车辐式索桁架拉索松弛敏感试验及可靠性评估

大跨空间钢结在实际工程操作或环境影响下势必会造成一定程度的松弛,拉索出现松弛后力系必定重新调整达到新的平衡,会引起杆件内力的增加或减小,影响结构安全性,以设计的跨度为6 m的车辐式索桁架结构为对象,进行了车辐式索桁架结构拉索松弛敏感性试验,研究了不同种拉索发生松弛时对结构的影响,得出环索松弛对结构力学性能影响最大,定义环索为车辐式索桁架结构敏感性构件;全部下径向索发生松弛时对结构影响最为不利.基于可靠性理论,运用响应面法和蒙特卡洛法得到可靠度指标,得到不同拉索发生松弛下对车辐式索桁架结构可靠度的影响和结构不同参数的灵敏度,可为车辐式索桁架结构发生预应力损失进行安全评估提供依据.

Sensitive Test on Relaxation of Cable and Reliability Assessment of Spoke Cable-truss Structure

Large-span steel structures will inevitably cause some relaxation under the influence of actual engineering operations or environmental influences. After the cables are loosened, the force system must be readjusted to a new equilibrium, which will cause the internal forces of the members increase or decrease, and affect the structural safety. The designed cable-truss structure with a span of 6 m as the object, the experiment on relaxation of cable was done. A study was made of the influence to spoke cable-truss structure when different cable was loosened. It is concluded that the effect of relaxation on the loop cable is most obvious, and the loop cable is defined as the relaxation sensitive component, the most unfavorable structure occurs when all the lower radial cables are relaxed. Based on the reliability theory, the influence of different cable tensions on the reliability of the spoke cable truss structure and the sensitivity of different parameters of the structure were obtained by the response surface method and Monte Carlo method, the safety assessment could be performed for the prestress loss of the spoke cable truss structure.