部分抗剪连接钢-混凝土组合梁负弯矩区剪力滞后效应研究OA

To study the shear lag effect of partially shear-connected steel-concrete composite beams under hog-ging moment,a theoretical model was developed based on the truss analogy theory and the assumption of a uniform interface shear distribution.This model elucidates the shear lag mechanism in partially shear-con-nected composite beams after concrete slab cracking.Numerical models were established using the finite ele-ment software DIANA,and their rationality was validated based on existing experimental results.Based on the calibrated model,the influence of key parameters on the shear lag effect was systematically analyzed,and the theoretical model was subsequently validated.The results indicate that after concrete slab cracking,the shear lag effect increases with increasing load until the longitudinal bars yield,and then rapidly decreases;however,there is still a significant shear lag effect under peak load.The shear lag effect increases with the in-crease of shear connection degree before yielding,while at peak load,the trend reverses.Except for the slab thickness,the influence laws of other design parameters are similar under different degrees of shear connec-tion.In addition,the shear lag effect increases with increasing distance from the zero bending point.The theo-retical model can reasonably predict the influence of various research parameters on the shear lag effect after cracking,and the calculation is most accurate under yield load.When the actual slab width approaches the ef-fective flange width specified by current Chinese codes,the shear lag effect in the negative moment region of composite beams is underestimated.