Numerical Simulation of the Restoring Effect from Post-Stress in the Slab of a Cast-in-Situ Reinforced Concrete Frame

A technique has been developed for finite element modeling of reinforcement of a cast-in-situ floor slab of a repeating fragment of a cast-in-situ frame with pre-stressed cables without adhesion to concrete. The analysis of the stress-strain state of the fragment, taking into account post-stress, is performed in linearly elastic setting. Three-dimensional plate and beam finite elements of the ANSYS Mechanical computational software were used to assemble the studied frame structure. The proposed concept of modeling the restoring force from a prestressed cable to concrete is based on the following sequence of steps: first, using truss and combined finite elements of the ANSYS Mechanical software, the plane problem of determining vertical and horizontal reactions caused by cable tension is solved, then spline interpolation of the obtained values of vertical reactions for setting the appropriate nodal forces on the slab elements is performed. The numerical simulation of the resulting restoring effect from the post-stress created in the floor slab is implemented using two-dimensional interpolation of the displacement distributions from the pre-stress according to two specified schemes onto an auxiliary regular finite element grid with subsequent superposition. The calculation results were compared using the proposed approach and methodology of the A.A. Gvozdev Scientific Research, Design and Technological Institute of Concrete (NIIZHB).