钢-混凝土组合梁挠度计算的修正换算截面法

修正换算截面法计算组合梁挠度的关键是求修正截面刚度ξEIeq中的截面刚度修正系数ξ,为此利用文献[1]考虑滑移效应的组合梁挠度理论计算公式,对4种典型荷载作用下组合梁截面刚度修正系数ξ进行了计算,结果表明:荷载形式对截面刚度修正系数ξ的影响很小,均布荷载作用下求得的截面刚度修正系数ξ可用于计算其他荷载作用下组合梁的挠度。根据7200根样本梁在均布荷载作用下的截面刚度修正系数ξ值的分析,得到了影响组合梁截面刚度修正系数ξ的关键参数λl,并以λl为变量,回归得到了截面刚度修正系数ξ的计算公式。通过变化设计参数对截面刚度修正系数ξ的影响分析,得到抗剪连接程度参数的变化对截面刚度修正系数ξ的影响最大,而混凝土强度等级和翼板宽度的变化对截面刚度修正系数ξ基本没有影响,由回归公式计算的截面刚度修正系数ξ值与理论公式、《钢结构设计规范》(GB 50017-2003)公式计算的截面刚度修正系数ξ值随各设计参数变化规律相同。与试验结果对比表明,截

Modified transformed-section method of deflection calculation of steel-concrete composite beams

Correction factor ξ of the transformed-section is the key factor to the deflection calculation of steel-concrete composite beams.Using the theoretic formula given by reference [1],correction factor of section stiffness of steel-concrete composite beams under four typical loads has been studied in this paper,with consideration of slip between steel beams and concrete slabs.Results show that load type has little effect on the correction factor ξ,and the correction factor under uniform load can be used for other types of loads.After analyzing the correction factor ξ of 7200 sample beams,it is found that λl is the key factor to ξ.Then formula of ξ is regressed in terms of λl.Also,effect of various design parameters to ξ has been studied,which shows the most significant parameter to ξ is the level of connection of shearing resistance,and strength of concrete or flange width has little effect.Varying tendency of ξ calculated by the regressed formula of this paper coincides with that of theoretic formula given by reference [1] and 'Code for design of steel structures'(GB 50017—2003).It shows from the result that the value of ξ calculated is consistent with that of tests.