全局布索预应力钢框架预应力参数的试验研究

Experimental study on prestress parameters of cable-supported and knee-braced steel frame

基于全局布索预应力钢框架的结构形式,设计两榀缩尺模型进行设计荷载条件下的静力试验,以分析不同拉索截面面积、预拉力对钢框架的影响。通过试验可知,随着索支索预拉力的增加,增大了索支撑杆对钢框架的顶推力,随着隅撑索预拉力的增加,增大了隅撑撑杆对钢框架的拖曳力。不同索截面面积的拉索初始预拉力在相同预应力的情况下对钢框架各截面产生的弯矩和扰度与其各自的索截面面积有关,且按其变化倍数增加。随着两索索截面面积的增加,在竖向荷载下使钢框架各截面弯矩扰度的增长率不断下降,且存在增长率下降幅度的峰值,其对应的索截面面积可认为是最经济的索截面面积,水平荷载下,索截面面积变化对钢框架各截面弯矩变形的增长率影响较小。

Based on the structural form of cable-supported and knee-braced steel frame,two scaled models were designed for the static test under load conditions to analyze the impact of different cable cross-section areas and pre-tension force on steel frame.It is found in the experiment that the increase of pre-tension force on cable-supporting cable increases the pushing force of cable-supporting rod on steel frame,and the increase of pre-tension force on knee-bracing cable increases the drag force of knee-bracing rod on steel frame.The bending moments and deformations of the initial prestressing forces of cables with different cross-sectional areas are related to the respective cross-sectional areas of cables under the same prestressing conditions,and increase according to their change multiples.The increase of cross-sectional area of two cables makes the increase rate of moment deformation of each section of steel frame decrease continuously under vertical load,and there is a peak of the decrease rate.The corresponding cross-sectional area of cables can be considered as the most economical cross-sectional area of cables.Under horizontal load,the change of cross-sectional area of cables has little influence on the increase rate of moment deformation of each section of steel frame.