EXPERIMENTAL DETERMINATION OF FLOOR PANELS DEFORMABILITY OF A LARGE-PANEL SYSTEM BUILDING AFTER RENOVATION

Abstract

This paper deals with a field tests of prefabricated reinforced concrete floor panels of a multistory building by the method of hydrostatic loading. Object of study is presented by 3 damaged floor slabs of a 9-storey residential building which was hit during the russian invasion. After renovation of panels using the constructive solution which consists of a reinforced build-up layer in the compressed zone (upper part) and additional external reinforcement in the stretched zone (lower part) connected to each other with the help of anchor connections, a series of tests with water loading were set. For creation of loading an inventory pool was used, which was gradually filled with water at a step of 1kN/m². Maximum created loading level was 5kN/m² which corresponds to the operational load. After reaching the maximum load, the panels were left under load for 15 hours and then fully unloaded in steps of 1kN/m². For each panel two type of tests were established: first when panel had both upper and lower part of reinforcement, and second – when lower reinforcement within steel beams was removed. The idea of dismantling of steel beams connected with previously performed numerical analysis which gave to little difference in deflections of panels for these two cases. Deflection measurements at critical locations along with thorough visual inspection were conducted during the loading and unloading cycles. No damage was observed during the in-situ loading and unloading cycles. Maximum vertical deflection for panel before dismantling of beams lies in the diapason of 1.95-2.1mm and 2.31-2.4mm after they were removed. These results meet the requirements of regulatory restrictions on the maximum deflection equal to 20 mm for this structure. Difference in deflection for two cases doesn’t exceed 20% which allows to abandon the use of lower reinforcement in the form of steel beams in the future. As the size of the pool doesn’t cover the whole panel area, the equivalent uniformly distributed load was also calculated using Lira software.