中文摘要：

2008年5月12日我国四川省汶川县发生8级大地震,造成大量公路桥梁破坏。本文详细介绍了百花大桥、小鱼洞大桥、庙子坪大桥、龙尾大桥等9座典型公路桥梁的震害情况及原因。这个地区的桥梁主要为桥面连续简支梁桥,支座多为直接搁置的板式橡胶支座,地震中稳定性较差,主梁与桥墩连接较为薄弱,更多地发生横、纵向移位,乃至最终落梁。这种薄弱连接一定程度上降低了桥墩的地震荷载,总体上看桥墩震害较轻,但从破坏的桥墩、拱肋、盖梁来看,直接剪切或形成弯曲塑性铰后的剪切破坏较为多见。提出了公路桥梁抗震设计若干建议,涉及桥台抗震稳定性及强度校核、曲线梁桥和高墩桥梁设计、支座及防落梁措施设计、桥墩及构件延性设计、场地液化等多个方面。强调了抗震构造措施能够维持公路桥梁大震后应急通行功能的＂最强设计原则＂。

英文摘要：

The great Wenchuan earthquake（ Ms =8.0）occurred on May 12, 2008 in Sichuan Province of China and caused damage to many highway bridges. A description of the damage and the probable causes are presented for nine bridges including Baihua Bridge, Xiaoyudong Bridge, Miaoziping Bridge and Longwei Bridge. Almost all highway bridges in the area affected by the earthquake are simply supported continuous girder bridges with rubber bearing placed on the cap beam directly and the connections between bridge columns and girders are weak. This caused the bridge girders to slide laterally or longitudinally and even to fall under earthquake actions. The poor bearing conditions also led to the decrease of seismic loads carried by bridge columns and the damage to bridge columns was not severe, but some induced the damage to columns, arch ribs or cap beams due to shear or combining shear and flexure. Based on the lessons learned from the Wenchuan earthquake, recommendations on the seismic design of highway bridges are presented including stability and strength calculation of bridge abutments, design of curved bridges and bridges with high piers, design of bearings and devices preventing the girders from falling down, ductility of bridge columns and other structural members and site liquefaction. For performing the emergency function of the bridge it is emphasized that attention should be paid to the structural details design to avoid collapse when an unexpected large earthquake occurrs.