大跨度轮辐式张弦梁构件失效后力学行为研究

Study on Mechanical Behavior of Long-span Spoke Beam String Components After Failure

以具体案例为依托,对大跨度轮辐式张弦梁结构的构件重要性进行分析并排序,探讨不同因素对关键构件重要性的影响,基于显示动力积分法模拟关键构件瞬间失效后的结构响应,考察结构在关键构件意外失效时的力学行为。分析结果表明:内环下弦杆、拉索、支座及靠近支座处上弦梁段为关键构件;单独增大上弦截面刚度时,各关键构件重要性随之降低,单独增大垂度、初始预应力时,拉索及支座的重要性随之提高,其余关键构件重要性随之降低;拆除内环下弦杆后,结构缺乏有效的备用荷载路径,内力重分布代价较大,局部区域出现严重变形,其余关键构件失效后,环梁为主要备用荷载路径;各关键构件瞬间失效后结构动力效应明显且不相同,对于此类结构,在分析时应考虑构件失效前的初始状态。

Based on specific cases,the importance of components of long-span spoke beam string structure is analyzed and ranked,and the influence of different factors on the importance of key components is discussed.Based on the explicit dynamic integration method,the structural response of key components after instantaneous failure is simulated,and the mechanical behavior of the structure under the unexpected failure of key components is investigated.The results show that the lower chord of the inner ring,the cable,the support and the upper chord beam near the support are the key components.When the stiffness of upper chord section is increased individually,the importance of each key component decreases.When the sag and initial prestress are increased separately,the importance of cables and supports increases,and the importance of other key components decreases.After the removal of the lower chords of the inner ring,the structure lacks an effective backup load path,the cost of internal force redistribution is high,and severe deformation occurs in local areas.After the failure of other key components,the ring beam is the main backup load path.The structural dynamic effect of each key component is obvious and different after the instantaneous failure.For such a kind of structure,the initial state before the component failure should be considered in the analysis.