移动荷载对桥梁动力响应的影响研究——以开裂预应力混凝土简支梁为例

混凝土桥梁在工作过程中会产生裂缝，为分析移动荷载对开裂混凝土桥梁结构刚度的影响，对开裂梁动力响应进行分析。建立简支T梁桥有限元模型，并将移动荷载施加至有限元模型中。根据简支T梁桥破坏横向分布位置和强度的不同，研究不同工况下各梁荷载横向分布及不同移动速度对裂缝扩展宽度的影响。结果表明，数值模拟结果能较好地验证计算模型的准确性；在较大的移动荷载作用下，混凝土开裂，导致结构刚度减小、位移增大；随着移动荷载和速度的增加，开裂时间增加，结构刚度降低，持续时间增加，位移增大，使结构响应呈现明显非线性。

Research on Influence of Moving Load on Dynamic Response of Bridges under Different Moving Load Values and Different Moving Speeds——Taking Cracked Prestressed Concrete Simply Supported Beam as An Example

Concrete bridges may have cracks during the working process. In order to analyze the effect of moving loads on the structural stiffness of concrete bridges with cracks, the dynamic response of cracked beams during moving loads is analyzed. A finite element model of a simply supported T-beam bridge is established, and a motion load is applied to the finite element model. According to the different locations and strengths of the transverse damage distribution of the simply supported T-beam bridge, the transverse distribution of the load of each beam under different working conditions and the influence of different moving speeds on the crack propagation width were studied. The results show that the simulation results can well verify the accuracy of the simulation model; under large moving loads, concrete cracks will open, resulting in a decrease in structural stiffness and an increase in structural displacement; with the increase of the motion load value and velocity, the crack opening time will be longer, the structural stiffness will be reduced, the duration will be longer, and the increase in displacement will be greater, which makes the structural response appear significantly non-linear.