中文摘要：

由于型钢增加了柱的侧移刚度,型钢混凝土（SRC）柱的二阶变形因此比钢筋混凝土柱明显减小,其偏心距增大系数已不能采用规范数值.在理论分析的基础上,提出SRC柱偏心距增大系数的两种求解方法,并以柱的受力特性为依据,采用以极限曲率为参数的偏心距增大法推导建立了计算公式.总结国内其他学者在此方面的研究成果,算例比较表明,所建议公式与已有公式的最大误差小于10%,其精度较高且便于使用,可为工程计算和规范修订提供参考.

英文摘要：

The secondary deformation of steel reinforced concrete（SRC） columns is much smaller than that of RC columns because of the use of section steel,and the current bias distance increase coefficient in Chinese design code is not suitable for composite columns.On the basis of theoretical analysis,two methods for calculating the bias distance increase coefficient are proposed,and formula about the coefficient is obtained by using the eccentricity increase method with the ultimate curvature as the main parameter based on the mechanical characteristics of SRC columns.Otherηexpressions are summarized,and an example is presented with the maximum error of less than 10%between the suggested and other available formulas,which thus indicates that the proposed formula has a high precision.