Vertical seismic action of psg is studied in this part and calculation method of seismic action are introduced . the method of how to determine vertical seismic spectrum by horizontal seismic spectrum is introduced also in this part . vertical seismic spectrum curve values are transformed so that it can be adopted by ansys spectrum analysis 介绍了网架在地震作用下的几种计算方法，对水平地震反应谱的确定及如何利用水平地震反应谱确定竖向地震反应谱进行了阐述，并对竖向地震反应谱的数值进行了转换，这也是利用ansys软件进行竖向地震反应谱分析的关键。
