为研究组合梁桥受跨中车轮荷载作用下的力学特征，进行了大比例钢混组合梁桥的试验与数值模拟.通过三点加载试验，模拟跨中固定轮载作用下钢混组合梁的受力状态，考虑了车轮加载的实际接触变形及梁端支座的实际约束影响，并对试验进行了有限元数值模拟分析，对钢筋混凝土桥面板、钢梁、抗剪连接栓钉和支座分别进行建模与计算，获得跨中轮载作用下组合梁的荷载-λ移曲线，并结合数值模拟方法分析了不同加载工况下应力应变变化以及混凝土板的裂缝发展情况.研究结果验证了本文数值模拟方法用于组合梁受力模拟的准确性，明确了跨中固定点加载情况下组合梁的破坏特征与受力状态，并准确分析了简支钢混组合梁在跨中车轮集中荷载下的受力特性.

In order to study the mechanical characteristics of composite girder bridge under mid span wheel load, the experiment and numerical simulation of largescale steelconcrete composite girder bridge were carried out. Through the threepoint loading test, the stress state of the steelconcrete composite beam under the fixed wheel load in the middle of the span was simulated, and the actual contact deformation resulted from the wheel loading and the actual constraint effect of the beam end support were considered, the finite element numerical simulation analysis of the test was carried out. The reinforced concrete bridge deck, steel beam, shear connection stud and bearing were modeled and calculated respectively. The load displacement curve of the composite beam under the mid span wheel load was obtained. Combined with the numerical simulation method, the stressstrain changes and the crack development of the concrete slab under different loading conditions were analyzed. The results verify the accuracy of the numerical simulation method in the composite beam stress simulation, clarify the failure characteristics and stress state of the composite beam under the fixed point loading in the middle of the span, and accurately analyze the stress characteristics of the simply supported steelconcrete composite beam under the concentrated wheel load in the middle of the span.