大跨度网架在动风载作用下的动力学分析

Dynamic Analysis of Long-Span Space Truss under Pulsating Wind Load

以某在建的大跨度网架为研究对象,对施工过程中的不同工况进行静力学分析,确定危险工况;将网架划分为多个大小均匀的区域,选择Kaimal谱为模拟脉动风速的目标功率谱,通过修正傅里叶法模拟网架各区域代表节点的脉动风速时程,依据公式计算出脉动风载时程;将脉动风载施加到相应网架节点后进行动力学分析,通过对比各观测节点最大应力、变形,找出最危险部位;将静载荷与脉动风载同时施加到网架模型,求解最危险节点的位移响应时程曲线,确定网架风振响应的最危险时刻,并求解此刻应力和变形。对比不同工况的计算结果,证明了施工过程中考虑脉动风载作用的必要性,为施工现场规避风险提供理论指导。

A large-span space truss under construction is taken as the research object.Static analysis of different working conditions in the construction process is conducted to determine dangerous working conditions.The space truss is divided into several regions with uniform size and Kaimal spectrum is selected as the target power spectrum for simulating pulsating wind speed.The pulsating wind load time history is calculated according to the formula by simulating the pulsating wind speed time history of representative nodes in each region of the space truss by Fourier Series Correction.After the pulsating wind load is applied to the corresponding space truss nodes,the dynamic analysis is carried out.By comparing the maximum Stress and Deformation of each representative node,the most dangerous part is found.The static load and pulsating wind load are simultaneously applied to the truss model in order to solve the displacement response time-history curve of the most dangerous node,determine the most dangerous moment of the wind-vibration response of the truss,and solve the Stress and Deformation at this moment.By comparing the calculation results of different conditions,it is proved that it is necessary to consider the pulsating wind load in the construction process.This study provides theoretical guidance for risk avoidance at the construction site.