独柱墩梁桥横向稳定计算理论与验证

Lateral Stability Calculation Theory and Verification of Single-column Girder Bridge

针对独柱墩梁桥横向稳定存在的隐患问题,通过对多座独柱墩梁桥倒塌现场残骸的调查研究提出了倾覆过程中的5种可能破坏模式。基于典型破坏模式,提出以所有抗扭支座失效(脱空)作为判断倾覆的准则。采用有限度的抗扭支座模拟支座尺寸对抗倾覆的有利影响,将独柱墩梁桥倾覆过程等效为箱梁变形体转动及刚体转动的叠加,并考虑箱梁大转动导致桥墩反力重分布对于桥梁抗倾覆的影响。在不考虑、考虑支座尺寸(即支座点支撑或面支撑)2种模式下,通过能量法和变分原理建立空间力系平衡来判断箱梁是否倾覆;最后以上虞春晖桥、哈尔滨三环路鸿福路段上行匝道桥、粤赣高速匝道桥和津晋高速匝道桥为例,对提出理论进行了验证,并进一步进行了影响因素分析。研究结果表明:相比于规范计算方法将倾覆简单地看作刚体的转动,由于综合考虑了变形体转动、刚体转动及箱梁大转动对桥梁倾覆的影响,提出的计算方法所得4座桥的临界倾覆荷载与实测倾覆荷载接近,可偏安全的计算梁桥的抗倾覆承载力。

In allusion to a hidden peril in the lateral stability of single-column girder bridge, five kinds of possible failure modes were proposed by the investigation on the collapsed wreckage of single-column girder bridges. Based on the typical failure mode, all the anti-torsion bearing failure （void） was considered as the criterion of judging the overturn. A limited anti-torsion support was used to simulate the beneficial effects of the size on the overturn. The overturning process was regarded as the superposition of the deformation rotation and rigid body rotation. Moreover, the effect of the reaction redistribution caused by large rotation on anti-overturn of the bridge was also considered. Furthermore, the space force system was established to judge whether the overturn occurred in two modes （with or without considering bearing size） based on energy method and variation principle. Taking Chunhui Bridge, the ramp bridge in Honghu section of the third ring road in Harbin, the ramp bridge in Yuegan Expressway and the ramp bridge in Jinjin Expressway as examples, the proposed theory was verified and the further analysis was carried out on influence factors. The results show that compared with the normative calculation which regards the bridge overturn as the rigid body rotation, the proposed computing method takes the effect of the deformation rotation, rigid body rotation and the large rotation of girder on bridge overturn into consideration. The calculated critical overturning loads of four bridges are close to measured values. Hence, the proposed computing method can be used to predict the anti-overturning capacity of the single-column girder bridge.