钢-混凝土组合梁负弯矩区裂缝宽度数值计算模型

Numerical calculation model of crack width in negative moment regions of steel⁃concrete composite beams

为得到较为准确的钢-混凝土组合梁负弯矩区裂缝宽度分析模式,综合考虑钢筋和混凝土间黏结应力-滑移关系、钢梁与混凝土界面的滑移效应、混凝土收缩应变以及拉伸硬化效应,基于黏结-滑移理论建立了静力荷载作用下组合梁负弯矩区裂缝宽度的数值计算模型,并将模型预测值与相关文献数据和规范公式计算结果进行了对比分析.结果表明:在组合梁达到屈服荷载前,模型计算值能够较好地模拟裂缝宽度的发展过程,不考虑钢梁与混凝土板之间界面滑移效应时得到的裂缝宽度比考虑界面滑移效应时增大10%左右;按照规范推荐公式得到的结果与试验值偏差较大,而采用数值模型所得结果与试验值吻合度较高,离散系数极小,进一步验证了模型的准确性和适用性.

To obtain a more accurate method for analyzing the crack width in negative moment regions of steel⁃concrete composite beams,a numerical calculation model of crack width under static loading based on bond⁃slip theory was established,considering the bond⁃slip relationship between reinforcement and concrete,the slip effect between steel beam and concrete slab,concrete shrinkage strain,and tension⁃stiffening effect.The predicted values of the model were compared with related literature data and the calculation results of standard formulas.Results show that the calculated values of the proposed model could well simulate the development process of crack width before the composite beam reached the yield load.The suggested model appeared to provide unreliable predictions that the crack width increased by 10%when the slip effect at the beam⁃slab interface was not considered.Compared with the experimental values,the results obtained from the standard formulas had a large deviation.While the results obtained from the proposed numerical calculation model were in good agreement with the measured values,and the dispersion coefficient was the minimum,which verified the accuracy and applicability of the model.