考虑场地土影响的高耸结构竖向地震作用分析

Analysis on vertical earthquake in high-rise building with site effect

高耸结构的震害资料表明,竖向地震作用对结构的破坏起很大的作用。根据冲击原理,考虑场地土的影响,对高耸结构的竖向地震作用进行了计算分析。结果表明,场地土类别对竖向地震作用的影响较大,场地土类别越高,竖向地震力越大。Ⅱ类场地土上的烟囱在9度区才会产生竖向拉力;Ⅳ类场地土上的烟囱在7度区就会产生竖向拉力,在9度区则会产生非常大的竖向拉力和竖向压力。因此在高耸结构的竖向地震作用计算中,场地土的影响因素应引起足够的重视。

Statistical data shows that damages of high-rise buildings are mostly caused by vertical earthquake action. Based on collision theory, the vertical earthquake action in high-rise buildings is calculated and analyzed, in which the site effect is considered. The calculated results indicate that higher the site type is, more notable the vertical earthquake action is. For chimneys in the second type of site, vertical tensile forces just generate at the top of chimneys where the seismic fortification intensity is 9. Whereas in the fourth type of site, vertical tensile forces already generate where the seismic fortification intensity is 7, and extraordinary vertical tensile and compressive forces will exist where the seismic fortification intensity is 9. Therefore, the site effect is all-important for vertical earthquake action in high-rise buildings, and should be considered in calculations.