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  Subjects -> ENGINEERING (Total: 2169 journals)
    - CHEMICAL ENGINEERING (186 journals)
    - CIVIL ENGINEERING (168 journals)
    - ELECTRICAL ENGINEERING (92 journals)
    - ENGINEERING (1176 journals)
    - ENGINEERING MECHANICS AND MATERIALS (356 journals)
    - HYDRAULIC ENGINEERING (56 journals)
    - INDUSTRIAL ENGINEERING (54 journals)
    - MECHANICAL ENGINEERING (81 journals)

CIVIL ENGINEERING (168 journals)                  1 2     

ACI Structural Journal     Full-text available via subscription   (Followers: 8)
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: 30)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 21)
Ambiente Construído     Open Access   (Followers: 2)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 21)
Architectural Engineering     Open Access   (Followers: 5)
Archives of Civil Engineering     Open Access   (Followers: 8)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 1)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 5)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 2)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 5)
Berkeley Planning Journal     Open Access   (Followers: 5)
Bioinspired Materials     Open Access  
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 12)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 16)
Canadian Journal of Civil Engineering     Full-text available via subscription   (Followers: 15)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 4)
Case Studies in Nondestructive Testing and Evaluation     Open Access  
Case Studies in Structural Engineering     Open Access  
Cement and Concrete Composites     Hybrid Journal   (Followers: 11)
Change Over Time     Full-text available via subscription   (Followers: 3)
Civil and Environmental Engineering     Open Access  
Civil And Environmental Engineering Reports     Open Access  
Civil and Environmental Research     Open Access   (Followers: 13)
Civil Engineering     Hybrid Journal   (Followers: 11)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 5)
Civil Engineering and Architecture     Open Access   (Followers: 3)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 5)
Civil Engineering and Technology     Open Access   (Followers: 4)
Civil Engineering Dimension     Open Access   (Followers: 4)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 103)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 9)
Computers & Structures     Hybrid Journal   (Followers: 26)
Concrete Research Letters     Open Access   (Followers: 2)
Constructii : Journal of Civil Engineering Research     Open Access   (Followers: 9)
Construction Engineering     Open Access   (Followers: 4)
Construction Management and Economics     Hybrid Journal   (Followers: 30)
Construction Science     Open Access   (Followers: 1)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access  
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal  
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 13)
Enfoque UTE     Open Access   (Followers: 2)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 4)
Engineering Structures     Hybrid Journal   (Followers: 14)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 16)
Environmental Geotechnics     Open Access   (Followers: 2)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 5)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 14)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access   (Followers: 1)
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 5)
Geomaterials     Open Access   (Followers: 2)
Geosystem Engineering     Hybrid Journal   (Followers: 3)
Geotechnik     Hybrid Journal   (Followers: 1)
Géotechnique Letters     Hybrid Journal   (Followers: 4)
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal   (Followers: 1)
Indoor and Built Environment     Hybrid Journal   (Followers: 1)
Infrastructure Asset Management     Full-text available via subscription  
Ingenio Magno     Open Access  
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 4)
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: 7)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 7)
International Journal of Condition Monitoring     Full-text available via subscription  
International Journal of Construction Engineering and Management     Open Access   (Followers: 6)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 1)
International Journal of Protective Structures     Full-text available via subscription   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 4)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 7)
International Journal of Structural Integrity     Hybrid Journal  
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Built Environment     Open Access   (Followers: 3)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 10)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 2)
Journal of Accessibility and Design for All     Open Access   (Followers: 6)
Journal of Advanced Research in Civil and Environmental Engineering     Open Access   (Followers: 1)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 18)
Journal of Building Engineering     Hybrid Journal  
Journal of Building Materials and Structures     Open Access  
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 5)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 3)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 12)
Journal of Civil Engineering Research     Open Access   (Followers: 12)
Journal of Civil Society     Hybrid Journal   (Followers: 3)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 3)
Journal of Composites     Open Access   (Followers: 39)

        1 2     

Journal Cover   Structural Concrete
  [SJR: 0.739]   [H-I: 9]   [9 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1464-4177 - ISSN (Online) 1751-7648
   Published by John Wiley and Sons Homepage  [1607 journals]
  • Towards the early‐age performance control in precast concrete
           immersed tunnels
    • Authors: Wei Jiang; Xian Liu, Yong Yuan, Shengnian Wang, Quanke Su, Luc R. Taerwe
      Abstract: In engineering practice, the prevention of early‐age cracking in massive concrete structures is of great importance to their serviceability during the whole‐life cycle. From the scientific aspect, this engineering concern requires the control of the early‐age performance of concrete structures. Following earlier research projects with the background project of the Hong Kong‐Zhuhai‐Macao Link, the focus of this work is to obtain insight into the evolution of the early‐age behavior of precast concrete in an immersed tunnel. To this end, a full‐scale test is performed, from which the behavior of early‐age concrete is observed directly. After validation of the developed constitutive model with the test results, the early‐age performance during the entire fabrication process of the precast concrete immersed tunnel is evaluated numerically. It is also found that stress relaxation is playing a major role for the stress development in the immersed tunnel, although the thermal strain is the main origin of the early‐age stresses. Through this in‐depth investigation, a comprehensive understanding is obtained of the early‐age behaviour of an actual precast concrete immersed tunnel. What is more important, the early‐age performance of concrete structures can be accurately evaluated and further adjusted or controlled with the merit of the validated numerical modeling, which is no doubt beneficial to the control of early‐age cracking in massive concrete structures in engineering.
      PubDate: 2015-04-23T04:13:41.472227-05:
      DOI: 10.1002/suco.201400125
       
  • Experimental analyses of an optimised shear load transfer in
           circumferential joints of concrete segmental linings
    • Authors: Thomas Putke; Roksana Bohun, Peter Mark
      Abstract: Coupling of subsequent rings in circumferential joints of tunnel lining systems is of particular interest in mechanised tunnelling and discussed as a controversial issue. On the one hand interlocking systems like “cam & pot” can be of use to limit the lining's deformation. But on the other hand unfavourable conditions lead to often repeated and significant damages decreasing the tunnel's lifetime. This paper provides experimental results of a three‐part optimisation concept (structural analysis, topological optimisation and experimental verification), tested for concrete linings at the example of the shear coupling mechanism. At first, geometrical dependencies are analysed that reveal predominantly stronger cams than corresponding pots. Hence, bearing capacities of pots are increased transferring topological optimisation results into reinforcement concepts featuring micro‐mesh reinforcement, steel fibre cocktails and rebars welded to anchor plates. Especially the latter resulted in comparatively stronger pots along with a considerably increased ductility. Nevertheless, pots still represent the weaker part and are crucial for the design. Therefore, a concept with steel dowels and predefined static boundary conditions is tested. Its results are characterised by a significantly lower scatter of bearing capacities accompanied by a strongly increased ductility.
      PubDate: 2015-04-20T05:10:31.541881-05:
      DOI: 10.1002/suco.201500013
       
  • Shear strength of self‐compacting concrete beams with small amounts
           of stirrups
    • Authors: Thomás Lima de Resende; Lidia da Conceição Domingues Shehata, Ibrahim Abd El Malik Shehata
      Abstract: In comparison with a vibrated concrete (VC) of the same strength class, the self‐compacting concrete (SCC) typically has lower coarse aggregate content and, eventually, smaller maximum aggregate size. This may result in reduction of aggregate interlock between fracture surfaces of SCC. Since the aggregate interlock plays an important role in the shear strength of slender beams, SCC beams may have a shear strength lower than similar VC beams, but studies on that subject are still limited. This article summarizes an experimental program that includes beams of high strength SCC and transverse reinforcement ratios around the minimum given by different codes, case that has not been investigated. The shear strengths of those beams are compared with the ones of VC beams with similar concrete compressive strength and small amounts of transverse reinforcement and also to the calculated ones according to different code procedures.
      PubDate: 2015-04-20T05:10:30.055478-05:
      DOI: 10.1002/suco.201400084
       
  • Concrete fatigue in composite dowels
    • Authors: Martin Claßen; Joerg Gallwoszus
      Abstract: In modern bridge construction, steel‐concrete composite structures with composite dowels are being applied more than ever, especially for small and medium spans. In contrast to headed studs, in which initial steel cracks occur after only a few load cycles [1], [2], the lifetime of composite dowels is characterized by the compression of the multiaxially stressed concrete in front of the composite dowel. Here, plastic compression strains occur in the concrete, which accumulate over load cycles, leading to a cyclical increase of relative displacements in the connection. Certain proportions of these relative displacements, called inelastic slip, remain in the connection, even after the loading is released. The inelastic slip changes the characteristics of the static dowel curve. The initially rigid connection degrades over the lifetime, leading to redistributions of internal forces, which may be decisive for fatigue design. In order to consider the degradation of the composite connection a cyclic dowel curve can be used, which may be developed from the static dowel curve by introducing the inelastic slip. In this paper, the results of cyclic shear tests on different composite dowel geometries are presented. Here, the effect of load‐dependent parameters (upper load level and load range) was investigated. Furthermore, an engineering model for determining the cyclic dowel curve is presented, which was developed based on the results of experimental and numerical investigations.
      PubDate: 2015-04-02T05:40:05.295233-05:
      DOI: 10.1002/suco.201400120
       
  • Behaviour of Eccentrically Loaded High Strength Concrete Columns
           Intersected by Lower Strength Concrete Slabs
    • Authors: Tadeusz Stanisław Urban; Michał Marcin Gołdyn
      Abstract: This paper presents the results of experimental investigations of the edge and corner high strength concrete columns intersected by concrete slabs. It was considered effect of intersection by weaker slab concrete on load carrying capacities of reinforced concrete columns. The only considered parameter was location of column with respect to the edge of the slab. It was stated that providing a small slab overhang beyond the column edge makes it possible to increase the actual strength of the joint concrete significantly. The results of the author's research have clearly demonstrated, that providing a sufficiently large slab overhang allows to treat the edge and corner column – slab connection joints as the internal joints. Existing code provisions concerning strength of concrete of edge and corner column – slab connection joints are in some cases too conservative and require clarification.
      PubDate: 2015-03-26T05:24:12.391819-05:
      DOI: 10.1002/suco.201400114
       
  • Nonlinear analysis of shear‐critical reinforced concrete beams using
           the softened membrane model
    • Authors: Wael Kassem
      Abstract: An analysis method for predicting the shear strength and behaviour of shear‐dominated reinforced concrete beams is presented in this paper. The proposed model is based on the softened membrane model that accounts for the Poisson's effect on the behaviour of reinforced concrete beams subjected to the combined effect of shear and flexure. The softened membrane model is appealing for modelling the shear behaviour of concrete elements as it is based on solid mechanics of materials fundamentals. The accuracy of the proposed mathematical model was validated against the experimental results of 66 reinforced concrete elements tested under pure shear as well as 167 shear‐dominated RC beams available in the literature. Analysis results showed that the proposed model could satisfactorily predict the shear strength as well as the entire shear stress‐shear strain behaviour of shear‐dominated beams.
      PubDate: 2015-03-26T05:24:12.254262-05:
      DOI: 10.1002/suco.201400093
       
  • Solution strategy for non‐linear Finite Element Analyses of large
           reinforced concrete structures
    • Authors: Morten Engen; Max A. N. Hendriks, Jan Arve Øverli, Erik Åldstedt
      Abstract: When performing non‐linear Finite Element Analyses during design of large reinforced concrete structures, there is need for a general, robust and stable solution strategy with a low modelling uncertainty that comprises choices regarding force equilibrium, kinematic compatibility and constitutive relations. In this paper, analyses of experiments with a range of structural forms, loading conditions, failure modes and concrete strengths showed that an engineering solution strategy was able to produce results with good accuracy and low modelling uncertainty. It was advised to shift the attention from a detailed description of the post‐cracking behaviour of concrete to a rational description of the pre‐cracking compressive behaviour for cases where large elements are used and the ultimate limit capacity is sought.
      PubDate: 2015-03-26T05:24:10.090639-05:
      DOI: 10.1002/suco.201400088
       
  • Toughness Behaviour of High Performance Lightweight Foamed Concrete
           Reinforced with Hybrid Fibres
    • Authors: Eethar Thanon Dawood; Ali Jihad Hamad
      Abstract: Lightweight foamed concrete (LWFC) is a high performance concrete having structural strength with lightweight density and high flowability. High performance lightweight foamed concrete (HPLWFC) is used in modern concrete technology and intensely in the construction applications of high‐rise buildings, long‐span concrete structures and road sub‐bases among others. The present work deals with the fresh and hardened properties of LWFC. The fresh properties of LWFC are measured by using the flow test and fresh density test. Whereas, the hardened properties include compressive strength, flexural strength, flexural toughness, static modulus of elasticity, ultrasonic pulse velocity, water absorption and oven dry density tests. Besides, the study focuses mainly on the effect of the added fibres to LWFC mixes. Two types of fibres have been used which are glass fibres and polypropylene fibres, the combination of the glass fibres (GF) and polypropylene fibres (PPF) to obtain the hybrid fibres (GF+PPF). Additionally, this study focuses mainly on the effect of hybrid fibres on flexural toughness of high performance lightweight foamed concrete. Trial mixes have been used to choose the optimum mix, the definition to choose the best mix depended on three parameters: oven dry density, flowability and compressive strength. The volume fraction of glass and polypropylene fibres are 0.06%, 0.2%, 0.4%, 0.6% and 0.2%, 0.6%, 1%, 1.4%, respectively. The percentages of hybrid fibres “GF+PPF” are “0.2+0.6”%, “0.4+0.6”%, “0.2+1”% and “0.4+1”%. The results show that adding fibres to the LWFC reduces the flowability and improve the hardened properties of such concrete. The greatest increment in compressive and flexural strength of LWFC is 51% and 21% due to the use of 0.6% glass fibres. On the other hand, the LWFC reinforced with polypropylene fibres exhibits a slight increase in compressive, splitting tensile and flexural strength. The best percentage of hybrid fibres which yields the highest increment in LWFC is “0.4% GF+ 0.6 PPF%”. Such increments are 21.4% and 16.7% for the compressive, flexural strength of LWFC. The results of flexural toughness indicate that the polypropylene fibres denote a higher efficiency in the flexural toughness than that of glass fibres. The flexural toughness results increase with volume fraction of fibres increases. The hybridization shows the best flexural toughness values due to the cooperative work of the glass and polypropylene fibres to boost the performance of flexural toughness at pre‐crack and post‐crack zones. Therefore, the use of 0.4 glass fibres + 1% polypropylene fibres gives the best results in this regards.
      PubDate: 2015-03-26T05:24:09.777434-05:
      DOI: 10.1002/suco.201400087
       
  • Blast resistance characteristics of concrete with different fibre
           reinforcement
    • Authors: Martina Drdlová; Jaroslav Buchar, Josef Krátký, Radek Řídký
      Abstract: The paper summarizes the results of the development of advanced fibre reinforced concrete intended for explosion resistant applications. Experimental research aimed at contributing to understanding the effect of different type of reinforcement on the behaviour of high performance fibre reinforced concrete subjected to the blast load was carried out. The fine grained concrete matrix was reinforced by various types of dispersed fibres – metallic, carbon, mineral and polymer ‐ with different lengths (6 – 55 mm) (0.24 – 2.16 in.) and combinations, while the volume content (3%) of fibres was kept constant. Physico‐mechanical and explosion tests were performed on prismatic and slab shaped specimens and the effect of different kinds of reinforcement on blast resistance and mechanical performance of the concrete samples was evaluated. The accelerations of the specimens within the blast load were captured. The material characteristics and explosion test data obtained were used for creation of finite element model in LS‐DYNA. The numerical and experimental investigation resulted in the design of concrete elements for population protection, which are able to resist the explosion defined by weight and placement of the charge. The resistance of the newly designed concrete element was confirmed by a field blast test.
      PubDate: 2015-03-20T07:10:47.381813-05:
      DOI: 10.1002/suco.201400080
       
  • Defects in epoxy coated reinforcement and their impact on service life of
           concrete structures
    • Authors: Sylvia Keßler; Ueli Angst, Marc Zintel, Christoph Gehlen
      Abstract: Epoxy coated reinforcement (ECR) as a protection against chloride‐induced corrosion of steel in concrete is used only in a few countries due to doubts concerning its effectiveness. A common misconception is that possible defects in the coating are particularly weak points as these may favor high local corrosion rates and thus loss of steel cross section. This work discusses why a certain number of small defects can be tolerated. It is argued that prolongation of the initiation phase is caused by a higher critical chloride content as compared to uncoated steel due to the “size effect”. Additionally, the propagation phase is with ECR likely to be extended due to the strongly limited cathodic area that limits the corrosion rate. This paper presents experimental and numerical tests to verify these assumptions.
      PubDate: 2015-03-20T04:40:21.902071-05:
      DOI: 10.1002/suco.201400085
       
  • Birmingham Gateway: Structural Assessment and Strengthening
    • Authors: John Orr; D. Pask, K. Weise, M. Otlet
      Abstract: Birmingham New Street is the busiest UK rail station outside of London. Growing demand following upgrade works to the West Coast Main Line has seen passenger numbers exceed the design capacity of the current station, which was constructed in 1967. To meet projected increases in passenger numbers, a redevelopment of the historic station is currently underway. Retaining all major structural features, the redevelopment is being undertaken over a live railway in the heart of Birmingham while maintaining existing passenger capacity. This paper details the structural assessment and strengthening design work undertaken to facilitate the regeneration of Birmingham New Street. The assessment methodologies used in examining this historic concrete structure are discussed before the design of subsequent strengthening works is presented.
      PubDate: 2015-03-20T04:40:20.714211-05:
      DOI: 10.1002/suco.201400068
       
  • Analysis of Cracking in Steel Fibre Reinforced Concrete (SFRC) Structures
           in Bending using Probabilistic Modelling
    • Authors: Pierre Rossi; Dominic Daviau‐Desnoyers, Jean‐Louis Tailhan
      Abstract: In this paper, an improvement of the probabilistic discrete cracking model of fibre reinforced concretes, originally developed by Rossi, is proposed. In this new model: – Crack creation and propagation in the concrete is taken into account by using special interface elements. These interface elements open once the normal tensile stress at their centre of gravity reaches the tensile strength of the element. The probabilistic aspect of the cracking process is taken into account by the fact that the tensile strength is randomly distributed through the mesh elements. – Immediately after the creation of cracks, the fiber bridging effect is considered by a damage model approach. The probabilistic aspect consists of randomly distributing the post‐cracking energy. The improved numerical model is used to analyze the bending behaviour of three SFRC beam sizes that consist of the same material. The numerical simulations are compared with experimental results in terms of the beams' global behaviour and the cracking process.
      PubDate: 2015-03-20T04:40:19.024096-05:
      DOI: 10.1002/suco.201400081
       
  • Shear Tests on Continuous Prestressed Concrete Beams with External
           Prestressing
    • Authors: Martin Herbrand; Martin Classen
      Abstract: Many of the existing road bridges exhibit calculative shear capacity deficits according to current design codes. This is partly because of increased traffic loads and changes in the code provisions. In order to extend the service life of these bridges, either refined design approaches may be used or strengthening measures may be performed. This paper describes the results of experimental investigations on the influence of additional external prestressing on the shear capacity of continuous prestressed concrete beams. Within the research project, six shear tests on three test beams with parabolic internal post‐tensioning and additional variable external prestressing were performed. The aim of the project was to determine the effect of external prestressing on the shear capacity of existing bridges, and whether current design approaches lead to conservative results when used for the recalculation of existing bridge structures.
      PubDate: 2015-03-20T04:40:17.877338-05:
      DOI: 10.1002/suco.201400082
       
  • ASR and sulphate performance of mortar containing industrial waste
    • Authors: Ana Mafalda Matos; Joana Sousa‐Coutinho
      Abstract: Greener concrete using adequate industrial waste is a preferred option for sustainable construction. Alkali‐silica reaction (ASR) and sulfate attack (SA) on concrete can be minimized by the use of mineral additions being particularly interesting if waste derived. Grits from a paper industry, waste glass and two types of biomass ash were used as 10% cement replacement in mortar and tested for ASR and SA. Results and Scanning Electron Mycroscopy observations were compared to plain mortar and to mortar containing commercial silica fume. All waste materials mitigated ASR compared to control mortar. Resistance to sulphates was increased for one of the biomass ashes used and especially for glass powder which surpassed silica fume. Therefore two of these waste materials seem to be promising to use as partial replacement material for cement leading to enhanced durability and thus contributing to sustainable construction.
      PubDate: 2015-03-20T04:40:16.421192-05:
      DOI: 10.1002/suco.201400095
       
  • Does EN 1992‐1‐1 and the European Concrete Platform comply
           with Tests? Commentary to the Rules for Strut and Tie Models with
           Corbels as Example
    • Authors: Thore Hagberg
      Abstract: EN 1992 [1] is presently under revision. In that context it is justified to set a critical eye on the standard, and in particular if the models and the resistance functions for the Ultimate Limit State complies with results from tests. The present contribution is limited to S&T models. The results of the analysis will primarily have relevance to corbels, however, some conclusions are general and should be considered when choosing the mathematical model for any S&T model. [1] is not sufficiently detailed to give basis for a complete dimensioning of e.g. corbels. The European Concrete Platform [2], which contains worked examples, has been prepared in accordance with and to support [1]. The two topics dealt with are 1) Selection of main model, and 2) Details and use of the S&T model in [1] + [2] and particularly its ability to predict results from tests. The tests for the analysis are taken from a thorough study described in [3]. To evaluate results from using [1] + [2] a concept for design of corbels suggested earlier has been used to calculate the same tests [4]. It will be claimed that the models in [1] + [2] and their ability to predict the outcome of tests has some flaws compared with calculations according to [4]. The detailed calculations are given in Annexes, i.e. Part 1 for dimensioning according to [1] + [2], and Part 2 for dimensioning according to [4]. The Annexes as well as reference [4] can be obtained by the publisher or the author.
      PubDate: 2015-03-16T07:20:13.53891-05:0
      DOI: 10.1002/suco.201400066
       
  • Displacement based simulation of time dependent behaviour of RC beams with
           prestressed FRP or steel tendons
    • Authors: Daniel Knight; Phillip Visintin, Deric J. Oehlers
      Abstract: Predicting the time dependent behaviour of prestressed concrete (PC) beams is crucial as time effects under serviceability loading can result in a critical loss of prestress. The conventional technique of moment‐curvature (M/χ) to simulate the behaviour of PC beams is based on the Euler‐Bernoulli corollary of a linear strain profile, in which all deformations are accommodated through changes in the material strain that is it is strain based. Consequently, the M/χ approach cannot directly accommodate discrete deformations associated with tension‐stiffening such as the formation of individual cracks and reinforcement slip. Hence the M/χ approach can simulate the behaviour prior to cracking purely through mechanics. However post‐cracking, it requires empirically derived correction factors, such as empirically derived flexural rigidities, to allow for the deformations associated with tension‐stiffening. This paper presents a displacement based moment‐rotation (M/Θ) approach for determining the behaviour of PC beams by applying the Euler‐Bernoulli theorem of plane sections, as opposed to the conventional M/χ approach of a linear strain profile. Being based on plane sections, the M/Θ approach deals directly with displacements and consequently can simulate the mechanics of tension‐stiffening directly. The approach is shown to accommodate time effects of concrete creep, shrinkage and reinforcement relaxation and can develop equivalent flexural rigidities directly from mechanics.
      PubDate: 2015-03-16T07:10:16.427876-05:
      DOI: 10.1002/suco.201400039
       
  • On shear verification according to the fib Model Code 2010 in FRC elements
           without traditional reinforcement
    • Authors: Simona Coccia; Alberto Meda, Zila Rinaldi
      Abstract: Fiber Reinforced Concrete (FRC) without any traditional reinforcement is extensively used in particular structures such as pavements or tunnels. Model Code 2010 introduced the possibility of using FRC for structural design and it is becoming a reference document for this kind of structures. The application of Model Code 2010 suggestions for flexural and axial forces, once the constitutive relationships of the material are defined, allows for safe design. However, the shear verification is often a cause of discussion in the design community. The aim of this paper is to clarify this aspect and to provide a procedure that can be followed in the design process. A case study is also presented.
      PubDate: 2015-03-16T07:10:15.278386-05:
      DOI: 10.1002/suco.201400026
       
  • Cover Picture: Structural Concrete 1/2015
    • Abstract: They have already become a new landmark: The six new water towers in the Al Jahra area in Kuwait City. Their mushroom‐shaped water tanks were post‐tensioned using DYWIDAG Strand Tendons. It goes without saying, that these buildings are of decisive importance for the inhabitants of cities in Kuwait (photo: DSI).
      PubDate: 2015-03-02T04:12:54.239077-05:
      DOI: 10.1002/suco.201590000
       
  • Annual table of contents 2014
    • PubDate: 2015-03-02T04:12:52.736458-05:
      DOI: 10.1002/suco.201590003
       
  • Contents: Structural Concrete 1/2015
    • PubDate: 2015-03-02T04:12:50.941366-05:
      DOI: 10.1002/suco.201590004
       
  • From accomplishments to challenges
    • Authors: Harald S. Müller
      Pages: 1 - 1
      PubDate: 2015-03-02T04:12:51.468459-05:
      DOI: 10.1002/suco.201590005
       
  • fib‐news: Structural Concrete 1/2015
    • Pages: 149 - 157
      Abstract: The fib in Russia: new standards; Worldwide representation at ACF 2014; DISC2014: the past and the future; Old for new: Penang Bridge; A venerable institute turns 80; JPEE2014 in Lisbon; fib MC2010 course in Brazil; Short notes; Nigel Priestley † 1943–2014; Congresses and symposia; Acknowledgement
      PubDate: 2015-03-02T04:12:56.038276-05:
      DOI: 10.1002/suco.201590001
       
  • Structural Concrete 2/2015
    • Pages: 158 - 158
      PubDate: 2015-03-02T04:12:55.360485-05:
      DOI: 10.1002/suco.201590002
       
  • Shear strength of deep beams: a mathematical model and design formula
    • Authors: Wael Kassem
      Abstract: A proposal for estimating the shear capacity of reinforced concrete deep beams is presented in this paper. The proposed model is based on the fixed‐angle softened truss model and utilizes a newly proposed formula for the effective transverse compressive stress acting on the beam web. The proposed formula is developed using a stepwise multiple linear regression analysis of the reported shear capacity values of 445 experimental deep beams. The validity of the mathematical model is examined by comparing its response with the experimental results as well as predictions of other formulas available in the literature, and it results as the one best fitting the measured shear strengths. The mathematical model leads to an explicit single closed‐form expression for computing the shear strength of deep beams. The proposed expression is dimensionless and contains four variables that express the horizontal and vertical reinforcement ratios, the concrete strength, and the shear span ratio. On the basis of results of this paper, a design formula is proposed with predictions more consistent and reliable than the ACI Code and Eurocode.
      PubDate: 2014-12-22T06:15:36.140243-05:
      DOI: 10.1002/suco.201400045
       
  • Shear force carrying of composite dowels in transversely cracked concrete
    • Authors: Martin Classen
      Abstract: In steel‐concrete composite girders, innovative composite dowels can be used to transfer the shear forces between the concrete slab and the steel profile. Today, composite dowels are predominately used in engineering structures such as prefabricated composite bridges. However, due to their ease of manufacturing, their good load‐bearing and deformation properties, and their applicability in slender concrete chords, these composite dowels are being applied more than ever in building construction as well. The present article describes shear tests on puzzle‐shaped composite dowels for slender concrete chords with a thickness of only 10 cm. Aside from different reinforcement configurations, the influence of different longitudinal stress states and transverse cracking in the concrete slab have been investigated. In previous studies on the shear force capacity of composite dowels, the influence of transverse cracking has been neglected. However, the own experiments described in this paper show that the composite dowels' shear carrying capacity is significantly impacted by concrete cracking. In order to simulate the performed experiments and to analyze the shear force carrying behavior of the composite dowels in cracked and uncracked concrete, a three‐dimensional, non‐linear finite element model of the shear tests was set up. The results of both, experimental and numerical investigations are summarized in this paper.
      PubDate: 2014-12-19T07:14:22.469139-05:
      DOI: 10.1002/suco.201400100
       
  • Effect of the location of broken wire wraps on the failure pressure of
           prestressed concrete cylinder pipes
    • Authors: Masood Hajali; Ali Alavinasab, Caesar Abi Shdid
      Abstract: The effect of the location of broken prestressing wire wraps on the overall strength of Prestressed Concrete Cylinder Pipes (PCCP) is investigated. An advanced computational model based on non‐linear finite element analysis is used to study three possible locations of broken wire wraps: at the spigot joint, at the bell joint, and in the barrel of the pipe. A sensitivity analysis was performed to evaluate the cracking of the concrete core and the yielding of the prestressing wires and steel cylinder with increasing internal pressure and with increasing number of broken wire wraps. Two classes of 2.44 m Embedded Cylinder Pipe (ECP) are modeled with 5, 35, 70, and 100 wire wrap breaks. The results show that broken wire wraps at the joint, and especially the spigot joint, decrease the overall strength of PCCP more so than at the bell joint or in the barrel of the pipe. The intensity of this effect increases with increased internal pressure and with larger number of broken wire wraps.
      PubDate: 2014-12-19T07:14:21.079744-05:
      DOI: 10.1002/suco.201400070
       
  • Influence of axial tension on the shear strength of floor joists without
           transverse reinforcement
    • Authors: David Fernández‐Montes; Enrique González Valle, Elena Díaz Heredia
      Abstract: The mechanism governing shear strength in reinforced concrete members without transverse reinforcement subjected to both bending and tensile stress is complex. Also, formulas used to estimate shear failure are inconsistent with one another and provide a poor fit to experimental findings. This Article highlights the differences between the results of experimental tests and the values of shear strength estimated with the equations of the ACI 318‐11, Eurocode 2 (EC‐2) and the Modified Compression Field Theory (MCFT). The tests considered are the ones reported in the literature consulted and the tests for this experimental investigation, some made with high performance concrete. The review also puts forward a proposal to improve the method and fitting procedure to estimate the shear failure in a longitudinal reinforced concrete member without transverse reinforcement due to excessive principal tensile stress on its web.
      PubDate: 2014-12-19T07:14:19.696422-05:
      DOI: 10.1002/suco.201400063
       
  • Chloride Ion Transport Mechanism in Concrete Due to Wetting and Drying
           Cycles
    • Authors: Xu Gang; Li Yun‐pan, Su Yi‐biao, Xu Ke
      Abstract: The transport mechanism of chloride ions in concrete during wetting and drying cycles subjected to varying durations is evaluated in this paper. The experimental test results were used to validate a numerical simulation model to assess the influence of diffusion coefficient, surface chloride ion concentration, and ratio of dry‐wet cycle durations on the transport mechanism of chloride ions in concrete. Experimental and numerical analysis results indicated that the maximum transmission depth of chloride ions in concrete depends on the diffusion coefficient and the dry‐wet cycle regime but has little relationship to the surface concentration of chloride. The chloride ion transmission in the surface zone accelerates only if the dry‐wet ratio is greater than 1. As the dry‐wet ratio increases, chloride ion transmission accelerates. It tends to become stable when the dry‐wet ratio reaches 5:1. The dry‐wet cycles accelerate the transport process of chloride ions within a certain distance from the surface, and beyond this distance, chloride ions in the complete immersion specimen transport more rapidly, than those under dry‐wet cycles. The peak concentration of chloride ions within the convection zone has a relationship with the diffusion coefficient, the surface chloride ion concentration and the wet‐dry regime. The smaller the diffusion coefficient, the higher the surface chloride concentration; the greater the dry‐wet ratio, the higher the peak of convection can reach.
      PubDate: 2014-12-19T07:14:18.272572-05:
      DOI: 10.1002/suco.201400035
       
  • Predicting the response of reinforced concrete slab strips subjected to
           axial tension and transverse load: a competition
    • Authors: Andreas Galmarini; Daniel Locher, Peter Marti
      Abstract: Six large‐scale tests on reinforced concrete slab strips were carried out at the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland, to investigate the load‐bearing behaviour of reinforced concrete slabs subjected to axial tension and transverse load. Four of these tests were used for an international competition to predict the response of the test specimens. The specimens differed in the axial tension applied and the presence of stirrups. This paper presents the test concept, the four test specimens, the test results and the predictions received and it evaluates the results of the competition. Simplified hand calculation analyses of the experiments are also included. The tests showed that there is significant shear strength in reinforced concrete slabs under axial tension, and that the system capacity of such slab strips is not limited by a local shear failure. The prediction competition revealed that the modelling of a cracked reinforced concrete slab strip still is a significant challenge, even for experienced researchers with the latest analysis tools.
      PubDate: 2014-10-28T06:10:14.28226-05:0
      DOI: 10.1002/suco.201400097
       
  • Pneumatic forming of hardened concrete – building shells in the 21st
           century
    • Authors: Benjamin Kromoser; Johann Kollegger
      Abstract: Double curved shells, used as supporting structures, are strong and material saving. Major parts of the applied loads can be carried by normal forces. Thus, the stresses are very uniformly and efficiently distributed over the entire cross section and large spans with small thicknesses can be built. The state of the art in the construction of shell structures is characterised by high labour input for formwork and falsework. A new construction method without formwork and falsework was invented at the Institute for Structural Engineering at Vienna University of Technology. The idea of this new construction method is to build concrete shells with double curvature originating from an initially plane plate. During the transformation process, the hardened concrete plate is lifted and the elements are bent with the aid of a pneumatic formwork until the required curvature is reached. Non‐linear Finite Element calculations, tension tests, bending tests and bonding tests were carried out in order to determine a suitable combination of concrete and reinforcement. In the second part of the paper a large scale experiment for the erection of a 17.6 × 10.8 m span and 2.9 m height free formed shell is presented. Finally, different application‐areas for the newly invented method are explained.
      PubDate: 2014-10-24T04:40:13.006359-05:
      DOI: 10.1002/suco.201400057
       
  • Self‐repair of thermal cracks in concrete sandwich panels
    • Authors: Kim Van Tittelboom; Elke Gruyaert, Pieter De Backer, Wim Moerman, Nele De Belie
      Abstract: While the use of insulated concrete sandwich panels results in more energy efficient buildings, the presence of this insulation layer can induce thermal crack formation. As cracks form a preferential path for aggressive agents to enter and degrade the concrete matrix and as they are not wanted in this application from an aesthetical point of view, they need to be treated. In this study it was aimed to invisibly seal the cracks in concrete sandwich panels in an autonomous way. Therefore, the efficiency of various encapsulated healing agents was compared by inducing thermal cracks in concrete sandwich panels causing capsule breakage and thus release of the agents into the cracks. It was shown that encapsulation of both polyurethane and a water repellent agent can result in a reduction of the water uptake by cracks, however, only in the case a water repellent agent was released, cracks were healed in an almost invisible way. From this study, it was shown that the self‐healing approach consisting of encapsulated polymer based healing agents can also be applied in concrete sandwich panels although more research will be needed to meet the specific healing requirements for this application.
      PubDate: 2014-10-24T04:30:09.44029-05:0
      DOI: 10.1002/suco.201400055
       
  • A design approach for tunnels exposed to blast and fire
    • Authors: Matteo Colombo; Paolo Martinelli, Marco di Prisco
      Abstract: In this work, a design procedure based on a simplified FE model for underground tunnels subjected to internal explosion eventually preceded by fire accidents is proposed. The procedure can provide a valuable tool for designers for checking the structural tunnel safety in case of an internal blast event. The tunnel geometry considered is that adopted for the Brescia metro line (Italy). It has an inner diameter of about 8.15 m, a length of about 13.7 km and is located from about 23.1 m below the surface. Six segments and a smaller key segment (6+1) compose the tunnel. The ring has an average width of about 1.5 m. The FE model is firstly tested under serviceability static loads. Dynamic analyses are carried out in order to reproduce the blast scenario. The aim of this work is the generation of pressure‐impulse (p‐i) diagrams for underground tunnel in case of internal explosion and pre‐explosion fire actions. An ultimate limit state criterion based on eccentric ultimate flexural capacity and capable to include fire‐blast interaction is introduced. An innovative layered precast tunnel segment solution made of different fibre‐reinforced cementitious composites is compared with a traditional solution where the lining section is made of R/C. The potentialities of this new solution are discussed in the paper.
      PubDate: 2014-09-26T06:24:01.933511-05:
      DOI: 10.1002/suco.201400052
       
  • Flexural behavior of recycled aggregate concrete gradient slabs
    • Authors: Jianzhuang Xiao; Chang Sun, Xinghan Jiang
      Abstract: This paper proposes a new concept of ‘recycled aggregate concrete gradient slabs’, through which gradient distribution for mechanical properties of the Recycled Aggregate Concrete (RAC) can be achieved. In this study, one four‐point bending test was applied to investigate six RAC gradient slabs and three homogeneous slabs with RAC. The major parameters considered are the layers with different Recycled Coarse Aggregates (RCAs) replacement percentage (0%, 50% and 100%), the gradient pattern (different casting methods) and the reinforcement ratio. It has been concluded that RAC gradient slabs have similar flexural behavior to that of homogeneous slabs with RAC. The reinforcement ratio, the layers with different RCAs replacement percentage and the gradient pattern can influence the flexural behavior of RAC gradient slabs. Furthermore, the effects of the three factors on both the flexural capacity and the deflection of the RAC gradient slabs were studied by the Finite Element Method (FEM) simulation with the software of ABAQUS. Both the experiments and the FEM analysis indicate that the flexural behavior of RAC gradient slabs can be improved by this suitable gradient method.
      PubDate: 2014-09-26T06:24:00.30028-05:0
      DOI: 10.1002/suco.201400008
       
  • Consideration of strength and size of beam‐column joints in the
           design of RC frames
    • Authors: Ricardo Costa; Paulo Providência, Alfredo Dias
      Abstract: Some experimental research studies reported that the longitudinal reinforcement of beams and columns shows larger strains inside the joint than at the joint periphery (defined as the intersection of the outer surfaces of beam and column) – this may explain why several technical specifications and state‐of‐the‐art programs recommend to base the design of beams and columns on values of the internal forces larger than those at the joint periphery. These results and procedures are questionable and are investigated in this paper. The presented non‐linear finite element analysis of reinforced concrete frames under gravity and quasi‐static monotonic lateral loads examines (i) the stress fields in reinforcement inside interior, exterior and roof exterior joints and (ii) the load carrying capacity of representative sub‐frame models incorporating such joints. The results prove that it is actually safe, with respect to the joint load capacity, to base the design of the longitudinal reinforcement of beams and columns on the value of the internal forces at the joint periphery; this result also contributes to the recommendation of real size beam column joint models in the analysis procedure.
      PubDate: 2014-09-16T02:40:09.18929-05:0
      DOI: 10.1002/suco.201400054
       
  • Derivation of the σ‐w relationship for SFRC from prism bending
           tests
    • Authors: Ali Amin; Stephen J. Foster, Aurelio Muttoni
      Abstract: The material characterization of steel fibre reinforced concrete (SFRC), which is required for its implementation in design codes, should be based on nominal properties that describe its post‐cracking strength in tension. In the case of brittle and quasi‐brittle materials, such as concrete, the tensile parameters are often derived indirectly; however, for materials with more ductility, such as SFRC, there is conjecture as to whether or not an indirect measure may be used to establish the stress versus crack opening displacement relationship, such as the use of a three‐ or four‐point prism test combined with an inverse analysis. In this paper a simple and efficient inverse analysis technique is developed and shown to compare well with data obtained from direct tension tests. Furthermore, the methodology proposed by the fib Model Code 2010 was investigated and recommendations made to improve its accuracy.
      PubDate: 2014-09-16T02:40:07.922172-05:
      DOI: 10.1002/suco.201400018
       
  • Eurocode 2 – Analysis of National Annexes
    • Authors: Anett Ignatiadis; Frank Fingerloos, Josef Hegger, Frederik Teworte
      Abstract: Eurocode 2 consists of four parts which have to be applied in conjunction with the respective National Annexes of the CEN‐member states. The National Annexes were introduced particularly to maintain the national safety level and to account for regional aspects in the different states. The CEN (European Committee for Standardization) will revise and extend all Structural Eurocodes up to 2018. As part of that process two main objectives for revising Eurocodes have been formulated, namely the reduction of the number of Nationally Determined Parameters (NDP) and the improvement of “ease of use”. In order to reduce the number of NDP, improve the ease of use and allow for a further harmonisation without changing the main structure and the design models of Eurocode 2, the National Annexes of EN 1992‐1‐1 of the different CEN‐member states were compared and analysed. Furthermore, the analysis of the National Annexes may help to identify some main aspects for the revision of Eurocode 2. This paper summarises the analysis of the National annexes of EN 1992‐1‐1 and makes first proposals for a further harmonisation.
      PubDate: 2014-09-10T09:40:17.270322-05:
      DOI: 10.1002/suco.201400060
       
  • Minimum Reinforcement of Concrete Members regarding Hardening Caused
           Stresses and Member Dimensions
    • Authors: Dirk Schlicke; Nguyen Viet Tue
      Abstract: The minimum reinforcement for crack width control of restrained concrete members is directed in the actual design code EC2 [1] by the limitation of the steel strain at taking up the cracking force of the cross section or relevant parts of it. But with the simplification of a restricted view on the cross section, this approach is unable to cover the central problem of restraint stressing. Hence, the consistent application of this approach can lead to high reinforcement amounts and was therefore empirically modified according to the practical experience, see [2]. But in particular, the main modification of a limited tensile strength seems very dubious as the primarily affected members are thick and have therefore a late cracking time with a strong developed tensile strength. Finally, this circumstance leaves the structural designer in a dilemma of being uneconomic or having no mechanical proof in a possible case of damage. However, the mechanically consistent estimation of the minimum reinforcement for crack width control can be achieved by considering the deformation compatibility of the restrained member, see [3]. And with the introduction of [4] this deformation based design concept became already state of the art for massive concrete members of water buildings. This contribution presents the general application of the deformation based design concept based on the findings of [5]. Concluding, the reliability and the practicability of this approach will be exemplified by the deformation based minimum reinforcement design of a massive trough structure.
      PubDate: 2014-09-04T05:10:15.345894-05:
      DOI: 10.1002/suco.201400058
       
  • Thin‐walled shell structure made of textile reinforced concrete
    • Authors: Alexander Scholzen; Rostislav Chudoba, Josef Hegger
      Abstract: The present paper describes the dimensioning approach for textile reinforced concrete (TRC) shells capturing the interaction between normal forces and bending moments based on the experimentally determined cross‐sectional strength characteristics of the material. The influence of oblique loading on the composite strength of TRC elements with flexible reinforcement is included in a normalized interaction diagram for combined loading. The dimensioning approach is exemplified for the ultimate limit state assessment of a doubly curved TRC shell. Furthermore, the general applicability of the dimensioning approach is discussed in the light of the non‐linear load‐bearing behaviour of TRC. Due to its strain‐hardening tensile response stress redistributions within the shell result in load‐bearing reserves. Details of the structural design and manufacturing solutions developed and applied during the realisation of the TRC shell structure are described in the companion paper (Part I).
      PubDate: 2014-09-04T05:10:13.685221-05:
      DOI: 10.1002/suco.201400046
       
  • Five‐spring model for complete shear behaviour of deep beams
    • Authors: Boyan Mihaylov
      Abstract: This paper presents a five‐spring model capable of predicting the complete pre‐ and post‐peak shear behaviour of deep beams. The model stems from a two‐parameter kinematic theory (2PKT) for the shear strength and displacement capacity of deep beams under single curvature. Four of the springs of the model represent the mechanisms of shear resistance of the beam, while the fifth spring models the flexural behaviour. The model predicts not only the load‐displacement response, but also the deformation patterns of the beam and how these patterns change with increasing loads. Validation studies are performed by using 28 tests from the literature showing excellent results. The model is used to interpret the tests and to draw conclusions on the behaviour of deep beams. It is shown that shear strength variations of up to 60% between nominally identical specimens can be caused by variations in the path of the critical shear cracks. It is also demonstrated that loss of bond of large reinforcing bars increases the shear capacity of deep beams. Finally, the five‐spring model is shown to effectively predict the post‐peak shear behaviour, which is important for the analysis of structures under extreme loading.
      PubDate: 2014-09-04T05:10:11.792529-05:
      DOI: 10.1002/suco.201400044
       
  • On the use of European and American building codes with low‐strength
           cement‐based composites
    • Authors: Francois Duplan; Ariane Abou‐Chakra, Anaclet Turatsinze, Gilles Escadeillas, Stephane Brule, Emmanuel Javelaud, F. Masse
      Abstract: The standard European building specifications, grouped in a 9‐volume Eurocode, describes different approaches for determining the properties of commonly used building materials such as steel, aluminium, concrete, ... The American Concrete Institute (ACI) also offers different reports concerning concrete structures (ACI 318R), lightweight concrete (ACI 213R) and its long‐term mechanical behavior (ACI 209R). Those reports, used as building codes, are also applicable when the material respects certain scope criteria. All materials which do not meet the scope criteria of Eurocode 2 or ACI reports because of their composition, properties values, or application cannot be used in the design of structures with those building codes. Regarding cement‐based materials, concretes and mortars which compressive strength is lower than the minima might not be useful for structures, however they present an interesting potential for applications such as infrastructure materials, low‐solicited slabs, ... When designing a structure/infrastructure made of those materials, the accuracy of any formula offered by those building codes should be checked before being used. This work shows the comparison between experimental measurements and the predictive formulas of the engineering properties (compressive and tensile strength, modulus of elasticity). The results show that the addition of specific aggregates which present low stiffness and strength modifies the relation between those engineering properties, which makes its estimation impossible without considering its unit weight.
      PubDate: 2014-09-04T04:40:05.933171-05:
      DOI: 10.1002/suco.201400020
       
  • Thin‐walled shell structure made of textile reinforced
    • Authors: Alexander Scholzen; Rostislav Chudoba, Josef Hegger
      Abstract: At RWTH Aachen University recently a pavilion has been constructed with a roof shell made of textile reinforced concrete (TRC), a composite material consisting of a fine grained concrete and a high‐strength, noncorroding textile reinforcement made of carbon fibres. The thin‐walled TRC shell structure demonstrates impressively the load‐bearing capacity of this innovative composite material. The present paper discusses the practical issues concerning the construction, such as the fabrication of the TRC shells using shotcrete, the concepts for the arrangement of the textile reinforcement developed, as well as the mounting of the shells on top of the precast concrete columns. The issues concerning dimensioning, assessment and numerical simulation of the load bearing behavior of TRC shells are presented in the companion paper (Part II).
      PubDate: 2014-09-04T04:40:04.635355-05:
      DOI: 10.1002/suco.201300071
       
  • Bond and anchorage of embedded steel reinforcement in the fib Model Code
           2010
    • Authors: John Cairns
      Abstract: The paper describes the changes to design provisions for embedded steel reinforcement in the fib Model Code 2010. The changes introduce new coefficients for steel grade and for clear spacing between bars, and extend the range of concrete strengths covered. The way in which the contribution of hooks or anchorages is determined calculated has been revised and the contribution of end bearing to laps and anchorages of compression bars is recognised. The revised rules represent a move away from a distinction between laps and anchorages per se towards a distinction based on the presence or absence of transverse pressure perpendicular to the bar axis within the bond length. The benefits of staggering of laps with only a proportion of bars lapped at a section are reviewed. Finally, the potential impact of performance of laps and anchorages on structural robustness is discussed, and it is concluded that this can only be achieved if bar yield precedes splitting mode bond failures.
      PubDate: 2014-08-12T06:30:07.305539-05:
      DOI: 10.1002/suco.201400043
       
  • Design of Composite Slabs with Prepressed Embossments Using
           Small‐scale Tests
    • Authors: Josef Holomek; Miroslav Bajer, Jan Barnat, Pavel Schmid
      Abstract: The load bearing capacity of steel and concrete composite slabs using thin‐walled steel sheeting with prepressed embossments is in most cases determined by its resistance in longitudinal shear. The designing of composite slabs still requires the performance of full‐scale laboratory bending tests. Small‐scale shear tests cannot include all of the influences affecting the bended slab but using an appropriate procedure the shear characteristics obtained from them can be used for determining the bending capacity of the slab. Two such procedures are compared in this paper. End constraints effectively increase the load bearing capacity of the composite slabs. Two different types of easily assembled additional end constraints are also tested and compared in this paper. Small‐scale tests are used to obtain their shear bearing characteristics and to predict the load bearing capacity of bended slabs using these constraints.
      PubDate: 2014-08-07T10:10:23.666635-05:
      DOI: 10.1002/suco.201400042
       
  • Extension of tabulated design parameters for rectangular columns exposed
           to fire taking into account second order effects and various fire models
    • Authors: Lijie Wang; Robby Caspeele, Ruben Van Coile, Luc Taerwe
      Abstract: Fire, as one of the most severe load conditions, has an important impact on concrete structures. It does not only affect the material strength, but also the structural stiffness and stability. A concrete column, compared to other structural members, has most often to cope both with vertical forces and bending moments transmitted by slabs and beams. Consequently, it is essential to find a reliable and practical way to establish interaction curves for the overall structural behaviour of concrete columns subjected to fire. In this paper, a cross‐section calculation method based on the material models of Eurocode 2 is explained and adopted to calculate interaction curves for a typical rectangular column exposed to the ISO834 standard fire. Subsequently, an iterative approach is introduced to develop interaction curves taking into account second order effects in case of four‐side heated fire exposure. The maximum permitted slenderness ratios of columns under different fire durations are obtained and compared with Eurocode 2 provisions. Finally, this method is applied to calculate the maximum permitted slenderness ratios for columns exposed to hydrocarbon fires and natural fires.
      PubDate: 2014-07-09T03:30:06.313185-05:
      DOI: 10.1002/suco.201400002
       
  • Bond behaviour of normal‐ and high‐strength recycled aggregate
           concrete
    • Authors: M. John Robert Prince; Bhupinder Singh
      First page: 56
      Abstract: The effect of concrete grade on bond between 12 mm diameter deformed steel bar and recycled aggregate concrete (RAC) has been investigated with the help of forty‐five pullout tests with concentric rebar placement for coarse recycled concrete aggregate (RCA) replacement levels of 25%, 50%, 75% and 100%. The measured bond‐slip relationships indicate similar mechanisms of bond resistance in the RAC and the natural aggregate (NA) concrete for all the grades and relatively the most accurate and least conservative predictions of the measured bond strengths were obtained from the local bond‐slip model in the fib Model Code 2010. Bond strength, when normalised to fc(3/4) gave an improved match with test data and increased with an increase in the RCA replacement levels and decreased with an increase in compressive strength and this behaviour has been sought to be explained in terms of brittleness index an analogous parameter from rock mechanics. An empirical bond stress‐versus‐slip relationship has been proposed for the 12 mm diameter bar and it is conservatively suggested that similar anchorage lengths for this bar in all the three concrete grades can be adopted for the RAC and the NA concretes.
      PubDate: 2014-06-16T06:10:14.443622-05:
      DOI: 10.1002/suco.201300101
       
  • Further Investigation of Transverse Stresses and Bursting Forces in
           Post‐Tensioned Anchorage Zones
    • Authors: Lin‐Yun Zhou; Zhao Liu, Zhi‐Qi He
      First page: 84
      Abstract: In the post‐tensioned anchorage zone, the load transfer path of anchor force can be visualized by infinite number of Isostatic Lines of Compression (ILCs), which was initially proposed by Guyon and recently attracted significant interests from a number of researchers. Based on these predecessors' work, an updated mathematical model has been proposed to analyze the bursting forces and the distribution of transverse stresses in the anchorage zone. Compared with the results of finite element analysis, the updated equations have better accuracy than the previous ones. Based on the observation that the sixth‐order polynomial expression is better than the fourth‐order, so far as the solution of bursting stresses is concerned, it can be reasonably postulated that a de facto function of the ILCs must be in existence. Additionally, it is equally interesting that the bursting forces derived by the updated analytical model is the same as the formula given by the current AASHTO‐LRFD Bridge Design Specifications based on numerical stress analyses.
      PubDate: 2014-06-16T06:20:17.066356-05:
      DOI: 10.1002/suco.201400005
       
  • Quality assessment of material models for reinforced concrete flexural
           members
    • Authors: Bastian Jung; Guido Morgenthal, Dong Xu, Hendrik Schröter
      First page: 125
      Abstract: Non‐linear constitutive models for concrete in compression are defined frequently in design codes. The engineer would generally use either the linear (in SLS) or the non‐linear (in ULS) compressive model. However, a large variety of different approaches exist in order to describe the behaviour of the cracked concrete tension zone and the selection of a corresponding model is usually based on qualitative engineering judgement. The aim of this paper is to assess the prediction quality of several concrete material models in order to provide a quantitative model selection. Therefore, uncertainty analysis is applied in order to investigate the model and parameter uncertainty in the bending stiffness prognosis for flexural members. The total uncertainty is converted into a prognosis model quality which allows the comparison between considered materials model in a quantitative manner. The consideration of the reinforced concrete in tension is based on the characterisation of the tension stiffening effect which describes the cracking in an average sense. No discrete crack simulations based on fracture mechanics are considered in the interest of the practical applicability of the considered models even for large structures. Finally, the assessment identify that the prediction quality depends on the loading level, and furthermore, the quality between the models can be quantitatively similar as well as diverse.
      PubDate: 2014-06-16T06:10:18.537099-05:
      DOI: 10.1002/suco.201300066
       
 
 
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