单向带抗剪键叠合板的力学性能及设计方法

Mechanical Properties and Design Method of One-way Laminated Slab with Shear Keys

针对现有钢筋桁架叠合板钢筋用量多、成本偏高的不足,提出了一种新型带混凝土抗剪键的叠合板,并通过对1块现浇板和6块叠合板的静力加载试验,分析了有无抗剪键、抗剪键沿横向个数和抗剪键结构形式对叠合板力学性能的影响。采用有限元软件ABAQUS模拟了试验中部分试件的受力过程,验证了有限元模拟方法的可行性。结果表明:与无抗剪键叠合板相比,设置一定数量抗剪键的叠合板和现浇板力学性能相近;抗剪键个数越多,叠合板的极限承载力与现浇板越接近,其破坏特征也与现浇板基本相同;不同结构形式的抗剪键均能保证预制底板与现浇层间的有效连接;预制底板与现浇层的接触面间采用绑定接触时有限元模拟结果与试验结果更加接近;考虑到结构设计的可靠性,在有限元模拟过程中,当叠合板的预制底板与现浇层间设置为摩擦接触时,改变抗剪键沿横向个数、抗剪键沿纵向个数和抗剪键截面面积,叠合板的屈服荷载和屈服位移均发生变化,但当三者增加到一定程度时,变化趋势不再明显;改变现浇层混凝土强度等级、抗剪键混凝土强度等级和接触面摩擦因数,叠合板的屈服荷载和屈服位移基本未发生变化;建立了带抗剪键叠合板的抗弯承载力和屈服位移简化计算式。

In view of the shortcomings of large amount of reinforcement and high cost for existing laminated slabs of reinforced truss,a new type of laminated slab with concrete shear keys was proposed.The effects of shear keys,number of shear keys along the transverse direction and structural forms of shear keys on the mechanical properties of laminated slabs were analyzed through static loading tests on one cast-in-place slab and six laminated slabs.In addition,the finite element software ABAQUS was used to simulate the stress process of some specimens in the test,which verified the feasibility of the finite element simulation method.Finally,the simplified calculation equations for the bending capacity and the yield displacement of the laminated slab with shear keys were established.The results show that the mechanical properties of the laminated slab with a certain number of shear keys are similar to those of the cast-in-place slab compared with the laminated slab without shear keys.The more the shear keys in number are put,the closer the ultimate bearing capacity of the laminated slab is to that of the cast-in-place slab,and it has almost the same failure characteristics as the cast-in-place slab.The shear keys of different structural forms can ensure effective connection between the prefabricated base plate and the cast-in-place layer.When the tie contact is used between the prefabricated base plate and the cast-in-place layer,the finite element simulation results are closer to the test results.When the friction contact is used between the prefabricated base plate and the cast-in-place layer in the finite element simulation process considering the reliability of structural design,the change of the number of shear keys along the transverse direction and the longitudinal direction and the section area of shear keys enables the change of both the yielding load and the yielding displacement of the laminated slab.However,when the three increase to a certain extent,the change trend is no longer obvious.When the strength grade of cast-in-place layer concrete,the strength grade of shear key concrete and the friction coefficient of surface are changed,the yielding load of the laminated slab and the displacement are basically unchanged.