The Features of Reconstruction for Floor Slabs of Multistorey Apartment House After Temperature Effects as a Result of Military Operations

This article presents a reconstruction procedure for prefabricated reinforced concrete floor slabs in a multistorey apartment building in Lviv (Ukraine). These floor slabs were exposed to enormous fire loading and were damaged due to explosions from two shells. The study revealed that the detected defects and damages significantly reduce the reliability and rigidity of floor slabs because of the loss of bond strength between the principal reinforcement and concrete. As a result of fire loading, the study also determined that there was a loss of prestressed and design resistance in the principal reinforcement. This research aimed to investigate how temperature fluctuations affect the stiffness of the studied floor slabs. The rigidity of floor slabs was related to the level of its fixed deflection (its value was 14.5 mm), determined under the action of only a constant load from its weight. In this article, the strengthening of damaged floor slabs is proposed by arranging cages of reinforcement in the hollows of slabs and increasing their effective height and correspondingly compressed zone at the expense of a monolithic reinforced concrete slab.