Nonlinear analysis of flat slab floors

A finite element procedure is developed to analyse reinforced concrete flat slabs as 3D-structures. A thick shell formulation accounting for shear deformation by employing the Reissner-Midlin plate theory is considered. Quadrilateral isoparametric degenerated shell elements are chosen to analyse the reinforced concrete structures based on a degenerated three-dimensional continuum element. The approach of a layered structure is chosen to account for variable material properties. Each element consists of eight nodes, and each node has five degrees of freedom. The analysis employs new modellings for columns and slab-column connections. A computer program is developed to implement the procedure. Geometric and material nonlinearities are considered. The material nonlinearities include the stress-strain relationship for concrete and reinforcement, cracking and tension stiffening effects. For the required data of slab, columns, beams and different connections of the structure a mesh generator is developed. This reduces the probability of errors in the input data. Verification studies are carried out by the analyses of some structures. The results are compared with analytical methods and National Building Codes as well as with test results to validate the capacity of the procedure through different stages of loading. Different examples of flat slab structures are analysed to investigate the effects of important parameters. The effects of edge beams, drop panels, column heights and presence of different lengths of cantilevers on the performance of slabs are investigated and discussed. (orig.)Available from TIB Hannover: RN 2279(80) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman