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  Subjects -> ENGINEERING (Total: 2255 journals)
    - CHEMICAL ENGINEERING (189 journals)
    - CIVIL ENGINEERING (180 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1196 journals)
    - ENGINEERING MECHANICS AND MATERIALS (386 journals)
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CIVIL ENGINEERING (180 journals)                     

Showing 1 - 0 of 0 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 15)
Acta Polytechnica : Journal of Advanced Engineering     Open Access  
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 31)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 24)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 27)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription  
Archives of Civil Engineering     Open Access   (Followers: 8)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 1)
ATBU Journal of Environmental Technology     Open Access   (Followers: 3)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 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: 3)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 5)
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: 8)
Case Studies in Structural Engineering     Open Access   (Followers: 8)
Cement and Concrete Composites     Hybrid Journal   (Followers: 15)
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: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 4)
Civil and Environmental Research     Open Access   (Followers: 17)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 14)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 2)
Civil Engineering and Technology     Open Access   (Followers: 8)
Civil Engineering Dimension     Open Access   (Followers: 7)
Civil Engineering Infrastructures Journal     Open Access  
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 230)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 9)
Computers & Structures     Hybrid Journal   (Followers: 29)
Concrete Research Letters     Open Access   (Followers: 3)
Construction Economics and Building     Open Access   (Followers: 1)
Construction Engineering     Open Access   (Followers: 7)
Construction Management and Economics     Hybrid Journal   (Followers: 18)
Construction Science     Open Access   (Followers: 3)
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: 15)
Enfoque UTE     Open Access   (Followers: 1)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 5)
Engineering Structures     Hybrid Journal   (Followers: 12)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 1)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 12)
Environmental Geotechnics     Hybrid Journal   (Followers: 3)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 6)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 14)
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: 2)
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: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 18)
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: 13)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 9)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 5)
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   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 3)
International Journal of Protective Structures     Full-text available via subscription   (Followers: 5)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 10)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 6)
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: 6)
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: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 9)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Science     Open Access   (Followers: 7)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Society     Hybrid Journal   (Followers: 3)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites     Open Access   (Followers: 77)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 23)
Journal of Construction Engineering     Open Access   (Followers: 5)
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: 8)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 2)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 3)
Journal of Green Building     Full-text available via subscription   (Followers: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 12)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 20)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Multifunctional Composites     Full-text available via subscription   (Followers: 4)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 9)
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   (Followers: 1)
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 Sustainable Architecture and Civil Engineering     Open Access   (Followers: 2)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 2)
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Jurnal Teknik Sipil dan Perencanaan     Open Access  
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: 15)
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 6)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 3)
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: 7)
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: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 4)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 4)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 5)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 9)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 4)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 58)
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: 2)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 2)
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: 10)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 25)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 11)
Structures     Hybrid Journal  
Study of Civil Engineering and Architecture     Open Access   (Followers: 9)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 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: 3)
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: 24)
Water Science and Technology : Water Supply     Partially Free   (Followers: 21)

           

Journal Cover Structural Concrete
  [SJR: 0.874]   [H-I: 14]   [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  [1612 journals]
  • Displacement-based finite layer element analysis on rotational behavior of
           reinforced concrete beam segments containing hinges
    • Authors: Binbin Zhou; Ruoyang Wu, Jian Feng
      Abstract: Rotation capacity of reinforced concrete (RC) beams is a vital property for its relationships with moment redistribution, energy absorbability and so on. Evaluations of the rotation capacity have still been one of the classic and intractable problems in structural engineering over the past decades. The precise prediction about rotational behavior of a RC beam is the primary basis of quantifying its rotation capacity. In this paper a displacement-based finite layer element method considering the factors of flexural cracks, concrete crushing and pre-and post-yield behavior of bond is presented to predict the rotational behavior. In conclusion, it shows the good agreement between simulation results, implemented by the proposed method, and the test results in the literature.
      PubDate: 2016-11-07T10:56:37.983818-05:
      DOI: 10.1002/suco.201600100
       
  • Flexible formwork technologies: A state of the art review
    • Authors: W. J. Hawkins; M. Herrmann, T. J. Ibell, B. Kromoser, A. Michaelski, J. J. Orr, R. Pedreschi, A. Pronk, H. R. Schipper, P. Shepherd, D. Veenendaal, R. Wansdronk, M. West
      Abstract: Concrete is our most widely used construction material. Worldwide consumption of cement, the strength-giving component of concrete, is estimated at 4.10 Gt per year, rising from 2.22 Gt just ten years ago [1]. This rate of consumption means that cement manufacture alone is estimated to account for 5.2 % of global carbon dioxide emissions [2].Concrete offers the opportunity to economically create structures of almost any geometry. Yet its unique fluidity is seldom capitalised upon, with concrete instead being cast into rigid, flat moulds to create unoptimised geometries that result in high material use structures with large carbon footprints. This paper will explore flexible formwork construction technologies which embrace the fluidity of concrete to facilitate the practical construction of concrete structures with complex and efficient geometries.This paper presents the current state of the art in flexible formwork technology, highlighting practical uses, research challenges and new opportunities.
      PubDate: 2016-11-07T10:52:01.290613-05:
      DOI: 10.1002/suco.201600117
       
  • CYCLIC LOADING TEST FOR COLUMN USING ULTRA STRENGTH FIBER REINFORCED
           CONCRETE AND TRACE ANALYSES BY FINITE ELEMENT ANALYSIS
    • Authors: Tadaaki NOZAWA; Joon-Ho CHOI, Masahiro HATTORI, Hisanori OTSUKA
      Abstract: Firstly cyclic loading tests of scale-down bridge column models using normal and ultra-strength fiber reinforced concrete with polyvinyl alcohol fiber (PVA-UFC), and normal and ultra-high strength rebar are conducted. The experimental results are compared focusing the relation of load and displacement, skeleton, crack distribution and failure modes. Secondly in order to evaluate the reproducibility by Finite Element Analysis for the cyclic loading test, trace analyses were conducted. In the FE analyses, the applicability of conventional analytical model of concrete for PVA-UFC was investigated. As compared with experimental results, overall hysteresis loops and maximum strength responses were reproduced with sufficient accuracy by using adequate analytical model. Lastly the parametric analyses varied the cross section areas of columns are conducted, and it was investigated that how much cross section areas could be reduced by using ultra-strength fiber reinforced concrete.
      PubDate: 2016-11-03T10:55:56.144101-05:
      DOI: 10.1002/suco.201600053
       
  • The relation between the compressive strength and modulus of elasticity of
           concrete with crushed brick and roof-tile aggregates
    • Authors: Ivana Miličević; Nina Štirmer, Dubravka Bjegović
      Abstract: This paper presents the results of experimental research into the effect of brick and roof-tile aggregates on the values of the modulus of elasticity of concrete made with crushed brick and roof-tile aggregates. The main purpose of this paper is to compare the formulae given in the code provisions for estimating the concrete elastic moduli for lightweight and normal weight concretes with experimentally obtained values. Sixty-two different concrete mixtures including crushed brick and roof tiles were made and experimentally tested. The differences between the empirical and experimental static moduli of elasticity are shown. In addition, formulae for the calculation of the static modulus of elasticity over compressive strength are shown, and compared with an experimentally estimated formula. As a result of this investigation, a universal equation for estimating the static modulus of elasticity over compressive strength for concretes with crushed brick and roof-tile aggregates is proposed.
      PubDate: 2016-11-02T03:35:16.404275-05:
      DOI: 10.1002/suco.201500207
       
  • SHEAR CAPACITY OF STEEL FIBER-REINFORCED CONCRETE BEAMS
    • Authors: Hang Lee Deuck; Sun-Jin Han, Kang Su Kim, James M. LaFave
      Abstract: This study proposes a shear strength model for steel fiber-reinforced concrete (SFRC) beams, which is the so-called dual potential capacity model (DPCM). It can properly consider the dominant shear failure mode, including the shear contributions of the compression side and the cracked tension side, at the considered section. In the proposed approach, the direct tension force transfer model (DTFTM), which can consider the random orientation and bond characteristics of steel fibers at a crack surface, has been introduced to calculate the shear contribution of steel fibers. Shear test results of SFRC beams have been collected from various references and compared to the analysis results by the proposed DPCM. A simplified version of the DPCM was also developed for practical applications, by reducing the iterative computational procedures.
      PubDate: 2016-10-31T09:45:36.401158-05:
      DOI: 10.1002/suco.201600104
       
  • Nondestructive assessment of corrosion of reinforcement bars through
           surface concrete cracks
    • Authors: Antonio Bossio; Gian Piero Lignola, Francesco Fabbrocino, Tullio Monetta, Andrea Prota, Francesco Bellucci, Gaetano Manfredi
      Abstract: Degradation of reinforced concrete (RC) structures is a serious safety problem affecting all industrialized countries, and economical aspect of this problem cannot be neglected. One of the main reasons for the degradation of RC is the corrosion of steel reinforcing bars as a result of concrete cover cracking and bar cross section reduction. As a consequence, the structural capacity of reinforced concrete elements decreases progressively as degradation develops. The use of nondestructive testing (NDT) and/or analytical formulation can represent high-quality and rapid methods to evaluate the corrosion penetration of bars, and provide a useful parameter to design a retrofit. This paper presents an additional tool that can be used to evaluate and assess the vulnerability of existing structures in terms of determination of bar cross section lost. This can be accomplished by calculating reinforcing bar cross section loss due to corrosion by measuring external crack widths of the concrete cover by using simple charts and formulas. Predictions were obtained by using two analytical models, developed by the authors. Their predictions have been satisfactorily compared to both the literature and novel experimental results, and compared to previous empirical models available in scientific literature. The experimental results were obtained by corroding real scale concrete specimens reinforced by using smooth and ribbed bars (according to old and modern building codes) using 3.5%wt sodium chloride solution and an imposed current.
      PubDate: 2016-10-31T08:35:59.787695-05:
      DOI: 10.1002/suco.201600034
       
  • BOND OF DEFORMED STEEL REINFORCEMENT IN LIGHTWEIGHT FOAMED CONCRETE
    • Authors: JOHANNES P. VILLIERS; GIDEON P.A.G. ZIJL, ALGURNON S. ROOYEN
      Abstract: Low weight and thermal insulating properties make lightweight foamed concrete (LWFC) an attractive substitute for normal weigh concrete (NWC). The unfamiliarity and paucity of design guidance challenge structural application of LWFC. One concern is the bond of steel reinforcement in LWFC. In this paper, the results of pull-out bond tests, as well as beam-end bond tests are presented. Parameters are a reference NWC and LWFC with densities of 1200, 1400 and 1600 kg/m3, rebar diameters of 10, 12 and 20 mm with embedded lengths of 3, 4 and 5 bar diameters. All concretes are characterised in terms of strength, stiffness and fracture energy. Clear differences in bond resistance are found from the two tests. Bond in LWFC is lower than in NWC. The results suggest that LWFC materials development to increase fracture energy holds potential to increase bond.
      PubDate: 2016-10-31T07:10:34.935678-05:
      DOI: 10.1002/suco.201600019
       
  • Experimental investigation on mechanical properties of basalt
           fibre-reinforced concrete
    • Authors: Sruthi Jalasutram; Dipti Ranjan Sahoo, Vasant Matsagar
      Abstract: This paper presents an experimental investigation on the effect of varying volume fractions of chopped basalt fibres on the mechanical properties of fibre-reinforced concrete (FRC). The fibre content is varied in the range of 0-2%. The main parameters investigated are workability, compressive strength, splitting tensile strength, flexural strength, and flexural toughness. Test results showed that the compression strength of concrete is marginally decreased with the addition of basalt fibers as compared to the plain concrete. However, the mode of failure of FRC under compression is changed from brittle to ductile. Splitting tensile strength of concrete is improved by 15% when the basalt fibres of 2% volume fraction is added to the concrete mix. A significant increase up to 75% is noticed in the flexural tensile strength of basalt fibre-reinforced concrete with better post-peak residual strengths as compared to the plain concrete. Further, the flexural toughness of BFRC is increased by nearly three times of the plain concrete based on the round panel tests.
      PubDate: 2016-10-31T04:50:28.107626-05:
      DOI: 10.1002/suco.201500216
       
  • Numerical study of reinforced and prestressed concrete components under
           biaxial tensile stresses
    • Authors: Robert Zobel; Manfred Curbach
      Abstract: The focus of this study is the numerical investigation of reinforced and prestressed concrete components under biaxial tensile stresses in ANSYS in order to display the state of stress of a containment wall. Solid elements for concrete, and beam elements for reinforcing steel, are used. The description and representation of the nonlinear material behaviour and the fundamental phenomena of the damage of concrete is implemented by using an elasto-plastic material model. Because, both the crack width and the crack spacing, as well as the deformation behaviour of components largely depend on the bond behaviour, a node-to-node contact between reinforcement and concrete is used. Therefore, a specific bond model is implemented. The implemented bond model defines, along the longitudinal reinforcement direction, the bond resistance as a function of the relative displacements between concrete and reinforcement.
      PubDate: 2016-10-28T10:06:31.647883-05:
      DOI: 10.1002/suco.201600077
       
  • Limitations of the use of concrete bulk resistivity as an indicator for
           the rate of chloride-induced macro-cell corrosion
    • Authors: Karla Hornbostel; Bernhard Elsener, Ueli Michael Angst, Claus Kenneth Larsen, Mette Rica Geiker
      Abstract: An experimental setup was designed to study the impact of concrete bulk resistivity on the rate of chloride-induced reinforcement corrosion. Small pieces of mild steel were used to simulate pits (anodes) that form when chlorides come into contact with the reinforcement. The galvanic current was measured between the simulated anodes and a large cathode network. Comparisons were made between the corrosion rates calculated from the galvanic currents and the bulk resistivity. The bulk resistivity was varied using two mortar mixes (made of plain Portland cement and a Portland cement – fly ash blend), which were exposed in different temperature and moisture conditions. Despite a high scatter in the results, it was clear that the relationship between bulk resistivity and corrosion rate depended on the mortars tested. The findings presented in this paper and the accompanying work strongly indicate that bulk resistivity alone does not provide sufficient information for assessment of the corrosion rate for chloride-induced macro-cell corrosion.
      PubDate: 2016-10-28T08:21:29.75861-05:0
      DOI: 10.1002/suco.201500141
       
  • OPTIMISATION OF ANCHORAGE CORNER BLISTERS OF POST TENSIONING TENDONS
    • Authors: Carla Marchão; Válter Lúcio, Hans Rudolf Ganz
      Abstract: The design of anchorage corner blisters of internal continuity post-tensioning tendons of bridges built with the cantilever method presents some peculiarities because they are intermediate eccentric anchorages. The simplified formulas for the design of the reinforcement required to resist transverse tensile forces due to the application of point loads, proposed by the current standards, are not sufficient as they do not cover all the effects that require reinforcement. The high density of steel reinforcement in anchorage blisters is the most common reason for problems with concrete cast in situ, resulting in zones with low concrete compacity, which may lead to concrete crushing failures under the anchor plates. The solution for this problem may involve the reduction of reinforcement by improving the concrete compression and tensile strength. An experimental program was carried out to study the transmission of prestressing force to the slab and web of the box girder, assess the strut-and-tie models used in design and to study the feasibility of using a high-performance fiber reinforced self-compacting mixture (HPFRC) only in the blister, either with casting in situ, either with precast solutions.
      PubDate: 2016-10-28T07:26:15.88093-05:0
      DOI: 10.1002/suco.201600057
       
  • Butterfly web effects on bridge design
    • Authors: Akio Kasuga
      Abstract: A new type of bridge called „Butterfly Web Bridge” has been constructed in Japan. In a butterfly web bridge, the panels used as the web are cut so as to appear pinched in the centre, giving a butterfly-wing shape. 80 MPa steel fibre reinforced concrete is used for the butterfly shaped web made of precast panels with a thickness of 150 mm. After the shear tests of butterfly webs, the design method was proposed. In this paper, four projects of expressway bridges using this new technology will be shown. By a simplified construction process, construction time can be reduced. Then, future development will be proposed in the last part of this paper. It is a 500-m-span extradosed bridge. The butterfly web technology will greatly affect bridge design and construction in the near future.
      PubDate: 2016-10-28T03:26:53.204185-05:
      DOI: 10.1002/suco.201600109
       
  • Residual compressive stress-strain relation of recycled aggregate concrete
           after being exposed to high temperatures
    • Authors: Haifeng Yang; Liangsheng Lv, Zhiheng Deng, Wenwu Lan
      Abstract: Complete compressive stress-strain curve of recycled aggregate concrete (RC) after exposure to high temperatures improves to assess the post-fire behavior of reinforced RC structure. In this paper, sixty specimens containing different levels of recycled coarse aggregate (i.e. 0%, 30%, 50%, 70%, and 100%) were fabricated to study the residual compressive stress-strain relation of RC after exposed to high temperatures. Those specimens designed for thermal temperatures were heated to temperatures of 300°C, 400°C, and 500°C for 6 hrs first, and then being submitted to test the compressive stress-strain curves after cooling to ambient temperature, with the test results compared with those of tested at room temperature (about 20°C). The effect of recycled coarse aggregate (RCA) and high temperatures on residual compressive strength, peak strain, and elastic modulus were discussed, the empirical formulas for these parameters were also established. Recommended equation of compressive constitutive relation for conventional concrete in Chinese code for design of concrete structures (GB50010-2010) was adopted to fit the test data, and was shown to be applicable to heated RC for different temperatures.
      PubDate: 2016-10-25T07:20:43.761692-05:
      DOI: 10.1002/suco.201500153
       
  • Physic-mechanical behavior of concretes exposed to high temperatures and
           different cooling systems
    • Authors: Germάn Ercolani; Néstor F. Ortega, Carla Priano, Lilia Señas
      Abstract: Along their lifetime concrete structures can suffer from different pathologies, one of them is the exposure to high temperatures, which diminishes their bearing capacity. In the present paper, different concrete types were exposed to high temperatures. To simulate fire extinction, where the temperature of the overheated concrete descends suddenly, different cooling systems were applied: slowly cooling in the open air and fast cooling by spraying different water volumes. Several physic-mechanical characteristics were analyzed such as compressive strength, splitting tensile strength, porosity, capillary suction and carbonation depth. Ultrasound non-destructive tests were conducted to quantify deterioration. A petrographic study using a stereo-microscope and microscopy of polarization was performed over thin sections to evaluate aggregates composition and concrete characteristics focusing on interface areas. Physical and mechanical properties were affected by the increase of the temperature, making damages worst by the appearance of cracks and micro-cracks, when water is used as cooling system.
      PubDate: 2016-10-25T07:20:26.251831-05:
      DOI: 10.1002/suco.201500202
       
  • Experimental Investigation of Continuous Two-Layer Reinforced Concrete
           Beam
    • Authors: Y. Ribakov; Iakov Iskhakov, Klaus Holschemacher
      Abstract: Models and full-scale statically determinate two-layer beams (TLB), made of steel fibre high strength concrete (SFHSC) in the compression zone and normal strength concrete (NSC) in the tensile zone, have been tested by the authors. The present study is a further stage of these investigations, focused on testing a continuous two span TLB with optimal steel fibre ratio as in the previous stages. This is the first experimental investigation of continuous TLB (CTLB). The study is aimed at testing the CTLB behaviour under positive and negative bending moments in the span and above the middle support respectively. An additional issue that is studied in the course of this work is the influence of bending moment redistribution on the behaviour of a CTLB. As in the previous research stages, interaction of the concrete layers in a CTLB was studied to demonstrate the efficiency of such beams for real structures. No cracks between the SFHSC and NSC layers were observed up to the ultimate limit state of the tested beam, which demonstrates proper interaction between the layers. The results obtained in the present study enable a recommendation of CTLB for practical application as effective and economical continuous bending elements.
      PubDate: 2016-10-21T09:30:21.16048-05:0
      DOI: 10.1002/suco.201600027
       
  • NUMERICAL MODELLING OF CONCRETE BEAMS AT SERVICEABILITY CONDITIONS WITH A
           DISCRETE CRACK APPROACH AND NON-ITERATIVE SOLUTION-FINDING ALGORITHMS
    • Authors: Daniel Dias-da-Costa; Ricardo Carmo, Rui Graça-e-Costa
      Abstract: This paper describes the development and validation of a comprehensive numerical model enabling the simulation of reinforced concrete beams at serviceability conditions using a discrete crack approach. The highly non-linear behaviour introduced by the different material models and the many cracks localising and propagating within the member pose a challenging task to classic iterative solvers, which often fail to converge. This limitation is solved with a non-iterative solution-finding algorithm, in which a total approach was used to overcome critical bifurcation points. The finite element model was validated using experimental data concerning lightweight aggregate concrete beams under flexural loading. The model was shown to properly simulate both overall and localised features of the structural response, including curvature, crack openings and crack patterns. The model was used to carry out a numerical study on the role of the longitudinal reinforcement ratio and crack widths in reinforced concrete beams. It was observed that the total crack openings along the member seem to remain nearly independent of the tensile reinforcement for ratios above 2.5% and the same level of strength.
      PubDate: 2016-10-18T01:05:30.029724-05:
      DOI: 10.1002/suco.201600130
       
  • Shear load testing of damaged hollow core slabs
    • Authors: Gregor Schacht; Guido Bolle, Steffen Marx
      Abstract: As a result of bad quality sealing, moisture and de-icing agents penetrated into prestressed hollow core slabs of the top floor in an uncovered parking garage. Caused by the chlorides the slabs showed especially heavy damage in the support regions near the joints. The theoretical shear bearing capacity according to the technical approval of these slabs was strongly questionable because of the damage. With the help of an experimental loading test in-situ the influence of the damage on the shear bearing capacity of the slabs with different damage-levels could be determined. Based on the results the amount of slabs that had to be replaced or could be repaired could be reduced.For the experimental investigation of the shear bearing capacity of the hollow core slabs a combination of Photogrammetry, Acoustic Emission Analysis and section-wise curvature measurement was used to determine the beginning shear damage on a very low level during the test. The comparison of the results of the different measuring techniques allowed a clear identification of the damage processes and increased the information quality about the bearing condition of the slabs during the experimental investigation significantly.
      PubDate: 2016-10-17T06:43:21.681079-05:
      DOI: 10.1002/suco.201600082
       
  • INVESTIGATION OF IMPACT BEHAVIOUR OF STEEL AND COMPOSITE PIPES WITH
           PROTECTIVE LAYER
    • Authors: Özgür ANIL; S. Oğuzhan AKBAŞ, Onur GEZER, M. Cem YILMAZ
      Abstract: In this study, a free-fall impact apparatus was used to examine the behavior of steel and composite pipe systems designed with three different protective layers considering both the efficiency and the energy adsorption capacity under impact loading. The three protective layers considered in this study are a granular soil layer of constant relative density, and sand layers reinforced with geotextile and geogrid layers, respectively. The magnitudes of impact load as well as the resultant accelerations on the pipes were measured as a function of time during the experiments. Time histories of accelerations recorded in each test were used to calculate the displacements and loads on the pipes, which in turn led the estimation of the level of energy adsorbed by the protective layer systems. This enabled a fair comparison of the relative performance of each protective layer under impact load conditions. It was observed that all of the three protective systems contributed significantly to the pipe safety. However, both the experimental results and the supporting finite element analyses indicate that the most successful pipe performance was achieved through the use of geotextile reinforced soil layer. Also, it was seen that the composite pipe has a higher energy adsorption capacity compared to the steel pipe, making it less vulnerable to impact forces under the same protection conditions.
      PubDate: 2016-10-17T05:07:12.084143-05:
      DOI: 10.1002/suco.201600128
       
  • Dynamic response assessment in compliance to Eurocodes for the elevated
           viaducts of Doha metro green line
    • Authors: Essam Ayoub; Sameh Mehanny, Charles Malek, Gamal Helmy
      Abstract: The double track elevated viaducts of Doha metro green line, currently under construction, is of 2.7 kilometers long and consist of cast-in-situ and precast segmental simply supported spans ranging from 20 to 35 m and continuous cast-in-situ two and three spans (39.5–57 m), (50–51–44 m) and (37–68–37 m) U-trough decks. The non-typical configuration of the continuous span was imposed due to utilities and infrastructures requirements. All viaduct decks (cast-in-situ and precast) are posttensioned to minimize any concrete cracking. To ensure passenger comfort and traffic safety during train operation, performing a dynamic analysis was vital. The dynamic analysis focuses on the vertical accelerations and vertical displacements. The actual train of the project composed of 6 vehicles with a total length of 120m and with actual axle loads (maximum axle load of 160 kN with 4 axles per vehicle) is adopted in the dynamic analysis. The analysis is carried out using both direct time integration of the equation of motion and modal time history analysis for different train speeds ranging from 60 km/hr to the maximum permissible speed along the metro line (160 km/hr). For each train speed the maximum vertical accelerations and the maximum vertical deflections are monitored using the CSI bridge software applied in the current project and are compared to the allowable values given in EN 1991-2 and EN 1990-Annex 2. According to relevant Eurocodes requirements, the vertical accelerations and the vertical deflections were found acceptable.
      PubDate: 2016-10-14T08:21:03.759697-05:
      DOI: 10.1002/suco.201600072
       
  • Engineering Field Tests for Alkali-Aggregate Reaction
    • Authors: Paulo Helene; Mariana Carvalho, Jéssika Pacheco
      Abstract: The Paulo Guerra Bridge in Recife, Brazil, was constructed in 1977 and, after about 15 years, presented some pathological symptoms such as map cracking, concrete expansion, steel corrosion and leaching stains. This article provides a discussion of the conducted specific inspection, which included visual observation of the foundation blocks (pile caps), cores extraction, ultrasonic pulse velocity tests, carbonation tests, chloride concentration, electrochemical resistivity, corrosion potential, compressive strength and modulus of elasticity, as well as X-ray diffraction and microscopy evaluations. The results of the inspection showed the occurrence of generalized alkali-aggregate reactions (AAR) on the pile caps (blocks) of the bridge. The recommended repair for the pile caps was a confinement enough to resist a tensile strength of 4MPa.
      PubDate: 2016-10-14T04:11:59.341904-05:
      DOI: 10.1002/suco.201600090
       
  • Progressive Collapse Assessment of Mid-Rise Reinforced Concrete Flat Slab
           Structures
    • Authors: Fatma Bakr; Hamed Hadhoud, Nabil Yehia
      Abstract: The progressive collapse resistance of mid-rise multi-story RC flat slab structure is numerically evaluated using Applied Element Method (AEM). The case study is designed according to ACI 318 and its progressive collapse is assessed in accordance with the UFC guidelines. The numerical results show that the considered case study generally satisfies the limits of the UFC guidelines except for the case of near-corner interior column loss at the tenth floor and edge shear wall loss at ground, fifth, eighth and tenth floors. The removal of the edge shear walls at the higher floors caused a partial collapse.
      PubDate: 2016-10-06T05:35:36.657097-05:
      DOI: 10.1002/suco.201600051
       
  • Corinthians Arena: General Concepts and the Application of Precast
           Concrete in Brazilian Arenas for the 2014 World Cup
    • Authors: Fernando Rebouças Stucchi; Marcelo Ungaretti, Gilson Fujii, Hugo Corres Peiretti, Sergio Doniak, Jose Soriano Martin
      Abstract: This paper describes the design and construction of the structure, under the roof, of the Corinthians Arena built for the 2014 World Cup. Due to many constraints the structure was solved, essentially, with prefabricated structural concrete members, some specific elements were solved with structural concrete cast‐in‐situ and some areas, with special construction problems, were solved with composite steel‐concrete structures.
      PubDate: 2016-09-26T08:16:00.697532-05:
      DOI: 10.1002/suco.201600086
       
  • Slenderness Limits for deflection control: a new formulation for flexural
           RC elements
    • Authors: ALEJANDRO PéREZ CALDENTEY; Javier Mendoza Cembranos, Hugo Corres Peiretti
      Abstract: The first step in the design of a structure is the definition of the geometry. This process includes the definition of the depth of slabs and beams. The depth of a flexural member is often determined by control of deflections, which can only be checked in detail at an advanced stage of the project. In order to optimize the design process, it is therefore very important to choose well the span‐to‐depth ratio at the beginning. In order to achieve this task in an easy manner a lower limit to the slenderness of the beams in terms of span divided by the effective depth is proposed in most major codes. However, current proposals are rather coarse and are not necessarily on the safe side. In this paper a new formulation for the slenderness limits, based on the physics of the problem, is presented. This formulation includes the effect of the composition of the load (live load to total load ratio) as well as the possibility of using different limits to maximum deflection and considering different, more general, support conditions. It is therefore more complete and has a larger application field than current proposals.
      PubDate: 2016-09-26T07:58:25.983806-05:
      DOI: 10.1002/suco.201600062
       
  • A reliability‐based approach to the robustness of corroded RC
           structures
    • Authors: Eduardo Soares Cavaco; Luis Neves, Joan Casas
      Abstract: Currently, decisions on infrastructural assets maintenance and repair, in particular on structures, are based, mostly, on the results of inspections and the resulting condition index, neglecting systems robustness, and, therefore, not making optimize use of the limited available funds. This paper presents a definition and a measure of structural robustness in the context of deteriorating structures, compatible with assets management systems for optimal maintenance and repair planning. The proposed index is used in defining the robustness of existing RC structures to rebar corrosion. Structural performance and the corresponding reliability index are assessed using combined advanced reliability and structural analysis techniques. Structural analysis explicitly includes deterioration mechanisms resulting from corrosion such as reinforcement area reduction, concrete cracking and bond deterioration. The First Order Reliability Method, combined with a Response Surface algorithm, is used to compute the reliability index for a wide range of different corrosion levels, resulting in a fragility curve. Finally, structural robustness is computed and discussed based on the obtained results. Robustness comparison of different structures can then be used to determine structural types more tolerant to corrosion and these results can be used for maintenance and repair planning.
      PubDate: 2016-09-26T07:58:15.235386-05:
      DOI: 10.1002/suco.201600084
       
  • SIMPLIFICATION AND VERIFICATION OF DUAL POTENTIAL CAPACITY MODEL FOR
           REINFORCED CONCRETE BEAMS SUBJECTED TO SHEAR
    • Authors: Deuck Hang Lee; Sun‐Jin Han, Jin‐Ha Hwang, Hyunjin Ju, Kang Su Kim
      Abstract: In authors' previous study, the dual potential capacity model (DPCM) was proposed to evaluate the shear strengths of reinforced concrete (RC) members, in which the shear contributions of both the cracked tension zone and the compression zone are considered. In this paper, the main concept and formulations of the proposed DPCM were briefly introduced, and the simplified DPCM was developed for the practical application of the proposed model. A total of 1019 data sets of shear test results on RC members were collected for detailed verifications of the detailed and simplified DPCM. The verification results demonstrated that the proposed models can appropriately assess the effects of key influential factors including compressive strength of concrete, shear span‐to‐depth ratio, size of coarse aggregate, sizes of members, and shear reinforcement on the shear strengths of RC members.
      PubDate: 2016-09-26T07:50:24.494717-05:
      DOI: 10.1002/suco.201600055
       
  • Structural Concrete 4/2016
    • PubDate: 2016-09-23T02:28:12.175342-05:
      DOI: 10.1002/suco.201670035
       
  • Contents: Structural Concrete 3/2016
    • PubDate: 2016-09-23T02:28:09.459571-05:
      DOI: 10.1002/suco.201670032
       
  • Cover Picture: Structural Concrete 3/2016
    • Abstract: One of the most important components in the currently largest infrastructure project of Portugal is the new 930 m long Rio Ceira Bridge, crossing the Ceira River near Coimbra at its highest point 140 m above the river bed. Since during construction the vertical plane curvature of the bridge had to be balanced, assymetric loads were counteracted by DYWIDAG Post‐Tensioning Tendons that were anchored in the pier foundations and connected to the top of the bridge deck. As soon as the individual segments of the box girder deck had been connected, these temporary tendons were removed. 1,450 t of prestressing steel were used for this purpose. (© DSI, see p. A5)
      PubDate: 2016-09-23T02:28:05.517024-05:
      DOI: 10.1002/suco.201670031
       
  • Dual potential capacity model for reinforced concrete beams subjected to
           shear
    • Authors: Deuck Hang Lee; Sun‐Jin Han, Kang Su Kim
      Abstract: The shear resistance mechanisms of a reinforced concrete (RC) member with shear reinforcement can be divided into the contributions of the concrete and the shear reinforcement. The shear resistance mechanisms of concrete can be further divided into the shear resistance of the intact concrete in the compression zone, the aggregate interlock in the cracked tension zone and the dowel action of the longitudinal tension reinforcement. The shear demand curves and potential shear capacity curves for both tension and compression zones have been derived in this study, with the assumption that the shear failures of RC members are dominated by the flexural‐shear strength. The shear capacity model was also proposed on this basis. In the proposed model, the crack width and the local stress increase in reinforcement were calculated based on the bond behaviour between the reinforcement and its surrounding concrete. Further, the crack concentration factor was introduced to consider the formation and propagation of the critical shear crack that developed from the flexural cracks. The results of a total of 1,018 shear tests were collected and compared with the analysis results provided by the proposed model. It was demonstrated that the proposed model provides a good estimate of the shear strengths of RC beams.
      PubDate: 2016-09-21T07:00:37.137005-05:
      DOI: 10.1002/suco.201500165
       
  • The structural redistribution coefficient KRd: a numerical approach to its
           evaluation
    • Authors: Marco Prisco; Paolo Martinelli, Daniele Dozio
      Abstract: Structures made of a material with a very high standard deviation, such as fibre‐reinforced concrete, exhibit an exceptionally safe prediction of the maximum bearing capacity when this is derived from characteristic values identified by means of small specimens. This is emphasized when the structures are characterized by high 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, the fib Model Code for Concrete Structures 2010 have introduced a coefficient (structural redistribution factor) that is able to take into account the reduced variability of mechanical bearing capacity when associated with a large volume involved in the failure process and/or when the structure is able to redistribute stresses significantly, thus favouring the average rather than the minimum strength. 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: 2016-09-21T04:56:04.223182-05:
      DOI: 10.1002/suco.201500118
       
  • Accuracy of design‐oriented formulations for evaluating the flexural and
           shear capacities of FRP‐strengthened RC beams
    • Authors: Tomasso D'Antino; Thanasis C. Triantafillou
      Abstract: Fibre‐reinforced polymer (FRP) composites have been employed in the last few decades largely for the strengthening and seismic retrofitting of existing reinforced concrete (RC) structures. Several studies are available in the literature and different analytical models have been proposed for evaluating the FRP contribution in strengthened RC elements. This paper analyses the accuracy of analytical models widely used for evaluating the flexural and shear contributions provided by the FRP. Some of those models are included in design guidelines. In particular, the analytical models for evaluating the FRP strain at intermediate crack‐induced debonding failure are analysed. The accuracy of each formulation is assessed comparing the analytical provisions with the experimental results collected from two databases, one for bending and one for shear. The results obtained show that most of the analytical flexural models achieve a good level of accuracy and only a few models provide inadequate results. A new formulation proposed for evaluating the FRP shear contribution is shown to be generally conservative, which comes at the expense of accuracy.
      PubDate: 2016-09-20T06:50:27.456525-05:
      DOI: 10.1002/suco.201500066
       
  • Mechanics‐based closed‐form solutions for moment
           redistribution in RC beams
    • Authors: Phillip Visintin; Deric J. Oehlers
      Abstract: When it comes to the efficient design of reinforced concrete beams and frames, moment redistribution is used to: reduce the absolute maximum magnitude of the moment in the critical region, equalize the critical moments on either side of interior columns and fully utilize the capacity of the non‐critical regions of a member. Although important, historically, moment redistribution has proved to be difficult to quantify due to the complexity of quantifying hinge rotations. Although numerous empirical expressions exist for plastic hinge lengths, i.e. the length over which the ultimate curvature can be integrated in order to give hinge rotations, a comparison with a global dataset yields poor results. Using a recently developed mechanics‐based moment‐rotation approach, it is possible to quantify the moment‐rotation characteristics of reinforced concrete hinges. In the tension region, the approach applies partial interaction theory directly to simulate the mechanisms associated with slip of the reinforcement relative to the surrounding concrete as cracks widen, whereas in the compression region, partial interaction shear‐friction theory is used to describe the formation and failure of concrete softening wedges. It is shown how the moment‐rotation approach explicitly allows for the size dependency. Furthermore, mechanics‐based solutions for moment redistribution are then derived and it is shown how these can be simplified at the ultimate limit state for use in the design office.
      PubDate: 2016-09-16T01:16:46.296103-05:
      DOI: 10.1002/suco.201500085
       
  • Numerical limit analysis of keyed shear joints in concrete structures
    • Authors: Morten A. Herfelt; Peter N. Poulsen, Linh C. Hoang, Jesper F. Jensen
      Abstract: This paper concerns the shear capacity of keyed joints that are transversely reinforced with overlapping U‐bar loops. It is known from experimental studies that the discontinuity of the transverse reinforcement affects the capacity and the failure mode. However, to the best knowledge of the authors, previous theoretical works and current design equations in standards do not account for this important effect. This paper introduces a detailed model based on finite element limit analysis to assess the effect of the discontinuous reinforcement. The model is based on the lower bound theorem and uses the modified Mohr‐Coulomb yield criterion, which is formulated for second‐order cone programming. The model provides a statically admissible stress field as well as the failure mode. Twenty‐four different test specimens were modelled and the calculations compared with the experimental results. The results of the model show satisfactory agreement with the experimental observations. The model produces estimates of the shear capacity that are significantly better than those of the Eurocode 2 design equations.
      PubDate: 2016-09-14T03:30:49.167993-05:
      DOI: 10.1002/suco.201500161
       
  • PERFORMANCE‐BASED DURABILITY DESIGN, CARBONATION PART 3: PARTIAL SAFETY
           FACTOR (PSF) APPROACH AND A PROPOSAL FOR THE REVISION OF
           DEEMED‐TO‐SATISFY RULES
    • Authors: Stefanie von Greve‐Dierfeld; Christoph Gehlen
      Abstract: A performance based safety factor durability design format is proposed and developed with respect to carbonation of concrete. Deemed‐to‐satisfy rules based on a partial safety factor design approach are developed for the carbonation of concrete. This design format follows the proposed design procedure in EN 1990. For the design format the limit state equation for the carbonation is introduced in its probabilistic and safety factor format. Utilizing the PSF‐approach, design charts have been derived. Values for the minimum concrete cover in dependence of material resistance and exposure class are proposed for critical environmental conditions and a design service life of 50 years.
      PubDate: 2016-09-06T07:47:13.57389-05:0
      DOI: 10.1002/suco.201600085
       
  • PERFORMANCE BASED DURABILITY DESIGN, CARBONATION PART 2 –
           CLASSIFICATION OF CONCRETE
    • Authors: Stefanie von Greve‐Dierfeld; Christoph Gehlen
      Abstract: At present prescriptive regulations with regard to concrete cover and composition are applied to provide sufficient durability of reinforced concrete members under exposure conditions of different severity. In view of current knowledge on deterioration mechanisms and their modeling, it is planned to change from these deemed‐to‐satisfy specifications to a performance based design approach in future standards. In such specifications, concrete durability design is based on the statistically characterized performance of concrete, determined in standardized tests with respect to defined classes of concretes of similar performance. This paper presents the results of a study in which concrete mixes were tested and analysed with respect to their carbonation resistance. Compositions with similar performance are grouped into carbonation resistance classes. The carbonation resistance classes are described statistically and requirements for performance testing are given. In addition, composition requirements are introduced in order to determine concrete performance in dependence of mix composition prescriptively. Finally, an example is given for the assessment of concrete performance with regard to carbonation. This work has been done on the request of JWG under CEN TC 250/SC2 and CEN TC 104/SC1 as an input and starting point for the ongoing committee work to implement the methodology from fib MC2010 into next generation (2021) of European concrete standards.
      PubDate: 2016-09-06T07:20:33.26545-05:0
      DOI: 10.1002/suco.201600067
       
  • The compression chord capacity model for the shear design and assessment
           of reinforced and prestressed concrete beams
    • Authors: Antoni Cladera; Antonio Marí Bernat, Jesús Miguel Bairan, Carlos Ribas, Eva Oller, Noemí Duarte
      Abstract: A simplified mechanical model for the shear strength prediction of reinforced and prestressed concrete members with and without transverse reinforcement, with I, T or rectangular cross section is presented. The model, derived after further simplifications of a previous one developed by the authors, incorporates in a compact formulation, the contributions of the concrete compression chord, the cracked web, the dowel action and the shear reinforcement. The mechanical character of the model provides valuable information about the physics of the problem and incorporates the most relevant parameters governing the shear strength of structural concrete members. The predictions of the model fit very well the experimental results collected in the ACI‐DAfStb databases of shear tests on slender reinforced and prestressed concrete beams with and without stirrups. Due to this fact and the simplicity of the derived equations it may become a very useful tool for structural design and assessment in engineering practice.
      PubDate: 2016-09-06T07:15:53.547878-05:
      DOI: 10.1002/suco.201500214
       
  • Structural Performance of Ultra‐High Performance Fibre Reinforced
           Concrete Beams
    • Authors: Charles Kahanji; Faris Ali, Ali Nadjai
      Abstract: Ultra‐high performance fibre reinforced concrete (UHPFRC) is a relatively new construction material. In comparison with conventional high strength concrete UHPFRC usually does not contain coarse aggregates larger than 6–7 mm in size. This paper presents the outcomes of an experimental study of UHPFRC beams subjected to four‐point loading. The effect of two parameters was studied, namely the fibre content and the temperature of curing water. Eight UHPFRC beams comprising 6 beams reinforced with rebars and two beams without rebars were tested. Three fibre contents were investigated in this study (1%, 2% and 4% in volume). The study investigated two curing temperatures of water which are 20°C and 90°C. The results presented in this paper include deflections, toughness energy and moment capacity and also includes a comparison with calculations according to EC2 provisions. A minor difference was observed in the deformation and flexural behaviour of beams with fibre contents of 1% and 2% (in volume). However, beams with 4% (in volume) fibres exhibited a higher flexural capacity. Only flexural failure was observed and no shear related failure was recorded. Beams with 1% (in volume) fibres for both curing regimes had the highest peak‐load toughness energy. Beams reinforced with rebars and cured at 20°C had a significantly higher bending resistance.
      PubDate: 2016-09-01T04:15:37.544352-05:
      DOI: 10.1002/suco.201600006
       
  • Strengthening Corbels Using Post – Installed Threaded Rods
    • Authors: Tadeusz Stanisław Urban; Łukasz Krzysztof Krawczyk
      Abstract: The paper presents the results of experimental research in which post‐installed threaded rods were used as additional reinforcement. An increase in load‐carrying capacity of up to 64% was obtained for strengthened corbels, in comparison with unstrengthened corbels (reference corbels). Calculations of the load‐carrying capacity of corbels have been performed using a model developed on the basis of the literature and the obtained results were confronted with results calculated according to the EN 1992‐1‐1. Strain diagrams for primary reinforcement, stirrups and the compressed surface of concrete are presented, alongside with a description of the development of cracking and photographs of the corbels after failure. In the second chapter, publications on calculating the load‐carrying capacity of corbels and on different reinforcement methods are quoted.
      PubDate: 2016-09-01T03:11:00.124294-05:
      DOI: 10.1002/suco.201500215
       
  • A new model for the analysis of the structural/mechanical performance of
           
    • Authors: Othman OMIKRINE METALSSI; Badreddine KCHAKECH, Stéphane LAVAUD, Bruno GODART
      Abstract: Concrete construction is becoming increasingly complex and the importance of producing structures that on the long term are both cost effective and durable has never been higher. Therefore, an understanding of concrete durability is considered fundamental for establishing the service life of new or existing structures. However, at present a significant number of existing concrete structures, bridges are already deteriorated by chemo‐mechanical processes known as Delayed Ettringite Formation (DEF). This phenomenon causes expansion of the affected concrete that generally leads to cracking and decrease of its mechanical properties. Therefore, this disease or deterioration mechanism induces serious problems regarding serviceability, sustainable operation and structural integrity. Thus, it is necessary to apply predictive models able to re‐assess the mechanical state of the affected structures. In this way, the chemo‐mechanical modeling must be dealt with by considering the influence of humidity, stiffness reduction and stress in the development of expansion. The elaborated 3D model was applied to an existing viaduct affected by DEF. The displacements and stresses were computed based on the experimental data obtained from the in‐situ measurements. The computed results highlight the relationship between the saturation degree and the expansion. Finally, comparisons between different calculations with and without considering the anisotropy of expansion and stiffness reduction are presented and discussed.
      PubDate: 2016-08-31T08:05:21.859235-05:
      DOI: 10.1002/suco.201500181
       
  • Investigations on the punching shear behaviour of eccentrically loaded
           footings
    • Authors: Katrin Wieneke; Dominik Kueres, Carsten Siburg, Josef Hegger
      Abstract: The punching shear design provisions according to various codes have been derived from results of tests conducted on centrically loaded flat slabs. The application on footings and ground slabs might lead to inconsistent results since more compact dimensions and soil‐structure interaction lead to higher punching shear capacities. In this context, Eurocode 2 introduced a new design equation for column bases which was derived by the evaluation of test results from centrically loaded footings. Since centrically loaded footings represent and exception in practice, Eurocode 2 and ACI 318‐14 consider load eccentricities by increasing the applied load, while fib Model Code 2010 proposes a reduced length of the control perimeter to determine the punching shear resistance. The different approaches were derived by the evaluation of tests on eccentrically loaded flat slabs and have yet not been verified for footings. Theoretical and experimental investigations on the punching shear behaviour of eccentrically loaded footings indicate a reduction of the multi‐axial stress state along the column face. Based on punching tests on eccentrically loaded footings described in literature, non‐linear finite‐element simulations were performed and subsequently the influence of load eccentricities on the punching shear behaviour was examined in parametric studies. In this article, the results of the numerical simulations are presented and compared to experimental results and various code provisions.
      PubDate: 2016-08-31T07:25:28.575005-05:
      DOI: 10.1002/suco.201500127
       
  • Investigation of the buckling behaviour of thin‐walled hollow
           concrete piers
    • Authors: Lin‐Yun Zhou; Zhao Liu
      Abstract: Tall hollow concrete piers with high width‐to‐thickness ratios are commonly used in long‐span box girder bridges. Such thin‐walled structures present the possibility of failure due to local buckling. So, in common practice, diaphragms are usually included in hollow piers to improve the local stability; however, is that necessary? Although experimental research on the buckling behaviour of hollow piers has been conducted extensively, few analytical attempts have been performed to reveal the effects of the width‐to‐thickness ratio on local buckling behaviour. To this end, an analytical model has been proposed to investigate the local buckling behaviour of hollow piers. Following the Ritz‐Timoshenko method, an analytical formula for critical local buckling stress has been developed and verified to have good accuracy compared with finite element analyses. Based on the buckling failure mode of a hollow pier with a slenderness ratio > 6, it can be reasonably postulated that the strength of the hollow pier will be unaffected by local compression flange buckling when the wall width‐to‐thickness ratio is < 24, and it is entirely unnecessary to include diaphragms in hollow piers for stability. Additionally, it is equally interesting that the critical width‐to‐thickness ratio of a hollow pier with a slenderness ratio > 4 derived using the proposed model is the same as the value given by the current AASHTO‐LRFD Bridge Design Specifications.
      PubDate: 2016-08-25T08:40:35.044613-05:
      DOI: 10.1002/suco.201500043
       
  • Estimating loads on shores during the construction of RC building
           structures
    • Authors: Manuel Buitrago; Jose M. Adam, Pedro A. Calderón, Juan J. Moragues, Yezid A. Alvarado
      Abstract: When constructing reinforced concrete (RC) building structures, knowing the loads to which the shoring system will be subjected during the entire process is one of the key aspects for ensuring safety during the work. Although various simplified methods of estimating the load transmission between shores and slabs during construction have been proposed to date, none of these methods can estimate the loads on individual shores during the different construction phases. This paper proposes a calculation method that allows the loads on individual shores to be calculated for each construction phase without having to resort to the use of advanced software. The proposal was validated by comparison with the results obtained from two actual buildings under construction and represents a step forward in the construction of RC building structures, as it is the first method that offers the possibility of estimating the loads acting on each shore during all the construction phases.
      PubDate: 2016-08-25T02:10:41.925216-05:
      DOI: 10.1002/suco.201500130
       
  • Axial loading capacity of concrete‐jacketed RC columns with pre‐ and
           post‐corrosion damage
    • Authors: Yuxi Zhao; Dawei Zhang, Shijun Shen, Tamon Ueda
      Abstract: The main objective of this study is to investigate the effect of pre‐ and post‐jacketing corrosion and loading damage on concrete‐jacketed reinforced concrete (RC) columns under uniaxial loading and to develop a methodology for predicting the corresponding compressive strength. The pre‐ and post‐damage involved preloading up to 50 % of the peak load of the core column, an electrochemical process to accelerate the migration of chlorides from an external electrolyte into the test columns and a wetting–drying cycle process with a controlled current to speed up the corrosion of the steel reinforcing bars in the test columns. Uniaxial loading tests were performed to determine the structural performance of the concrete‐jacketed columns with and without corrosion damage. The failure mode and load–displacement and load–strain responses of the test columns were recorded, and the related mechanisms are discussed. A model capable of evaluating the compressive strength of unjacketed or jacketed RC columns with and without corrosion damage was then developed. The analytical approach considered the effect of reinforcement corrosion on the effective loadbearing area of the concrete and the confinement effect of the stirrups. The analytical results agree well with the experimental results, indicating the reliability and effectiveness of the models developed.
      PubDate: 2016-08-23T07:56:41.166279-05:
      DOI: 10.1002/suco.201400113
       
  • Structural performance of continuous RC slabs strengthened in negative
           moment regions with a mineral‐based composite
    • Authors: Ahmad Atta; Fahmy Zaher, Emad Etman
      Abstract: An experimental programme was proposed and carried out to assess the effectiveness of the mineral‐based composite (MBC) technique for the flexural strengthening of negative moment regions in continuous reinforced concrete slabs. In addition to the testing of the two reference specimens, the experimental programme included the testing of nine continuous RC slab specimens with different strengthening techniques, namely, using ordinary steel bars and MBC material. This experimental programme was conducted to study the failure modes, the load‐deflection behaviour and the failure loads.Furthermore, we present and describe a comparative study between the two strengthening techniques, namely, steel reinforcing bars with MBC or steel bars with epoxy mortar. Based on the experimental results presented, both strengthening techniques for continuous slabs are evidently efficient. In this study the measured results for the average crack spacing were compared with the limits stipulated in CEB‐FIP code 1990 and the failure load calculations were extended with an analytical approach based on the ultimate theory for the failure load calculation. In conclusion, the results obtained from the analytical model are in agreement with the experimental results.
      PubDate: 2016-08-17T09:05:29.403944-05:
      DOI: 10.1002/suco.201500026
       
  • Performance based durability design, carbonation part 1 – Benchmarking
           of European present design rules
    • Authors: Stefanie von Greve‐Dierfeld; Christoph Gehlen
      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?
    • Authors: Olivér Czoboly; György L. Balázs
      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
    • Authors: Jesper H. Sørensen; Linh Cao Hoang, John F. Olesen, Gregor Fischer
      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
    • Authors: Francesco Marchetto; ALEJANDRO PéREZ CALDENTEY, Hugo Corres Peiretti
      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
    • Authors: Jiri Strasky; Pavlina Juchelkova, Pavel Kalab, Radim Nečas
      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
       
  • Component based reinforced concrete beam‐column joint model
    • Authors: Ricardo Costa; Paulo Providência, Alfredo Dias
      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
    • Authors: Akanshu Sharma; Rolf Eligehausen, Jörg Asmus
      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
    • Authors: Giancarlo Groli; Alejandro Pérez Caldentey
      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
       
  • Real‐time damage detection based on pattern recognition
    • Authors: João Pedro de Oliveira Dias Prudente dos Santos; Christian Crémona, António Paulo Campos da Silveira, Luís Calado de Oliveira Martins
      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
       
  • Experimental Evaluation of Optimized Strut‐and‐Tie Models for
           a Dapped Beam
    • Authors: Rodrigo Oviedo; Sergio Gutiérrez, Hernán Santa María
      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
       
  • High cycle fatigue behaviour of reinforcing steel under the effect of
           ongoing corrosion
    • Authors: Christoph Gehlen; Kai Osterminski, Tim Weirich
      Abstract: This paper presents results on the corrosion fatigue behaviour of profiled reinforcing steel bars. Cyclic loaded rebar was simultaneously exposed to different corrosive environments – moderate up to severe corrosive environments simulating XC or XD/XS exposure. Corrosion was naturally configured without any external polarization. Rebar was either directly exposed to the corrosive solutions or, when embedded in concrete, indirectly. In this case corrosive agents penetrated through an open crack towards the steel surface. Low frequency was applied to enable extended corrosion periods. In order to detect and quantify the crack initiation and crack growth of the rebar, the potential drop method was utilized. Based on this method, ratios of the number of cycles to initiate a crack to cycles to failure could be determined. Based on this method, the Nini/NF‐ratios were almost always between 0.8 and 0.9 ‐ values which are similar to ratios determined for air tested rebar (reference). This indicates that the fatigue life of rebar in carbonated or chloride containing concrete is strongly related to the crack initiation and less on the crack growth. The S‐N curves derived from the corrosion fatigue tests deviate significantly from the curve that was measured from the reference fatigue tests (tests in air). The S‐N curves of rebar tested under corrosion fatigue load were linear with a slope which was much steeper than the slope of the of the reference rebar tested in air.
      PubDate: 2016-02-09T06:28:39.736187-05:
      DOI: 10.1002/suco.201500094
       
  • Old and new meet at the 2017 Maastricht fib Symposium!
    • Authors: Dick Hordijk
      Pages: 307 - 308
      PubDate: 2016-09-23T02:28:09.373857-05:
      DOI: 10.1002/suco.201670033
       
  • Punching shear strength of flat slabs – critical review of Eurocode 2
           and fib Model Code 2010 design provisions
    • Authors: Marcus Ricker; Carsten Siburg
      Pages: 457 - 468
      Abstract: The fib Model Code for Concrete Structures 2010 introduces a new design concept for punching shear based on critical shear crack theory. This paper presents and provides the background to the design provisions for punching shear according to fib Model Code 2010, Eurocode 2 and the corresponding German National Annex to Eurocode 2. The different punching shear design provisions are critically reviewed by means of parameter studies and a comparison of the calculated resistances and test results. The safety levels of the code provisions are verified and the influence of the different punching parameters on the calculated resistances is examined in detail.
      PubDate: 2016-09-23T02:28:08.051446-05:
      DOI: 10.1002/suco.201500106
       
  • fib‐news: Structural Concrete 3/2016
    • Pages: 513 - 519
      Abstract: Contents Issue 3 (2016) Technical Council meets in Madrid · 2017 AAYE · Redefining fib Commission · fib Bulletin 78 · ICCS16 · Short notes · Congresses and symposia
      PubDate: 2016-09-23T02:28:11.920093-05:
      DOI: 10.1002/suco.201670034
       
 
 
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