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Reinforced Concrete Waffle Slabs as an important force structure housing, with one-way and two-way floor plate ribbed ribbed floor plate, compared with stiffness, good integrity, small deformation, structural height is small, light weight , economy and good. However, reinforced concrete Waffle Slabs force is more complex, at different loads and different boundary conditions, the internal force distribution varies; same time, because the interaction of bending and torque, increasing the difficulty of the analysis. The calculation method is currently focused on the analysis of the elastic stage, after cracks appeared on the structural components of flexural stiffness and torsional rigidity determined, still use the stiffness of the elastic stage, therefore, resulting in a calculated internal forces and deflections does not match with the actual situation, not conducive to structural reinforcement design, resulting in some parts of the structure due to insufficient reinforcement premature cracks, while others parts of the reinforcement too much, resulting in unnecessary waste of material. Therefore, this paper Reinforced Concrete Waffle Slabs elasticity and plasticity characteristics of the different stages, using the finite element method, the structure of the elastic force and deformation and internal force and deformation of plastic stage for comparison, the situation is closer to the actual answers. The main work is as follows: 1. In summing up the various Waffle Slabs elastic computing method, this paper consider the synergies bending shear and torsion beam cross-line basis, using the finite element method to the structure of the elastic force analysis phase, and verify the finite element method is reasonable. 2. This stage of the preparation of the plastic finite element program, using an iterative method for nonlinear equations iterative calculation, the component after cracking, according to specifications of the structure of reinforced concrete cracks after bending stiffness of the torsion test provisions and abroad resultant structure after cracking torsional stiffness, flexural rigidity recalculated member and torsional stiffness, the structural state of the internal forces in the elastic and plastic state forces for comparison, the plastic changes in the distribution of internal forces. 3. Identify structural deflection in the plastic state distribution rule was established in the different boundary conditions deflection after cracking component is calculated. 4. This procedure is not considered for the factors proposed in the calculation using the program sources of error may occur, therefore, in order to further improve the accuracy of calculation, can be modified in several aspects. That provide the basis for the design of floor types.
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