连续梁桥纵向阻挡型限位装置防落梁效果分析

Analysis of unseating-prevention effect of longitudinal blocking restrainers in continuous girder bridges

阻挡型限位装置在我国作为一种防落构造措施,没有经过计算和设计,难以对其防落梁效果进行有效评估。针对我国现阶段被广泛采用的多跨连续梁桥梁结构,采用非线性时程分析方法,探讨了阻挡型限位装置对结构地震反应的影响,结果表明:这种限位装置能够有效限制墩梁相对位移,发挥防落梁作用。但是由此引起的限位装置与过渡墩碰撞会显著增大过渡墩的地震响应,实际设计中应引起注意。安装限位装置还能够在一定程度上减小固定墩的变形,对结构进行延性设计时的变形能力也可以相应减小。本文还提出了针对40m跨径连续梁桥抗震设计时,阻挡型限位装置与过渡墩间隙的建议取值范围。

Domestic unseating prevention system has done as constructive measures, without design, which, can＇ t ascertain the effect of the system. Based on a widely adopted multi - span continuous bridge in our country, an seismic response analysis about the effect of blocking restrainers was being applied, using a nonlinear time - history method, which turned out to be useful to unseating prevention; howerer, the increasing seismic response of the transitional pier caused by the apply of restrainers should arrest our attention in practical design ; it also, reduce the deformation of the fixed pier in part, which was beneficial to the structure ductility design. This paper also raises a suggested value of the gap between restrainers and transitional pier for the 40m span continuous beam.