一、前言在多跨连续网架下悬挂吊车时,网架杆件的内力计算是一个有待于探讨的问题。网架空间刚度大,稳定性好,因而比平面桁架更适应集中荷载的作用。但由于其节点及杆件数量多,是高次超静定结构,在悬挂吊车荷载作用下,要准确地求出网架每根杆件在最不利荷载组合下的内力值是很困难的。国内有些单位已编制出能进行内力组合的计算程序,但由于机器容量关系,很难满足多跨连续网架在悬挂吊车作用下内力计算的需要。在唐山齿轮厂联合厂房网架屋盖设计中,为满足工程急需,我们采用了近似的简化计算。现介绍如下。二、工程概况唐山齿轮厂联合厂房为机械加工厂房,分高、低跨两部分。低跨部分屋盖采用了多跨连续正放抽空四角锥,其平面尺寸为156×84m,由伸缩缝分 I. INTRODUCTION Calculation of the internal force of a pole part is a problem to be explored when a crane is suspended under a multi-span continuous grid. The space of the grid is large in rigidity and good in stability, so it is more suitable for the effect of concentrated loads than the plane truss. However, due to the large number of nodes and rods, it is a high-order statically indeterminate structure. It is difficult to accurately determine the internal forces of each pole of the grid under the most unfavorable load combination under the effect of the suspension crane load. Some units in China have compiled a calculation program that can perform internal force combination. However, due to the relationship of machine capacity, it is difficult to meet the need for the calculation of internal force of a multi-span continuous network frame under the effect of a suspended crane. In the design of the grid roof of the joint factory building of Tangshan Gear Factory, in order to meet the urgent needs of the project, we have adopted an approximate simplified calculation. The introduction is as follows. II. Project Overview Tangshan Gear Factory’s joint factory is a mechanical processing factory with two parts: high and low span. The low-span part of the roof adopts a multi-span continuous positive-empty square pyramid with a plane size of 156×84m divided by expansion joints.