伸臂桁架工作性能研究和设计建议

Study and design suggestions on work performance of outrigger trusses

带加强层的框架-核心筒结构在伸臂桁架的作用下可以形成更大的刚度,抵抗倾覆力矩。通过不同形式的伸臂桁架模型分析对比,研究伸臂桁架与核心筒之间的传力机理,对比了不同形式的伸臂桁架的工作效率。结果表明,K形、V形和人字形伸臂桁架的抗侧刚度效率较高。同时,K形桁架的弦杆轴力较小,而V形桁架所形成的核心筒剪力墙抗剪负担较小,传力相对合理有效。伸臂桁架的设置,对核心筒剪力墙、周边框架柱的受力产生很大影响,增加加强层核心筒的刚度可能造成受力更为集中的不利影响。还分析了设置伸臂桁架对结构受力和非受力位移角的影响。

With the help of outrigger trusses, the frame-core tube structure with strengthened story can form larger stiffness to resist the overturning moment. Working efficiency and load transfer mechanism of different styles of outrigger trusses were studied. The results show that K-shaped, V-shaped and herringbone outrigger trusses are more efficient than others. The axial force in chords is smaller in K-shaped truss, and the shear force in the core tube shear walls produced by V-shaped truss is smaller. The force transmission is relatively reasonable and effective. The settings of outrigger trusses have a great impact on the forces of the core tube shear walls and frame columns. It might suffer more stress concentration on the condition that the core tube of the strengthened storey was reinforced to have larger stiffness. The effect of outrigger trusses on physical inter-story displacement angle and un-physical inter-story displacement angle was analyzed.