大跨径钢管混凝土桥梁拓扑易损性分析研究

The Analysis and Study on Topological Vulnerability of Large-span Concrete-filled Steel Tube Bridge

以某中承式钢管混凝土肋拱桥为例,利用有限元软件,分析了桥梁的拓扑易损性特点,并着重分析了单根吊杆断裂、上下游各一根吊杆断裂、同侧双吊杆断裂情况下桥梁的桥面位移和易损性,得到以下结论:在S15Y吊杆(跨中位置)、S15Y、X15Y吊杆(上下游各一根吊杆)以及S15Z、S15Y吊杆(同侧双吊杆)断裂瞬间,桥面相比于静态时挠度分别增加了22.2 mm、25.2 mm和74.5 mm,之后桥面又缓慢上浮并于40 s前后逐渐趋于平衡,即同侧双吊杆带来的危害更大。对于短吊杆断裂,易损性值较小,而长吊杆断裂时易损值较大,即长吊杆断裂对桥面稳定带来的影响更大;相比于短吊杆断裂,上下游各一根吊杆断裂时的易损性更高。

The paper analyzed topological vulnerability of the bridge using finite element software with emphasis on analyzing bridge deck displacement and vulnerability under the circumstance of single suspender fracture,one suspender fracture at the upstream and downstream separately and two suspenders fracture at the same side.It is concluded that the moment S15Y suspender(midspan),S15Y and X15Y suspenders(one suspender at the upstream and downstream separately),and S15 Z and S15Y suspenders(two suspenders at the same side)broke,the deflection of bridge deck increased by 22.2 mm,25.2 mm and 74.5 mm respectively compared to static state,then the bridge deck ascended slowly and tended to be balanced around 40 s,namely,two suspenders at the same side were more harmful.The short suspender fracture had small vulnerability value,while long suspender fracture had big vulnerability value.However,compared with short suspender fracture,one suspender fracture at the upstream and downstream separately had higher vulnerability.