Steel-concrete Composite Members Research Articles

Finite Element Analysis of Anchor Leg Improved Trough Embedded Parts Based on ABAQUS

Reasonable and accurate simulations of failure behaviors of steel-concrete composite members with trough embedded parts is of great significance for the study of joint failure mechanism of prefabricated components in assembled buildings. Based on the implicit solution module of ABAQUS, the anchor legs of 5234 trough embedded parts are redesigned. The cylindrical anchor legs are designed as anchor plates with different diameter holes. The finite element model of the anchor leg of improved 5234 trough embedded parts and that of concrete are established. The mechanical properties of the specimens under bending and shear failure are simulated. And take a research on the improved trough embedded parts. The results show that the ultimate stress of concrete and the ultimate stress of embedded parts decrease first, then increase and then decrease with the increase of the diameter of circular hole, and the displacement of anchor leg of embedded parts decreases first and then increases with the increase of the diameter of circular hole. When the diameter of circular hole is 10.0 mm, the ultimate stress of concrete, the ultimate stress of embedded parts and the displacement of anchor leg are the smallest, and the mechanical properties of embedded parts are improved the most.

Design resistance evaluation for steel and steel-concrete composite members

This study evaluates the performance of the design equations given in the Australian/New Zealand bridge and steel structures design standards AS 5100.6, AS 4100 and NZS 3404.1 based on reliability analysis. For this evaluation, the following two methods were utilised: (i) a capacity factor calibration method to meet the target reliability level when there are a limited number of steel yield strength tests; and (ii) an inverse reliability analysis method to calculate the required minimum number of steel yield strength tests to achieve the target reliability level when using capacity factors provided in the design standards. The methods were applied to steel and composite members including I-beams, hollow section columns, CFST columns, and composite beams. To ensure the adoptability of imported steel for these members, structural steel that conforms to European, Korean, Japanese, American, Chinese and Australasian manufacturing standards were considered in the analyses. The results showed that, for an infinite range of manufacturing data, the capacity factors were insensitive to the different manufacturing tolerances. Furthermore, when a limited number of mechanical tests were available, a much larger number of results were needed to achieve the target capacity factor for composite members in comparison with non-composite members. Finally, when considering hollow sections used as columns, the current design equations were unable to deliver the target reliability levels for any of the manufacturing standards used internationally.

Concrete-filled bimetallic tubes (CFBT) under axial compression: Analytical behaviour

Concrete-filled bimetallic tubes (CFBT) could be recognized as a type of steel-concrete composite members, and have the potential to be applied in engineering structures. A three-dimensional finite element analysis (FEA) model is established to further study the axial compressive behaviour of circular CFBT stub columns in this paper. The preciseness of the FEA predictions is evaluated by comparison with experimental results collected from ten CFBT column specimens tested in a companion paper (Ye et al., 2016) [15]. Good agreement is obtained between the FEA predictions and the test results in terms of failure pattern, load versus deformation response, ultimate strength, and strain development of the two steel tube layers. In light of the FEA results, the stresses of concrete and steel, as well as the interactions and load distribution between different components of the composite section are investigated. Finally,parametric study is performed and a simplified model is proposed to be used to calculate the ultimate strength of circular CFBT stub columns.

Behaviour of steel tubular members infilled with ultra high strength concrete

This study is motivated by increasingly prevalent use of high strength steel and concrete materials in high-rise buildings to achieve better structural performance with less material usage. Previous studies and many modern design codes place some limits on the strength of steel and concrete for designing steel-concrete composite members, attributed to insufficient test data and design experience on their applications in construction. With this research gap being identified, an experimental program has been carried out to investigate the composite behaviour of concrete filled steel tubes (CFST) employing high tensile strength steel (HTS) and ultra-high strength concrete (UHSC). Both concentric and eccentric compression loads were applied to evaluate the overall buckling resistances and moment-axial force interaction with second-order effect considered. The yield strength of HTS under the investigation was about 800N/mm2 and the concrete compressive cylinder strength was up to 200N/mm2. To examine the test results, the rotational stiffness of semi-rigid end supports was analytically derived and the stress-strain models of HTS and UHSC were properly calibrated to predict the composite behaviour through finite element analysis. The Eurocode 4 approach was then checked regarding its applicability to the said high- and ultra-high strength construction materials for composite design. A new database including 1160 test data was established to further study the reliability of the use of HTS and UHSC, and suggestions were made to extend the Eurocode 4 design approach.

Comparative investigation on influences of concrete material constitutive models on structural behavior

This analysis was carried out based on the smeared crack model and plasticity damage model in general finite element program ABAQUS. Comparison and analysis were made on the key factors of concrete constitutive models that have effect on the static mechanical behavior of structural members. Then the mechanical behavior of reinforced concrete members and steel-concrete composite members under monotonic loading and cyclic loading were simulated using various concrete constitutive models. Both the smeared cracking model and the plasticity damage model could accurately simulate the macroscopic response of flexural concrete members or flexural composite members subjected to monotonic load, and the smeared cracking model was more accurate in simulating the cracking behavior of concrete, applicable for analyzing the stress situation of concrete during stress-strain space constantly changing after cracking. Besides, the plasticity damage model could be adopted to simulate the stress behavior of concrete structures or composite structures under the action of cyclic load. The two models could not accurately simulate the whole process of stress behavior of concrete in two-dimensional or three-dimensional stress state.

Flexural performance of concrete filled tubes with high tensile steel and ultra-high strength concrete

The use of high strength materials in steel-concrete composite members is expected to provide greater resistance meanwhile fulfilling the requirements of sustainable construction. Many of the modern design codes place some limits on the strength of steel and concrete in designing steel-concrete composite members due to limited test data and design experience on their applications in construction. The use of high strength materials was found to have noticeable benefits in high-rise building construction. To extend their applications, a comprehensive experimental program has been carried out to investigate the behaviour of concrete filled steel tubes (CFSTs) with high tensile steel and ultra-high strength concrete at ambient temperature. This paper presented new test results on the structural performance of CFST members subject to flexural loads. High tensile steel with yield strength up to 780MPa and ultra-high strength concrete with compressive cylinder strength up to 180MPa were used. The test results seek to clarify if the cross-section plastic moment resistance can be achieved if high tensile steel and ultra-high strength concrete are used in CFST members. The maximum moment resistance from tests were compared with the analytical results predicted by Eurocode 4 method. Then design recommendations were provided so that Eurocode 4 method could be safely extended to determine the flexural resistance of CFST members with high tensile steel and ultra-high strength concrete.

Behavior of Hollow Composite Steel-concrete Members under Long-term Axial Compression

Research results related to the behavior of hollow composite steel-concrete members under short-term loading are well known. Such members consist of two materials — steel and concrete with very different properties. They have different rheological behavior. Steel rheological behavior can be neglected at normal temperatures, but deformations are significant for concrete creep. Concrete creep phenomenon is well examined, but such knowledge cannot be applied directly to a composite member. Permanent actions are responsible for a large portion of external actions acting on compressed structural members. Research of composite members under long-term actions is necessary to ensure the reliable design of such structures.

Analytical equations for interfacial stresses of composite beams due to shrinkage

Long term effects due to shrinkage may lead to deformations in steel-concrete composite members that are to be taken into account in the verification of the in-service condition. Simultaneously, tangential and normal stresses develop at the connection between concrete and steel and they can result in uplift effects, especially in end regions. In this paper, an analytical model is presented and closed-form solutions are derived in order to quantify deflections of composite members with partial interaction, as well as stresses and relative displacements at the connection. It is shown that deflections and tangential stresses/slips can be properly obtained if equal curvatures between the components of the composite member are assumed. Nevertheless, such a hypothesis must be abandoned in order to reproduce uplift effects at the interface and a new model is presented to derive the distribution of normal stresses.

Shear Strength of the Perfobond Connection of a Steel-Concrete Composite Slim Floor System

The use of steel-concrete composite members has been significantly increased as they have the advantages of the reduction of cross sectional areas, excellent ductility against earthquake loadings and a longer life span than typical steel frame members. In this paper, push-out tests were performed on six specimens to investigate the structural behavior and shear strength of perfobond connection of a steel-concrete composite slim floor system. An equation to theoretically estimate the shear strength of the perfobond connection is proposed, and its accuracy is examined by comparing its predictions with the test results. A finite element analysis model is also developed and used to confirm the effectiveness of the proposed strength equation.

Frame Element with Mixed Formulations for Composite and RC Members with Bond Slip. I: Theory and Fixed-End Rotation

AbstractThis paper proposes a composite frame element for the simulation of the inelastic response of structural members made up of two or more components with different materials, such as reinforced concrete (RC), steel-concrete composite members, prestressed members, and members with fiber-reinforced polymer (FRP) reinforcement. The element accounts for the relative slip at the interface between the components. Nonlinear geometry effects are accounted for through the corotational formulation, which permits the response simulation of composite frame elements under large displacements. The element formulation enhances the standard Hu-Washizu variational principle with fields describing the bond-slip behavior between components. Three alternatives for the mixed formulation of the element are derived in this paper, which focuses on theory and implementation: mixed-displacement, mixed-force, and mixed-mixed. The paper presents the benefits and shortcomings of the formulation alternatives for modeling the pul...

Cracking in Concrete near Joints in Steelconcrete Composite Slab / Zarysowanie Płyty Żelbetowej W Strefie Przywęzłowej Stropu Zespolonego

Abstract In this paper results of the experimental tests of four full-scale composite steel-concrete elements are reported. In the steel-concrete composite elements, a steel beam was connected with a slab cast on profiled sheeting, by shear studs. The end-plates were (the thickness of 8 mm, 10 mm and 12 mm) thinner than in ordinary design. Joints between the column and the beams have been designed as semi-rigid, i.e. the deformations of endplates affect the distribution of forces in the adjacent parts of the slab. The paper presents the theory of cracking in reinforced concrete and steel-concrete composite members (according to the codes), view of crack pattern on the surface of the slabs and a comparison of the tests results and the code calculations. It was observed, that some factors influencing on crack widths are not taken in Eurocode 4 (which is based on Eurocode 2 with taking into account the phenomenon called „tension stiffening”).

Failure Mode and Experimental Method Research for Bond-Slip of Cold-Formed Thin-Walled Steel and Foam Concrete Composite Member

According to the previous experimental research on bond-slip, select push-out test as experimental method research on bond-slip between cold-formed thin-walled steel and foam concrete. Through the observation of the specimens in the push-out test, combining with the natural bonding mechanism and influencing factors summarized the failure mode and its law of composite member. The reference and basis for the experimental research and theoretical analysis of it in the future are provided.

Flexural Behavior of Prestressed Steel-Concrete Composite Members with Discontinuous Webs

The corrugated webbed prestressed (CWPS) composite member was developed to improve the efficiency of the prestress introduced into the steel beam, and experimental studies were performed to examine its structural behavior. Additionally, a unified analysis model that can estimate the nonlinear flexural behavior of the composite member and the accordion effect of the corrugated webbed steel beams at the prestressing stage was proposed. As a consecutive experimental series, in this study, the discontinuous-webbed prestressed (DWPS) composite member was developed, and this innovative composite member can reduce the amount of steel materials used, compared with the former CWPS composite member. Flexural tests were carried out to investigate their structural performances, and their behaviors were analyzed in detail by a nonlinear finite element analysis.

Shear resistance of stud connectors in high strength concrete

The use of steel-concrete composite members has been significantly increased as they have the advantages of the reduction of cross sectional areas, excellent ductility against earthquake loadings and a longer life span than typical steel frame members. The increased use of composite members requires an intensive study on the shear resistance evaluation of stud connectors in high strength concrete. However, the applicability of currently available standards is limited to composite members with normal and lightweight strength concrete. In this paper, push-out tests were performed on 24 specimens to investigate the structural behavior and shear resistance of stud connectors in high strength concrete. Test parameters include the existence of shear studs, height to diameter ratio of a shear stud, its diameter and concrete cover thickness. A shear resistance equation of stud connectors is proposed through a linear regression analysis based on the test results. Its accuracy is compared with those of existing shear resistance equations for studs in normal and lightweight concrete.

Recent progress of seismic research on tall buildings in China Mainland

As a result of rapid economic growth and urbanization in the past two decades, many tall buildings have been constructed in China Mainland, offering researchers and practitioners an excellent opportunity for research and practice in the field of structural engineering. This paper reviews progress by researchers throughout China Mainland on the seismic research of tall buildings, focusing on three major topics that impact the seismic performance of tall buildings. These are: (1) new types of steel-concrete composite structural members such as steel-concrete composite shear walls and columns, (2) earthquake resilient shear wall structures such as shear walls with replaceable structural components, self-centering shear walls and rocking walls, and (3) performance-based seismic design, including seismic performance index, performance level and design method. The paper concludes by presenting future research needs and directions in this field.

Experimental Study on Seismic Behavior of Full Encased Steel-Concrete Composite Columns

AbstractWith the rapid development of high-rise buildings in China, the steel-concrete composite structure is widely used because of its excellent seismic performance. So far, all of the high-rise buildings that rise more than 300 m in China are of a steel-concrete composite structure, which are designed based on Chinese codes. During the construction process, two main problems are encountered, as follows: (1) minimum stirrup ratio, and (2) embedded depth ratio for steel-concrete composite columns, which are strictly limited by Chinese codes. To solve those problems, 26 steel-concrete composite columns were tested under low cyclic reversed loading to simulate an earthquake load. By analyzing the failure patterns, hysteresis loops, skeleton curves, energy-dissipation capacity, and ductility of such specimens, the influence of the axial compression ratio, stirrup ratio, steel section shape, and steel embedded depth ratio on the seismic behavior of steel-concrete composite members are discussed. In accordanc...

Experimental study on concrete filled elliptical/oval steel tubular stub columns under compression

A concrete filled elliptical/oval steel tubular (CFEST) member consists of elliptical/oval steel tube and in-filled concrete. The CFEST member is a new type of steel–concrete composite member and is part of a family of concrete filled steel tubular members known as CFT. The present study aims to investigate, experimentally, the characteristics of CFEST stub columns under centric loading. The main test parameters selected are diameter-to-thickness and diameters ratios of elliptical/oval steel tube. From the results, local buckling of the elliptical/oval steel tube associated with shear failure of in-filled concrete could be observed. Axial loading capacity decreased as diameter-to-thickness ratio increased. Whereas, those capacities normalized by the summation of the individual strengths, namely the elliptical/oval steel tube and in-filled concrete strengths, are regulated in case the diameter-to-thickness ratio becomes larger. Finally, a method to predict the axial loading capacity induced by confinement effects of the in-filled concrete is proposed.

土木分野・鋼・コンクリート合成版（沈埋トンネル）

土木分野・鋼・コンクリート合成版（沈埋トンネル）

Concrete Creep and Shrinkage Effect Analysis Program Development

In order to analysis of concrete based on ABAQUS, A creep and shrinkage of concrete analysis program TDPA was developed. Firstly, the theory of creep and shrinkage effect of concrete was introduced. with the help of a Dirichlet series properties, creep stepwise recursive method was introduced to avoid stress history of large capacity storage; Secondly, using three user subroutine interface USDFLD, GETVRM, UEXPAN provided by ABAQUS, analysis program TDPA was developed by Fortran program language; Finally, typical long-term load tests of pre-stressed concrete and steel concrete composite members long term tests were selected to prove the reliability of TDPA. Research results show that: the TDAP has high applicability and reliability. It is suitable for a variety of creep and shrinkage prediction model, and provides an effective method for creep and shrinkage of concrete analysis on ABAQUS platform.

Steel and Steel-Concrete Composite Columns of HEA-Cross-Sections with Member Imperfections, Subjected to Buckling Compression

The paper deals with the problems of the load-carrying capacity of steel and steel-concrete composite members composed of high-strength materials, subjected to compression. The attention is mainly paid to the buckling resistance in the connection with member imperfections, which are usually covered by the equivalent initial geometrical imperfection expressed as the maximal initial member curving in the mid-length of the buckled member subjected to compression. The paper is oriented to the analytical solution of the initial eccentricity based on the conception of the buckling strength and to the possibilities how to verify the initial imperfection experimentally. The analysis of this problem is shown on the examples of steel and steel-concrete composite columns represented by open HEA cross-section and by the same cross-sections partially encased by normal-strength and high-strength concrete. Using test results of the specimens subjected to compression the comparison of actual values of initial imperfections with the corresponding theoretical values is presented here.