正交正放单层鞍型网壳在强震下的失效研究

Failure of orthogonal single-layer saddle-curve reticulated shells under severe earthquakes

对跨度40m正交正放单层鞍型网壳在强震作用下的失效机理进行研究。通过典型算例探讨结构在强震作用下的响应特征,考察结构的节点位移、不同屈服程度杆件比例、不同失效程度杆件等多项结构响应随荷载强度递增的变化规律;可认为单层鞍型网壳在强震下发生明显的动力强度破坏,综合结构的典型响应提出一种失效极限荷载的确定方法。在系统参数分析的基础上,讨论高跨比、屋面质量、初始缺陷等因素对结构失效极限荷载的影响规律,并讨论考虑下部支承结构刚度因素对上部鞍型网壳强震失效极限荷载、失效模式的影响规律。

The failure mechanism of orthogonal single-layer saddle-shape reticulated shells of 40m span subjected to severe earthquakes is studied.According to a typical example,the characteristic response of such structures under severe earthquakes is investigated,and the variations of the characteristic responses of displacement,element of different yielding ratios and element of different failure degrees with the load strength are investigated.It is concluded that single-layer saddle-shape reticulated shells under severe earthquakes are going through dynamic strength failure.A method is established for discrimination on the ultimate strength load based on the comprehension of various characteristic responses.The relationship between the variation of rise to span ratio,difference of roof mass together with geometric imperfections and ultimate load are discussed.The influence of supporting structures on the ultimate load and the failure mode is determined.