强震作用下桥台对斜交连续梁桥抗震性能的影响研究

为研究强地震作用下,桥台及台后土体对斜交连续梁桥抗震作用的影响。以一座三跨连续斜交箱梁桥为依托,应用sap2000建立不同斜度的模型,针对有、无桥台两种工况,采用非线性时程分析方法,研究了纵向不同地震动强度输入下,桥台及台后土体作用对不同斜度的连续梁桥主梁和桥墩位移的影响规律,并对桥墩的延性性能进行分析。研究结果表明:桥台及台后土体的存在会抑制主梁的纵向位移,大大增加主梁梁端的横向位移,地震动幅值越大,这种作用越明显;桥台及台后土体作用会减小墩顶纵向位移和墩底纵向弯矩,降低桥墩纵向位移延性需求,提高桥墩纵向安全性,斜交角越大,该影响效果越小;桥台作用对桥墩的横向反应几乎无影响。建议在桥梁抗震设计时应考虑桥台以及台后土体的作用,并针对不同斜度的连续梁桥采取相应的抗震措施,以提高其抗震性能。

Study on the influence of abutment on seismic performance of skew continuous girder bridge under strong ground motion

In order to study the influence of abutment and soil behind abutment on the seismic behavior of skew continuous girder bridge under strong ground motion.Based on a skew box girder continuous bridge with three spans,bridge models with different skew angles were constructed using the software of SAP2000.The nonlinear time-history analysis method was used to study the working conditions of bridge with abutment and non-abutment.Under different amplitude of seismic waves,the influence of abutment and abutment backfilling on the displacement of main girder and piers of continuous girder bridges with different skew angles were studied,and the ductility of pier was also analyzed.The results show that the existence of abutment and soil behind abutment can restrain the longitudinal displacement of the girder,and greatly increase the lateral displacement of the edge of girder.The greater the earthquake amplitude,the more obvious the effect is.The absence of abutment will reduce the longitudinal displacement of pier and bending moment of pier,reducing the ductility requirement of pier longitudinal displacement,and improve the longitudinal safety of pier.The bigger the skew angle is,the smaller the effect will be.The effect of abutment on the transverse response of piers has little effect.In order to improve the seismic performance of bridge,it is suggested that the effect of abutment and abutment backfilling should be considered in design of the bridges,and corresponding seismic measures should be taken for continuous girder bridges with different angles.