulations. When there are problems with concrete strength, cores are used, and this situation usually involves two or more parties with different views on the proper interpretation of the core results. An experimental study was carried out, with five lots of prototypes concrete slabs of 20, 30, and 35 MPa specified strength, 210 cylinders of 10 × 20 cm, 296 cores of 10 cm diameter, and slenderness 2, as well as temperature and maturity control. Estimated strength of cores and cylinders was compared according to the criteria of European standards UNE-EN 13791 and the American code ACI 318. Tests were performed at 3, 5, 7, and 28 days. It is concluded that the European and American regulations present similar results for concretes with specified strength between 30 and 35 MPa, whereas in the range of 16–30 MPa, the European standard is more rigorous than the American Code, being the latter more favorable to the concrete producer.
      PubDate: 2017-11-23T17:41:26.603054-05:
      DOI: 10.1002/suco.201700115
       
  • Experimental investigation on the compressive behavior of short-term
           preloaded carbon fiber reinforced polymer-confined concrete columns
    • Authors: Marco Filippo Ferrotto; Oliver Fischer, Roland Niedermeier
      Abstract: Strengthening of concrete columns with fiber reinforced polymer sheets provides a good improvement to the existing structural members in terms of load and strain capacity due to the properties of the composite jacket. A proper knowledge of the load–strain response of the composite members is necessary to design retrofitting intervention of existing structures; however, so far the available design methods do not allow to take into account the effect of the possible presence of service loads on the compressive behavior of the reinforced columns. An experimental investigation on the compressive behavior of preloaded circular concrete columns reinforced with carbon fiber reinforced polymer was carried out to determine the load and deformational capacity of confined concrete subjected to short-terms loads. Nineteen compression tests were performed to underline the difference respect to the standard compressive stress–strain response of the confined specimens. The results indicate that the compressive behavior seems to be not particularly influenced by the preloading. As the preloading level increases, ultimate axial load and axial strain do not have significant change respect to the test performed without preloading; however, the load–strain response of the confined concrete is affected by a reduction of the secant stiffness.
      PubDate: 2017-11-23T17:26:59.789095-05:
      DOI: 10.1002/suco.201700072
       
  • Stress–strain evaluation of steel-strapped high-strength concrete with
           modified self-regulating end clips
    • Authors: Chee-Loong Chin; Chau-Khun Ma, Abdullah Zawawi Awang, Wahid Omar, Ahmad Beng Hong Kueh
      Abstract: High-strength concrete (HSC) is increasingly used in columns of building all over the world. Although it offers superior properties, it is relatively a brittle material. This study intends to improve the ductility of HSC using modified pretensioning confinement technique. It investigates the effects of the technique on the performance of the column and develops equations to predict the stress–strain. The basis of the technique is to apply a pretensioning force to relatively low-cost steel straps wrapped around the specimens. A modified end clip which is able to be self-regulated is used to secure the strap ends. The parameters studied include various spacing between straps and number of layers of straps. The confined specimens were tested in compression until failure under monotonic loading conditions, focusing particularly on the mode of failure, loads at peak and ultimate conditions and longitudinal and lateral strains in both concrete and straps. It was observed that the pretensioning technique using steel straps enhanced the ductility as well as the strength of the concrete as the confining ratio increases. Moreover, the layers of straps had also delayed the onset of volumetric expansion and therefore, the concrete failure. Based on the regression analysis, new equations of strength and strain for the confined HSC column have been developed to predict its stress–strain behavior.
      PubDate: 2017-11-23T17:16:35.692684-05:
      DOI: 10.1002/suco.201700134
       
  • Load-carrying capacity of steel fiber reinforced concrete beams at large
           deflections
    • Authors: Akshay Venkateshwaran; Kiang Hwee Tan
      Abstract: Discrete steel fibers are known to control crack widening in concrete members thereby enabling them to carry loads up to large deflections. This study examined the flexural behavior of steel fiber reinforced concrete (SFRC) beams reinforced with steel fibers by conducting four-point bending tests on eight beam specimens. The effect of reinforcing index (defined as the product of the volume fraction and the aspect ratio of steel fibers), fiber type, and beam depth was investigated. The load-carrying capacity corresponding to different beam deflections was predicted using available constitutive stress–strain/crack width laws in tension. Although existing constitutive relations in tension predict the peak load capacity well, they fail to accurately predict the load-carrying capacity at large deflections. Subsequently, a constitutive law is proposed using a back-calculation technique which was validated with the results from four-point bending tests conducted on 24 SFRC beams including 16 results found in the literature. The deviation of the predictions of the proposed model with regard to the average load-carrying capacity at large deflections is within 12% from the observed values.
      PubDate: 2017-11-21T21:33:27.642909-05:
      DOI: 10.1002/suco.201700129
       
  • Parking slabs made of carbon reinforced concrete
    • Authors: Alexander Schumann; Harald Michler, Frank Schladitz, Manfred Curbach
      Abstract: Parking garage buildings are usually comprised of steel reinforced concrete (RC) slabs. Unfortunately, there are often cases of damage caused by the high exposure to corrosive chemicals. To prevent corrosion of the reinforcement, especially the ceilings must be coated with expensive protection systems. Due to the not-corrosive nature of carbon fibers, carbon RC is a perfect solution for those structures. But before using carbon RC for parking slabs, the problem of the end anchorage of the reinforcement by short-end anchorage lengths had to be solved. Therefore, a new anchorage method for carbon RC is described in detail in this publication. A large-scale test had been conducted to show the potential of carbon RC for parking slabs and to prove the ability of the developed new-end anchorage method. Also, an analytical recalculation of the large-scale test is presented.
      PubDate: 2017-11-21T21:17:26.258364-05:
      DOI: 10.1002/suco.201700147
       
  • Experimental and theoretical evaluation of punching strength of steel
           fiber reinforced concrete slabs
    • Authors: Nuno D. Gouveia; Massimo Lapi, Maurizio Orlando, Duarte M. V. Faria, António M. P Ramos
      Abstract: This paper deals with the experimental and theoretical evaluation of punching shear capacity of steel fiber reinforced concrete (SFRC) slab–column connections. Five experimental specimens with a thickness of 160 mm, different fiber volume contents (0, 1.0, and 1.5%) and different flexural reinforcement ratios (0.75 and 1.5%) have been tested. The experimental results were evaluated using a physical–mechanical model based on the critical shear crack theory (CSCT). The model has given a good approximation of experimental punching shear strengths. In general, tests have highlighted a significant increase in load and deformation capacity of fiber reinforced concrete slab–column connections in comparison with reinforced concrete connections.
      PubDate: 2017-11-15T23:16:32.934709-05:
      DOI: 10.1002/suco.201700136
       
  • Structural concrete based on alkali-activated binders: Terminology,
           reaction mechanisms, mix designs and performance
    • Authors: Annemarie Herrmann; Andreas Koenig, Frank Dehn
      Abstract: The interest in concretes based on alkali-activated binders (AABs) is increasing significantly along with the continued research into and development of these novel construction materials from lab scale to practical application. The paper summarizes current knowledge about concretes based on AABs to address the following questions: What are structural concretes based on AABs' What are the specific characteristics with regard to the chemical binder reaction' What has to be considered for the mix designs of AACs' And which material performances can be expected'
      PubDate: 2017-11-15T23:05:51.537348-05:
      DOI: 10.1002/suco.201700016
       
  • Flexural response of high-strength steel-ultra-high-performance fiber
           reinforced concrete beams based on a mesoscale constitutive model:
           Experiment and theory
    • Authors: Jianan Qi; Jingquan Wang, Zhongguo John Ma
      Abstract: This paper presents the results of experimental and theoretical studies undertaken to assess the flexural performance of high-strength steel-ultra-high-performance fiber reinforced concrete (HSS-UHPFRC) beams. A total of nine HSS-UHPFRC beams were tested, and the influence of fiber volume fraction, fiber type, longitudinal reinforcement ratio, and concrete strength on the flexural response was evaluated. The results indicate that sufficient longitudinal reinforcement should be provided in a UHPFRC beam to avoid abrupt failure and possible catastrophic collapse. After the loss of the fiber bridging effect, corresponding to the fibers being pulled out from the matrix, which occurs one by one with audible sound which is sizzling, redistribution, and homogenization of the concrete stress beside cracks, induced by the dispersed fibers, takes place and more flexural cracks with small spacing appear besides the existing cracks. The beam stiffness was about 85% of the initial beam stiffness at flexural cracking state and was only approximately 25% of the initial beam stiffness at the ultimate state. A constitutive model is proposed, including a bilinear model for compression and a drop-down model for tension, taking into account uniform distribution, embedment length, and orientation of fibers for the multi-scale mechanics analysis. A flexural strength model was subsequently derived on the basis of the proposed mesoscale constitutive model; strain compatibility and force equilibrium were taken into account. The prediction of the ultimate flexural capacity and the overall post-cracking response with the proposed model show a good agreement with the test results.
      PubDate: 2017-11-08T22:26:11.583471-05:
      DOI: 10.1002/suco.201700043
       
  • Field experimental study on the retrofit of cracked onshore wind turbine
           foundations using externally prestressed anchor bolts
    • Authors: Minjuan He; Xue Bai, Renle Ma, Dongpin Huang, Huiqun Liu
      Abstract: Inserted rings are considered as a crucial element of onshore wind turbine foundations to resist uplift and compressive forces at the interface of the steel towers and concrete foundations. These inserted rings can be deficient because of the crushing of the concrete and the occurrence of cracks as the result of the vibration of the tower and the shrinkage of the concrete. Therefore, it is very important to develop an efficient retrofitting system in order to restore the lost capacity and/or even outperform it. The objective of this paper is to develop a retrofit strategy for the deficient foundations using external prestressing technique and verify it using field data. A field test was conducted on two onshore wind turbine foundations with almost the same level of cracks. One of them was retrofitted using externally prestressed anchor bolts after the appearance of cracks, and the other was the control foundation. Strain sensors were installed in the foundation and strain signals were recorded in the period of construction, prestressing, and operation. Field test results showed that the prestressing technique can limit the crack width and improve the section stiffness.
      PubDate: 2017-11-08T00:57:00.160905-05:
      DOI: 10.1002/suco.201600186
       
  • Experimental studies and analysis on compressive strength of normal-weight
           concrete at low temperatures
    • Authors: Jian Xie; Jia-Bao Yan
      Abstract: The construction of liquid nitrogen gas storages and engineering structures in cold regions exposed reinforced concrete structures to low temperatures. This paper investigates the compressive strength of normal-weight concrete under low temperatures to −165°C through a 174-specimen test program. The key parameters studied in this test program included low temperature T ranging from −165 to +20°C, water/cement ratio ranging from 0.33 to 0.57, and water content Wc ranging from 0 to 6%. Their influences on the compressive strength of the concrete under low temperature were highlighted and analyzed. With the scanning electron microscope (SEM), the influence of these parameters on the microstructures of the concrete under low temperature was observed and presented. These test data and SEM analyses revealed the failure mechanism and provided proofs on the improvements of the compressive strength of the concrete under low temperature. Based on these test data, a mathematical model has developed to describe the relationship between the increasing factor of the compressive strength of the concrete under low temperatures and the influencing parameters of T, w/c ratio, and Wc. Finally, design equations are provided to predict the increasing factor of the compressive strength of the concrete under low temperature.
      PubDate: 2017-11-07T21:11:36.109518-05:
      DOI: 10.1002/suco.201700009
       
  • Finite element modeling of debonding mechanisms in carbon fiber reinforced
           polymer-strengthened reinforced concrete continuous beams
    • Authors: Mohammed A. Sakr
      Abstract: This paper presents three-dimensional (3D) and two-dimensional (2D) finite element models to analyze strengthened reinforced concrete (RC) continuous beams with carbon fiber reinforced polymer (CFRP) which has become familiar technique in the last decade. Experimental results in the literature showed that two different debonding failure modes, either by interfacial debonding of fiber reinforced polymer (FRP) or by concrete cover separation may occur. This study takes the two possible debonding failure modes into account by considering two cohesive surfaces; the first is inserted in the adhesive layer, whereas the second is inserted between the reinforcing steel and the concrete cover. The proposed cohesive surfaces take the slippage into account considering the cohesive surface fracture energy. The numerical models are verified utilizing five symmetrical RC continuous beams available in the literature. The numerical results of 3D and 2D models for the plated beams (beams strengthened with FRP plates) agreed well with the experimental results. Additionally, the effect of the CFRP plate length, and the parameters of the cohesive surfaces on the behavior and debonding failure modes (in the adhesive layer and between the reinforcing steel and the concrete cover) of CFRP-strengthened RC continuous beams are investigated.
      PubDate: 2017-11-06T19:27:33.082091-05:
      DOI: 10.1002/suco.201700011
       
  • Seismic evaluation of engineered cementitious composites
           beam–column–slab subassemblies with various column-to-beam flexural
           strength ratios
    • Authors: Xingwen Liang; Tingting Lu
      Abstract: Previous studies showed that the column-to-beam flexural strength ratio, the effect flange width, and the material nonlinearity were the major factors in determining the failure mechanism of frame structure during seismic loading. For the purpose of evaluating the seismic performance of frame structures, five beam-column–slab subassemblies with various column-to-beam flexural strength ratios were tested, four of which used engineered cementitious composites (ECC) at the joint and plastic hinge regions of the beam, column, and slab (referred to as the expected damaged position below). The findings suggest that the specimens that used ECC material in the expected damaged positions had a greater tendency toward the “strong column–weak beam” failure mechanism compared with the reinforced concrete specimens, and the use of ECC in the subassemblies enhanced their seismic performance with regard to energy dissipation, ductility, and integrity. The ECC specimen with the expected column-to-beam strength ratio of 1.2 (the ratio in the test was 1.12) still had serious damage at the lower column end. However, the specimen with the expected ratio of 1.6 (the ratio in the test was 1.45) only had multiple cracks at the column ends and did not exhibit obvious damage.
      PubDate: 2017-11-06T19:20:47.697302-05:
      DOI: 10.1002/suco.201600119
       
  • Seismic response and life-cycle cost of reinforced concrete special
           structural wall buildings in Dubai, UAE
    • Authors: Mohammad AlHamaydeh; Nader Aly, Khaled Galal
      Abstract: The primary objective of this paper is to quantify the effect of Dubai's diverse seismicity estimates on the seismic response of reinforced concrete shear wall buildings. In this regard, three 12-story office buildings are designed and detailed in accordance with common practices and building codes utilized in Dubai. The buildings are designed for three possible seismic hazard estimates of Dubai (i.e., high, moderate, and low) with specially detailed shear walls. The seismic response is evaluated based on FEMA P695 methodology and fragility analysis. The methodology is based on nonlinear pseudo-static pushover and incremental dynamic analyses (IDA). Pushover analysis is performed and its results are compared against design levels. IDA is performed using the set of 22 far-field ground motion records recommended by FEMA P695. The results of this research confirm that designing for the conservative seismicity estimate significantly enhances the seismic response of the buildings. The building designed for the highest seismicity showed a favorable structural response, while the moderate seismicity design had a reasonable response. For the lowest seismicity design, results showed a poor seismic performance. Furthermore, the resulting enhancements in the seismic response reduce potential earthquake damages and collapse probabilities. Therefore, the marginal increase in initial investment is outweighed by the reduction in the buildings’ life-cycle (repair and downtime) cost.
      PubDate: 2017-11-06T19:10:51.379013-05:
      DOI: 10.1002/suco.201600177
       
  • Comparison study on hysteretic energy dissipation and displacement
           components between cast-in-place and precast piers with high-strength bars
           
    • Authors: Wei-Ding Zhuo; Zhao Liu, Jian-Dong Zhang, Wen-Ming Zhang
      Abstract: Precast piers incorporated with high-strength bars (≥500 MPa) have great potential to accelerate bridge construction and enhance seismic performance. Four large-scale pier column specimens using high-strength bars by cast-in-place (CIP) and precast construction were experimentally studied. The distinctions of damage pattern between CIP and precast piers were characterized by plastic hinge and toed hinge, which expounded the smaller damage in precast piers. In contrast with CIP piers, the energy dissipation of precast pier was reduced by approximately 50–60% after pier yielding. An appropriate reinforcement ratio was essential for CIP piers to maintain enough displacement ductility and prevent premature fracture of energy dissipation bars. In terms of displacement components, the plastic term of precast pier was much smaller than that of CIP pier, and the gap opening-induced displacement predominates after pier yielding. The toed hinge was elaborated to disclose the displacement mechanism in precast piers. The experimental findings in this paper can provide additional input for seismic design of precast piers with high-strength bars.
      PubDate: 2017-11-02T01:02:48.744043-05:
      DOI: 10.1002/suco.201700050
       
  • An overview of the flexural post-cracking behavior of steel fiber
           reinforced concrete
    • Authors: Giuseppe Tiberti; Federica Germano, Antonio Mudadu, Giovanni A. Plizzari
      Abstract: This paper provides a general overview of recent developments in the study of the flexural post-cracking behavior of steel fiber reinforced concrete (SFRC). The results of three-point-bending tests (3PBTs) performed at the University of Brescia during the last lustrum were collected in a broad database consisting of 81 series for a total amount of 528 beams. Several experimental parameters were investigated: strength of concrete matrix, fiber dosage, fiber aspect ratio, fiber filament tensile strength, as well as fiber orientation. The latter was deeply studied by means of image analysis of cut cross sections. The results, discussed in terms of post-cracking flexural residual strengths, highlight that all the parameters studied contribute to the post-cracking performances exhibited by SFRCs.
      PubDate: 2017-10-26T00:15:43.696442-05:
      DOI: 10.1002/suco.201700068
       
  • Shear strength of concrete interfaces with infra-lightweight and foam
           concrete
    • Authors: Michael Frenzel; Manfred Curbach
      Abstract: Ceiling and floor slabs made of horizontal layers of regular and lightweight concrete could lead to an efficient use of materials. In this context, the bond between the different types of concrete is of particular importance. This paper shows the shear strength and failure mode of unreinforced concrete interfaces with high-quality, lightweight concretes in dependence of different interface roughness. To achieve this, a regular and a structural lightweight concrete were bonded to an infra-lightweight and a foam concrete. Small-scale shear specimens consisting of five layers were manufactured and loaded to investigate their shear behavior as a whole. Both concrete and interface failures were detected in dependence of interface roughness and the type of core layer concrete. Additionally, it is shown that the observed behavior can be satisfactorily reproduced by a finite-element model using the material parameters of concrete standard tests. The experimental and numerical investigations provide clearly defined interface parameters to design efficient load-bearing slabs made of different concrete layers.
      PubDate: 2017-10-26T00:11:04.340152-05:
      DOI: 10.1002/suco.201700015
       
  • Reliability-based evaluation of bond strength for tensed lapped joints and
           anchorages in new and existing reinforced concrete structures
    • Authors: Giuseppe Mancini; Vincenzo I. Carbone, Gabriele Bertagnoli, Diego Gino
      Abstract: The definition of design equations from semi-empirical or empirical models is a matter of fundamental importance in structural engineering. The direct application of partial safety factors for materials strength in such models is not appropriate in order to obtain design formulations coherent with some level of reliability, as empirical or semi-empirical formulations are calibrated adjusting empirical coefficients to fit a set of experimental data. Therefore, applying partial safety factors on material properties alone does not allow a correct estimation of structural reliability. In this paper, a reliability-based design bond strength relationship for tensed lapped joints and anchorages in reinforced concrete structures is derived applying a consistent reliability format. The semi-empirical model for mean laps and anchorages strength calculation proposed in fib Bulletin No 72 is studied. The probabilistic calibration of this model is performed defining the related model uncertainties, grounding on an extensive experimental database and distinguishing between new and existing structures. As a conclusion, the design expression for bond strength proposed by the authors is compared to current standards and its implications in laps and anchorage design in reinforced concrete structures are analyzed.
      PubDate: 2017-10-24T22:40:49.5447-05:00
      DOI: 10.1002/suco.201700082
       
  • Analysis of concrete crack growth based on micro-plane model
    • Authors: Farzad Peyman; Seyed A. Sadrnejad
      Abstract: The crack geometry effect is encountered in compliance matrix as a tensor containing 17 on-plane stress/strain component interrelation. The components of compliance matrix vary due to the effects of the directional fabric behavior of the material created by inherent/induced anisotropy that can be differed in any of the multi-direction through material. Mathematically, any alterations in multi-directional material behavior are numerically integrated and affected in material compliance matrix. The main objective of this paper is to develop a numerical approach to determine the crack initiation and its growth for brittle materials such as concrete. Upon the numerical integration technique, any multi-directional behavior aspect is affected by components of compliance matrix to reflect historically in the next step material behavior. Accordingly, the proposed model results are investigated to satisfy both equilibrium and compatibility equations. In this paper, previous selected 13 sampling points in numerical integration are updated to 17 planes to overcome the compatibility problem. To show the capability of the model, a few fractured concrete test results under different loading stress/strain paths were examined. The significant advantage of the proposed multi-laminate model is to present a complete pre-failure history of stress/strain progress on different predefined sampling planes which leads to the illustration of the final damaged or failure mechanism.
      PubDate: 2017-10-24T00:02:07.28809-05:0
      DOI: 10.1002/suco.201600208
       
  • Numerical formulation of confined compressive strength and strain of
           circular reinforced concrete columns using gene expression programming
           approach
    • Authors: Ehsan Sadrossadat; Behnam Ghorbani, Morteza Hamooni, Mohammad H. Moradpoor Sheikhkanloo
      Abstract: In reinforced concrete (RC), concrete’s relatively low tensile strength and ductility are counteracted by reinforcement of materials having higher tensile strength or ductility, such as steel reinforcing bars. A remarkable concern in design of RC columns confined with transverse reinforcement is to achieve an acceptable estimation of confined compressive strength and strain factors when they are subjected to compressive and lateral loading. To cope with this issue, various models have been proposed by researchers due to the costly procedure of experimental studies and lack of high-capacity testing equipment. Despite this fact, there still exists the necessity to develop more robust estimation models. This paper explores the capability of gene expression programming for the prediction of confined compressive strength and strain of RC columns with circular cross section. A reliable database is used to develop two new models which can be used via hand calculations for design purposes. In order to verify and validate the proposed models, several analyses are conducted and the results are compared with those provided by other researchers. Consequently, the results explicitly represent that the proposed models accurately estimate the confined compressive strength and corresponding strain of circular concrete columns and reach a notably better prediction performance than the traditional models.
      PubDate: 2017-10-19T23:40:45.035557-05:
      DOI: 10.1002/suco.201700131
       
  • Management system of preventive maintenance and repair for reinforced
           concrete subway tunnels
    • Authors: Tetsuya Ishida; Mitsuhiro Kawabata, Akira Maruyama, Satoshi Tsuchiya
      Abstract: The authors propose a maintenance management system for reinforced concrete subway tunnels to perform efficient maintenance management in view of preventive maintenance and repair of distressed concrete. The proposed system consists of three subsystems and has been put into trial use on an actual subway line. Based on the deterioration prediction using numerical models coupled with on-site measurement information, priorities, and timings are assigned to repair work based on the thresholds uniquely determined by the company, and maintenance management plans are created within imposed budget constraints. Through a couple of case studies on corrosion of reinforcing bars used for the actual structure, the proposed system is shown to be capable of predicting deterioration propagation almost approximately. Further, it is also demonstrated to be helpful to calculate maintenance management cost and to make an appropriate maintenance management plan under various repair strategies.
      PubDate: 2017-10-19T02:06:26.198265-05:
      DOI: 10.1002/suco.201700004
       
  • Issues concerning the assessment of concrete compressive strength in
           existing buildings: Application to a case study
    • Authors: Maria T. Cristofaro; Raffaele Nudo, Marco Tanganelli, Angelo D'Ambrisi, Mario De Stefano, Raffaele Pucinotti
      Abstract: The estimate of concrete compressive strength is a major aspect in the assessment of reinforced concrete existing structures since it involves safety issues. The method of extracting concrete cores from the buildings under investigation is considered in this paper. In the first part, a brief review concerning procedures proposed by international technical codes as well methods available in the scientific literature, is made. In particular, formulations proposed for the determination of the actual concrete strength, starting from the one obtained from laboratory tests on cores, are examined. Special attention is devoted to the various factors affecting the estimate of the actual strength and relative correction coefficients. In the second part, the considered procedures are applied to a case study concerning a school building in Tuscany; comparison among different formulations allows some considerations on the reliability of the adopted procedures.
      PubDate: 2017-10-12T20:51:04.300914-05:
      DOI: 10.1002/suco.201700070
       
  • Comparing test methods for the mechanical characterization of fiber
           reinforced concrete
    • Authors: Antonio Conforti; Fausto Minelli, Giovanni A. Plizzari, Giuseppe Tiberti
      Abstract: Different tests are proposed by international standards for the evaluation of the mechanical properties of fiber reinforced concrete (FRC); among them, either beams or round determinate panels are generally used. However, different tests are accepted by design codes if reliable correlation factors between standard parameters are provided (fib Model Code 2010). Within this context, a broad experimental program on both beams and round determinate panels was carried out in order to provide a critical discussion on material characterization and to evaluate possible correlation factors. Beam tests according to European (EN 14651), American (ASTM 1609), and Japanese (JCI-SF4) standard, as well as small round panels and large round panels (according to ASTM 1550) were studied within an experimental program comprising 189 beams and 90 round panels. Unlike previous researches, mainly focused on steel fibers, two types of macro-synthetic fibers were considered. Based on these experimental results, a comparison between test methods is presented, along with correlation approaches are proposed and critically discussed.
      PubDate: 2017-10-11T02:26:11.350202-05:
      DOI: 10.1002/suco.201700057
       
  • Full-scale shear tests on post-tensioned bridge girders of existing
           bridges
    • Authors: Patrick Huber; Markus Vill, Anton Schweighofer, Johann Kollegger
      Abstract: Many post-tensioned girders of existing bridges contain a low amount of transverse reinforcement. The shear strength of these girders, calculated according to current semi-probabilistic design codes, like Eurocode 2, is often less than that required in the codes. In this paper, the experimental results of four shear tests on post-tensioned bridge girders of existing bridges are presented. The specimens were extracted from two different road bridges, both built in 1959. In this paper, the results of this test series are used to analyze the shear behavior and failure modes of existing post-tensioned bridge structures with a low amount of shear reinforcement. Furthermore, the experimental results are compared with the shear strengths calculated according to various design codes. Finally, the shear behavior is analyzed according to the zone-based, shear assessment concept with its refined shear models. The calculation results agree well with the data from the experiments.
      PubDate: 2017-10-10T20:46:07.582773-05:
      DOI: 10.1002/suco.201700123
       
  • Effect of drywall and brick wall on fire behavior of concrete-filled steel
           tube column
    • Authors: Gholamreza Abdollahzadeh; Alireza Afaghi-Darabi
      Abstract: The walls around the columns play a decisive role in temperature distribution and mechanical behavior of the column under fire. This study has been conducted to investigate the effects of the presence of two types of walls, including clay masonry wall and dry wall on temperature distribution, and mechanical behaviors of the column compared to the adiabatic condition. A three-dimensional finite element model was developed and validated using the experimental results of the column under the non-uniform fire. In this state, three different wall locations around the columns were considered. In modeling clay masonry wall, the thermal properties of the brick block and the cement mortar and in dry wall modeling the thermal properties of Gypsum panel and the applied insulator were extracted from the prior research. The outputs of the model consist of temperature distribution in the cross section of the wall and the column, fire resistance time, and residual strength of the column. The results of the research showed that the presence of brick and dry walls, under the best conditions, increases the resistance time to 46 and 53%, respectively, and residual strength of concrete-filled steel tube to 27% as compared to the adiabatic condition.
      PubDate: 2017-10-09T00:56:01.377453-05:
      DOI: 10.1002/suco.201700054
       
  • Performance evaluation of innovative hybrid rebar coupler in reinforced
           concrete beams subjected to monotonic loading
    • Authors: Rajendran Siva Chidambaram; Pankaj Agarwal
      Abstract: This paper presents the outcome of an experimental study on the performance of mechanical rebar coupler (MRC) in broken reinforcement connection over the conventional technique. An in-house-made hybrid MRC is introduced to connect broken rebars ranging from 10 to 16 mm in diameter. A detailed experimental program is conducted to explore the influence of MRC with filler as a broken rebar connector. Four types of reinforced concrete (RC) beams with different reinforcement configurations are used with and without MRC at tension zone. RC beams with and without MRC are used and tested under monotonic loading. Rebar connector in different locations is used to examine the load distribution behavior of the connector. The effectiveness of rebar connector is investigated using the uni-axial tensile test of rebar with MRC, load–deflection behavior, energy dissipation, stiffness behavior, and failure pattern of RC beams and is compared with conventional specimens. The significant enhancement in post-yield behavior and energy dissipation of RC beam specimen with rebar connector authenticates the effectiveness of employed technique in structural engineering work.
      PubDate: 2017-10-04T00:01:23.057657-05:
      DOI: 10.1002/suco.201700083
       
  • Degree of external restraint of wall segments in semi-massive reinforced
           concrete tanks: Part I rectangular segments
    • Authors: Mariusz Zych
      Abstract: This paper presents graphs and formulas serving to define the distribution of the restraint degree of wall segments in rectangular reinforced concrete tanks. The most frequent cases occurring in engineering practice are analyzed, that is, wall segments erected during the first concreting stage and those restrained along three edges. For the latter ones, this paper defines the influence of vertical stiffness in construction joints (depending on the reinforcement degree) on the distribution of the restraint degree. This paper shows a substantial impact of the temperature profile (i.e., imposed strain resulting from the development of hydration heat) on the area where cracks occur first, and on the value and distribution of tensile stresses. A practical aspect of the analysis performed is the possibility of defining the restraint degree for cases and assumptions not included in EN 1992–3.
      PubDate: 2017-09-28T02:46:35.610456-05:
      DOI: 10.1002/suco.201700036
       
  • Design-oriented approach to predict shear strength of reinforced concrete
           beams
    • Authors: Hadi Baghi; Joaquim A. O. Barros
      Abstract: There are different approaches to predict the shear strength of reinforced concrete (RC) beams, but their predictive performance is still relatively low due to several and complex resisting mechanisms involved in shear. In addition, most of design approaches ignore the influence of the flange of T cross section beams on the ultimate shear capacity. This paper aims to present a design-oriented approach to predict the load carrying capacity of RC beams failing in shear. This approach is based on the simplified modified compression field theory (SMCFT). A sensitivity analysis is carried out to assess the importance of the input parameters that mostly affect the shear strength of RC members. Taking into account the results of the sensitivity analysis, two simple equations are proposed for obtaining the: (a) tensile stress factor in the cracked concrete (β) and (b) inclination of the diagonal compressive stress in the web of the section (θ). The obtained equations eliminate the iterative process required by the SMCFT and provide a straightforward design methodology to find β and θ with suitable accuracy for design purposes. In addition, a coefficient is presented to take into account the effect of the flange on the shear capacity of T shaped cross section beams. To appraise the predictive performance of the new approach, a database is set. By evaluating the ratio between the experimental results and the analytical predictions, an average value of 1.24 with a coefficient of variation of 20.9% is obtained.
      PubDate: 2017-09-25T20:06:39.270859-05:
      DOI: 10.1002/suco.201700095
       
  • Design of steel fiber reinforced concrete beams for shear using inverse
           analysis for determination of residual tensile strength
    • Authors: Stephen J. Foster; Ankit Agarwal, Ali Amin
      Abstract: The behavior of steel fiber reinforced concrete (SFRC) has been extensively investigated in the last four decades. For the most part, however, existing design models for shear are based on empirical equations where fiber–concrete is considered as a unique material and fibers and concrete components to shear are considered collectively, or where the concrete and fiber components to shear are considered separately and each are derived independently. As demonstrated in this paper, the problem with this latter approach is that the influence of the concrete and the fiber components are each affected by the other—that is, they are coupled. In this paper, a rational model is outlined for determining one-way shear strength of SFRC beams and slabs. The model is developed from the modified compression field approach with due consideration given to the inter-relationship between the concrete–steel–fiber components to the shear resistance. Introduced into the model is an inverse analysis method for determining the post-cracking residual tensile strength of SFRC from prism bending tests, a core materials property needed for design. In determining this strength, due attention is provided to the influences of notches, specimen boundaries and bias in fiber orientation that occurs as part of the casting process. The results of the design model predictions are compared with a dataset of test specimens collected from the literature, with very good correlation observed.
      PubDate: 2017-09-25T20:06:20.890162-05:
      DOI: 10.1002/suco.201700100
       
  • Degree of external restraint of wall segments in semi-massive reinforced
           concrete tanks: Part II: Rectangular and cylindrical segments
    • Authors: Mariusz Zych
      Abstract: This paper presents graphs and formulas serving to define the distribution of the restraint degree of wall segments in cylindrical reinforced concrete tanks. The analyses were carried out according to the same assumptions as presented in the first part of this paper. It is proved that, for certain cylindrical tanks, the restraint degree in relation to code values (EN 1992–3) is significantly lower, while for others it is significantly higher. For cylindrical walls, the dependence of the wall thickness and its radius on the restraint coefficient is shown. Special attention is given to its further potential applicability; therefore, it was crucial to consider accurately and in a universal way at the same time issues like geometrical parameters of wall segments, edge restraint conditions, and the temperature profile in a given wall cross section. A practical aspect of the analysis performed is the possibility of defining the restraint degree for cases and assumptions not included in EN 1992–3.
      PubDate: 2017-09-25T19:55:55.276574-05:
      DOI: 10.1002/suco.201700037
       
  • Cyclic response of a precast composite hollow reinforced concrete column
           using longitudinal rebars and base plate
    • Authors: Kyung-Ryul Cha; Jihye Seo, Seungjun Kim, Young-Jong Kang, Deokhee Won
      Abstract: In this research, the precast segmental construction of composite hollow reinforced concrete (RC) columns was studied. The precast segmental construction of composite hollow RC column requires guidelines for the connections between the bent cap and column segment, connections between column segmental joints, and connections between column segment and footing. The connection methods for different precast composite hollow RC piers were experimentally studied for rational resistance against shear force and bending moments. Two types of precast composite hollow RC columns and cast-in-place column were studied in this paper. The performance of these columns was evaluated through experiments. The precast column erected with a base-plate connection exhibited a performance similar to the cast-in-place column.
      PubDate: 2017-09-14T20:22:10.536015-05:
      DOI: 10.1002/suco.201700044
       
  • Combined shear and flexure performance of prestressing concrete T-shaped
           beams: Experiment and deterministic modeling
    • Authors: Alfred Strauss; Bernhard Krug, Ondrej Slowik, Drahomir Novak
      Abstract: The development of a nonlinear numerical computational model for the detailed description of destructive tests generally requires a multiple-stage, strategic model updating procedure. In this contribution, a model updating procedure is applied to the simulation of prestressed reinforced concrete (RC) beams. The combined ultimate shear and flexure capacity of the beams is affected by many complex phenomena, such as the multi-axial state of stress, the anisotropy induced by diagonal concrete cracking, the interaction between concrete and reinforcement (bond), and the brittleness of the failure mode. In this research, a series of material, small-scale component fracture tests were carried out by two collaborating laboratories. These tests provided advanced statistical identification of the fracture-mechanical parameters of the optimized concrete mixtures for the prestressed laboratory-tested beams mentioned above (with a span of 5.00 m) and associated field-tested, long-span concrete TT roof elements (with a span of 30.00 m). Ten scaled laboratory-tested beams with heights of 0.30, 0.45, and 0.60 m were used in a procedure for the comprehensive updating of the nonlinear numerical model with respect to shear resistance performance. The objectives of this research are, in addition to the analysis, the effective development of an updating process for nonlinear numerical modeling which is based on the information from different monitoring systems. Hence, this contribution focuses on the presentation of a comprehensive updating procedure for the shear capacity of nonlinear numerical models of prestressed beam elements using information about fracture-mechanical material parameters gained from (a) different monitoring systems and (b) code-based methods.
      PubDate: 2017-09-14T20:16:58.065781-05:
      DOI: 10.1002/suco.201700079
       
  • Erratum
    • PubDate: 2017-09-06T22:25:23.015969-05:
      DOI: 10.1002/suco.201770051
       
  • Experimental study on frame structures with recycled aggregate concrete
           under lateral cyclic loads
    • Authors: Zhanggen Guo; Chen Chen, Bingjie Fan, Dawn E. Lehman, Weimin Sun
      Abstract: This paper presents an experimental study on the seismic behavior of frame structures made with recycled aggregate concrete (RAC). Three 1:2 scaled frame specimens were tested under lateral cyclic loads and constant vertical load. One of these frames was conventional concrete frame, while the remaining two frames were RAC frames with a recycled coarse aggregate (RCA) replacement percentage of 25 and 50%, respectively. The structural performances, in terms of the failure pattern and mechanism, ultimate lateral load capacity, hysteretic response, backbone curve, ductility capacity, energy dissipation capacity and stiffness degradation were analyzed in detail. The effect of RCA replacement percentage on the seismic performance of RAC frames was investigated carefully. The experimental results indicate that the seismic performance of RAC frame is similar to that of conventional concrete frame and not significantly affected by the incorporation of RCA. All of the tested frames behaved with the same failure pattern, which is a ductile failure mechanism. The average value of the ductility coefficient and the equivalent viscous damping ratio of the RAC frame are 3.55 and 0.089, respectively. The RAC frame structure with an RCA replacement percentage of 50% still has adequate capabilities of ultimate strength, deformation and energy dissipation and is able to withstand an earthquake attack.
      PubDate: 2017-09-05T22:42:51.491996-05:
      DOI: 10.1002/suco.201600169
       
  • Sustainability evaluation of butterfly web bridge
    • Authors: Toshio Shibata; Kenichi Kata, Akio Kasuga, Koji Sakai
      Abstract: The authors developed the butterfly web bridge structure, an “innovative” bridge technology, to tackle the issues on lifespan extension, durability enhancement, high seismic resistance by reducing the weight and member size, and shortening of construction term. This bridge structure is characterized by the use of butterfly-shaped prefabricated prestressed high-strength, concrete panels for the webs. The butterfly web bridge seems to have a great advantage. However, the major issue is how to evaluate the advantage afforded by the “innovative” bridge technology that completely differs from conventional techniques. “Sustainability thoughts” is a solid foundation for such evaluation. The purpose of this paper is to quantify the performance of the butterfly web bridge from the standpoint of sustainability that consists of social, economic, and environmental aspects, thereby objectively evaluating the advantage of this “innovative” bridge technology. From the sustainability evaluation, it is concluded that the butterfly web bridge developed to meet a wide variety of complicated requirements is superior than conventional structures from the social, economic, and environmental aspects and also an innovative structure with high sustainability can be created through a comprehensive development approach involving design/execution methods in consideration of all sustainability elements.
      PubDate: 2017-09-05T00:13:17.857975-05:
      DOI: 10.1002/suco.201700010
       
  • The theoretical principles of the critical shear crack theory for punching
           shear failures and derivation of consistent closed-form design expressions
           
    • Authors: Aurelio Muttoni; Miguel Fernández Ruiz, João T. Simões
      Abstract: The mechanical model of the critical shear crack theory (CSCT) has been used in the past to investigate a number of shear-related problems, such as punching of slab–column connections with and without transverse reinforcement. In this paper, a discussion on the differences and analogies between slender slabs and squat members (footings) without transverse reinforcement is presented on the basis of the CSCT. This discussion highlights how bending and shear deformations influence the opening of the critical shear crack and eventually its ability to transfer shear forces. On that basis, it is investigated and justified a power-law expression to characterize the failure criterion of the CSCT. This criterion, in combination with a suitable load–deformation relationship, can be used to derive closed-form expressions for punching shear design. The accuracy of these expressions is verified against databases of slender slabs (121 specimens) and footings (34 specimens) with consistent agreement.
      PubDate: 2017-09-04T01:56:06.498877-05:
      DOI: 10.1002/suco.201700088
       
  • Contribution to sustainable seismic design of reinforced concrete members
           through embodied CO2 emissions optimization
    • Authors: Panagiotis E. Mergos
      Abstract: The embodied CO2 emissions of reinforced concrete (RC) structures can be significantly reduced by structural optimization that maximizes structural efficiency. Previous studies dealing with design of RC structures for minimum CO2 emissions do not address seismic design provisions. This is the case despite the fact that in many countries around the world, including most of the top 10 countries in CO2 emissions from cement production, RC structures have to be designed against earthquake hazard. To fill a part of this gap, this study, using exhaustive search, examines optimum designs of RC beam and column members for minimum embodied CO2 emissions according to Eurocode-8 for all ductility classes and compares them with optimum designs based on material cost. It is shown that seismic designs for minimum CO2 footprint lead to less CO2 emissions but are more expensive than minimum cost designs. Their differences strongly depend on the assumed values of the environmental impact of reinforcing steel and concrete materials. Furthermore, it is concluded that seismic design for high ductility classes can drive to significant reductions in embodied CO2 emissions.
      PubDate: 2017-09-04T01:30:32.633503-05:
      DOI: 10.1002/suco.201700064
       
  • Overlapping Lattice Modeling for concrete fracture simulations using
           sequentially linear analysis
    • Authors: Beyazit B. Aydin; Kagan Tuncay, Baris Binici
      Abstract: Modeling concrete fracture is important in order to uncover accurately the sources of distress which lead to the damage or failure of structures. Many different numerical approaches have been used in the past employing either a smeared or a discrete cracking approach. Those models have difficulty in capturing the local nature of cracking, as well as the direction of crack propagation. Lattice modeling and peridynamics (PD) are some of the more recent nonlocal fracture simulation tools which possess advantages, such as ease of modeling and accuracy of crack propagation simulations with few key parameters. In this work, we employ an overlapping lattice approach, where the continuum is discretized using truss elements extending over a predefined horizon similar to the concept used in PD with the sequentially linear analysis technique. Simulation results for several reinforced concrete (RC) and un-RC tests demonstrate the ability to estimate crack propagation directions and widths accurately, with the proposed modeling approach also offering a rather simple and intuitive approach.
      PubDate: 2017-09-04T01:26:31.334779-05:
      DOI: 10.1002/suco.201600196
       
  • Criteria and influencing parameters for the design of piers of
           semi-integral bridges
    • Authors: Daniel Gebauer; Marina Stümpel, Christoph von der Haar, Steffen Marx
      Abstract: This article deals with the challenges of semi-integral construction of long viaducts. The main characteristic of semi-integral bridges is the monolithic connection of most parts of the substructure with the superstructure. This leads to complex load-bearing behavior, in which several structural components interact with each other. Because of the longitudinal movement of the superstructure, constraint forces and moments occur in the piers. They induce additional stresses in the structure compared to conventionally supported bridges. An important issue during the design process is the choice of the pier cross section. The stiffness and ductility of the piers influence the constraint moments and failure behavior of the pier. This is the reason why the detailed investigation into the influencing parameters (normal-force utilization, reinforcement ratio, and width-to-height ratio) described in this paper was carried out. In this investigation, the moment–curvature relationship was used and the failure behavior as well as the constraint moments in the structure were evaluated.
      PubDate: 2017-09-04T01:16:19.15731-05:0
      DOI: 10.1002/suco.201700087
       
  • Application of sustainability design to an existing viaduct in a hilly
           area
    • Authors: Toshio Shibata; Hirotaka Asai, Taisuke Fujioka, Akio Kasuga, Koji Sakai
      Abstract: The World Commission on Environment and Development of the United Nations defined “sustainable development” for the first time in 1987, indicating the necessity for considering development that fulfils the needs of both present and future generations. However, the current situation of the sharp growth in the population and resources/energy consumption that adversely affects the global climate has been adding significance to the concept of sustainable development. From this background, the authors proposed a sustainability design system. This design method includes systems to clearly set the performance requirements to be considered with respect to social, economic, and environmental aspects, calculate the attained performance, and verify if the performance requirements are met. This paper describes the application feasibility of the sustainability design through the above procedures using an existing prestressed concrete viaduct. Additionally, comprehensive evaluation is carried out regarding the relationship between the elements of sustainability in comparison with the general method to clarify the effectiveness of sustainability design. It is concluded that sustainability design system has great potential of its applicability to concrete structures and promoting technical innovation based on setting of high-performance requirements.
      PubDate: 2017-08-29T00:37:03.291579-05:
      DOI: 10.1002/suco.201600237
       
  • Flexural rotation capacity models fitted to test results using different
           statistical approaches
    • Authors: Sofia Grammatikou; Dionysis Biskinis, Michael N. Fardis
      Abstract: Practical models for the ultimate deformations of flexure-controlled members were fitted to a database of thousands of tests. They cover beams, rectangular columns or walls, members with T-, H-, C-, or box section, conforming or not to seismic design codes, with or without fiber reinforced polymer jackets, in monotonic or cyclic uniaxial flexure with axial force. Model parameters were statistically derived assigning to each test (a) a weight of unity; (b) weight inversely proportional to the number of tests in a testing campaign, or (c) weight inversely proportional to the root-mean-square error of tests in a campaign. Predictions correlate well to those of a physical model based on curvatures and a plastic hinge length. Analysis of variance suggests that the scatter of model predictions with respect to test results comes more from the testing itself than from the model. Intralab and interlab variabilities are quantified and pure error is estimated from tests of nominally identical specimens.
      PubDate: 2017-08-29T00:27:03.890762-05:
      DOI: 10.1002/suco.201600238
       
  • Time-dependent serviceability behavior of reinforced concrete beams:
           Partial interaction tension stiffening mechanics
    • Authors: Alexander B. Sturm; Phillip Visintin, Deric J. Oehlers
      Abstract: The partial interaction (PI) mechanics of tension stiffening governs crack widening and the consequential deflection of reinforced concrete (RC) beams and, therefore, is essential in the serviceability design of RC structures. Both behaviors are dependent on the PI global load slip behavior of the tensile reinforcement relative to the surrounding concrete at a crack face, which in turn is dependent on the local PI material bond-stress/slip relationship between the reinforcement and adjacent concrete. Due to the complexity of PI theory, it has been difficult to directly incorporate PI mechanics into design procedures. Consequently, empirical approaches to quantify effective flexural rigidities and crack widths are commonplace. While empirical approaches can be derived relatively simply for short-term loading, the influence of concrete shrinkage and creep is difficult to incorporate. In this paper, pure mechanics-based PI solutions to describe the crack spacing and tension stiffening behavior of RC beams subjected to long-term loads are derived. They only require material properties and clearly show the interaction among shrinkage, creep and bond properties. They are simple enough to use directly in design and will help in the experimental derivation of the material properties. The results of these PI analyses are used in a companion paper to develop design rules for the time-dependent serviceability deflection of RC beams and compared with test results.
      PubDate: 2017-08-29T00:16:37.851195-05:
      DOI: 10.1002/suco.201700021
       
  • Mechanical properties of epoxy/basalt polymer concrete: Experimental and
           analytical study
    • Authors: Mostafa Hassani Niaki; Abdolhosein Fereidoon, Morteza Ghorbanzadeh Ahangari
      Abstract: In this paper, first we investigated the effects of the amount of crushed basalt aggregates on the compressive strength, flexural strength, and splitting tensile strength of a polymer concrete (PC) obtained by epoxy resin. We found that increasing the amount of epoxy resin to the basalt aggregates to 25 wt% improved mechanical properties of the concrete. After determining the optimum weight percentage of basalt in epoxy, the mechanical properties of the optimized PC were experimentally investigated at three different temperatures: 50°C, 75°C, and 100°C. Our results indicate that as the temperature increases, the highest maximum stress rapidly decreases, but the yield displacement increases significantly. Moreover, the PC sample became barrel shaped under compression stress because of its ductility at high temperatures. Afterwards, effects of four different aggregate sizes, 3–5 mm, 1.2–3 mm, 0.6–1.2 mm, and microsized particles, on mechanical properties of the optimized PC were experimentally studied. We found that, the larger aggregate size outcomes higher compressive strength and lower flexural and splitting tensile strength. Finally, an empirical model for the relationships between compressive, splitting tensile, and flexural stress was derived that can be used to predict the strength of PCs.
      PubDate: 2017-08-29T00:07:22.333264-05:
      DOI: 10.1002/suco.201700003
       
  • New nonlinear dynamic response model of squat/slender flanged/non-flanged
           reinforced concrete walls
    • Authors: Rabab Allouzi; Amer Alkloub
      Abstract: The response of reinforced concrete (RC) shear wall as a lateral resisting member has been studied extensively, but it still demands a general practical model that identifies the envelope within which load–drift paths occur during cyclic loading. Such a broad model is vital to ensure adequate lateral strength to resist reversal loadings imposed on these walls during earthquake events and ductility to measure inelastic deformation capabilities. A new model to define the backbone curve is developed in this paper for squat, intermediate, and slender flanged and non-flanged RC walls. The most common failure modes observed in the field and laboratory experiments are investigated and incorporated in the proposed model to estimate the response of these walls from elastic range until ultimate failure. The main parameters controlling the estimation of drifts that features the backbone curve thresholds are presented in this paper. The results of proposed model are compared with the outcomes of 117 specimens experimentally tested by other researchers. Also, the results are compared with Federal Emergency Management Agency (FEMA) 356, the updated American Society of Civil Engineers (ASCE)/Structural Engineering Institute (SEI) 41, and Eurocode (EC8 and EC2) provisions which reveal that only one general model, proposed in this paper, can capture the response of RC structural walls with an aspect ratio ranging from 0.35 to 2.5 and an axial load ratio from 0 to 0.4 with good agreement with experimental outcomes.
      PubDate: 2017-08-24T23:26:03.180606-05:
      DOI: 10.1002/suco.201700066
       
  • Issue Information: Structural Concrete 6/2017
    • Pages: 835 - 836
      PubDate: 2017-12-22T01:24:55.368635-05:
      DOI: 10.1002/suco.201770063
       
  • Improvements and innovations in 2017
    • Authors: Luc Taerwe
      Pages: 837 - 838
      PubDate: 2017-12-22T01:24:59.05547-05:0
      DOI: 10.1002/suco.201770061
       
  • Verification of deflection according to Eurocode 2
    • Authors: Nenad Pecić; Snežana Mašović, Saša Stošić
      Pages: 839 - 849
      Abstract: Code provisions for a simplified check of the long-term deflection of concrete structures are generally developed for predefined values of the relevant input parameters. Deflection calculation may be of interest to account for different design situations. EN 1992-1-1 advocates the integration of curvatures calculated using the effective modulus of concrete. This paper presents an efficient procedure for calculation of the long-term deflection due to a sustained load. A nondimensional analysis of the mean curvature is applied to evaluate the deflection. The deflection is calculated using a set of algebraic expressions. The result is close to the value obtained by the numerical integration of curvatures. The values of relevant parameters in the expressions may be selected within the common range for the design of engineering structures. The efficiency of the deflection prediction based on the integration of curvatures is tested on the available experimental data. In the first approach, the measured material properties are used. In the second approach, the required values are derived from EN 1992-1-1 expressions to predict the material properties.
      PubDate: 2017-06-29T23:20:30.289218-05:
      DOI: 10.1002/suco.201600234
       
  • Long-term data of reinforced concrete beams subjected to high sustained
           loads and simplified prediction method
    • Authors: Nicky Reybrouck; Pieterjan Criel, Tim Van Mullem, Robby Caspeele
      Pages: 850 - 861
      Abstract: In 1967–1985, a research campaign comprising a unique set of long-term experimental data on concrete beams was conducted in joint collaboration with four Belgian research institutes to determine the influence of creep and shrinkage on the long-term behavior of reinforced concrete members. The main aim of the research campaign was the determination of the long-term behavior of cracking and deformations subjected to permanent loads considering the influence of the magnitude of the loads and various reinforcement ratios.The objective of this article is twofold: to provide an overview of the measured data of the reinforced beams of the research campaign, which has never been published before, and to propose a simplified calculation method based on available models in literature that can predict the available measurement data. A simplified calculation model is proposed, which accounts for nonlinear creep strains due to high stresses, shrinkage, aging, and cracking in reinforced concrete beams. This numerical method is based on a cross-sectional analysis formulated using the layered Euler-Bernoulli beam theory, allowing fast and accurate predictions of strains, stresses, and deflections as a function of time based on fib Model Code 2010 and EN1992-1-1. The measurements of the beams subjected to high permanent loads during a time period of 4 years are compared to the results evaluated with the proposed simplified calculation model. The results show that the proposed simplified calculation method based on the current models of EN1992-1-1 and fib Model Code 2010 can predict the long-term behavior of reinforced concrete beams subjected to high loads in good agreement with the measurements.
      PubDate: 2017-07-04T18:13:02.190451-05:
      DOI: 10.1002/suco.201700040
       
  • Effect of structural features and loading parameters on bond in reinforced
           concrete under repeated load
    • Authors: Yang Sun; Zhen-xue Gu, Ang Li, Guo-jian Shao
      Pages: 862 - 871
      Abstract: Some reinforced concrete structures are subjected to repeated loads during their service lives, and the effect of repeated loads is stronger and more complex than static loads. This paper reports the results of the tests performed on cylindrical reinforced concrete specimens under uniaxial repeated loads. The effect of structural parameters (e.g., stirrup configuration, bond length, confinement method, and concrete cover) and loading parameters (e.g., amplitude, peak load, loading rate, and initial load cycles) on the bond properties of the reinforced concrete under repeated loads was studied in detail. In addition, the degradation mechanisms and failure modes of the specimens’ bond stress were analyzed. It is found that the use of stirrups, increase of bond length, and concrete cover, as well as confinement can effectively curb the widening and expansion of cracks in concrete and significantly improve ductility and repeated load bearing capability. As the rigidity of confinement material increased, the enhancement effect of confinement on bond stress increases. Compared to the role of confinement (e.g., carbon fiber reinforced polymer), increasing the concrete cover can more effectively improve the bond stress. The rebar's subsequent residual bond stress declines as the number of early-stage load cycle increases.
      PubDate: 2017-08-03T22:46:41.172082-05:
      DOI: 10.1002/suco.201600170
       
  • Tests on strengths of steel strand and strand-concrete (or cement slurry)
           bond stress under cryogenic temperatures
    • Authors: Jian Xie; Er-Cong Kang, Jia-Bao Yan, Zhi-Meng Nie
      Pages: 872 - 882
      Abstract: This paper experimentally studied the strengths of the steel strand and strand-concrete (or cement slurry) bond stress under different cryogenic temperatures ranging from 20 to −160 °C. Twenty one tensile tests were firstly carried out to obtain the yield and ultimate strengths of the steel strand under different cryogenic temperatures. The influences of the cryogenic temperatures on the yield strength, ultimate strength, and fracture strain of the steel strand were discussed and analyzed. Sixty six pull-out tests with 3 identical specimens for each parameter were carried out to obtain the ultimate strength behaviors of the strand-concrete (or cement slurry) bond. The failure modes, strand-concrete (or cement slurry) bond stress, and influences of the low temperature and strength of concrete on the bond stress were reported, discussed, and analyzed. Design equations were also developed to predict the yield and ultimate strengths of the steel strand under temperature intervals of 20 to −160 °C, and their accuracies were checked through validations against the test results. Prediction models in the literature were also used to predict the strand-concrete bond stress, and their accuracies were checked by the reported test results. Empirical design equations were also developed to predict the strand-cement slurry bond stress at cryogenic temperatures.
      PubDate: 2017-05-02T10:15:16.035493-05:
      DOI: 10.1002/suco.201600158
       
  • Numerical strategy for developing a probabilistic model for elements of
           reinforced concrete
    • Authors: Christian Nader; Pierre Rossi, Jean-Louis Tailhan
      Pages: 883 - 892
      Abstract: This paper introduces a new approach to model cracking processes in large reinforced concrete structures, like dams or nuclear power plants. For these types of structures it is unreasonable, due to calculation time, to explicitly model rebars and steel–concrete bonds. To solve this problem, we developed, in the framework of the finite element method, a probabilistic macroscopic cracking model based on a multiscale simulation strategy: the probabilistic model for (finite) elements of reinforced concrete (PMERC).The PMERC’s identification strategy is case-specific because it holds information about the local behavior, obtained in advance via numerical experimentations. This information is then projected to the macroscopic finite element scale via inverse analysis.The numerical experimentations are performed using a validated cracking model allowing a fine description of the cracking processes.The method used in the inverse analysis is inspired from regression (supervised learning) algorithms: data on the local scale—the training data coupled with working knowledge of the mechanical problem—would shape the macroscopic model.Although the identification phase can be relatively time-consuming, the structural simulation is as a result, very fast, leading to a sensitive reduction of the overall computational time.It is proposed a first validation of this multiscale modeling strategy on a reinforced concrete slab-beam subjected to three-point bending. We achieved promising results in terms of global behavior and macrocracking (mainly crack openings), and an important reduction in calculation time—up to 99% reduction! So we believe this is a promising approach to solve bigger and more complex structures in shorter time.
      PubDate: 2017-05-29T19:35:40.326747-05:
      DOI: 10.1002/suco.201600217
       
  • A new model for concrete edge failure of multiple row anchorages with
           supplementary reinforcement—Reinforcement failure
    • Authors: Akanshu Sharma; Rolf Eligehausen, Jörg Asmus
      Pages: 893 - 901
      Abstract: The paper presents a new model for predicting the resistance of anchorages with supplementary reinforcement loaded in shear toward and perpendicular to the edge in case of reinforcement failure. The model is based on the evaluation of the results of a comprehensive test program performed on anchorages with multiple anchor rows and supplementary reinforcement, reported in an earlier paper. It is shown that the existing models available in the codes and standards are conservative for low to medium amounts of supplementary reinforcement but tend to be unconservative for high amounts of reinforcement. The new model is able to predict the failure loads corresponding to reinforcement failure under shear loads very well. The approach to incorporate other failure modes into the design model for anchorages with supplementary reinforcement under shear loads toward the edge will be presented in another paper.
      PubDate: 2017-07-10T21:51:02.807774-05:
      DOI: 10.1002/suco.201700002
       
  • Corrosion of anchorage head system of post-tensioned prestressed concrete
           structures under chloride environment
    • Authors: Fumin Li; Xiaoya Luo, Zhenguo Liu
      Pages: 902 - 913
      Abstract: Corrosion of anchorage head system may lead to severe structural failure. To understand the characteristics of corrosion and the risks of anchoring failure, 11 post-tensioned prestressed concrete specimens with single-hole anchorage-plate system sealed with postcast concrete contaminated by NaCl were fabricated and then corroded for 8 months. By periodically monitoring corrosion current density and breaking the specimens to detect mass loss, the time-varying law of corrosion rate and the influences of chloride concentration and cover layer depth on corrosion rate were found. The mean corrosion rate of each component of anchorage head system varies with effective prestress level in a light growing trend with approximate linear relationship. The plates were corroded most severely and manifested relatively full and uniform corrosion characteristics, whereas the barrels and wedges were corroded slightly and exhibited relatively local and pitting corrosion characteristics. The average corrosion rate of the plates is 50 times and 80 times higher than that of the barrels and wedges, respectively. The interfaces of the contacted components were hardly corroded. Finally, the corrosion risk of the anchorage head system was analyzed.
      PubDate: 2017-05-02T17:55:55.952271-05:
      DOI: 10.1002/suco.201600140
       
  • Development and multiaxial distribution of expansions in reinforced
           concrete elements affected by alkali–silica reaction
    • Authors: David M. Wald; Morgan T. Allford, Oguzhan Bayrak, Trevor D. Hrynyk
      Pages: 914 - 928
      Abstract: Understanding the development and multiaxial distribution of expansions is of critical importance in the appraisal of structures affected by alkali–silica reaction. Such expansions were monitored for 33 480-mm reinforced concrete cubes in an effort to develop an improved understanding of the expansion mechanisms in reinforced concrete and broaden the database of experimental results available from which to build tools to aid in the performance assessment of affected structures. The cubes were fabricated using three different concrete mixtures of varying reactivity and contained uniaxial, biaxial, and triaxial reinforcement layouts with different reinforcement ratio combinations. In all cases, the cubes expanded at greater rates in unreinforced directions than in reinforced directions. Furthermore, the reinforcement ratios did not significantly influence expansion behavior, especially in the cases of uniaxially, equal biaxially, and equal triaxially reinforced specimens. Increasing the number of reinforced directions resulted in reduced volumetric expansion development over time and greater differences between expansions in reinforced and unreinforced directions. Cubes with end-anchored, deformed steel reinforcing bars placed in three layers developed expansions exceeding steel yield strains in all directions. Cubes with bars placed in two layers exhibited differential expansions between locally reinforced concrete regions at the edges of elements and unreinforced core regions. Mixture reactivity and environmental conditioning influenced expansion rates but not trends of the multiaxial distribution of volumetric expansions.
      PubDate: 2017-05-09T18:20:39.208586-05:
      DOI: 10.1002/suco.201600220
       
  • Nonlinear finite element analyses of fiber-reinforced polymer-strengthened
           steel-reinforced concrete beams under cyclic loading
    • Authors: Prabin Pathak; Y. X. Zhang
      Pages: 929 - 937
      Abstract: A new finite element model is developed for nonlinear finite element analyses of structural behavior of fiber-reinforced polymer (FRP)-strengthened steel-reinforced concrete (RC) beams under cyclic loading in this paper. All the components of the beam, including concrete, steel rebar, FRP sheet, adhesive, and shear strengthening stirrups, are included in the model. Material nonlinear properties of concrete and steel rebars are accounted for, while the FRP and adhesive are considered to be linearly elastic until rupture. The degradation of each material under cyclic loading is considered and defined using the user-programmable features in ANSYS. The developed finite element model is validated against experimental results, and demonstrated to be effective for structural analyses of FRP-strengthened RC beams under cyclic loading. Furthermore, parametric studies are carried out to learn the effects of types, thickness, and length of FRP on the structural behavior of FRP-strengthened RC beams based on the new model. Research findings are summarized finally.
      PubDate: 2017-04-27T11:53:55.883355-05:
      DOI: 10.1002/suco.201600122
       
  • Seismic collapse assessment of self-centering hybrid precast walls and
           conventional reinforced concrete walls
    • Authors: Xilin Lu; Hao Wu, Ying Zhou
      Pages: 938 - 949
      Abstract: The past studies have demonstrated the superior performance of self-centering hybrid precast (SCHP) walls in terms of reducing structural damage and residual drifts compared with conventional reinforced concrete (RC) walls following an earthquake. This study evaluates the collapse performance of SCHP walls through numerical analyses, and compares the results with that of RC walls. For this purpose, analytical models of code compliant four-story and six-story prototype SCHP and RC wall structures designed with varying structural and seismic parameters were developed. Based on the results of incremental dynamic analysis, the adjusted collapse margin ratio (ACMR) of each prototype structure was determined and compared to the established limits specified in the FEMA P695 procedure. The results reveal that the collapse capacities for the SCHP walls are comparable to that of RC walls. The slightly larger collapse margin ratio for the six-story RC wall over the six-story SCHP wall might be attributed to the less sufficient energy-dissipating capacity of the SCHP wall as demonstrated by the cyclic pushover analyses. It is found that the computed ACMRs (ranging from 3.13 to 3.79) are more than twice the accepted ACMR limit (1.56), indicating that all the structures have enough seismic collapse safety against maximum considered earthquakes.
      PubDate: 2017-06-27T00:02:58.128019-05:
      DOI: 10.1002/suco.201600174
       
  • Experimental evaluation of lightweight aggregate concrete beam–column
           joints with different strengths and reinforcement ratios
    • Authors: Ricardo N. F. do Carmo; Hugo Costa, Gonçalo Gomes, Jonatas Valença
      Pages: 950 - 961
      Abstract: The performance of beam–column joints significantly affects the overall behavior of reinforced concrete (RC) frames and, in some cases, can reduce the load carrying capacity and increase the lateral displacements of the frames. Also, when simultaneously small cross sections and a high number of rebar are used, the reinforcement detailing and the casting of concrete can be a difficult task. Despite this, there is a lack of attention for design and detailing the RC joints. The experimental study herein presented is focused on the behavior of exterior beam–column joints of lightweight aggregate concrete (LWAC) under monotonic loads. The study aims to evaluate the influence of rebar detailing of LWAC strength and of reinforcement ratio on the joints’ behavior. Five specimens, combining different reinforcement ratios and concrete strengths, were properly monitored and tested. The strength capacity, deformability, and stiffness of the LWAC joints were analyzed. The experimental results enhance the importance of an adequate reinforcement detailing of the beam–column joint, because incorrect detailing decreases considerably the load capacity. Based on the results, it is highly recommended to use larger columns than beams, to reduce the cracking and increase the joint's stiffness.
      PubDate: 2017-05-04T18:01:09.22987-05:0
      DOI: 10.1002/suco.201600166
       
  • Analytical study of the response of reinforced concrete walls with
           discontinuities of flag wall type
    • Authors: Leonardo M. Massone; Fabian R. Rojas, Matias G. Ahumada
      Pages: 962 - 973
      Abstract: Slender walls with discontinuities at their bases, such as flag walls or walls with door openings or access, are common in Chilean practice because of the architectural requirements at facades, first floors, and underground levels. However, there is limited information about the behavior of such elements, and no designs or guidelines in the current codes consider the effects of discontinuities at the base. In this work, two analytical models are presented that estimate the yield displacement, yield curvature, and ultimate curvature of walls with openings, such as flag walls (setback), based on the dimensions of the opening and the longitudinal boundary steel ratio calibrated from a parametric analysis of a nonlinear finite element model. The results indicate that these discontinuities can have a major impact on the elastic displacement, reducing it because of the presence of a more rigid section above the opening, and also on the inelastic component, by increasing the curvature (and the strain) at the wall base because the opening tends to confine the plastic hinge within that area.
      PubDate: 2017-05-14T20:00:57.590444-05:
      DOI: 10.1002/suco.201600107
       
  • Penetration of rigid projectiles into concrete based on improved cavity
           expansion model
    • Authors: Yanyan Zhang; Wanxiang Chen, Songsong Cheng, Huihui Zou, Zhikun Guo
      Pages: 974 - 985
      Abstract: The main objective of the present work is to develop an approximate approach for nondeformable projectile normal penetration into concrete targets with clear mechanics concepts. The normal/tangential stress acting at the projectile–target interface in the tunnel region is obtained according to the spherical cavity expansion penetration model, where the fractured target medium near the expansion cavity is perfectly described by Tresca's law. Then, the penetration resistances on projectile with spherical nose, ogive nose, and conical nose are further derived by composing stress along the projectile's axis respectively. The prediction formula of penetration depth for nondeformable projectile normal into concrete targets is presented according to Newton's second law. Comparisons between the predicted penetration depth and the experimental data are in reasonable good agreement in a broad range of projectile geometry, impact velocity, and concrete target. Moreover, the results of this prediction model are very close to those of Forrestal et al's analytical model, and the parameters of presented model have important mechanics concepts that are easy to obtain.
      PubDate: 2017-05-11T19:51:48.248023-05:
      DOI: 10.1002/suco.201600195
       
  • Influence of polypropylene fibers on the flexural behavior of reinforced
           concrete slabs with different opening shapes and sizes
    • Authors: Rajai Al-Rousan
      Pages: 986 - 999
      Abstract: The effect of polypropylene fibers (PF) on the flexural behavior of reinforced concrete one-way slabs with opening was investigated in this paper. The evaluated parameters included four different PF volume percentages (0, 0.3, 0.6, and 0.9%), with and without opening, two opening shapes (square and circular), and three opening sizes (100, 150, and 200 mm). Three groups of tested slabs were casted: without opening, with square opening, and circular opening, resulting in a total of 28 slabs. The behavior of each slab was evaluated in terms of the cracking load, ultimate capacity, initial and yielding stiffness, deflection ductility, and energy ductility. In addition, the steel and concrete strains, crack opening, and mode of failure were measured and monitored. The minimum design load capacities were calculated theoretically based on the sectional analysis and compared with the tested ones. The results showed that the use of PF at percentages greater than 0.6% significantly enhanced the performance parameters of the slabs with small opening size (2% opening ratio) and provided acceptable enhancement for slabs with large opening size (8% opening ratio). Therefore, the PF can be optimized to substitute the conventional steel reinforcement of slabs with small openings, especially circular openings.
      PubDate: 2017-06-19T21:01:25.003588-05:
      DOI: 10.1002/suco.201600222
       
  • Bamboo-reinforced self-compacting concrete beams for sustainable
           construction in rural areas
    • Authors: Mark Adom-Asamoah; Jack Osei Banahene, Jacqueline Obeng, Eugene Antwi Boasiako
      Pages: 1000 - 1010
      Abstract: The use of bamboo as longitudinal reinforcement, coupled with the application of self-compacted concrete (SCC) in the construction industry, may be a promising solution to issues involving sustainable development in developing countries. This study seeks to investigate the flexural performance of bamboo-reinforced SCC beams with adequate transverse reinforcement. The major design parameters were the shear span-to-depth ratio, the percentage of longitudinal reinforcement, and the maximum size of coarse aggregate. The load–deflection curves, serviceability and ultimate failure characteristics, cracking behavior, and ductility measures were evaluated and discussed among tested beams. Results indicated that their structural performance at service and ultimate failure would be adequate when a material reduction factor of three is used with BS 8110 design code. However, to achieve maximum ductility, the level of longitudinal reinforcement should be in range of 2.6–3.1%. Furthermore, an increase in the size of coarse aggregate will greatly impact the degree of ductility.
      PubDate: 2017-06-06T19:55:27.829508-05:
      DOI: 10.1002/suco.201600205
       
 
 
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