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  Subjects -> ENGINEERING (Total: 2265 journals)
    - CHEMICAL ENGINEERING (188 journals)
    - CIVIL ENGINEERING (179 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1210 journals)
    - ENGINEERING MECHANICS AND MATERIALS (384 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (60 journals)
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CIVIL ENGINEERING (179 journals)                     

Showing 1 - 0 of 0 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 13)
Acta Polytechnica : Journal of Advanced Engineering     Open Access  
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 1)
Advances in Civil Engineering     Open Access   (Followers: 27)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 18)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 22)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil Engineering     Open Access   (Followers: 6)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access  
ATBU Journal of Environmental Technology     Open Access   (Followers: 1)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 5)
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: 8)
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)
Berkeley Planning Journal     Open Access   (Followers: 5)
Bioinspired Materials     Open Access   (Followers: 2)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 13)
Building and Environment     Hybrid Journal   (Followers: 13)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 14)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 4)
Canadian Journal of Civil Engineering     Full-text available via subscription   (Followers: 9)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 3)
Case Studies in Structural Engineering     Open Access   (Followers: 4)
Cement and Concrete Composites     Hybrid Journal   (Followers: 13)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 4)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 6)
Civil And Environmental Engineering Reports     Open Access   (Followers: 4)
Civil and Environmental Research     Open Access   (Followers: 15)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 9)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 2)
Civil Engineering and Technology     Open Access   (Followers: 5)
Civil Engineering Dimension     Open Access   (Followers: 5)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 215)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 8)
Computers & Structures     Hybrid Journal   (Followers: 28)
Concrete Research Letters     Open Access   (Followers: 2)
Construction Economics and Building     Open Access   (Followers: 1)
Construction Engineering     Open Access   (Followers: 5)
Construction Management and Economics     Hybrid Journal   (Followers: 18)
Construction Science     Open Access   (Followers: 1)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 1)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 14)
Enfoque UTE     Open Access   (Followers: 1)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 5)
Engineering Structures     Hybrid Journal   (Followers: 11)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 1)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 12)
Environmental Geotechnics     Open Access   (Followers: 3)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 6)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 13)
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: 1)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 1)
Géotechnique Letters     Hybrid Journal   (Followers: 4)
HBRC Journal     Open Access   (Followers: 1)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indoor and Built Environment     Hybrid Journal   (Followers: 1)
Infrastructure Asset Management     Hybrid Journal   (Followers: 1)
Ingenio Magno     Open Access  
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 15)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 2)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 10)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 7)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 1)
International Journal of Construction Engineering and Management     Open Access   (Followers: 4)
International Journal of Geo-Engineering     Open Access  
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Masonry Research and Innovation     Hybrid Journal  
International Journal of Pavement Research and Technology     Open Access   (Followers: 2)
International Journal of Protective Structures     Full-text available via subscription   (Followers: 4)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 9)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Built Environment     Open Access   (Followers: 3)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 7)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 4)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal  
Journal of Building Materials and Structures     Open Access   (Followers: 1)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 5)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 6)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Science     Open Access   (Followers: 6)
Journal of Civil Engineering Research     Open Access   (Followers: 5)
Journal of Civil Society     Hybrid Journal   (Followers: 3)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites     Open Access   (Followers: 72)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 12)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 21)
Journal of Construction Engineering     Open Access   (Followers: 4)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Construction Engineering, Technology & Management     Full-text available via subscription   (Followers: 2)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 6)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 2)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 5)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 3)
Journal of Green Building     Full-text available via subscription   (Followers: 10)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 10)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 19)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 4)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Multifunctional Composites     Full-text available via subscription   (Followers: 3)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Journal of Offshore Structure and Technology     Full-text available via subscription  
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  
Journal of Solid Waste Technology and Management     Full-text available via subscription  
Journal of Structural Engineering     Full-text available via subscription   (Followers: 37)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Structures     Open Access   (Followers: 2)
Journal of Sustainable Architecture and Civil Engineering     Open Access  
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 1)
Latin American Journal of Solids and Structures     Open Access   (Followers: 1)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 11)
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 3)
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: 6)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 6)
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: 3)
Random Structures and Algorithms     Hybrid Journal   (Followers: 3)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 2)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 4)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 7)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 2)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 54)
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: 1)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 1)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 8)
Structural Concrete     Hybrid Journal   (Followers: 9)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 6)
Structural Engineering International     Full-text available via subscription   (Followers: 9)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 24)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 9)
Structures     Hybrid Journal  
Study of Civil Engineering and Architecture     Open Access   (Followers: 7)
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: 5)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 5)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 1)
Thin-Walled Structures     Hybrid Journal   (Followers: 2)
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)
Water Science & Technology     Partially Free   (Followers: 21)
Water Science and Technology : Water Supply     Partially Free   (Followers: 21)

           

Journal Cover Structural Concrete
  [SJR: 0.739]   [H-I: 9]   [9 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  [1598 journals]
  • Performance based durability design, carbonation part 1 –
           Benchmarking of European present design rules
    • Abstract: The paper reports on a benchmark of European deemed‐to‐satisfy rules for exposure class XC (carbonation exposed structural members). The benchmark of the descriptive rules was carried out following the probabilistic design approach for carbonation‐induced corrosion developed in [1] and adopted in fib bulletin 34: Model Code for Service Life Design (2006) [2] and fib Model Code for Concrete Structures 2010 [3], respectively. To perform a representative study, three groups of European countries were selected, representing different parts of Europe, south (Spain, Portugal), middle (Netherlands, Great Britain and Germany) and northern Europe (Denmark, Norway). Reliability ranges for carbonation‐induced depassivation of rebar were calculated for ‘favourable’ and ‘unfavourable’ design situations in exposure classes XC2, XC3 and XC4 [4]. In each design situation the deemed‐to‐satisfy rules of selected countries were followed. The probabilistic calculations were mainly based on short‐term carbonation data. However, some calculations were also based on long‐term observation. The latter was implemented for independent validation purposes. The calculated reliability ranges are very broad and in some ‘unfavourable’ situations, the deemed‐to satisfy requirements do not guarantee the required limit state (LS) target reliabilities for the particular exposure. In ‘favourable’ situations less stringent demands would have been sufficient.
      PubDate: 2016-07-18T04:20:55.959388-05:
      DOI: 10.1002/suco.201600066
       
  • Mechanism of Shear Strength Degradation of RC Column Subjected to Cyclic
           Loading
    • Authors: Li Fu; Hikaru Nakamura, Hiroki Furuhashi, Yoshihito Yamamoto, Taito Miura
      Abstract: The purpose of this study was to investigate the mechanism of shear strength degradation of RC member under cyclic loading. First, the shear failure after flexural yield of tension reinforcing bars of a RC column designed as bridge pier under cyclic loading was simulated by the method of three dimensional Rigid‐Body‐Spring‐Model (3‐D RBSM) and the shear strength degradation was quantitatively evaluated by a numerical approach. Afterwards, based on the shear resistant mechanism, the degraded shear strengths after each load cycle were decoupled into the contributions provided by beam action and arch action, with the use of the numerical local stress results. As the important finding, the mechanism of shear strength degradation due to cyclic loading of the RC column was concluded as with the increase of deformation level, the arch action first degraded gradually whereas the beam action maintained its original capacity; then after losing most capacity of the arch action, the beam action began to decrease rapidly, which caused the shear failure.
      PubDate: 2016-07-12T05:51:13.684387-05:
      DOI: 10.1002/suco.201600052
       
  • ELASTIC MATERIAL PROPERTY INVESTIGATION OF CLASS G CEMENT
    • Authors: Dogukan Guner; Hasan Ozturk, Mustafa Erkayaoglu
      Abstract: Class G cements are sulphate‐resistant Portland cements with different setting time requirements and have a common usage field in the oil industry. Compared to other API class cements, Class G has a utilization of more than 95% worldwide in oil well applications. Different additives are used together with Class G cement to achieve optimum hardening conditions. In this study, elastic material properties of high sulphate resistant (HSR) Class‐G cements are investigated for a special case implemented in solution mining. There are no published studies on the mechanical properties of Class G oil well cements for more than three days of curing time and various water cement ratio to date. Uniaxial compressive strength, Young's modulus, and Poisson's ratio determination are carried out on a total of 108 samples with different curing times (2, 7, and 14 days) and water‐cement ratios (0.4, 0.5, 0.6, and 0.8). Laboratory results were subject to Dixon's Q‐test for outlier elimination and were analysed by fitting a multi‐variable non‐linear regression model to estimate uniaxial compressive strength and Young's modulus.
      PubDate: 2016-07-12T05:45:26.114553-05:
      DOI: 10.1002/suco.201600020
       
  • Sustainability design of concrete structures
    • Authors: Koji Sakai; Toshio Shibata, Akio Kasuga, Hikaru Nakamura
      Abstract: Concrete became the most used material on Earth over 200 years following the invention of modern cement. The design concept has undergone a transition from the allowable stress design method, limit state design method, and to the performance‐based design method, in response to the evolution of materials, sophistication of experimental facilities, and advancement of computation skills. From the issues on resources and energy depletion, global warming, and resilience etc., it is necessary to create a new design framework taking into consideration the required performance beyond the conventional concept, in order to construct infrastructure and buildings in a more rational way. In other words, one should construct a design system which sets the continued existence of the diverse and rich global environment as its most important criterion of value. In this paper, the authors review the design and technology system developed in the past and discusses it based on the above‐mentioned new viewpoint, while constructing and presenting a new design system for concrete structures, focusing mainly on the concept of sustainability which is regarded as the most important in achieving conservation of the Earth's rich resources as well as sound socioeconomic activities of humankind in the future, and discusses its feasibility.
      PubDate: 2016-06-13T07:20:23.936229-05:
      DOI: 10.1002/suco.201600069
       
  • ARE FIBRES SENSITIVE FOR MIXING?
    • Abstract: The post‐cracking behaviour of fibre reinforced concrete is mostly influenced by the fibre type, the amount of fibres, fibre orientation and the concrete strength. Manufacturers of fibres propose a minimum mixing duration after fibres are added to concrete to obtain an acceptable dispersion of fibres. What about the maximum mixing time? Fibre properties (tensile strength, length, surface characteristics, shape and density) are normally specified by the fibre producer. However, the properties of hardened FRC (fibre reinforced concrete) are influenced by the properties of fibres after mixing. An important question is whether the properties of fibres change due to an occasionally long mixing time. Can surface characteristics, length or tensile strength of fibres change during mixing and can this affect the properties of FRC? In an extensive experimental study two types of macro polymer fibres, two types of steel fibres (without coating or with brass‐coating), two basalt fibres (with different lengths), two braids of hemp fibres (without protection and with lensed oil protection) were tested. The test results indicate possible deterioration for some of the fibres in concrete for too long mixing times. Possible modes of deterioration are shown.
      PubDate: 2016-06-13T07:15:32.192054-05:
      DOI: 10.1002/suco.201600039
       
  • Test and Analysis of a New Ductile Shear Connection Design for RC Shear
           Walls
    • Abstract: This paper presents a new and construction‐friendly shear connection for assembly of precast reinforced concrete shear wall elements. In the proposed design, the precast elements have indented interfaces and are connected by a narrow zone grouted with mortar and reinforced with overlapping U‐bar loops. Contrary to the classical shear connections, the planes of the U‐bar loops are here parallel to the plane of the wall elements. This feature enables a construction‐friendly installation of the elements without the risk of rebars clashing. The core of mortar inside each U‐bar loop is reinforced with a transverse double T‐headed bar to ensure transfer of tension between the overlapping U‐bars. Push‐off tests show that a significantly ductile load‐displacement response can be obtained by the new solution as compared to the performance of the conventional keyed shear connection design. The influence of the interface indentation geometry was investigated experimentally and the failure modes in the push‐off tests were identified by use of digital image correlation (DIC). For strength prediction, rigid plastic upper bound models have been developed with inspiration from the observed failure mechanisms. Satisfactory agreement between tests and calculations has been obtained.
      PubDate: 2016-06-13T07:15:27.87812-05:0
      DOI: 10.1002/suco.201600056
       
  • Experimental and non‐linear numerical analysis of underwater
           housings for the deep sea made of ultra‐high performance concrete
           (UHPC)
    • Authors: Sebastian Wilhelm; Manfred Curbach
      Abstract: The paper describes the design and analysis of underwater housings made of ultra‐high performance concrete (UHPC) within the Helmholtz Alliance "ROBEX" to provide cost efficient alternatives to expensive titanium housings [2]. The research is related to former investigations on spherical und cylindrical shells under hydrostatic pressure made of normal strength concrete, performed from 1960 to 1980 at the Civil Engineering Laboratory, Port Hueneme, California. Several housings made of UHPC have been manufactured and the short‐term implosion resistance has been determined experimentally. Since neither the mechanical equations for thin‐ or thick‐walled shells nor the empirical equations for implosions pressure of shells made of normal strength concrete by ALBERTSEN [1] can describe the behaviour sufficient, two non‐linear material laws for concrete, multiPlas Law 9 (modified WILLAM‐WARNKE model) and Law 14 (MENETREY‐WILLAM model) by DYNARDO for ANSYS, have been calibrated with results from uni‐ and biaxial strength tests and the results of non‐linear FEM with ANSYS 16 have been compared. To study the long‐term behavior, an in‐situ test at the arctic sea at 2,500 m is currently performed.
      PubDate: 2016-06-10T09:05:24.598689-05:
      DOI: 10.1002/suco.201600018
       
  • Structural performance of Corner Joints Subjected to a Closing Moment
           Using Mechanical Anchorages: an Experimental Study
    • Abstract: This paper presents an experimental campaign aiming to explore the behaviour of corner joints using headed reinforcement bars. The anchorage plates are designed using a theoretical formulation proposed by the authors for the side‐face blowout strength of the anchorage, aiming to verify the adequate performance of the proposed solution for these elements with respect to a conventional detail. The test set‐up, involving eight knee joints with different concrete strengths, detailing and size of the main tensile reinforcement, is first described. The characteristics, constructability and performance of mechanical anchorages are discussed. The test results are presented and compared with a conventional detailing showing the equivalence, in terms of ultimate load, load‐displacement diagrams, cracking performance and ductile failure typology. The main objective of this investigation is to encourage the use of headed reinforcement bars in common structures by presenting the results of an experimental campaign based on a simple and mechanically sound design formulation.
      PubDate: 2016-06-10T08:13:16.823244-05:
      DOI: 10.1002/suco.201500222
       
  • CATENARY ACTION EFFECTS ON THE STRUCTURAL ROBUSTNESS ASSESSMENT OF RC SLAB
           STRIPS SUBJECTED TO SHEAR AND TENSILE FORCES
    • Authors: Beatrice Belletti; Cecilia Damoni, Vladimir Cervenka, Max A.N. Hendriks
      Abstract: In this paper the behavior of RC slab strips subjected to transverse loads and axial tensile forces is investigated by means of analytical and numerical simulations. The results obtained are compared to the experimental results from tests performed at the Swiss Federal Institute of Technology (ETH). The pre‐diction of the structural response was part of an international benchmark study [1]. The aim of the paper is to investigate the capability of the adopted models and their main influencing parameters, especially from the perspective of a reliable structural robustness assessment. It is known that in some cases axial tensile forces have a beneficial effect on the bearing capacity of slab strips, thanks to the development of catenary actions. Such kind of hidden strength resources are usually not taken into account in the current design process. For this reason the validation of suitable numerical tools, able to properly predict the structural response, are useful for a reliable structural robustness assessment. The paper underlines the importance of benchmark development, especially for specimens in which both mechanical and geometrical nonlinearities play an important role.
      PubDate: 2016-06-10T08:12:33.659598-05:
      DOI: 10.1002/suco.201500157
       
  • Full‐Scale Lateral Impact Testing of Prestressed Concrete Girder
    • Authors: Yuan Jing; Z. John Ma, David B. Clarke
      Abstract: The increasing occurrence of over‐height vehicle collisions with bridges in the United States comes the concern of the damage due to lateral impact to bridge superstructures by over‐height vehicles. However this issue is not fully addressed in current bridge specifications. Previous researchers have conducted a number of small‐scale tests to study the impact process. Also, finite element method (FEM) has largely been used to analyze the complicated collision mechanism. This paper provides an opportunity of full‐scale lateral impact testing of a prestressed concrete (PC) girder, which leads to a realistic level of damage and mechanism analysis. A full‐scale lateral impact testing facility was designed and built on a construction site in Knoxville, Tennessee. The over‐height vehicle impact is simulated by impacting the bottom of an AASHTO Type‐I prestressed concrete girder with an impact cart. This paper describes the details of the impact testing facility as well as the response of the prestressed concrete girder during lateral impact. The collected testing data was calibrated by using finite element (FE) software ABAQUS.
      PubDate: 2016-06-10T08:11:58.129334-05:
      DOI: 10.1002/suco.201500224
       
  • Roofs from Prestressed Concrete Membranes
    • Abstract: Prestressed membrane roofs have been designed from the beginning of prestressed concrete. They are described in basic books written by pioneers of prestressed concrete. For illustration, four architecturally most successful roofs are reminded. The authors are convinced that the prestressed membrane roofs are still modern, structurally efficient and architecturally interesting. If they are assembled of precast members, they can be erected without scaffolding. Recently they have studied different membrane structures from point of view of their architectural and structural arrangement, process of erection and static and dynamic behavior. Deep studies were done for membranes of simple curvature situated above the whole or portion of the rectangle area and selfanchored membranes supported by arches or shells. Also selfanchored suspension membranes situated above the circular or elliptical plans, hypar membranes and membranes of a free form that are suspended on arches or suspension cables were analyzed.
      PubDate: 2016-06-03T08:09:56.294753-05:
      DOI: 10.1002/suco.201600037
       
  • Contents: Structural Concrete 2/2016
    • PubDate: 2016-06-03T05:20:52.956207-05:
      DOI: 10.1002/suco.201670025
       
  • Structural Concrete 3/2016
    • PubDate: 2016-06-03T05:20:52.601728-05:
      DOI: 10.1002/suco.201670023
       
  • Cover Picture: Structural Concrete 2/2016
    • Abstract: With a catchment area of approx. 269 km2, the waste water treatment plant in Wuerzburg is one of the largest purification plants in Bavaria, Germany. Due to the limited capacity of the plant, just under half of the sludge that was produced could be digested. Consequently, the decision was made to construct two new digesters with an additional volume of 5,000 m3 each. (© DSI)
      PubDate: 2016-06-03T05:20:50.989164-05:
      DOI: 10.1002/suco.201670021
       
  • Component based reinforced concrete beam‐column joint model
    • Abstract: A reinforced concrete beam‐column (RCBC) joint model for the quasi‐static monotonic analysis of cast in situ reinforced concrete (RC) frames is developed and implemented in a finite element analysis program for framed structures. The joint model was developed in the framework of the component method, a method originally developed for steel joints, which consists of three steps: (i) identification of the joint relevant basic components, their interaction and contribution to overall joint behaviour, (ii) characterization of the mechanical behaviour of each component and (iii) assembling of the components. With regard to the model implementation, the materially nonlinear analysis is performed by the Fictitious Forces method ⊮ all the required steps being presented and explained ⊮ while the P‐Δ method for the geometrically nonlinear analysis of frames is extended to include the beam‐column joint model. The paper closes with illustrative and validation examples; while some of these are fully analytical the others simulate lab tested sub‐frames subjected to quasi‐static monotonic loads.
      PubDate: 2016-06-02T05:32:42.868416-05:
      DOI: 10.1002/suco.201600024
       
  • An innovative joint connecting beam for precast concrete shear wall
           structures
    • Authors: Xilin Lu; Lu Wang, Dun Wang, Huanjun Jiang
      Abstract: The precast shear wall structure has outstanding features in green buildings, due to the construction convenience, safety, high quality and low pollution. In general, precast concrete shear walls are connected by multiple joints. The joint between precast walls has very strong influence on the whole structure, which calls for more detailed investigation. A new kind of connection – joint connecting beam was developed to connect the vertical reinforcements in precast concrete shear wall structures. This innovative connecting method has the advantages of convenient operation and saving steel. To evaluate the performance and for better application of joint connecting beam, an experiment on seven full‐scale specimens was conducted under cyclic loading, including two cast‐in‐situ walls and five precast walls varying in different reinforcement and sectional height of joint connecting beam. The comparison between cast‐in‐situ walls versus precast walls with joint connecting beam was performed, focusing on failure mode, hysteretic curve, skeleton curve, bearing capacity, ductility and energy‐dissipating capacity. The result shows that the joint connecting beam can effectively transfer the load of precast walls, especially for squat precast walls. Moreover, the finite element models were built up to simulate the performance of the specimens. The simulation results agree well with experimental results.
      PubDate: 2016-06-01T08:45:58.253515-05:
      DOI: 10.1002/suco.201500193
       
  • Erratum
    • PubDate: 2016-05-20T06:11:51.508507-05:
      DOI: 10.1002/suco.201670070
       
  • EXPERIMENTAL INVESTIGATIONS ON CONCRETE EDGE FAILURE OF MULTIPLE ROW
           ANCHORAGES WITH SUPPLEMENTARY REINFORCEMENT
    • Abstract: The presence of supplementary reinforcement, in the form of edge reinforcement and stirrups, has a significant influence on the load‐carrying capacity of the anchorage groups with multiple anchor rows loaded in shear perpendicular to the edge. The current 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. This paper presents the results of a comprehensive test program carried out to investigate the behavior of anchor groups with supplementary reinforcement loaded in shear towards the edge. The test results are discussed in detail to highlight the influence of supplementary reinforcement on load carrying capacity of the anchorages. Based on the evaluation of these test results, a realistic and rational model has been developed to predict the concrete edge failure loads for anchorages with supplementary reinforcement that will be presented in another paper.
      PubDate: 2016-05-20T03:51:16.601422-05:
      DOI: 10.1002/suco.201600015
       
  • Functionally Graded Concrete – Numerical Design Methods and
           Experimental Tests of Mass‐Optimised Structural Components
    • Authors: Michael Herrmann; Werner Sobek
      Abstract: Functional gradation of concrete elements makes it possible to align the internal composition of structural components with specific structural and thermal performance requirements. This alignment is made possible by continuously altering the characteristics of the material, including its porosity, strength or rigidity, in up to three spatial dimensions. This principle can be applied to minimise the mass of the element and to create multifunctional properties. Numerical design methods are used to develop the gradation layout that serves as a digital blueprint for such components. This paper describes tests performed on functionally graded beams. These tests have made it possible to derive conclusions with respect to the elements' structural behaviour. These tests also allow for a precise assessment of the weight savings that can potentially be achieved compared to structural components made from normal concrete. Test results were subsequently replicated by numerical simulations. The models calibrated in this step have established the basis to develop numerical design methods that rely on the principle of topology optimisation.
      PubDate: 2016-05-20T03:51:13.852845-05:
      DOI: 10.1002/suco.201600011
       
  • Levels of Approximation for the shear assessment of reinforced concrete
           slab bridges
    • Authors: Eva Lantsoght; Ane de Boer, Cor van der Veen
      Abstract: Since a large number of existing reinforced concrete bridges in the Netherlands are suspected to be insufficient for shear, a methodical approach is necessary. This paper aims at providing a structured approach for assessment, here applied to reinforced concrete slab bridges, which make up a considerable fraction of the Dutch bridge stock. The proposed method uses the Levels of Approximation, introduced in the 2010 fib Model Code. The recommendations at all levels are linked to experimental research. The different levels include spreadsheet‐based calculations (the Quick Scan), linear finite element models, non‐linear finite element models and analysis of a structure with cracked concrete and, for exceptional cases, proof loading of the structure. The result of this approach is a structured method of Levels of Assessment that can be used when a large number of bridges need to be assessed. For most bridges, assessment at the lowest Level of Assessment will prove sufficient capacity. For a limited number of cases, higher Levels of Assessment will offer options and guidelines for a more in‐depth study of the structure that is being assessed.
      PubDate: 2016-05-20T03:51:00.754854-05:
      DOI: 10.1002/suco.201600012
       
  • Drying Shrinkage of Concrete Elements
    • Authors: Marek Vinkler; Jan L. Vitek
      Abstract: The paper deals with shrinkage of large concrete specimens. The segments of walls of the thicknesses 200 mm, 400 mm and 800 mm were cast. Four sides were sealed in order to simulate the drying of the infinite walls of different thicknesses. The elements are equipped with vibrating wire strain gauges which measure strains inside the elements. The strains in vertical as well as in horizontal directions have been recorded for the period of 6 months. The segments of walls are stored in a laboratory. Relative humidity and temperature of the environment are not controlled, but recorded very closely. Additional tests have been executed. The concrete compression strength was measured on cubes and uniaxial shrinkage is measured on standard cylinders using embedded vibrating wire strain gauges. The cylinders are stored in three different environments, in the laboratory and in the rooms with controlled relative humidity of 65 % and 100 %, respectively. A comparison of measured shrinkage with various shrinkage models is provided (Model Code 2010, Eurocode 2, Model B3, Model B4, Model B4s and Model ACI 209R‐92).
      PubDate: 2016-05-19T09:05:23.93483-05:0
      DOI: 10.1002/suco.201500208
       
  • Analytical investigation on shape configuration of CFRP strips on lateral
           loading capacity of strengthened RC shear wall
    • Authors: Ali Delnavaz; mohammad HAMIDNIA
      Abstract: In the past few years, use of carbon fiber reinforced polymer (CFRP) has increased, because of their high strength in concrete components such as shear wall. In this study, the behavior of shear wall, strengthened with different layout configurations of CFRP, under lateral loading was investigated. For this purpose, a model is first verified by a laboratory work, then in the next step, the models were analyzed by increasing in number of fiber layers and the effect of fiber layers on shear wall capacity was studied. The sliding between fibers and concrete was neglected. Also the effect of increasing concrete strength of reinforced concrete (RC) wall on CFRP strengthening was studied. In all models, the comparison between the results of CFRP configurations on increasing lateral strength and also ductility was made. Finally, by comparing the results, the best fiber configuration based on the maximum load capacity was determined.
      PubDate: 2016-05-19T08:35:33.814462-05:
      DOI: 10.1002/suco.201500196
       
  • Durability of Steam‐cured Concrete with Slag under the Combined
           Deterioration of Freezing‐thawing Cycles and Deicing Chemicals
    • Authors: Taeseok Seo; Younsu Jung, Junhyung Kim, okpin na
      Abstract: In previous studies on the durability of slag‐mixed concrete against the combined impacts of deicing chemicals and freeze‐thaw cycles, scaling resistance of concrete was improved using replacement amounts of slag from 25% to 35% of the total cement content. However, the resistance decreased rapidly when the amount of slag replacement increased above 40% of cement content. Furthermore, in these studies, only normal cured concrete products were used rather than steam‐cured ones. Thus, the research on the scaling resistance of steam‐cured concrete products with slag replacement has not been studied enough. In this study, the durability characteristics of slag‐replaced steam‐cured concrete against the impacts of concrete deicing chemicals and freeze‐thaw cycles were investigated with the aim of improving the quality of precast concrete products. Scaling, chloride ion penetration, pull‐off strength, and relative dynamic modulus of elasticity were evaluated for both the pouring and bottom sides of the specimens. This was done because it was expected that the concrete pouring side would suffer more degradation than the bottom side owing to weakened concrete strength caused by bleeding effects.
      PubDate: 2016-05-19T08:35:28.070165-05:
      DOI: 10.1002/suco.201500201
       
  • Post‐Cracking Shear Strength and Deformability of HSS‐UHPFRC
           Beams
    • Authors: Jianan Qi; Z. John Ma, Jingquan Wang, Tongxu Liu
      Abstract: Eleven T‐beams, reinforced with high strength steel (HSS), were tested to failure to investigate the effect of shear span to depth ratio, fiber ratio, fiber type, concrete strength and stirrup ratio on the shear behavior, especially post‐cracking shear strength and deformability, of ultra‐high performance fiber reinforced concrete (UHPFRC) beams. Test results indicated that fibers were efficient not only in enhancing the post‐cracking shear strength but also in improving the post‐cracking deformability of UHPFRC beams. In addition, fibers could bridge the cracks gap and help in re‐distributing and homogenizing the concrete stress beside cracks, allowing more fine and short diagonal shear cracks with small spacing to develop around the existed cracks. A moderate amount of stirrups can effectively restrain shear cracks and allow more parallel diagonal shear cracks to develop and propagate thoroughly within shear span. The UHPFRC beams stiffness at ultimate state was about 50% of beam initial stiffness, which was considerable in strength calculation and ductility analysis, especially in seismic performance evaluation. Lastly, the current shear provisions were evaluated by the experimental results.
      PubDate: 2016-05-19T06:10:55.058891-05:
      DOI: 10.1002/suco.201500191
       
  • INFLUENCES OF SUPERPLASTICIZERS ON BASIC AND DRYING CREEP OF CONCRETE
    • Authors: Chunxiang Qian; Yi Zhang, Haoliang Huang, Jun Qu, Jingqiang Guo
      Abstract: The influences of naphthalene‐based plasticizers and polycarboxylate acid/salt superplasticisers on creep of concrete, including basic creep and drying creep, were investigated. Internal relative humidity and pore structure of concrete and the surface tension of pore solution were tested. The results show that polycarboxylate acid/salt superplasticizers refine capillary pores in concrete and reduce surface tension of pore solution. In addition, restrain internal moisture transmission and redistribution. As a result, creep of concrete is reduced. Compared with naphthalene‐based plasticizer, polycarboxylate acid/salt superplasticizer causes a greater reduction of drying creep, but a smaller reduction of basic creep. This is because the moistures redistribution is quite feeble and quickly balanced in sealed condition. Concrete with polycarboxylate acid/salt superplasticizer has the lowest creep value because polycarboxylate acid/salt superplasticizer improves hydration degree and reduces porosity of macro pores.
      PubDate: 2016-05-19T06:10:50.803031-05:
      DOI: 10.1002/suco.201500185
       
  • Improving cracking behaviour with Recycled Steel Fibres, targeting
           specific applications. Analysis according to MC2010
    • Abstract: A new and appealing means of improving cracking behaviour of RC elements is the combined use of rebars and fibres. Previous research has shown Steel Fibres Recycled from End‐of‐Life Tyres to be effective for this purpose. In this paper practical applications that would benefit from the use of this technique are presented and discussed. Firstly, two previously published examples of crack width calculation according to MC2010 are expanded to the case of study. These practical applications show how a fibre reinforced concrete (FRC) with a rather low post‐peak behaviour can provide large improvements in cracking behaviour, being also economically attractive. Then, the case of jointless structures is considered, and the improvements in terms of maximum achievable length are presented and discussed. Finally an analysis regarding the effectiveness of this solution as a function of the reinforcement ratio is discussed for both tension and bending. The main objective of this paper is to encourage the use of Recycled Steel Fibres as an effective and sustainable means of dealing with cracking behaviour for specific applications.
      PubDate: 2016-05-18T08:57:58.247295-05:
      DOI: 10.1002/suco.201500170
       
  • NUMERICAL ANALYSIS OF A BRIDGE PIER SUBJECTED TO TRUCK IMPACT
    • Authors: Pavel Jiricek; Marek Foglar
      Abstract: The impact of heavy trucks on a bridge substructure can lead to progressive collapse of the bridge superstructure, and to disastrous accidents. This type of load should therefore be taken into consideration, especially in the design of motorway bridges. For some structural arrangements, vehicle impact is the decisive loading for the design of the bridge substructure. This paper presents verification of the detailed procedures given by European standard EN 1991‐1‐7 for bridge pier impact load – dynamic analysis, which is compared with the outcomes from a detailed FEM model of a truck impact prepared using AUTODYN software. A nonlinear material model of concrete with damage and strain‐rate effect is used to assess the impact performance of a bridge pier. The paper further presents the results of a numerical study focused on the influence of different types of bridge pier reinforcement arrangement on its resistance to vehicle impact. The performance of various types of reinforcement is analyzed and compared. Practical recommendations are drawn for the design of bridge piers which can be subjected to vehicle impacts in an urban environment.
      PubDate: 2016-05-18T08:57:43.330474-05:
      DOI: 10.1002/suco.201500184
       
  • Correlation among selected fracture‐mechanical parameters of
           concrete obtained from experiments and inverse analyses
    • Authors: Thomas Zimmermann; David Lehky, Alfred Strauss
      Abstract: The correlations among selected parameters of concrete were investigated for concrete mixtures of the strength classes C20/25, C25/30, C30/37, C40/50 and C50/60. The focus was laid on correlations between basic mechanical parameters such as compressive strength, tensile strength and modulus of elasticity as well as parameters related to concrete fracture, represented here by specific fracture energy. Laboratory tests examining the fracture behaviour and mechanical properties were carried out in order to determine the fundamental concrete parameters. In particular, standard compression tests on cubic specimens and three‐point bending tests on beams with central edge notch were performed. Additional material parameters were identified using the inverse analysis technique. Finally, correlation factors between different parameters of concrete were identified using the rank‐order correlation method.
      PubDate: 2016-05-18T08:57:40.624859-05:
      DOI: 10.1002/suco.201500147
       
  • EXPERIMENTAL AND NUMERICAL EVALUATION OF PROPOSED PRECAST CONCRETE
           CONNECTIONS
    • Authors: Mohammad Yekrangnia; Amir Taheri, Seyed Mehdi Zahrai
      Abstract: In this article, cyclic performance of an innovative precast beam‐to‐column connection is evaluated experimentally and numerically. Two full‐scale beam‐column cross‐shape interior connection specimens named PF‐1 and PF‐2 are tested. By adding extra nuts to the connecting bolts, specimen PF‐2 behaves in more shear‐dominant pattern and shows less pinching. Comparison of performance of these specimens with the numerical monolithic model in terms of stiffness, strength, ductility and energy dissipation capacity indicates the proposed system can provide conditions close to the monolithic connection. However, to reduce the pinching drawback, a minor modification was made leading to performance improvement in strength and equivalent viscous damping ratio up to 51% and 29%, respectively. The results of this study have a direct industrial relevance and may be used for development of reliable seismic guidelines for precast concrete structures.
      PubDate: 2016-05-18T08:57:37.649972-05:
      DOI: 10.1002/suco.201500168
       
  • Long‐term aging effects on tensile characterization of steel fibre
           reinforced concrete
    • Authors: Thomaz Eduardo Teixeira Buttignol; Matteo Colombo, Marco di Prisco
      Abstract: The paper discusses the effect of aging on steel fibre reinforced concrete (SFRC) after 10 years. The aim is to observe the change in mechanical properties, especially of the residual post‐cracking tensile strength, due to long‐term aging. For this purpose, a comparison between the results of four‐point bending tests (4PB) at the age of 1 year and 10 years was carried out and it indicates that aging affects the serviceability post‐cracking residual strength, increasing fibre interfacial bond strength. Material classification is performed according to fib Model Code 2010 for 1‐year‐old and 10‐years‐old specimens. The objective is to estimate possible changes in the material class through the years. Three‐ and four‐point bending test results of 10‐years‐old specimens are presented, together with a comparison between those tests. Both tests have shown very similar results, slightly higher values were obtained with the three‐point bending (3PB) test. The tensile constitutive law is obtained according to fib Model Code 2010 and it is compared with results of direct tensile tests on cylindrical specimens and Double Edge Wedge Splitting tests on prismatic specimens. A plane section (PS) approach adopting the tensile constitutive law is applied to predict the bending behavior in terms of nominal stress versus crack mouth opening displacement and it is compared with the bending test results.
      PubDate: 2016-05-18T08:57:31.490074-05:
      DOI: 10.1002/suco.201500149
       
  • Mechanical Properties of Light‐Weight Concrete After Fire Exposure
    • Authors: Neno Toric; Ivica Boko, Sandra Juradin, Goran Baloevic
      Abstract: The paper presents an experimental research project focused on the analysis of the short‐term residual mechanical properties of light‐weight concrete after exposure to temperatures up to 600°C, and its effects on the post‐fire load bearing capacity of different concrete sections. The experimental programme was conducted on four different concrete mixes by determining the mechanical properties immediately after cooling and up to 96 hours after cooling. The following properties were investigated: compressive strength, ultrasonic pulse velocity and stress‐strain curves. The results show that the compressive strength exhibits additional reduction in comparison to the initial residual strength (0‐hour property) up to 20% in the reference time period. A numerical study at the end of the paper is presented in order to quantify the effects of short‐term strength reduction on the axial load bearing capacity of slender and stocky concrete columns.
      PubDate: 2016-05-18T05:11:22.451239-05:
      DOI: 10.1002/suco.201500145
       
  • Dynamic response of cracked simply‐supported concrete beam subjected
           to a moving vehicle load
    • Authors: Linyun Zhou; Huanqin Liu, Zhao Liu
      Abstract: The dynamic response of the cracked beam subjected to moving loads has been studied extensively in the past decades. However, very little is known about the dynamic impact factors and crack propagation when vehicles move along the cracked beam. It can be reasonably postulated that the crack extension may occur when the vehicle loads cross the cracked bridge at a high speed. As a result, the dynamic response will be enlarged significantly due to the flexural rigidity reduction induced by cracks, which may result in a dangerous effect on structures. To address this problem, a three‐dimensional vehicle‐bridge model was developed to investigate the dynamic response of cracked bridges with breathing cracking. Crack breathing is simulated at the crack surface using contact elements. The modified crack closure method is adopted to calculate the stress intensity factors. The results showed that the impact factors of the damaged bridge under a moving load could be notably larger than those of the intact bridge, and could exceed the value specified in AASHTO bridge design code. Meanwhile, crack propagation may occur when the vehicles move along the cracked bridge at a high speed. So, it is very necessary to limit the velocity and transverse position of the vehicles to avoid further damage of the cracked bridge.
      PubDate: 2016-05-18T05:11:07.876641-05:
      DOI: 10.1002/suco.201500138
       
  • The Critical Shear Displacement theory: On the way to extending the scope
           of shear design and assessment for members without shear reinforcement
    • Authors: Yuguang Yang; Joop den Uijl, Joost Walraven
      Abstract: This paper presents a new theory for the shear capacity of reinforced concrete members without shear reinforcement. While recognizing that there are multiple failure mechanisms, the theory attributes the opening of a critical flexural shear crack as the lower bound of the shear capacity. It proposes that the shear displacement of an existing flexural crack can be used as the criterion for the unstable opening of the critical flexural shear crack. Based on the theory, a simplified shear evaluation model is presented in the paper. Compare to the current shear provisions in the design codes, the model is characterized by good accuracy and a solid physical background. It shows great flexibility to deal with complex design conditions. As an example, the paper discusses the possibility of extending the theory to the shear resistance of higher strength concrete. The suggested method provides a more logic and fluent transition from normal strength to high strength concrete and shows good agreement with experimental observations.
      PubDate: 2016-05-18T05:11:06.29719-05:0
      DOI: 10.1002/suco.201500135
       
  • MECHANICAL PROPERTIES OF CONCRETE WITH RECYCLED AGGREGATES AND WASTE GLASS
    • Abstract: The present investigation analyses the mechanical behaviour of concrete with recycled aggregates from precast debris and waste glass. The combination of both recycled materials allows increasing the amount of recycled coarse aggregates reducing the loss in the mechanical performance of the concrete, and enhances the environmental value of the final material. Four variables are considered: the percentage of recycled course aggregates, the amount of mortar adhered to their surface, the amount of cement replaced by recycled glass powder and the maximum size of its particles. The final goal is to determine the significance of each variable in the final product and the most efficient combination to optimize the performance of the concrete, maximizing its environmental value. Significant results have been obtained that show that the calibration of the parameters may not be trivial.
      PubDate: 2016-05-18T05:11:03.978703-05:
      DOI: 10.1002/suco.201500143
       
  • Comparison of Main Models for Size Effect on Shear Strength of Reinforced
           and Prestressed Concrete Beams
    • Abstract: This paper presents a critical comparison of the existing code provisions for shear strength of concrete beams. The comparison is based on the computer filtering of inevitable statistical bias from the available multivariate database on shear strength, on the examination of the predicted size effects on shear strength and their underlying hypotheses, and on the results of recent high‐fidelity numerical simulations of shear failure. In addition to examining the existing models, the present comparison also provides several key considerations for testing the scientific soundness of any model of shear failure of concrete beams, which is necessary for future revisions of the design code provisions.
      PubDate: 2016-05-17T09:05:29.930795-05:
      DOI: 10.1002/suco.201500126
       
  • Nanoscale modifier as an adhesive for hollow microspheres to increase the
           strength of high‐strength lightweight concrete
    • Authors: Aleksandr Sergeevich; Evgenij V. Korolev, Vladimir A. Smirnov
      Abstract: The paper presents the results of the study of physical‐mechanical and operational properties of the high‐strength lightweight concrete and influence of nanoscale modifier on these properties. The nanomodifier and method of its application to improve the properties of lightweight concrete with hollow microspheres at 10–25% was proposed. It is shown that the control process of the structure formation of the cement stone which leads to the acceleration of the hydration of portland cement and the formation an additional amount of calcium hydrosilicates at the phase boundary during reaction of nanoscale silicon‐oxygen shell grafted onto the surface of the microspheres with the cement hydration products (calcium hydroxide). This provides growth of operational properties. The high‐strength lightweight concrete with an average density less than 1500 kg/m3 is characterized by strength more than 40 MPa (specific strength Rspã30 MPa). The optimum range of concentrations of the precursor for preparation of nanomodifier is defined to be 1.25≤[Na+]/[Cl‐]≤2.5. We can conclude that the developed compositions has dense and strong structure which can resist intense cracking. Application of nanoscale modifier allows to increase the elastic modulus at 13–36% (it is equal to 6.2–8.5 GPa depending on the average density), to decrease the water absorption (to 1%) and to improve the water resistance (coefficient of water resistance is more than 0.95) and freeze‐thaw resistance (up to F300). The nanomodified high‐strength lightweight concrete has beneficial values of heat‐conduction coefficient (0.48‐0.70 W/(m·°C)), temperature conductivity coefficient ((3.43–4.04)·10‐7 m2/s) and specific heat capacity (1080–1175 J/(kg·°C)). It allows us to consider this concrete as a multifunctional material with both structural and thermal insulation properties.
      PubDate: 2016-05-17T09:05:25.314655-05:
      DOI: 10.1002/suco.201500048
       
  • Increasing the flexural capacity of RC beams using steel angles and
           pre‐tensioned stainless steel ribbons
    • Authors: Piero Colajanni; Antonino Recupero, Nino Spinella
      Abstract: This article presents an experimental campaign on reinforced concrete beams retrofitted with steel angles and pre‐stressed stainless steel ribbons to increase their flexural strength and ductility. Two different configurations of the steel ribbon were designed, and two companion specimens for each type considered were subjected to four point bending test to facilitate a direct comparison in the analysis of the effectiveness of the retrofitting technique. The influence of longitudinal steel angles and transverse stainless steel ribbons is analyzed, and the concrete confinement due to stainless steel ribbons examined. The strengthened beams show remarkable increments in flexural strength and ductility with respect to the as‐built beam. Moreover, a simple cross sectional model was adopted to calculate the flexural strength; then sophisticated numerical tools were used to reproduce both the experimental load‐displacement curve and crack pattern for each specimen.
      PubDate: 2016-04-11T07:40:57.090873-05:
      DOI: 10.1002/suco.201500187
       
  • The monitored and theoretical ultimate moment and ductility of
           pre‐tensioned HSSCC bridge girders
    • Authors: Mohammad Maghsoudi; Aliakbar Maghsoudi, Arash Ali Heshmati
      Abstract: Self‐compacting concrete (SCC) is defined as highly flowable and none‐segregating concrete that does not require mechanical vibration during its application. The load test of bridge girders was investigated on constructed full scale T‐beams of pre‐tensioned high strength self‐compacting concrete (PHSSCC). The girders were monitored by fixing different types of sensors at different locations. Results of ultimate moment are compared to evaluate if such girders can be designed using AASHTO Load and Resistance Factor Design (LRFD) Specifications; AASHTO Standard Specifications for Highway Bridges (STD) and the PCI Bridge Design Manual are for structures constructed using conventional (none vibrated) concrete. It is concluded that good agreement in results exists for the two methods. Investigations (theoretical and experimental) are needed on the issue of ductility in structural prestressed elements constructed in seismic zones or even, the issue of high strength in SCC. These have been studied here too, and it has been concluded that, suitable ductility for this type of structure, as would be needed in seismic regions, can be achieved.
      PubDate: 2016-04-11T07:40:43.547163-05:
      DOI: 10.1002/suco.201500219
       
  • Bond Behaviour of Straight, Hooked, U‐Shaped and Headed Bars in
           Cracked Concrete
    • Abstract: Most classical investigations on bond properties in reinforced concrete have been performed on the basis of pull‐out tests, where a reinforcement bar is pulled out from an uncracked concrete cylinder, prism or cube. In these tests, bond is governed by the concrete strength and bar surface properties of the reinforcement (bond index, rib geometry) or by the splitting strength of concrete (concrete cover). In the latter case, failure in bond occurs due to uncontrolled cracking of the concrete specimen. Contrary to these fundamental tests, in many structural members, bond is activated within already cracked concrete. This is particularly relevant for the reinforcement in beams and slabs (both for the flexural and transverse reinforcement), as the reinforcing bars might be located at planes where flexural cracks develop. The opening of these cracks along the reinforcement is nevertheless not uncontrolled (as opposed to splitting failures), but it is governed by the bending deformations. The bond properties and strength of the reinforcement in actual members are, therefore, influenced by the opening of these cracks and are potentially different from those observed from classical pull‐out tests. The present paper aims to address this topic by presenting the results of an experimental investigation on 89 monotonic pull‐out tests performed on cracked ties. The opening of the cracks was controlled while transverse bars ‐located in the plane of these cracks‐ were pulled out from the specimens. The tests were performed for crack openings ranging from 0.2 mm to 2.0 mm in order to cover conditions both at serviceability and ultimate limit states. The results show a very significant influence of in‐plane cracking on both the strength and bond‐slip stiffness, with decreasing mechanical performance for increasing crack openings. The performance of different actual anchorage types (straight, hooked, U‐shaped and headed bars) ‐ generally characterized through force ‐slip relationships‐ is finally analytically investigated and compared to the test results.
      PubDate: 2016-04-11T07:40:30.474197-05:
      DOI: 10.1002/suco.201500199
       
  • Flexural Strengthening and Repair of RC Slabs by Adding a New RC Layer
    • Abstract: The present paper summarizes the findings of an experimental program dedicated to investigate a strengthening/repair technique, the introduction of a new RC layer to the existing slab. Six RC slabs, composed of twelve cantilever and six interior spans, were tested under monotonic transverse loading. The behavior of statically determinate cantilever spans and indeterminate interior spans was examined by comparing the test results of these specimens to the results of reference slabs, in which the existing and additional layers were cast monolithically. The influence of recovering the permanent slab deformations before repair and the spacing of the shear connectors between the existing and additional layers were investigated. The tests indicated that recovering the permanent deformations of a slab before repair reduces its rigidity substantially while having little influence on the ultimate load. Furthermore, debonding of the reinforcement was observed to decrease the load capacities and rigidities of the slabs considerably.
      PubDate: 2016-04-11T07:36:02.315007-05:
      DOI: 10.1002/suco.201500182
       
  • EXPERIMENTAL BEHAVIOUR AND DEFLECTIONS OF LOW STRENGTH CONCRETE BEAMS
           REINFORCED BY FRP BARS
    • Authors: CONFRERE ADELINE; Laurent Michel, Emmanuel Ferrier, Gilles Chanvillard
      Abstract: The primary objective of this new study on Fibre‐Reinforced Polymer (FRP)‐reinforced concrete (RC) beams is to evaluate the mechanical performance of RC beams made of low strength concrete internally reinforced by FRP. The association of FRP rebar with low compressive strength concrete is desirable to avoid the accelerated corrosion processes that could occur with steel rebar. For this purpose, an experimental programme was designed to identify the failure modes and bending behaviour. The experimental results are compared with equations from ACI 440.1R‐06, CSA S806‐12 and other design codes, as well as with other results from a review of the literature. The comparisons indicate that resistant moment is well predicted by codes for flexural failure. At ultimate loads, deflection of the beams is further underestimated compared to that of beams reinforced by higher compressive strength concrete. An analytical simulation of 690 beams indicates that deflection is the major limiting criterion at the Service Limit State. Finally, the problem formulation of the optimal FRP design for reinforced concrete beams can be cast into a programming problem. The space of feasible design solutions and the optimal solutions can be obtained using only a reduced number of design variables and an existing design method.
      PubDate: 2016-04-11T07:35:47.531103-05:
      DOI: 10.1002/suco.201500046
       
  • New structural joint by rebar looping applied to staged box girder bridge
           construction. Static tests
    • Authors: Sergi Villalba; Joan R. Casas
      Abstract: This paper shows the design, development and experimental checking of a modified type of structural joint with limited length between concrete segments cast “in‐situ”. The design concept is based on the development length of an anchorage hook stiffened by transverse reinforcement bars and is particularly suited for the case of in‐situ construction of staged box girder bridges, seeking to the possibility of using lighter scaffolding. The studies focusing on the strength, stiffness and serviceability of the proposed joint are presented. The research work comprises the bending behaviour of reinforced concrete slabs with loop joints with regard to the diameter of loop bar, loop joint width and ultimate and fatigue load. The results are compared to the behaviour of reinforced concrete slabs without joints. A total of 16 slabs were tested by static and fatigue loading tests. The present paper evaluates the flexural behaviour under static loading test. The results of fatigue tests have also shown an excellent performance. In the static tests, crack width and crack pattern were observed at service load levels, and the ultimate behaviour was evaluated by means of up to failure tests. From the test results, the service performance of the loop joints was confirmed similar to slabs without joints. The static loading tests confirm the good performance and effectiveness of this loop joint type under static loads. Details of loop joints design criteria are also suggested.
      PubDate: 2016-04-11T07:35:35.207835-05:
      DOI: 10.1002/suco.201500117
       
  • Variation in fibre volume and orientation in walls: Experimental and
           numerical investigation
    • Abstract: Previous research with fibre‐reinforced slab elements has shown that the surface roughness of formwork and the presence of rebars affect fibre orientation and fibre volume distribution. This paper discusses the orientation and volume distribution of steel fibres in wall elements cast from a single point. In particular, the effect of formwork tie bars on fibre orientation and distribution was studied. To quantify the fibre orientation and distribution, numerical simulations and X‐ray computed tomography were applied, and the mechanical performance was determined using three‐point bending tests on sawn beams. The Thorenfeldt model (applied in the Norwegian proposal of the new fibre‐reinforced concrete guideline) was used to estimate the residual flexural tensile strength based on fibre orientation and distribution. The simulation results show that the fibre orientation can be related to the flow pattern. The results indicate a large variation in fibre orientation, which was experimentally confirmed. The fibre volume distribution was mostly uniform, except for an area with fewer fibres at the casting point. The large variation in fibre orientation was reflected by a large variation in residual flexural tensile strengths. Weak zones due to anisotropic fibre orientation caused by formwork tie bars were observed.
      PubDate: 2016-03-16T09:05:39.832375-05:
      DOI: 10.1002/suco.201500060
       
  • Experiments about load bearing behaviour of lightweight sandwich beams
           using textile reinforced and expanded polystyrene concrete
    • Authors: Viet Anh Nguyen; Frank Jesse, Manfred Curbach
      Abstract: Textile reinforced concrete (TRC) it is a combination of small grain high performance concrete (HPC) and high strength textile reinforcement. TRC allows thin layers and has high tensile and compressive strength. In this paper, TRC was used for the face layers and it was combined with a core of lightweight expanded polystyrene concrete (EPC) to create lightweight sandwich beams without special joint reinforcement to connect the layers. The experimental testing of the load bearing behaviour of this kind of sandwich beams, along with the influence of the shear span to depth ratio (aȏd) as observed during 3‐point and 4‐point bending tests will be summarized. The failure behaviour of the sandwich beams is influenced by the shear span to depth ratio, the type of bending test and the tensile capacity of the TRC layer. The diagonal tension failure occurred in experimental beams with 2.6≤ aȏd ≤ 5.2 for 3‐point bending tests and 3.1 ≤ aȏd ≤ 4.1 for ‐point bending tests. The shear strength of the beams could be conservatively estimated according to the current European standards.
      PubDate: 2016-03-16T09:01:47.877063-05:
      DOI: 10.1002/suco.201500156
       
  • ANALYTICAL MODELING OF BOND STRESS AT STEEL‐CONCRETE INTERFACE DUE
           TO CORROSION
    • Authors: Luaay Hussein; Lamya Amleh
      Abstract: An analytical model for bond stresses at the corroded steel‐concrete interface in a reinforced concrete is proposed. The concrete around the corroded bar is modeled as a thick‐walled cylinder, consisting of an inner cylinder of an anisotropic material, and an outer cylinder made of an isotropic material, and subjected to internal pressure exerted from the growth of corrosion products on the concrete wall at the interface. A frictional model is used to combine the action of confining pressure from the radial pressure produced by principal bar ribs, and the pressure resulted from expansion of corrosion products. The analysis results using the proposed model showed good agreement with the experimental results from several researchers.
      PubDate: 2016-03-16T09:01:45.20972-05:0
      DOI: 10.1002/suco.201500109
       
  • Influence of Reinforcement Type on Macrocrack Propagation under Sustained
           Loading in Steel Fibre Reinforced Concrete
    • Abstract: To meet the growing challenges of sustainability, it is necessary to control and anticipate cracking problems of structures under sustained loadings. At the structural scale, very little information is available regarding the combined effect of SFRC and reinforcement under sustained flexural loading. This paper presents the results of four flexural creep tests on steel fibre reinforced concrete large beams reinforced with fibres only or in combination with unbonded prestressing strands, bonded prestressing strands, or traditional reinforcing bars. The main objective was to assess the influence of the reinforcement type on crack propagation, crack openings, and compliance evolution under sustained loading in SFRC. The results show that the thriving mechanism of crack propagation is the same for all beams, regardless of the reinforcement type, and is therefore governed by type of fibre concrete.
      PubDate: 2016-03-07T10:13:00.703234-05:
      DOI: 10.1002/suco.201500069
       
  • On the reliability of design approach for FRC structures according to
           Model Code 2010: the case of elevated slabs
    • Authors: Marco Di Prisco; Paolo Martinelli, Benoit Parmentier
      Abstract: The paper focuses on the reliability of the design approach proposed in Model Code 2010 for the estimation of the ultimate capacity of fibre‐reinforced concrete (FRC) elevated slabs on the basis of different tests for material characterisation. The fracture properties of the material are determined through three‐point bending tests on notched beams, and through double edge wedge splitting (DEWS) tests carried out on cylinders cored in the full‐size test structure. As a case study, an FRC elevated flat slab is considered, consisting of 9 bays (panels) of a 6×6 m2 dimension and supported by sixteen circular concrete columns having a thickness of 0.2 m and a full‐size of 18.3×18.3 m2. The ultimate bearing capacity of the slab experimentally determined is compared with the design value predicted by means of a procedure based on limit analysis following the Model Code 2010. The results show that the method proposed in the Model Code 2010 using the characteristic values and the classification is reliable. Even if the tests are affected by a significant standard deviation and the two experimental campaigns with 3‐point bending tests give a significant difference from class “5c” to class “3e”, the structural test presents a bearing capacity that is always larger than the predicted one, which considers a safety coefficient for the material γF = 1.5.
      PubDate: 2016-03-07T10:12:29.915913-05:
      DOI: 10.1002/suco.201500151
       
  • DESIGN PROCEDURE OF PRECAST FIBER REINFORCED CONCRETE SEGMENTS FOR TUNNEL
           LINING CONSTRUCTION
    • Authors: Fabio Di Carlo; Alberto Meda, Zila Rinaldi
      Abstract: A procedure for the design of precast tunnel segments for mechanical excavated tunnel lining in fiber reinforced concrete, without any traditional steel reinforcement, is presented herein. Both Ultimate and Serviceability Limit States are considered, as well as structural checks at different construction stages of the segment, including demoulding, positioning on floor, storage, transportation, handling and the final stage concerning the loads due to the ground pressure. The structural checks are performed by means of bending moment – axial force interaction envelopes for both the considered Limit States, once defined the constitutive relationship of the material in each stage. Traditional interaction envelopes are drawn for the Ultimate Limit State check, while for Serviceability Limit State check, envelopes obtained by limiting the maximum crack opening and the maximum concrete compressive stress are proposed. The shear action is also accounted for by reducing the bending moment – axial force envelope. The possibility of having an assisted by test procedure for particular loading situation is also proposed. Finally, a case study related to a precast steel fiber reinforced concrete segment is analysed in order to clarify the procedure and to show practically how to define the actions and to evaluate the interaction envelopes.
      PubDate: 2016-03-07T10:12:16.573549-05:
      DOI: 10.1002/suco.201500194
       
  • Reinforced concrete thin wall dome after eighty years of operation in
           maritime climate environment
    • Abstract: The paper presents a description of the construction elements of the Gdynia Seaport main hall dome. First of all, it provides information about the dome's structure technical conditions. Secondly, it treats about the strength analysis of the thin‐walled reinforced concrete dome covering. Throughout the last 80 years the building was exposed to an unfavorable marine climate. The analysis of the state of stress and deformations of several construction elements was carried out using a special model worked out with help of the FEM considering the combination of loads: dead weight, wind and snow, as well as the additional combination: dead weight and hurricane wind of velocity 200 km/h (55.5 m/s). The computed results of static quantities were also obtained according to F. Dischinger's method which was used in design of the RC Gdynia Seaport dome in 1932. The computational analysis and the assessment of the technical state made it possible to make a decision concerning further safe operation of the building. To sum up, it can be concluded that the results obtained with the FEM analysis and the analysis of the technical state 80‐years old dome made it possible to carry out an assessment of the factor of safety of the dome's reinforced concrete elements. That in turn made it possible to come to a decision on the possibility of its further operation without causing any major local demolition. What is more, it permitted to construct a new dome after tearing‐down of the old one.
      PubDate: 2016-03-07T10:12:02.621839-05:
      DOI: 10.1002/suco.201500180
       
  • Reliability‐Based and Life‐Cycle‐Cost Oriented Design
           Recommendations for Prestressed Concrete Bridge Girders
    • Authors: Makato Yanaka; Seyed Hooman Ghasemi, Andrzej S. Nowak
      Abstract: There are several methods available to decide on appropriate design recommendations against corrosion of reinforcing steel in prestressed concrete bridge girders. With respect to chloride‐induced corrosion, in the present study two methods are considered. The first one is based on the target probability of corrosion initiation and the initial cost. The other method is based on the life cycle cost that includes the initial cost, maintenance cost, and expected failure cost. This paper deals with the development of recommendations for durability design of structures in marine environments from the reliability point of view, taking into consideration of the life cycle cost of a structure. In order to approach the problem, the chloride diffusion coefficient of a cracked area under service load is obtained considering opening and closing motion of cracks. Utilizing the diffusion coefficient of a cracked area, the development over time of the chloride concentration at the surface of reinforcement can be predicted. This information is used to quantify probability of initiation of corrosion of prestressing steel as well as the distribution of life cycle cost. Based on the findings recommendations for durability design in various exposure environments are developed.
      PubDate: 2016-03-07T10:11:49.622723-05:
      DOI: 10.1002/suco.201500197
       
  • Cyclic behavior of interior reinforced concrete beam‐column
           connection with Self‐Consolidating Concrete
    • Authors: Jalal Salehi Mobin; Mohammad Taghi Kazemi, Nader K.A. Attari
      Abstract: A significant amount of research in Self‐Consolidating Concrete (SCC) technology has been devoted to evaluate the suitability of the material to be used in structural applications. However, more researches are required to confirm the adequacy of SCC structural members to resist gravity and seismic loads. This study focuses on the experimental investigation of the seismic performance of interior reinforced concrete beam‐column connections with SCC. In this experimental study, four beam‐column connection specimens, three SCC and one normally vibrated concrete (NC), were designed. Factors such as the concrete type (SCC and NC) and axial load ratio (0%, 7.5% and 15% of column section capacity) were assumed to be the variables in designing the specimens. Beam‐column connections made with NC and SCC were studied and compared under reversed cyclic loading. The performance of SCC specimens is comparable with NC specimens in terms of strength, displacement and ductility, but SCC specimens show lower energy dissipation capacity.
      PubDate: 2016-02-25T03:12:16.231596-05:
      DOI: 10.1002/suco.201500133
       
  • ESTIMATION OF CORROSION ATTACK IN REINFORCED CONCRETE BY MEANS OF CRACK
           OPENING
    • Authors: Carmen Andrade; Alessandro Cesetti, Giuseppe Mancini, Francesco Tondolo
      Abstract: The corrosion of reinforcements in concrete is the most common degradation phenomenon of reinforced concrete structures. Reinforced concrete elements subjected to corrosion generally crack due to the expansive nature of oxides. A very important task is to estimate the corrosion level using a non‐destructive method, in order to establish both the actual safety of the structure and a priority intervention plan. Many researches have studied the relationship between the corrosion phenomenon and the corresponding crack openings and their evolution; several statistical analyses, based on test data from experimental campaigns, under a wide range of test conditions, are available. The present work tries to contribute to the finding a relationship between the crack opening and the amount of corrosion induced in the reinforcing bars. The result of the analysis is that only a reduced number of tests can be used to establish an empirical model on a reliable test data set. A simple relationship between crack opening and corrosion penetration is not recommended, due to the different parameters that are able to influence this correlation. Therefore two fundamental parameters, that is, the ratio of the concrete cover to the rebar diameter and concrete strength have also been considered. The considerations made on these parameter test results have been rearranged, and the result is that a formulation has been found that shows reduced scatter.
      PubDate: 2016-02-25T03:11:08.780739-05:
      DOI: 10.1002/suco.201500114
       
  • Flexural capacity enhancement of rectangular high‐strength concrete
           columns confined with post‐tensioned steel straps: Experimental
           investigation and analytical modeling
    • Abstract: Load carrying capacity and deformability of concrete column can be substantially enhanced after confined with post‐tensioned steel‐straps. As the interests in the high‐strength concrete (HSC) grow among structural engineers and researchers due to its superior performance, this confining technique is extended to HSC columns with the hope that it can eliminate the undesired properties of HSC especially its brittleness. However, experimental studies in confined HSC columns subjected to eccentric loads is comparatively limited. It can be observed in the past research that most of the studies in external confinement were conducted on small‐scale normal‐strength concrete (NSC) cylinders subjected to concentric loads. Since most of the columns are subjected to eccentric loads in reality, the scarcity of test data has prevented the full potential use of this confining technique. In this paper, this confining technique is termed as steel‐strapping tensioning technique (SSTT) hereafter for brevity. Nine HSC columns were tested under eccentric loads. The specimens were grouped into three groups with each group had an unconfined HSC column as control specimen, a two layer SSTT‐confined HSC column and a four layer confined HSC column. The experimental results show that the flexural capacities of HSC columns can be enhanced with SSTT. The deformability of confined HSC columns is significantly improved with the confinement provided.
      PubDate: 2016-02-25T03:10:53.655428-05:
      DOI: 10.1002/suco.201500123
       
  • Derivation of design rules for innovative shear connectors in steel
           concrete composites by systematic use of nonlinear Finite Element Analysis
           (FEA)
    • Abstract: Today, the development of novel shear connectors for steel‐concrete‐composites is accompanied by an extensive amount of experimental investigations, obligatory to propose suitable design formula and to carve out their limitations of use. Using the example of the so called pin‐connector, the present paper illustrates to which degree validated finite element models of novel shear connectors can be used to substitute expensive and time‐consuming shear tests and in which manner these finite element models can support the deduction of design concepts. The regarded pin connector was developed for the connection of steel sections with very slender high strength concrete slabs, in which conventional shear connectors like headed studs cannot be applied due to the limited embedment depth. In order to clarify the shear behavior and load carrying mechanisms of these novel connectors, non‐linear finite element models have been set up, using the commercial FE‐Software ABAQUS. The numerical simulations were validated by shear tests. Subsequently, the validated models were used to perform systematic parametric studies. The paper documents the numerical results and finally explains the stepwise development of an entire engineering model to determine the longitudinal shear capacity of small‐scaled pin connectors including all required limitations of use. The proposed modeling strategy and the methodology for the deduction of design rules can be transferred and assigned to other types of shear connectors.
      PubDate: 2016-02-18T08:59:42.75961-05:0
      DOI: 10.1002/suco.201500217
       
  • Recent Advances in Experimental Study on Mechanical Behaviour of Natural
           Fibre Reinforced Cementitious Composites
    • Authors: He Tian; Y.X. Zhang, Chunhui Yang, Yining Ding
      Abstract: This paper presents a review of the recent research and development of natural fibre‐reinforced concrete (NFRC). The recent developments on NFRC reinforced with different types of natural fibres, such as sisal fibre, bagasse fibre, coir fibre, banana fibre, eucalyptus fibre, flax fibre, jute fibre and pinus radiate fibre are covered. Natural fibres and their modification methods are firstly introduced, and the development history of natural fibre reinforced concrete and the relevant research on the mechanical behaviour of NFRC in both short term and long term are reviewed. The applications of NFRC are also summarized.
      PubDate: 2016-02-18T08:59:28.145913-05:
      DOI: 10.1002/suco.201500177
       
  • Development of stiffness and ultrasonic pulse velocity of dynamically
           loaded concrete
    • Authors: Christoph von der Haar; Steffen Marx
      Abstract: Damage processes in dynamically loaded concrete structures depend on the number and amplitude of applied load cycles. Damage evolution is linked to a reduction in concrete stiffness, and it is thought that this reduction causes stress redistributions at the component level, which have a favorable impact on the service life of the structure. Until now, the stiffness reduction and stress redistribution have never been successfully measured in laboratory tests or in situ. It is only known that the real service life is greater than the calculated one and that indicators of stiffness reduction, such as the component deflection, increase with the number of applied load cycles. Ultrasonic measurement techniques are considered to be well suited for detecting degradation processes caused by dynamic loading. By using ultrasonic pulse velocity measurements, it is expected that the stiffness reduction of dynamically loaded concrete structures can be recorded reliably. Against this background, fatigue tests on small‐scale concrete specimens were performed. The aim of the tests was to understand the correlation between the observed stiffness degradation of the specimens and the results of ultrasonic pulse velocity measurements and to estimate the potential of ultrasonic pulse velocity measurements for continuous structural health monitoring.
      PubDate: 2016-02-18T08:59:15.140464-05:
      DOI: 10.1002/suco.201600007
       
  • Behaviour of reinforced concrete rectangular sections based on tests
           complying with seismic construction requirements
    • Abstract: The prediction of the seismic behaviour of reinforced concrete elements by using numerical models has become a field of growing interest in recent years, due to the importance of adequately knowing the effects induced by seismic loads applied to reinforced concrete structures. The simulation of the hysteretic behaviour of the plastic hinges generated in the structure when the seismic load acts requires the use of models capable of describing the sectional behaviour of structural members. Thus, the main objective of the present paper is the adjustment of several empirical expressions that reduce the computational time to simulate the yield and ultimate behaviour of a given reinforced concrete rectangular section under either monotonic or cyclic loading. The expressions are calibrated with a selection of tests, from a published database of more than 1000 tests, under the criterion that the selected specimens comply with the seismic construction requirements of the main international building codes (EC‐2, EC‐8 and ACI‐318). Due to their robustness and acceptable computation time for low‐dimensional problems, genetic algorithms are used for this calibration. The equations proposed can be employed by structural engineers for the design and analysis of actual structural elements used in ordinary reinforced concrete buildings located in seismic areas, providing more accurate results than other expressions.
      PubDate: 2016-02-18T08:57:07.971531-05:
      DOI: 10.1002/suco.201500107
       
  • DESIGN RECOMMENDATIONS FOR REINFORCED CONCRETE INTERFACES BASED ON
           STATISTICAL AND PROBABILISTIC METHODS
    • Abstract: A concrete interface is a material discontinuity which requires special care in structural design and assessment. Therefore, the definition of design expressions, based on experimental testing data, must ensure the needed reliability depending on the type of structure and its use. In the present work, a new proposal for the design of concrete interfaces subjected to shear loading is presented for different roughness profile types. The proposal is characterized by 3 linear branches (for monotonic loading), an S‐N curve (for cyclic loading) and is the result of a parametric analysis of existing experimental data (obtained by the authors and also from an extensive literature search) based on statistical and probabilistic methods. Design expressions were defined in order to minimize dispersion and variability of the safety factor values for each considered experimental test, and also to assure that those values are within a target range (defined according to reliability considerations). These improvements became clearer when the new proposal was compared with the most common design code recommendations.
      PubDate: 2016-02-18T08:55:53.312573-05:
      DOI: 10.1002/suco.201500083
       
  • Real‐time damage detection based on pattern recognition
    • Abstract: Structural Health Monitoring (SHM) can be defined as the process of developing and implementing structural damage detection strategies. Ideally, this detection should be carried out in real time before damage reaches a critical state and impairs structural performance and safety. Hence, it must be based on sensorial systems permanently installed on the target structures and on fully automatic detection methodologies. The ability to detect damage in real‐time is most important for controlling the safety of aged structures or for post‐retrofitting / post‐accident situations, where it might even be mandatory for ensuring a safe service. Under these constraints, SHM systems and strategies must be capable of conducting baseline‐free damage identification, i.e., they must not rely on comparing newly acquired data with baseline references in which structures must be assumed as undamaged. The present paper describes an original strategy for baseline‐free damage detection based on the application of artificial neural networks and clustering methods, in a moving windows process. The proposed strategy was tested and validated on numerical and experimental data obtained from a concrete cable stayed bridge and proved effective in automatically detecting small stiffness reductions in single stay cables as well as the detachment of neoprene pads in anchoring devices, resorting only to a small amount of inexpensive sensors.
      PubDate: 2016-02-18T08:55:40.412952-05:
      DOI: 10.1002/suco.201500092
       
  • The structural redistribution coefficient KRd: A numerical approach to its
           evaluation
    • Authors: Marco di Prisco; Paolo Martinelli, Daniele Dozio
      Abstract: Structures made of a material with a very high standard deviation, such as fibre‐reinforced concrete, show a too safe prediction of the maximum bearing capacity when derived from characteristic values identified by means of small specimens. This is emphasized when the structures are characterized by a large redundancy. In this regard, two reference tests representing two extreme situations are considered: (a) simply supported unnotched full‐scale beams characterized by a statically determinate loading scheme and (b) full‐scale slabs on the ground characterized by a statically indeterminate loading scheme. The Italian Standard and more recently Model Code 2010 have introduced a coefficient (structural redistribution factor) that is able to take into account the reduced variability of the mechanical strength when associated with a large volume involved in the failure process or when the structure is able to significantly redistribute stresses, favouring the average strength rather than the minimum one. A numerical procedure taking into account the expected heterogeneity of the mechanical characteristics in the structure is introduced for the first time to evaluate the redistribution factor.
      PubDate: 2016-02-18T08:55:26.599252-05:
      DOI: 10.1002/suco.201500118
       
  • PUNCHING SHEAR TESTS ON COMPACT FOOTINGS WITH UNIFORM SOIL PRESSURE
    • Abstract: Punching shear is usually the governing failure criterion for the selection of the depth of reinforced concrete footings. Despite the fact that large experimental programmes have been performed in the past aimed at the punching strength of slender flat slabs, only a few experimental campaigns on full‐scale compact reinforced concrete footings can be found in the literature. In this paper, the results of an experimental programme including 8 reinforced concrete footings with a nominal thickness of 550 mm is presented. These experiments investigated the influence of the column size, member slenderness and the presence of compression and shear reinforcement. The tests were performed using an innovative test setup to ensure a uniform soil pressure. The experimental results show that the slenderness influences the punching shear strength as well as the effectiveness of the shear reinforcement. It is also experimentally shown that an important interaction amongst bending and shear occurs for high levels of shear forces near the column (typical case of compact footings or members with large amounts of shear reinforcement). Different continuous measurements recorded during the experimental tests allow a complete description of the kinematics and strains at failure. On that basis, experimental evidence is obtained showing that crushing of the concrete struts near the column is the phenomenon that triggers the punching failure of compact footings.
      PubDate: 2016-02-18T08:55:14.661851-05:
      DOI: 10.1002/suco.201500175
       
  • Fatigue behaviour of a normal‐strength concrete – number of
           cycles to failure and strain development
    • Abstract: The fatigue behaviour of concrete is gaining new relevance against the backdrop of continuous development in concrete construction. Modern types of concrete achieving ever higher strengths; hence concrete constructions are becoming increasingly attractive for new fields of application such as onshore and offshore wind turbines. The fatigue of concrete has a special relevance for these cyclic‐loaded constructions. Knowledge of the number of cycles to failure is no longer sufficient for the design of these kinds of constructions. There are further questions concerning strain and stiffness development and the combination of fatigue loading and maritime environmental conditions which have been investigated with new testing methods at Leibniz Universität Hannover within the research project “ProBeton”. The first results of this research project, which is supported by the Federal Ministry for Economic Affairs and Energy, are presented here.
      PubDate: 2016-02-18T08:54:59.611208-05:
      DOI: 10.1002/suco.201500139
       
  • Modification of the simplified method of crack control included in EN
           1992–3
    • Authors: Mariusz Zych
      Abstract: The methods of liquid retaining RC tank walls crack control are analysed taking into account external load (EN 1992‐1‐1) and imposed strain occurring at the elevation stage (EN 1992‐3), i.e. during concrete hardening period. The convergence ranges of the simplified method of crack control included in EN 1992‐3 and the detailed calculation methods included in EN 1992‐1‐1 and EN 1992‐3 are defined. Apart from the compatibility areas, overestimation of the acceptable reinforcement bar diameter φs⋆ displayed in Fig. 7.103N in EN 1992‐3 was proved. Coefficients κφ1 and κφ2 are defined, which enabled a calculation of the acceptable reinforcement bar diameter φs⋆ in order to obtain the values complying with the direct calculations. For practical purposes, graphs were plotted, which facilitates the definition of coefficients κφ1 and κφ2 without performing direct calculation. On the basis of the analyses performed and the relations proposed it can be concluded that there is a possibility or a necessity to increase or decrease the acceptable reinforcement bar diameter φs⋆, depending on the concrete mechanical properties and geometrical properties of a RC tank wall.
      PubDate: 2016-02-18T08:50:40.451423-05:
      DOI: 10.1002/suco.201500077
       
  • Experimental Evaluation of Optimized Strut‐and‐Tie Models for
           a Dapped Beam
    • Abstract: Strut‐and‐Tie modeling provides a powerful tool for the design of complex structural reinforced concrete elements. It has been proved numerically that strut‐and‐tie models obtained with the application of structural optimization methods produce designs that are more efficient. However, to the best of the authors' knowledge, no experimental evidence of such results has been published. This paper presents experimental results for nine test specimens: five of them are designed using optimal models derived from a Full Homogenization structural optimization algorithm, and the remaining four are designed using conventional strut‐and‐tie models, for comparison purposes. While all specimens carry loads higher than the factored design load, specimens based on ST models derived using Full Homogenization with reinforcement parallel to the ties, exhibit better structural performance, regarding crack growth control, more ductile modes of failure, and larger increase in load capacity.
      PubDate: 2016-02-18T08:50:28.588161-05:
      DOI: 10.1002/suco.201500037
       
  • AN IMPROVEMENT OF THE EUROCODE 2 AND fib MODEL CODE 2010 METHODS FOR THE
           CALCULATION OF CRACK WIDTH IN R.C. STRUCTURES
    • Authors: Pier Giorgio Debernardi; Maurizio Taliano
      Abstract: The analysis of the mechanical behaviour of a reinforced concrete tie subjected to a monotonic loading, in the stabilized cracking stage, is here performed through a theoretical general model that considers the effect of the so‐called Goto cracks or secondary cracks. It is shown, in particular, that the average bond stress along the transmission length depends not only on the concrete strength as assumed by fib Model Code 2010, but also on the reinforcement ratio and bar diameter. To this regard, tabulated theoretical values of the average bond stress are proposed as a function of the aforementioned parameters. Moreover, the secondary cracks reduce the effect of tension‐stiffening on the relative mean strain. On the basis of the main results obtained with the general model some improvements to the calculation methods proposed by fib Model Code 2010 and Eurocode 2, concerning the average value of the bond stress and taking account of the influence of the secondary cracks on the mean deformation, are suggested. An improved calculation method is therefore performed. Finally, the theoretical results of crack spacing and crack width obtained with the general and improved methods are compared to the experimental data obtained from an extensive research on r.c. ties.
      PubDate: 2016-02-09T06:28:51.638222-05:
      DOI: 10.1002/suco.201500033
       
  • The fib and the development of structural concrete
    • Pages: 133 - 134
      PubDate: 2016-06-03T05:20:55.169992-05:
      DOI: 10.1002/suco.201670026
       
  • fib‐news: Structural Concrete 2/2016
    • Pages: 298 - 305
      Abstract: Contents Issue 2 (2016) The fib in Slovakia fib Bulletin 77 HiPerMat Short notes Congresses and symposia Acknowledgement
      PubDate: 2016-06-03T05:20:52.662193-05:
      DOI: 10.1002/suco.201670022
       
 
 
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