摘要
斜交桥广泛应用于各级公路和城市道路中,墩台的非对称支承特性使得斜交桥在强震作用下比正交桥更容易发生整体或局部落梁。文章基于显式动力接触算法,建立斜交桥有限元计算模型,分析了斜交桥的落梁形态及挡块破坏模式。结果表明:斜交装配式简支梁桥的落梁会经历三个阶段:主梁与背墙以及主梁与挡块的碰撞、挡块的大变形破坏、主梁失去竖向支承产生落梁;不同地震动作用下斜交简支梁桥的落梁数量和落梁形态有一定差别,可能是全部主梁落梁或两片边主梁落梁,也可能是主梁两端同时落梁或先后落梁;落梁发生时往往伴随着挡块的严重破坏。锐角处挡块的碰撞破坏程度大于钝角处挡块的破坏程度,锐角处挡块会出现大变形破坏,而钝角处挡块不会出现大变形。
Skew bridges are widely used in highways and urban roads. Asymmetric supporting feature makes skew bridge more vulnerable total or local unseating under strong earthquakes. Based on explicit dynamic contact algorithm,three dimensional finite element model of bridge is established and the unseating mode is analyzed for an assembled skew simply supported beam bridge. The results indicate that the unseating process of skew simply supported beam bridge includes three stages of collision of beam and block,great deformation damage of block and unseating with beam losing vertical support. The number and form of beam unseating are different under different ground motions. It may be all beam unseating or two side beam unseating. It may be the two ends of beam unseating at the same time or unseating successively. When beam unseating occurs the transverse displacements of the two abutments are reverse,and there is horizontal rotational deformation in the beam body. The blocks are violently collided by beam body and destroyed,so the local unseating of corner falling happens in the assembled skew beam bridge. The beam on obtuse corner unseats first and damage degree of acute block more severe than that of obtuse block.
出处
《山东建筑大学学报》
2015年第5期416-422,428,共8页
Journal of Shandong Jianzhu University
基金
国家自然科学基金项目(51178258)
关键词
斜交简支梁桥
显式动力接触算法
落梁模式
挡块碰撞破坏
skew simply supported beam bridge
explicit dynamic contact algorithm
unseating mode
block damage for collision
