Abstract:
Designing problem and theoretical analyses of steel-concrete composite structures are especially emphasized in bridge engineering. Method of modelling composite constructions developed and established by standards had been improved by use of finite element method and modern software. By this paper authors wanted to point out the importance of adequate structure modelling assuming all features of steel-concrete bond, and comparing results of experimental research with results of software calculation based on FEM and calculation based on plane theory approach with certain simplifications. Because of research tests necessities the bridge was loaded with four heavy test vehicles. Results, which are represented graphically and numerically were essence for suggestion of giving advantages to area element discretization of composite section over the other one.

Abstract:
Nonlinear behaviour of stud connected steel-concrete composite girders is numerically studied in this paper. Focus of the study is to develop and validate a three-dimensional finite element model. Numerical results are compared with that obtained from an experimental study conducted by authors. Brief description of the experiment to the extent required for validation is provided in the paper. A sophisticated 3D finite element model of the composite girder is developed using ABAQUS software. Nonlinear damage plasticity model is considered for modelling concrete. Suitable interface elements combined with the constraints are used to describe interaction among the concrete slab, steel beam and studs. Besides the interaction between concrete and steel, appropriate value of friction coefficient is also used. Validation of the model is done in terms of comparing the predicted energy absorption capacity, slip at interface, cracking and crushing of the concrete, yielding and local buckling of steel beam flanges with the corresponding values obtained in the experiments. Energy absorption capacity of the composite girder obtained from the finite element analysis corroborated well with corresponding measured values. It is observed that the FE model predicts a conservative value for ultimate load.

Abstract:
Steel-framed buildings are typically constructed using steel-deck-reinforced concrete floor slabs. The in-plane (or diaphragm) strength and stiffness of the floor system are frequently utilized in the lateral load-resisting system design. This paper presents the results of an experimental research program in which four full size composite diaphragms were vertically loaded to the limit state, under static or dynamic loads. Two test specimens were provided with longitudinal steel-deck ribs, and the other two specimens with cross steel-deck ribs. Typical composite diaphragm limit states are described, and the controlling limit state for each of the full size tests is indicated. The interaction effects between the reinforced concrete slab and the steel girder on the composite slab strength and stiffness were mainly studied.

Abstract:
A simple technique is proposed to compute interface slip of stud connected steel-concrete composite (SCC) girders based on the results of a flexure test. The technique makes use of relative longitudinal displacement of the concrete slab and steel beam to calculate the interface slip. In the flexure test of a SCC girder, a cost-effective instrumentation arrangement consisting of mechanical dial gauges is used to measure the relative longitudinal displacement. Responses measured from experiments on SCC girders conducted by the authors are used for numerical implementation and validation of the technique. Alternatively, interface slip is also evaluated by applying an analytical model which is based on first principles of mechanics. The values of interface slip computed by using the proposed technique are found to have close correlation with those of the analytical model. The effect of edge restraint on slip due to friction between steel and concrete is also studied

Abstract:
为定量了解组合梁中钢与混凝土界面上粘接力及摩擦系数等基本物理参数的大小，通过一系列试验测试了工程上常用的钢与混凝土界面涂装形式的黏结强度和摩擦系数.设计制作了16组试件测试钢与混凝土之间的抗剪黏结强度，考虑了试件界面尺寸效应、不同界面涂装形式及不同的法向压力的影响；设计制作了6组试件测试不同界面涂装形式下的钢与混凝土界面抗拉黏结强度；设计制作了6组试件测试了不同界面涂装形式下钢与混凝土界面的静、动摩擦系数.研究表明：界面尺寸效应对钢与混凝土界面的强度影响不大；界面涂装形式对界面的黏结强度影响较大，抗剪强度在0.04~0.28 MPa之间，抗拉强度在0.38~0.82 MPa之间，静摩擦系数在0.73~1.06之间，动摩擦系数在0.5~0.74之间；法向压力对界面的剪切黏结强度影响较大，且满足库仑摩擦模型. In order to quantify the basic physical parameters of steel concrete interface of composite girders, a series of experiments were conducted to measure the bond strength and friction coefficients of steel concrete interface with different painting ways which are commonly used in engineering. 16 groups of specimens were designed and tested to measure the shear bond strength of steel concrete interface with a consideration of the influence of specimen size effect, painting way and normal pressure of the interface. 6 groups of specimens with different painting ways were designed and tested to measure the tensile bond strength of steel concrete interface. Another 6 groups of specimens with different painting ways were designed and tested to measure the static and dynamic friction coefficient of steel concrete interface. The results of tests show that the size of steel concrete interface has little influence on the bond strength, but the painting way of the interface has great effect on the bond strength. With different painting ways, the shear bond strength is between 0.04 and 0.28 MPa, the tensile bond strength is between 0.38 and 0.82 MPa, the static friction coefficient is between 0.73 and 1.06, and the dynamic friction coefficient is between 0.50 and 0.74. The normal pressure and shear bond strength of steel concrete interface are correlated, which follows the Coulomb friction model

Abstract:
为准确分析单箱双室组合箱梁的剪力滞效应，考虑钢混凝土的界面滑移效应和钢腹板的剪切变形，针对顶底板和翼板定义不同的剪力滞翘曲位移函数，基于能量变分法推导出单箱双室组合箱梁剪滞效应的控制微分方程及其闭合解。以单箱双室组合箱梁算例为基础，利用该方法分析其剪力滞效应的规律，结果表明：在同时考虑滑移和剪切变形时，组合箱梁的挠度比初等梁理论解大，且其挠度随界面滑移刚度的增大而减小；组合箱梁在均布荷载作用下，滑移量与荷载值近似成正比关系；在相同条件下，钢箱梁底板的剪力滞效应较混凝土顶板显著。 The effect of slip of the steel-concrete interface and shear deformation of the steel webs were considered to accurately analyze the shear lag effect of the double-cell composite box girder. The different shear lag warping displacement functions for the top and bottom plates are defined. Based on energy method, the control differential equation and the closed-form solution for the double-cell composite box girder are derived. As an example, the shear lag effect of a single box double-cell composite box girder is analyzed by using proposed method. The results show that the deflection of the composite box girder when considering the slip and the shear deformation is obviously larger than that obtained by the elementary beam solution, and which will decrease with the increase of interface slip stiffness. The slip value is approximately proportional to load heavy. The effect of shear lag on bottom steels lab of the box girder is more significant than that on top concrete slab.

Abstract:
为了研究后结合预应力技术改善混凝土桥面板组合梁在负弯矩作用下的受力性能，特别是混凝土的开裂性能，设计制作了2根组合梁（一根是常规混凝土桥面板组合梁，另一根是后结合预应力混凝土桥面板组合梁），进行了2根组合梁的静力试验.测试了在不同荷载作用下组合梁的变形、不同截面上构件的应变分布、混凝土的裂缝、钢与混凝土之间的相对滑移以及极限承载力等.试验结果表明：后结合预应力混凝土板连续组合梁的初始开裂荷载和正常使用状态的极限荷载分别是普通连续组合梁的3.87倍和5.38倍，说明采用后结合预应力混凝土桥面板能够大大提高组合梁负弯矩区混凝土的抗裂性能. In order to study the improving mechanical behavior of composite girder on the hogging moment zone with post combined prestressed concrete slab, especially on the concrete cracking property in this range, two composite girders, one being common composite girder and the other composite girder with post combined prestressed concrete slab, were designed and fabricated, on which static tests were conducted. The main mechanical behaviors including girder deformation, strain distribution, concrete cracks, relative slip between steel and concrete, bearing capacity etc were tested. The testing results show that the load for initial concrete cracking and that for serviceability limit state of composite girder with post combined prestressed concrete are 3.87 times and 5.38 times of those of common composite girder respectively, which indicates that adopting post combined prestressed concrete slab for composite girder can significantly improve the resistance cracking ability in the negative zone of composite girder

Abstract:
为探讨波形钢腹板内衬混凝土和焊接加劲肋的两种构造波形钢腹板组合梁抗震性能，通过剪跨比为1.67的波形钢腹板组合梁缩尺模型拟静力加载试验，比较分析了破坏特点、滞回曲线、承载力、延性、强度与刚度退化、耗能能力、变形恢复能力等基本力学特性.研究结果表明：钢腹板内衬混凝土和焊接加劲肋的波形钢腹板组合梁分别为弯剪和剪切破坏，腹板分别发生局部屈曲和整体屈曲，混凝土板根部均产生剪切斜裂缝；内衬混凝土相比焊接加劲肋的波形钢腹板组合梁的承载力、延性和耗能能力较高；两种构造均可提高腹板稳定性，滞回曲线形状相对饱满，强度退化系数均大于0.9，粘滞阻尼系数大于0.2，残余变形率小于0.61，表明两种构造的波形钢腹板组合梁强度退化不明显，耗能能力和变形恢复能力较强. To investigate the seismic behaviors of partially encased composite girder with corrugated steel web and composite girder with stiffened corrugated steel web, the pseudo static models tests with shear span ratio of 1.67 were conducted. The basic seismic performances including failure features, hysteretic curves, load-carrying capacity, ductility, strength and stiffness degradation, energy dissipation and deformation recovery ability were analyzed. The results indicate that the partially encased specimen presented bending-shear failure with local buckling of the corrugated steel web, while the stiffened one was failed by shearing and overall buckling of the web. In addition, the inclined cracks appeared at the end of fixed part for all tested bodies. Compared with the stiffened girder, the partially encased one exhibited a higher load-carrying capacity, ductility and energy dissipation ability. These two kinds of webs can improve the stability of the corrugated steel web, the hysteretic curves are relatively plump and the strength degradation coefficients are greater than 0.9, the viscous damping coefficients are more than 0.2, and the residual deformation ratios are less than 0.61. All of these data indicate that the proposed webs have the smaller strength degradation, and greater energy dissipation and deformation recovery ability.

Abstract:
为定量了解组合梁桥中钢与混凝土界面上各种连接效应的作用，提出一种能够考虑钢与混凝土界面上包括连接件效应、黏结效应和摩擦效应的计算分析方法，通过试验验证该方法是可行的.利用该方法计算分析了组合梁中不同连接效应对组合梁应力及钢与混凝土界面滑移的影响，也研究了考虑钢与混凝土界面黏结效应与否对组合梁各部分构件受力的影响,得知钢与混凝土界面黏结效应对组合梁中钢梁和混凝土的受力影响较少，但对连接件剪力影响较大，在不同荷载作用下剪力降低最大可达到25%. In order to quantitatively reveal the combination of steel and concrete interface, an analysis method was provided for the calculation of composite girder considering connectors, bond stress and friction in the interface between the steel and the concrete. The feasibility of the method was also verified through the experiment. This method was used to analyze the relationship between different steel concrete connecting conditions and interface slip and also the effect of the present or not of the interface bonding on the mechanical behavior of the composite girder was analyzed. The results show that, the steel concrete interface bonding effect has a tine effect on the stress of the concrete slab and steel girder, but has a large effect on the shear force of the connectors where the maximum effect can reach 25 percent under different loads

Abstract:
为研究箱梁剪力滞效应和钢腹板剪切变形对波形钢腹板PC箱梁桥挠度的影响，基于能量变分法对该桥型的挠度计算进行了分析.首先，从箱梁翼板的面内剪切变形和弯曲剪力流的分布规律出发，在理论上推得可同时考虑箱梁剪力滞效应和钢腹板剪切变形的纵向位移函数；其次，以所得的纵向位移函数为基础，运用能量法推导出该桥型的挠度计算公式，并用模型试验及有限元法对公式的正确性进行了验证；最后，分析在箱梁宽跨比和钢腹板高度变化时，在不同荷载类型作用下，箱梁剪力滞效应和腹板剪切变形分别对波形钢腹板PC简支和连续箱梁桥挠度的影响.研究结果表明：当宽跨比为0.108~0.650时，在集中荷载作用下，剪力滞效应和钢腹板剪切变形对波形钢腹板PC连续箱梁桥的挠度影响较大，不可忽略；当宽跨比为0.108~0.650时，在均布荷载作用下，波形钢腹板PC简支和连续箱梁桥仅需考虑波形钢腹板剪切变形对其挠度的影响，只有在特定的宽跨比和特定的波形钢腹板截面高度下，才需要考虑剪力滞效应对其挠度的影响. ：In order to study the effects of shear lag and shear deformation caused by corrugated steel webs on the deflections of prestressed concrete (PC) box girder bridges with corrugated steel webs (CSWs), the deflection calculation for this type of bridge was calculated based on the energy variational method. First, based on the in-plane shear deformation of the flange plates and the distribution law of flexural shear flow, the longitudinal displacement function for this type of bridge was derived. This function can be used to estimate the shear lag effect and the shear deformation of CSWs. Second, based on the obtained longitudinal displacement function, the deflection formulas for a box girder bridge with CSWs were obtained using the variational principle method. The effectiveness of the formulas was verified using model tests and the ANSYS finite element analysis. Finally, variations in the width-span ratio and the heights of CSWs were made, under different types of loads, to study their influences on shear lag and shear deformation, and thereby on the deflections of simply supported and continuous box girder bridges with CSWs. The results show that when the width-span ratio is 0.108-0.650, the shear lag and the shear deformation of CSWs have significant effects on the deflection of continuous box girder bridges with CSWs, when under a concentrated load, which cannot be ignored. When the width-span ratio is 0.108-0.650, the effects of shear deformation of CSWs on the deflection of simply supported and continuous box girder bridges with CSWs, should only be considered under uniform load, while the effect of the shear lag should only be considered under specific span-width ratios and specific heights of CSWs