故宫灵沼轩风振响应分析

故宫灵沼轩是一座砌体结构与钢结构组合而成的文物建筑。为有效对其保护,采用数值模拟方法,研究了风振作用下结构的动力响应。基于灵沼轩结构现状,建立了有限元模型。通过模态分析,获得了灵沼轩的基频和主振型;通过对结构施加y向脉动风荷载,研究了重现期为50年时结构的风振特性,评价了结构在风荷载作用下的安全现状。结果表明:灵沼轩结构基频为f=5.75Hz,在x及y向的主振型以局部振动为主;脉动风压作用下,结构保持稳定振动状态,但顶部位置加速度峰值偏大。另风压作用下,砌体结构部分位置的抗拉强度不足,应在日常维护中予以重视;钢结构部分由于材料强度大,因而不会出现强度破坏。

Windinduced responses of the LingZhao Veranda in the Forbidden City

The LingZhao Veranda in the Forbidden City is a historical building, built of steel and masonry parts. To protect the building effectively, the windinduced responses of the building were studied by digital simulation. Based on its structural status, a finite element model of the LingZhao veranda was built. Then the basic frequency and main vibration modes were calculated. After applying a fluctuating wind pressure over a period equivalent to 50 years in thedirection, the vibration responses were analyzed, and the safety status of the whole structure was evaluated. The results show that the basic frequency of the structure is f=5.75Hz; its main modes vibratein both x and ydirections. Under conditions offluctuating wind, the structure keeps vibrating at a stable rate. However, peak acceleration values on the top of the structure are quite large. Compared with the steel parts, the masonry parts of the building are more proneto damage because of tensile strength failure. The different responses to wind require attention during daily maintenance.