四角锥体系三层网架的动力分析

三层网架是基于双层网架的一种新的结构形式，适用于大跨度屋盖类结构，三层网架具有刚度大，内力分布均匀，节省钢材，制作安装方便等优点。本研究根据子空间迭代法和振型迭加反应谱法，用Fortran90语言编制了网架结构动力分析程序，对5种不同形式的四角锥体系三层网架在不同跨度、不同高度、不同场地和不同烈度区的自振特性及其竖向地震反应进行了分析研究，指出三层网架的自由振动特性及其竖向地震内力分布规律。分析结果表明：斜搁四角锥三层网架和斜放四角锥三层网架是两种较好的三层网架形式。

The dynamic analysis for pyramid system triple*.layer space trusses

Triple Layer space trusses come from the development of double layer space trusses. When applied in long span space structures,triple layer space trusses have many advantages of larger stiffness, reasonable distribution of internal force, favorable technical economic characteristics and manufacture convenient etc. In this paper, a dynamic analysis program of space trusses was compiled with FORTRAN 90 computer language based on subspace iteration method and the mode superposition response spectrum method. With this program, five different types of triple layer space trusses in different span, different height, different site and different earthquake intensity site were studied. The results put out the laws of the free vibration characteristics and the pattern of internal force in the triple layer space trusses under vertical earthquake. The analysis indicates that the leaning laid pyramid space trusses and diagonal pyramid space trusses are two better types of triple layer space trusses.