北京某景观桥钢结构的检测鉴定与加固设计

Detecting and Strengthening Design of Steel Structure of a Certain Sight Bridge in Beijing

北京某景观桥为新建钢结构人行桥,为保证桥梁投入运营后的长期安全,对该桥进行了检测鉴定以及评估工作,以评定桥梁的实际工作状态,以及桥梁的承载性能与设计的符合程度。此次检测工作采用表观损伤检查、现场静动载试验与有限元建模计算分析相结合的办法。本文介绍了该桥结构检测鉴定的总体流程,首先对桥梁进行了表观检查,以评定桥梁的技术状况,然后对静载试验加载方案进行了设计,包括荷载工况和测点布置,此后进行了标准设计荷载和试验荷载下的桥梁上部结构有限元建模计算,得到了此次静载试验的效率系数、两种荷载下的静力响应以及位移校验系数等重要数据,在此基础上,对静载测试结果进行了理论分析。此外,为进一步验证静载试验结果,还进行了该桥的动载试验,获得了该桥的前几阶自振频率。在前文工作的基础上对该桥进行安全评定,指出该景观桥整体刚度偏弱,且相关指标不能满足规范要求,需要进行加固处理,并提出了加固方案。

A certain sight bridge located in Beijing is a footbridge of steel structure. With the purpose of ensuring long-term safety of the bridge after coming into use, some work of inspection, identification and appraisal are taken on it to appraise the actual working conditions of the bridge and the coincident degree between the actual carrying performance and that of design. Apparent damage investigation as well as static and dynamic tests in field are involved in this inspection combined with FEA. In this paper, a general introduction of detecting and appraisal procedures of the bridge structure is given. Firstly aspect inspecting is proceeded to assess technical conditions of the bridge. Then loading test, including loading scenarios and measure point disposal is designed. After that, some important datum, such as static test loading efficiency, static response and displacement adjustment factor, are gained by a FEA of the upper structure of the bridge under standard design load and testing load, based on which theoretical analysis of test results is accomplished. What＇ s more a dynamic loading test is executed to further check the results of static one and frequencies are measured. On a basis of previous, a safety appraisal of the bridge is drawn that the global rigidity of the bridge is slightly weak with some relative index dissatisfying items of the codes and strengthening is needed. At last a sort of strengthening design is presented on found of the foregoing conclusions.