（1 浙江大学建筑设计研究院，杭州 310027； 2 浙江方远建设集团有限公司，杭州 318000； 3 浙江大学建筑工程学院，杭州 310027）

［摘要］采用混合型三层空腹钢桁架作为某连体的主要承力结构，整体建模分析了其静力、动力特性，指出支座节间加设斜腹杆可以大大提高空腹桁架的竖向刚度。三层空腹桁架的整体弯矩转化成为上下弦杆的轴向力，而中间层弦杆处于中和轴位置，仅承受本层的局部弯矩作用。动力特性分析表明，混合型三层空腹桁架竖向振动频率大于3Hz，满足舒适度的要求。工程处于6度抗震设防地区，地震作用对桁架构件截面不起控制作用。

［关键词］空腹桁架；连体结构；竖向刚度；振动频率

Application of three-layer vierendeel trusses with partial diagonals in portal structure

Zhao Guoxing¹，Guan Haifeng²，Xiao Nan³，Gan Gang¹(1 Architectural Design and Research Institute of Zhejiang Univ.，Hangzhou 310027，China；2 Zhejiang Fangyuan Construction

Group Co.，Ltd.，Hangzhou 318000，China； 3 College of Civil Eng. and Arch.，Zhejiang Univ.，Hangzhou 310027，China)

Abstract:A three-layer vierendeel truss with partial diagonals, which were utilized as portal structure, had great vertical stiffness from the analysis results of global model. The global moment of vierendeel truss was transferred to the axial forces of upper and lower chords while the midlayer chord took on null axial force as neutral position. The results from dynamic analysis show that the flutter frequency of the vierendeel truss is bigger than 3Hz, which satisfies the requirements of relevant codes. Furthermore, the seismic impacts on the vierendeel structure utilized for portal structure are not mainly important for determining section of the members in 6 degree earthquake areas with results from response-spectrum method.

Keywords:vierendeel truss； portal structure； vertical stiffness； flutter frequency

作者简介：赵国兴，高级工程师，Email:zhaogx65@163.com。

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