Mechanical Behavior Of Precast Ribbed Panels Used For Concrete Composite Slabs

The most common form of floor slabs including cast-in-place slabs and precast slabs. Both of them have their advantages and disadvantages. The RC composite slab can take advantage of their advantages, which makes the structure performance better.The RC composite slab with precast ribbed bottom panel is a new composite slab. And the bottom precast ribbed panels play a key role in the use of RC composite slab with precast ribbed bottom panel. So Mechanical behavior of bottom precast ribbed panels is researched in this paper.Firstly, three precast ribbed panels occurred crushed concrete flexural failure under loading test and load-deflection diagram was analyzed for each panels. Secondly, Finite element models were built to simulate the experiment. The carrying capacity, cracking load and deflection of simulation were close to the experiment. Then, the expression of failure mode have been carried out and the reason of flexural failure have been studied. The calculated values of simulation, calculation and experiment have been compared to each other. The reasonable shear length of precast ribbed bottom panel were studied, the results show that if the flexural failure was prior to the shear failure, the shear length would be large and the advantages of precast ribbed bottom panel would be weakened. If the shear failure were not occurred in construction, the requirements of precast ribbed bottom panel were satisfied. The lengths have been calculated with the types of precast ribbed bottom panels in local drawings and the results were satisfied.Through the content above, the results show that:The carrying capacity, cracking load and deflection of double ribbed panels composed by two single ribbed panels are similar to single ribbed panels, which proved the double ribbed panels didn’t change the mechanical properties of the single ribbed panels.The results of finite element simulation showed good agreement with experimental results, which indicate the constitutive relation and the method of adding prestress load were suitable. There were no big differences among the values of calculation, simulation and experiment, so the calculation method were suitable. Calculation formula of equivalent stiffness coefficient was revised and simplified, which showed good agreement. Calculation of equivalent defection was revamped, and the result could improve the fitting with the result of simulation, which could provide some advises for the construction.The lengths have been calculated with the types of precast ribbed bottom panels in local drawings and the results were satisfied.