考虑轴压比影响时框架侧移计算的试验及理论研究  

Experimental and theoretical research on lateral displacement calculation considering influence of ratio of axial compressive force to axial compressive ultimate capacity of section in frame structures

作　　者：张明[1] 孟焕陵[1] 沈蒲生[1] 

机构地区：[1]湖南大学土木工程学院

出　　处：《建筑结构学报》2007年第6期191-197,共7页Journal of Building Structures

基　　金：国家自然科学基金资助项目(50378035)

摘　　要：为研究轴压比对框架柱侧移的影响,以轴压比为框架柱的主要变化参数,完成了10根钢筋混凝土柱与5根钢柱压弯试验。试验结果表明:随轴压比增加,框架柱抗侧刚度增加,侧移减小;对于混凝土柱,裂缝间距和宽度都增大,裂缝越集中于柱底,压区混凝土破坏越严重,延性越差;对于钢柱,则压区屈曲越严重。随着名义偏心距的增大,二阶效应加剧,轴力对框架柱抗侧刚度的提高有所减弱;轴力对钢柱抗侧刚度的有利影响不及混凝土柱明显。结合试验数据,拟合了考虑轴压比影响的柱抗侧刚度计算公式。根据此公式计算内力侧移的框架算例表明,考虑轴压比影响时,框架结构侧移明显减小;轴力从上至下逐渐增大,轴压比对框架结构的影响愈大,结构侧移减小愈明显。考虑轴压比对框架柱抗侧刚度的影响,符合工程实际,能为现行规范对高层框架侧移计算的完善提供参考。Experiment in compression and bending was conducted for 10 reinforced concrete columns and 5 steel columns with various ratios of axial compressive force to axial compressive ultimate capacity of section, and the influence formulae of the ratio of axial compressive force to axial compressive ultimate capacity of section on sideway stiffness of frame columns were derived. The calculation steps of displacement in frame structures were given when the influence of ratio of axial compressive force to axial compressive ultimate capacity of section was considered. Increasing ratio led to the growth of sideway stiffness and the drop of lateral displacement. As for concrete columns, increasing ratio led to wider cracks, larger space between cracks, cracks＇ being closer to the bottom of columns. In addition, the ductility became worse as the failure of the concrete column in press zone was more considerable and the steel columns were more flexuous when the ratio increased. With the growth of nominal eccentricity, the extent of increase narrows as the second order effect increases. The favorable influence of axial load on sideway stiffness of steel frame columns is not as significant as the one on the concrete frame columns. It shows that the lateral displacement of frame structure will evidently decrease when the influence of axial load on sideway stiffness of frame columns is considered, and the degree of the influence on the lateral displacement will become lager when the axial force increases from the top to the bottom ofthe columns. Taking the influence of axial load on sideway stiffness of frame columns into account is in accordance with the engineering practice and may serve as a reference to the revision of the existing design codes for calculating the sideways of frames.

关 键 词：轴压比 抗侧刚度 框架结构 侧移 影响 

分 类 号：TU375.3[建筑科学—结构工程] TU317.1