Numerical and on-site assessment of RC slab behavior in a multi story building under various loading combinations

This study investigates slab damage, the underlying causes of these damages, and the post-damage performance of a five-story reinforced concrete building with shear walls under construction.Deflections and visible cracks resulting from these deflections were observed in the slabs and beams of the building under investigation.To assess the risk and progression potential of the existing damage, the vertical structural elements in the 1st normal floor of the building and the beams and slabs in the ceiling were modeled in Midas Gen finite element software.This model was subjected to the loads from structural elements, construction loads, coating loads, material loads intended to correct the existing slab slope, and live loads.Additionally, an in-situ loading test was conducted to evaluate the post-damage performance of the slabs under vertical loads, and this test was incorporated into the numerical analysis.To represent the structure's behavior under loads during the construction process, the time-dependent change in concrete strength was considered.For the cracked section analysis of the slabs, the EN 1992-1-1 standard was considered, and cracked section stiffness was applied for each mesh element representing the slab.When cracking occurred, the effective moment of inertia was calculated in both directions, and displacements for the cracked section were determined based on this moment of inertia.The analysis model contains approximately 3,000 meshes representing the slabs.Instead of employing a single effective moment of inertia for the entire slab, the effective moment of inertia is calculated separately for each mesh segment.The analyses, which considered five different load combinations, revealed that the slab displacements in service conditions exceeded the limit values specified in the applicable codes, indicating that the slabs require strengthening.