The Calculation Method Of Reinforced Concrete Two-way Slab Deflections

The reinforced concrete(RC) two-way slab is widely used in the practical engineerings. However,at present, one-way flexural member stiffness calculation formula is only presented in the standard Codes for Design of Concrete Structures, without the calculation formula for RC two-way slab deflection. In practice design, the tiny deflection theory of thin plates is only appropriated for calculating RC two-way slab deflection in elastic stage. However, RC two-way slab plays work with cracks at service loads. So, developing the calculation methods for RC two-way slab deflection under service loads is of great theory significance and practical value.In this paper, the finite element analysis software ANSYS SOLID65 unit was used to build nonlinear FEM models for RC two-way slab under uniformly distributed loads. According to spans of slab and loads in practical engineerings, the integral model was used to simulate 18 RC two-way slabs. Based on the two-way loaded property in RC two-way slabs, and the simulation results and cross- section rigid calculation method for one-way flexural member, took into account factors such as the ratio of long-short span, two way load distribution and stiffness of slab, an formula for calculating the RC two-way slab rigidity was proposed. The correlation coefficients in the formula were determined by using tested deflection data from RC two-way slabs of 18 and curve fitting method by MATLAB program. The calculation method of the interior slab,the edge slab and the corner slab of reinforced concrete two-way slab-and-beam floor system was researched. In the end, the flexure test data of RC slabs of 21 were collected for checking deflection calculation methods. The results showed that the deflection values obtained by the deflection formula in this paper are closely with the test results. In addition, the deflection values obtained by the deflection formulas are slightly higher than the test results. These mean that the methods and formula proposed is reasonable and feasible. It is of the theoretical significance and practical value.