Finite element modeling of push-out tests for large stud shear connectors

An accurate nonlinear finite element model of the push-out specimen has been developed to investigate the capacity of large stud shear connectors embedded in a solid slab. The material nonlinearities of concrete, headed stud, steel beam and rebar were included in the finite element model. The damage and failure were included in the material model for the headed stud to accurately obtain the ultimate strength of the stud connector. The capacity and ductility of the connection, the load–slip behaviour and failure mode of the headed stud were predicted. The results obtained from the finite element analysis were verified against experimental results of other researches. An extensive parametric study was conducted to study the effect of the changes in stud diameter and concrete strength on the capacity and behaviour of the shear connection. The capacity and ductility of the shear connection obtained from the finite analysis were compared with those specified in EC4 and AASHTO LRFD. It is observed that the AASHTO LRFD specifications overestimated the capacity of the large stud shear connectors, whereas the design rules specified in Eurocode-4 were generally conservative for stud diameters of 22, 25 and 27 mm, and unconservative for diameter of 30 mm. The ductility of the large stud shear connectors is sufficient for practical application in composite bridges.     

Performance and design of shear connectors in composite beams with parallel profiled sheeting at elevated temperatures

This paper describes an extensive experimental and numerical study conducted to evaluate the thermo-structural response of shear connectors embedded in composite slabs with steel sheeting parallel to the steel beam, with particular focus on opentrapezoidal profiles. For this purpose, eight push-out tests were carried out at different levels of temperature. A threedimensional finite element model was developed in Abaqus and its accuracy was validated against the experimental measurements collected as part of this study. The model was then used to perform a parametric study to gain insight into the structural response at different temperatures. The experimental and numerical results were then used to evaluate the accuracy of available European guidelines for predicting the capacity of shear connectors at elevated temperatures (when embedded in composite slabs with the profiled sheeting parallel to the steel beam). Finally, a new design equation was proposed to calculate the degradation factor defining the resistance of shear connectors for different levels of temperature.     

Effect of shear connector spacing and layout on the shear connector capacity in composite beams

A three dimensional nonlinear finite element model has been developed to study the behaviour of composite beams with profiled sheeting oriented perpendicular to its axis. The analysis of the push test was carried out using ABAQUS/Explicit with slow load application to ensure a quasi-static solution. Both material and geometric nonlinearities were taken into account. Elastic-plastic material models were used for all steel components and the Concrete Damaged Plasticity model was used for the concrete slab. The post-failure behaviour of the push test was accurately predicted, which is crucial for realistic determination of shear capacity, slip and failure mode. The results obtained from finite element analysis were verified against the experimental push tests conducted in this research and also from other studies. After validation, the model was used to carry out an extensive parametric study to investigate the effect of transverse spacing in push tests with double studs placed in favourable and staggered positions with various concrete strengths. The results were also compared with the capacity of a single shear stud. It was found that shear connector resistance of pairs of shear connectors placed in favourable position was 94% of the strength of a single shear stud on average, when the transverse spacing between studs was 200 mm or more. For the same spacing, the resistance of staggered pairs of studs was only 86% of the strength of a single stud. The strength of double shear studs in favourable position was higher than that of the staggered pairs of shear connectors.     

Strength and ductility of headed stud shear connectors in profiled steel sheeting

This paper details the results and subsequent analysis of 27 push tests performed using a new push rig, which investigate the effect of variables such as mesh position, transverse spacing of shear connectors, number of shear connectors per trough and the slab depth on the resistance of headed stud shear connectors through-deck welded into a transverse deck.The analysis of these tests not only allowed characteristic resistances to be determined for the headed stud shear connectors in each case, but also enabled comparisons to be made to determine the effect of the different variables on the resistance. It found that within the limits tested the transverse spacing of the shear connectors has little effect on the resistance, and that including a third shear connector gives no benefit over using shear connectors in pairs. Locating the mesh at the top of the slab, as is common practice for crack control, gives sufficient ductility for design using the minimum shear connection rules in BS EN 1994-1-1, 6.6.1.2 (i.e. the characteristic slip capacity is greater than 6 mm, as required by BS EN 1994-1-1, 6.6.1.1(5)), but a strength enhancement of approximately 30% can be found by locating the mesh directly on top of the profiled steel sheeting. The results also indicated that the resistance increases with slab depth, but it is not clear if this is an effect of the push test or is a genuine effect of composite construction. Design rules based on these tests are proposed.     

Behaviour of headed stud shear connectors for composite steel-concrete beams at elevated temperatures

The behaviour of composite steel-concrete beams at elevated temperatures is an important problem. A three-dimensional push test model is developed herein with a two-dimensional temperature distribution field based on the finite element method (FEM) and which may be applied to steel-concrete composite beams. The motivation for this paper is to increase the awareness of the structural engineering community to the concepts behind composite steel-concrete structural design for fire exposure. The behaviour of reinforced concrete slabs under fire conditions strongly depends on the interaction of the slabs with the surrounding elements which include the structural steel beam, steel reinforcing and shear connectors. This study was carried out to consider the effects of elevated temperatures on the behaviour of composite steel-concrete beams for both solid and profiled steel sheeting slabs. This investigation considers the load-slip relationship and ultimate load behaviour for push tests with a three-dimensional non-linear finite element program ABAQUS. As a result of elevated temperatures, the material properties change with temperature. The studies were compared with experimental tests under both ambient and elevated temperatures. Furthermore, for the elevated temperature study, the models were loaded progressively up to the ultimate load to illustrate the capability of the structure to withstand load during a fire. It is concluded that finite element analysis showed that the shear connector strength under fire exposure was very sensitive. It is also shown that profiled steel sheeting slabs exhibit greater fire resistance when compared with that of a solid slab as a function of their ambient temperature strength.     

基于ANSYS的自攻螺钉波峰连接的抗剪性能有限元分析

为了满足防水要求,目前许多轻钢结构的屋面体系采用在压型钢板波峰处与构件连接的形式。由于波峰连接形式中,压型钢板和檩条不是紧密接触,因此比波谷连接形式的受力情况更加复杂。本文利用ANSYS程序,采用实体建模,并引入接触非线性,对自攻螺钉波峰连接的抗剪性能进行有限元模拟分析,并与试验结果进行对比分析。分析结果表明:有限元模型可以精细模拟出真实试件的变形和荷载位移曲线的走势,与试验结果拟合很好,应力分布规律也符合其变形和破坏模式。因此,此有限元模型可以作为替代试验分析的理想模型。     

The influence of profiled sheeting thickness and shear connector’s position on strength and ductility of headed shear connector

A three-dimensional finite element model is developed, validated and used in the parametric study to investigate the influence of shear stud’s position and profiled sheeting thickness on the strength, ductility and failure modes of the headed shear stud welded to the modern profiled sheeting. A total of 240 push tests were analysed with different sheeting thicknesses, positions of the shear stud in the trough, concrete strengths and transverse spacings. The results showed that the sheeting thickness influenced the shear connector resistance of studs placed in the unfavourable position more than studs placed in favourable and central positions. The strength of the shear connector placed in the unfavourable position increased by as much as 30% when the sheeting thickness was increased. The shear connector resistance of the unfavourable stud was found to be primarily a function of the strength and the thickness of the profiled sheeting rather than the concrete strength. The strength prediction equations for unfavourable and central studs were also proposed. The results suggested that the strength of the shear connector increased as the distance of the shear stud increased from the mid-height of the deck rib in the load bearing direction of the stud. The load-slip behaviour of the studs in the unfavourable position was more ductile than the studs in the favourable position, with slip of 2-4 times higher. It was found that the increase in sheeting thickness and transverse spacing improved the ductility of the stud in unfavourable position, but had no effect on the stud in the favourable position. The failure modes suggested that the favourable and central studs failed by concrete cone failure and unfavourable studs failed by rib punching together with crushing of the narrow strip of the concrete in front of the stud.     

Experimental and analytical investigations on the hat shaped shear connector in the steel-concrete composite flexural member

Over the last decade, there are many research results on the new type shear connectors to solve the problems associated with the headed stud shear connector. It was revealed that the new type shear connector has better structural safety, welding quality, constructability, cost-effectiveness, etc. Especially, perforated shear connector (perfobond shear connector) which has superior fatigue resistance and constructability is receiving attention among various types of shear connectors. In this study, we suggest the new type shear connector which improved the perfobond shear connector. Newly suggested hat shaped shear connector can be used instead of headed stud shear connector commonly used in the concrete-steel composite beam. To evaluate the load carrying capacity of this hat shaped shear connector, push-out tests are carried out and test results are analyzed. In addition, the finite element analysis is conducted on the concrete slab having shear connector to investigate the stress distribution pattern affected by the presence of hat shaped shear connector. The existing design equations for the perfobond shear connectors are reviewed briefly and the equation for the prediction of load carrying capacity of new type hat shaped shear connector is suggested based on the experimental results, finite element analysis results, and existing equations suggested in the previous studies.     

栓钉剪力连接件滑移性能试验研究及受剪承载力计算

根据3组栓钉剪力连接件推出试验,研究栓钉直径和栓钉屈服强度对试件受剪承载力的影响。应用ABAQUS有限元分析软件对栓钉剪力连接件进行精细三维实体有限元分析,栓钉、钢梁和混凝土均采用C3D8R单元,计算结果与试验结果符合较好。基于有限元法进行参数分析,研究栓钉直径、数量、长径比、屈服强度、混凝土强度和横向配筋率等对栓钉剪力连接件荷载-滑移性能的影响,有限元计算结果表明,栓钉受剪承载力随着栓钉直径、屈服强度和混凝土强度的增大而提高。提出了考虑栓钉直径、屈服强度和混凝土强度影响的单个栓钉受剪承载力计算式和荷载-滑移关系计算方法,计算结果与文中试验结果和收集到的81组栓钉剪力连接件有效试验结果进行对比,吻合较好。建议的受剪承载力计算式与现行规范建议公式进行比较,建议的计算式具有较高的精度。荷载-滑移曲线实用计算方法与Ollgaard提出的计算方法比较表明建议计算方法具有较广泛的适用性。     

In-plane shear behaviour of profiled steel sheeting

This paper will describe the behaviour of profiled steel sheeting under inplane shear and its application in building frames. Analytical models for shear strength and stiffness of the profiled steel sheeting are developed and validated by small scale model tests and finite element analyses. The strength, stiffness, failure modes and strain conditions are found to be greatly influenced by the boundary condition of the sheeting. The values of several factors related to the mode of attachment of the sheeting to practical building frames are studied to verify the suitability of design equations.     

Experimental investigation on behaviour of steel-concrete composite bridge decks with perfobond ribs

This paper introduces a test program conducted for steel-concrete composite bridge decks with perfobond rib shear connectors. The composite deck consists of profiled steel sheeting, perfobond ribs, steel reinforcements, and concrete. To provide longitudinal shear resistance between the profiled sheeting and the concrete, perfobond ribs were used. For a prototype steel-box girder bridge, two types of deck profiles with deck-to-girder connections were designed. To validate the effectiveness of the proposed deck system for bridge application, push-out, full-scale flexural, and deck-to-girder connection tests for each deck profile have been conducted. The results of tests have shown that the perfobond ribs can be effectively used for shear connection in the steel-concrete composite decks.     

钢-压型钢板混凝土组合梁计算的修正折减刚度法

由于滑移效应的影响 ,采用栓钉剪力连接件的钢 压型钢板混凝土组合梁的刚度和抗弯承载力均有所降低。本文在折减刚度法的基础上 ,建立了适用于钢 压型钢板混凝土组合梁的修正折减刚度计算公式 ,并进一步建立了考虑滑移效应影响的弹性抗弯承载力计算公式。公式计算结果与试验梁的实测值吻合良好     

Experimental and finite element study of profiled steel sheet dry board folded plate structures

Folded plate structures constructed with profiled steel sheeting connected to dry boards by self drilling, self tapping screws (known as the PSSDB system) are being proposed as an alternative to traditional forms of roof construction. This paper describes the analysis, testing, and the structural behaviour of such kind of structures. The proposed efficient and load bearing structural system consists of an assembly of individual PSSDB panels connected by steel angle plates at the ridges, formed to the required shape, width and span. An analytical model using finite element method has been proposed. The profiled steel sheeting was idealised as an equivalent homogeneous orthotropic thin shell plate elements of constant thickness. Two directional plate elements were proposed in modelling the connection between profiled steel sheeting and dry board to include biaxial shear deformation. The proposed analytical method has been used to analyse the results of full-scale folded plate PSSDB tests and is found to give good results.     

对组合钢梁-预制空心板中栓钉连接件的性能分析

在钢-混凝土组合梁中,剪切连接件的机械作用使得纵向剪力转移到钢翼缘/混凝土板的接合处。这种转移能力取决于剪切连接件的强度和混凝土板抵抗由剪力高度集中所导致的纵向开裂的能力。大多数对组合结构的分析都集中在传统的钢筋混凝土和金属面板结构,而对预制空心板中栓钉的剪切能力研究很少。本文对带栓钉的预制空心板组合梁结构提出标准的推力试验方法。一共进行7组测试性试验,试验结果显示新方法符合钢筋混凝土楼板规范要求。在确定这个新的标准方法后,对栓钉进行了72个足尺推力试验,确定了该类型连接件的性能,通过分析试验结果,还指出了各类参数对连接件强度和延性的作用。本文还提出了这种剪力连接件的设计公式。     

《钢结构设计规范》(GB50017—2002)钢-混凝土组合梁修订内容介绍

本文简要介绍了《钢结构设计规范》(GB50017—2002)钢-混凝土组合梁一章所做的主要修订及补充内容,包括连续组合梁负弯矩区、组合梁变形、部分抗剪连接组合梁和压型钢板组合梁的设计计算方法及理论依据。同时,对需要进一步开展的工作进行了总结。     

压型钢板组合梁滑移性能的有限元分析

利用ANSYS有限元软件对压型钢板组合梁模型进行了有限元数值模拟分析,将有限元分析结果与试验结果进行了比较,验证了模型的合理性,利用ANSYS软件对压型钢板组合梁在栓钉布置方式和混凝土板强度影响下交界面的滑移性能进行了探讨.     

Non-linear analysis of steel-concrete composite frames with full and partial shear connection subjected to seismic loads

The seismic performance of moment-resisting frames consisting of steel-concrete composite beams with full and partial shear connection is investigated. To this end, six full scale composite substructures with headed stud shear connectors have been tested and the corresponding inelastic response to both monotonic and variable reversed displacements have been investigated. Three-dimensional finite element models of the substructures set with the ABAQUS code and based on shell elements are established in order to evaluate different modelling assumptions and local effects; and to calibrate a one-dimensional model conceived with the Drain-3DX code relying on layered beam-column elements. The one-dimensional model is then exploited for a parametric study on two four-storey frames by means of non-linear dynamic analyses. The analyses have revealed that composite frames with a low shear connection degree of about 0.4 perform as well as their companion frames with full shear connection under severe seismic loads. Nonetheless, the shear connection degree should be high enough in order to protect shear connectors in the central part of beams from failure. Although their equivalent damping is not very high, shear connectors could reduce the ductility demand on other parts of a composite frame, such as beam ends or partial strength beam-to-column joints. This design option could provide a further means to achieve a favourable performance of a composite moment-resisting frame, in addition to the benefit of cost reduction.     

Capacities of headed stud shear connectors in composite steel beams with precast hollowcore slabs

In steel-concrete composite beams, the longitudinal shear force is transferred across the steel flange/concrete slab interface by the mechanical action of the shear connectors. The ability of the shear connectors to transfer these longitudinal shear forces depends on their strength, and also on the resistance of the concrete slab against longitudinal cracking induced by the high concentration of shear force. Most of the research in composite construction has concentrated on the more traditional reinforced concrete and metal deck construction, and little information is given on shear capacity of the headed studs in precast hollowcore slabs. In this paper, a standard push test procedure for use with composite beams with precast hollowcore slabs is proposed. Seven exploratory push tests were carried out on headed studs in solid RC slabs to validate the testing procedures, and the results showed that the new test is compatible with the results specified in the codes of practice for solid RC slabs. Once a standard procedure is established, 72 full-scale push tests on headed studs in hollowcore slabs were performed to determine the capacities of the headed stud connectors in precast hollowcore slabs and the results of the experimental study are analysed and findings on the effect of all the parameters on connectors’ strength and ductility are presented. Newly proposed design equations for calculating the shear connectors’ capacity for this form of composite construction are also be given.     

Performance of composite girders strengthened using carbon fibre reinforced polymer laminates

This paper highlights the structural performance of steel–concrete composite girders strengthened using advanced composite laminates. Nonlinear 3-D finite element models have been developed to investigate the flexural behaviour and load carrying capacity of the girders. The composite laminates comprised carbon fibre reinforced polymer (CFRP) plates and sheets as well as steel reinforced polymer (SRP) sheets. The elastic modulus and ultimate tensile strength of the laminates varied from low to high 60–300 GPa and 700–3100 MPa, respectively. The nonlinear material properties of the strengthened composite girder components comprising concrete, structural steel beam, reinforcement bars, adhesive and composite laminates were incorporated in the finite element model. The interfaces between the composite girder components were also considered allowing the contact and bond behaviour to be modelled and the different components to retain its profile during the deformation of the strengthened composite girder. Furthermore, the load-slip characteristic of headed stud shear connectors was incorporated in the finite element models based on previous experimental and numerical investigations conducted by the author. The finite element models have been validated against published tests on composite girders strengthened using different advanced composite laminates and having different cross-section geometries, lengths, layers of laminates with different elastic moduli and ultimate tensile strengths, concrete strengths and structural steel strengths. The load carrying capacity of strengthened composite girders, load–vertical displacement behaviour and failure modes were predicted from the finite element analyses and compared against test results. Parametric studies were conducted to study the effects on the load carrying capacity and structural behaviour of strengthened composite girders owing to the change in the composite laminate elastic modulus, number of laminate layers, concrete strengths and structural steel strengths. The study has shown that the increase in the load carrying capacity and ductility of strengthened composite girders due to the increase in steel beam strength is significant with high strength concrete slab. Also, it has been shown that the increase in concrete strength offers a considerable increase in the initial stiffness of strengthened composite girders, while the increase in structural steel strength offers a considerable increase in the stiffness of strengthened composite girder in the post-yielding stage.     

Finite element studies on profiled steel composite beams

This article is concerned with finite element studies on profiled steel composite beams to investigate their elastic and ultimate load behaviour. Finite element code LUSAS is used to carry out the non-linear analyses to determine the load carrying capacity of the beams. Results from the experimental studies reported by other researchers are first used to assess the accuracy of the finite element modelling. Analyses are carried out thereafter to study different shapes, arrangements and number of steel sheeting ribs. Effects of the parameters such as concrete compressive strength f _c, yield stress f _yp of the profiled steel sheeting, and thickness of the steel sheeting on the ultimate load capacity of the profiled steel composite beams are examined. The results are presented in the form of load-deflection plots and ultimate load values. It is concluded that the ultimate load capacity of the profiled steel composite beams can be predicted with an acceptable accuracy by the proposed finite element modelling. Results show that the load carrying capacity of the beams are influenced by shapes, arrangements and number of ribs. It is also found that compressive strength f _c of the concrete, and yield stress f _yp and thickness of profiled steel sheeting have significant influences on the performance of these beams.