The steel-concrete composite girder bridge is a new type of bridge. The steel girder and concrete slab are connected together by connectors and bear the common force so that the tensile performance of steel and the compressive performance of concrete can be fully utilized. The advantages are obvious. However, research on the dynamic analysis of steel-concrete composite beam bridges is still relatively rare, and the dynamic effects on these bridges from vehicles are becoming increasingly significant. In this paper, a more complex steel-concrete composite simply supported beam bridge model and the entire vehicle model are established, and five steel-concrete connection levels of the bridge model are considered. Using the finite element model, the effects of five factors, namely, bridge natural frequency, vehicle natural frequency, vehicle speed, vehicle lateral position and bridge deck roughness, on the dynamic load allowance (DLA) of the composite girder bridge are studied. The influence of vehicle speed and bridge surface roughness on the DLA has a strong regularity. The change in the DLA of the lateral position of the vehicle is highly symmetrical, and the DLA value at the side beam is larger than that of the center beam. Changes in bridge vibration frequency and vehicle vibration frequency can bring about significant changes in the DLA, and the closer the two frequencies are, the more significant the DLA increases, and the more likely it is to produce resonance.

钢-混凝土组合梁桥是一种新型的桥梁。钢梁和混凝土板通过连接器连接在一起并承受共同的力，从而可以充分利用钢的拉伸性能和混凝土的压缩性能。优点是显而易见的。但是，对钢-混凝土组合梁桥的动力分析研究仍然相对较少，车辆对这些梁的动力影响越来越重要。在本文中，建立了一个更复杂的钢-混凝土复合简支梁桥模型和整个车辆模型，并考虑了桥梁模型的五个钢-混凝土连接层。使用有限元模型时，五个因素的影响，即桥固有频率，车辆固有频率，车辆速度，研究了组合梁桥的DLA）。车速和桥面粗糙度对DLA的影响具有很强的规律性。车辆的横向位置的DLA的变化高度对称，并且侧梁的DLA值大于中心梁的DLA值。桥梁振动频率和车辆振动频率的变化会引起DLA的显着变化，并且两个频率越近，DLA的增加就越显着，并且更可能产生共振。