四边简支带抗剪键双向叠合板的力学性能分析

Analysis of Mechanical Properties of Four-sided Simple Supported Two-way Laminated Slab with Shear Keys

为研究四边简支带抗剪键双向叠合板的力学性能,进行了该种叠合板的试验,并基于试验结果验证了有限元模拟方法的准确性。通过模拟参数不同的双向叠合板的受力过程,分析了抗剪键剪力分布规律及叠合板的力学性能影响因素,并建立了其屈服弯矩和屈服位移简化计算式。结果表明:预制底板与抗剪键间、预制底板与现浇层混凝土间虽然存在混凝土二次浇筑现象,但整体性仍然较好;竖向均布荷载作用下,抗剪键表现为脆性破坏;只有当抗剪键的破坏数量达到一定程度后,叠合板才发生破坏;结合面间设置为摩擦接触时,随抗剪键行数、列数及横截面面积增加,叠合板的屈服荷载增加,屈服位移减小,当上述3个因素增加至一定程度后,影响不再明显;布置一定数量抗剪键的双向叠合板,现浇层及抗剪键混凝土强度等级、结合面摩擦系数对叠合板的承载力影响很小;建立了带抗剪键叠合板屈服弯矩和屈服位移简化计算式,可供工程参考应用。

In order to study the mechanical properties of the four-sided simply supported two-way laminated slab with shear keys, the test of the laminated slab was carried out and the feasibility of the finite element simulation method was verified based on the experimental results. By simu- lating the loading process of the laminated slab with different parameters, the distribution law of shear force of shear key and the influence factors on mechanical properties of laminated slab were analyzed, and the simplified calculation equations of yield bending moment and yield displace- ment were established. The results showed that a secondary concrete pouring phenomenon existed between the precast base plate and the shear key, between the precast base plate and the cast-in-place concrete. However, it still had a good integrity. Under the vertical uniform load, the shear key showed a brittle failure. Only when the number of shear keys in failure reached a certain extent could the laminated slab be failed. When the joint surface was set to the frictional contact mode, the yield load of the laminated slab increased and the yield displacement decreased with the in- crease of the number of rows of shear key, the number of columns and the cross-sectional area. When the three factors above increased to a cer- tain extent, the influence was no longer obvious. For the two-way laminated slab with a certain number of shear keys, the strength grade of the concrete of the cast-in-place layer and shear key, and the friction coefficient of joint surface had little influence on the bearing capacity of the lam- inated slab. The simplified calculation equations established for the yield bending moment and yield displacement of the laminated slab with shear keys can be referenced in engineering.