龙卷风作用核电常规岛主厂房随机响应及结构体系可靠度

Stochastic response and structure reliability of nuclear power plant main house under tornado loads

在基于实际龙卷风观测记录的基础上,推导了极值Ⅲ型龙卷风强度概率分布函数并建立了龙卷风随机荷载模型。以核电常规岛主厂房钢框架结构为计算模型,采用谱随机有限元法,在厂房位于龙卷风中心、厂房位于龙卷风上游最大风速半径处及厂房位于龙卷风下游最大风速半径处三种工况,考虑龙卷风荷载和结构抗力参数的不确定性,对结构进行随机响应和可靠度分析。分析结果表明:厂房位于龙卷风中心时,龙卷风荷载对厂房产生明显的扭转效应,结构顶点位移对规范限值的超越概率为三种工况中最大;当厂房位于龙卷风最大风速半径处,龙卷风对结构主要产生指向龙卷风中心的侧向推动作用,顶点位移的超越概率较小;龙卷风位于厂房中心处为三种工况中的荷载最不利位置。针对不同的位移限值,绘制了结构在龙卷风荷载最不利工况下的易损性曲线。

Based on the actual tornado observation records,tornado intensity probabilty distribution function of extreme value type Ⅲ was derived and tornado random load model was established. By taking steel frame structure of conventional island main house as computational model and taking into account the uncertainty of tornado load and structural resistance parameters,analysis of spectral stochastic finite element method( SSFEM) was carried out considering three load cases where the structure is located at the center of tornado,at the upper maximum wind speed radius of tornado and at the second maximum wind speed radius respectively. The results show that tornado load produces strong torsional effect on structure and exceeding probability of top node displacement to the specification limit is the largest in three load cases when the main house is located at the center of tornado; tornado load produces pushing force towards tornado center to structure,and the exceeding probability of top node displacement is relatively small when the main house is located at the radius of tornado maximum wind speed. Being located at the tornado center is the most unfavorable load position to the main house in three load cases. At last,fragility curves for different displacement limits of structure under the most unfavorable load case are plotted.