整浇楼盖梁扭转刚度与活载折算系数的解析  

Analyses of beam torsional stiffness and live load reduction coefficient in floors cast in-site

作　　者：肖南[1] 林恒屹 张杰 钱晓倩[1] XIAO Nan;LIN Hengyi;ZHANG Jie;QIAN Xiaoqian(College of Civil Engincering and Architecture,Zhejiang University,Hangzhou 310058,China;The Architectural Design&Research Institute of Zhejiang University Co.Ltd.,Hangzhou 310028,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058 [2]浙江大学建筑设计研究院有限公司,浙江杭州310028

出　　处：《华中科技大学学报（自然科学版）》2021年第4期73-78,共6页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：浙江省科技计划资助项目(2018C03033-1)。

摘　　要：为定量地确定整浇钢筋混凝土肋梁楼盖设计中活载折算系数与支承梁扭转刚度的关系,在给出了支承梁扭转刚度的代数表达式后,为满足荷载折算法求得的弯矩不小于考虑支承梁扭转刚度时的弯矩,建立了等截面和等跨度的二、三、四、五跨连续梁各跨中和支座截面处,活载折算系数与支承梁扭转刚度关系的条件解析式.分析表明:对于已确定的结构,活载折算系数具有最大值;对于给定的活载折算系数,结构支承梁的抗扭刚度具有最小值.算例表明:当板和次梁分别取固定的活载折算系数0.50和0.25时,无法定量地体现出支承梁的扭转刚度对梁板弯矩的影响,在某些截面会出现过小的弯矩而导致设计不安全.To quantitatively determine the relationship between the live load reduction coefficient and the torsional stiffness of the supporting beam in the design of reinforced concrete ribbed beam floors cast in-site,after the algebraic expression of the torsional stiffness of the supporting beam was given,and to satisfy that the bending moments calculated by load conversion method were not less than those from the method of considering the torsional stiffness of supporting beam, the analytical expressions of the relationship between the live load reduction coefficient and the torsional stiffness of supporting beam were established for uniform cross-section and span long continuous beams of spans of two, three, four and five at their midspan and support sections,respectively.Analyses show that there is a maximum value for live load reduction coefficient for the given structure,and there is a minimum value for the torsional stiffness of supporting beam for a given live load reduction coefficient.The case study shows that adopting the live load reduction coefficients of 0.50 and 0.25 for the slab and the secondary beam respectively cannot quantitatively reflect the effect of the torsional stiffness of the supporting beam on the bending moment of the slab-beam structure,which may cause bending moments at some sections underestimated,leading to unsafety design.

关 键 词：整浇钢筋混凝土楼盖 梁扭转刚度 活载折算系数 解析解 矩阵位移法 

分 类 号：TU311.1[建筑科学—结构工程]