开洞轻骨料混凝土深梁受剪性能试验研究OA

In order to investigate the influence of web openings in shear span on shear performance of lightweight aggregate concrete deep beams,nine lightweight aggregate concrete deep beams with web openings were tested under symmetric concentrated loads,taking parameters including opening dimensions,location and extra reinforcement as variables.The influence mechanisms and variation laws of crack development,failure modes,diagonal cracking load,shear capacity,midspan deflection,and reinforcement strains were analyzed.Regarding the shear failure mode of the solid portion of the web opening zone in deep beams with web openings,a shear distribution principle based on the shear stiffness ratio was proposed.A kinematic mechanism for shear failure in deep beams with web openings was established,the demand function for shear capacity was modified,and a shear capacity model for deep beams with web openings was developed.Test results indicate that the initial stiffness,post-cracking nonlinear characteristics,and shear capacity of the deep beams with web openings are significantly influenced by the sizes of the openings,while the effect of the openings' locations is relatively minor.Opening reinforcement mainly improves the stress concentration at opening corners and the stress distribution after diagonal cracking,while having little influence on shear capacity.The established shear model for deep beams with web openings can effectively quantify the influence of parameters such as opening size and location on the shear capacity.The predicted shear capacities agree well with the experimental results,demonstrating the rationality of the proposed model.