十字型底架由于其构造简单,运输方便,已在塔式起重机上得到越来越多的应用。该底架为空间结构体系,计算中属超静定问题,通常的算法是简化为平面结构,忽略了对角线平面结构的互相影响。本文将底架主梁作为正交粱系统处理,利用正交结点位移协调条件来求解出主梁的内力和位移,计算比较简便。1 受力分析当塔式起重机臂架处在塔身对角线方向 Cross-shaped chassis because of its simple structure, easy transportation, tower cranes have been more and more applications. The chassis is a space structure system, and the calculation is an outdated problem. The usual algorithm is to simplify the planar structure and neglect the mutual influence of the diagonal planar structure. In this paper, the main girder of the chassis is treated as an orthogonal beam system, and the internal force and displacement of the main girder are solved by using the displacement coordination of orthogonal nodes. The calculation is relatively simple. 1 Force Analysis When the tower crane jib in the tower diagonal direction