The steel truss is often used in petrochemical industry; the current common truss structure is parallel chord truss. According to the different arrangement of their web members, parallel chord truss can be divided into many forms, mainly including: monoclinic type, chevron type and the truss without vertical web member. In this paper, taking an actual project as an example, PKMP was used to calculate and make a contrast on economy, internal stress and deformation of three kinds of parallel chord trusses. The results show that, under the common load condition, the truss without vertical web member has more advantages on economy, internal stress and deformation, but its safety margin is small, we can solve the problem by increasing the section dimension of key parts.%钢结构桁架在石油化工管廊中会经常被用到，目前常用的钢结构桁架形式为平行弦桁架。平行弦桁架根据腹杆布置方式的不同又可以细分为以下几种：单斜式桁架、人字形桁架、无竖杆式桁架。以工程实例作为分析对象，通过 PKPM 建模分析计算对三种平行弦桁架的经济性、内力和变形进行了对比，通过对比得出：在常规荷载下无竖杆式桁架经济性、抵抗变形能力和承载力均比较突出，但是超静定次数较少安全富余度相对较少，在具体工程中可以通过加大关键部位的截面予以解决。
展开▼
