基于敏感性分析的结构抗倒塌能力提升方法研究

为提高荷载作用下结构抵抗倒塌破坏的能力,该文基于构件应变能对材料弹性模量的敏感性及构件失效后对结构应变能的影响,提出了静载下的构件易损性及其冗余度评价指标,以衡量构件受损破坏的容易性及其失效后对结构整体性能的影响。在此基础上通过加强冗余低、易损性高的构件,同时对冗余度高、易损性低的构件进行适当削弱,充分发挥各构件在结构中的作用,使构件的破坏顺序发生转变。结果表明,构件的易损性、冗余度系数值的大小能够反映构件发生破坏的容易性及其失效对结构整体性能的影响。根据构件的冗余度、易损性分布,通过调整构件的截面面积,可以实现结构“低易损-高冗余”非重要构件的破坏先于“高易损-低冗余”结构关键构件,从而改变荷载作用下的结构破坏路径,有效提升了结构的极限承载能力和抗连续倒塌的能力。

A METHOD FOR THE ENHANCEMENT OF STRUCTURAL ANTI-COLLAPSE CAPACITY BASED ON SENSITIVITY ANALYSIS

To increase the structural anti-collapse capacity,and to reveal the fragility of structural member and its failure effort on the structural performance,two evaluation indexes were established to measure the vulnerability and redundancy of structural member based on the sensitivity of strain energy of member to material elastic modulus.The change of structural strain energy caused by the failure of member was also taken as an important parameter in the redundancy index.Then,the members with high vulnerability and low redundancy were strengthened,and the ones with low vulnerability and high redundancy were weakened by the means of increasing or reducing the section area of member.By this way,the structural member failure sequence was changed,and all the members could be fully utilized.The results show that the coefficient value of redundancy and vulnerability can reflect the fragility and the failure effort of structural member,respectively.By adjusting the member section area according to the distribution of structural redundancy and vulnerability,the less-important members which have low vulnerability and high redundancy will be failed before the key members which have high vulnerability and low redundancy.Thus,the structural failure path will be transformed to a safe way,and the loading capacity and the ability to resist progressive collapse of the structure can be enhanced effectively.