强震下钢筋混凝土连续梁桥非线性动力响应分析

Nonlinear dynamic response analysis of reinforced concrete continuous girder bridge under strong earthquake excitations

为了探索连续梁桥的地震损伤演化和破坏历程,在连续梁桥1∶3模型地震振动台台阵试验基础上,对该模型桥进行了非线性动力响应分析,考虑了主梁与桥台间以及横向挡块之间的碰撞效应对地震响应的影响,弥补了模型试验未考虑碰撞效应的不足.分析结果表明:数值分析结果与振动台试验结果较为吻合,两跨连续梁模型的主要破坏模式为墩柱破坏,中墩墩底为关键截面;纵向地震动作用下该模型结构加速度反应谱小于17.4 m/s2则结构不发生倒塌破坏;若考虑桥台对主梁的纵向约束作用,则主梁加速度响应增加、主梁位移减小、墩柱受力减轻,且该约束作用随接触间隙减小而越发显著;若考虑梁和挡块之间的碰撞,则主梁加速度增大,墩柱受力随着间隙的增加而增加.该研究成果可为后续连续梁桥的抗倒塌设计和抗震加固提供参考.

To explore the seismic damage evolution and failure history of the continuous girder bridge model, a nonlinear dynamic response analysis was made based on the shaking table test of a scaled 1：3 bridge model. Collisions between the girder and the abutment and those between the girder and the shear key were discussed to compensate for test results without considering the impact of collision. The analysis results indicate that numerical analysis results are consistent with those from the shaking table array test. The main failure mode of a two-span continuous girder model is the destruction of piers, and the lower cross section of middle pie is the vital place. The bridge model will not collapse under longitudinal shaking on the condition that the acceleration response spectrum of the girder is less than 17. 4 m/s^2. If the collision between the girder and the abutment is considered, the acceleration of main girder becomes larger, the displacement of main girder becomes less, and the internal forces of pier column will be less. The effects are more significant with the decrease of contact gap. If considering the collision between the girder and the shear key, the acceleration of main girder increases, and the force of pier column increases with the increase of contact gap. This study provides references for sub-sequent anti-collapse design and seismic retrofit of concrete continuous girder bridges.