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针对“5.12”汶川地震中公路桥梁破坏严重,且破坏形式在映秀—北川断裂带南北两段出现了显著差异的情况,从震源机制、断裂带运动方式和桥梁结构本身特点等方面分析了产生这一差异的原因;并在汶川地震典型的桥梁震害分析的基础上,对强震区梁桥和拱桥的抗震设防提出了一些建议。结果表明:在断裂带南段由于地震释放能量巨大,断层逆冲作用显著,桥梁结构在强大竖向和水平地震力的共同作用下出现了桥墩、拱圈断裂导致的结构垮塌等强度失效型破坏;在断裂带北段断层右旋走滑作用显著而逆冲作用微弱,桥梁结构在剧烈的地面水平错动下出现了上部结构的落梁和双曲拱的垮塌等位移型破坏。
In view of the significant damage to the road and bridge during the “5.12” Wenchuan earthquake, and the damage pattern in the two sections of the Yingxiu-Beichuan fault, significant differences have occurred. The focal mechanism, the movement mode of the fault zone and the characteristics of the bridge structure are analyzed The reasons for this difference are also discussed. Based on the analysis of the typical seismic damage of bridges in Wenchuan earthquake, some suggestions are put forward for the seismic fortification of girder bridge and arch bridge in strong earthquake area. The results show that in the southern section of the fault zone, due to the huge energy released by the earthquake and the significant thrust fault, the failure of the structural collapse and strength failure of the bridge caused by the failure of piers and arch rings under the strong vertical and horizontal seismic forces The dextral strike-slip function of the fault in the north segment of the fault zone is significant and the thrusting effect is weak. Under the violent ground level dislocation, the bridge structure has the displacement type failure such as falling beam and double arch collapse.