Enhancing punching shear capacity of flat slab: review of strengthening and repairing techniques

Abstract

A significant number of concrete flat slabs need to be strengthened against brittle punching shear failure due to conversion of existing buildings, material deterioration, the growth of standards, and detailed defects. Furthermore, there are some traditional approaches to strengthen and repair reinforced concrete slabs which can be either cumbersome or expensive. The repairing of the slabs is very important and not optional because, they will be lost without repairing and reconstruction may not be appropriate due to lack of time or other exceptional circumstances. There were many techniques to strengthening and repair the flat slab depend on suitable way and material availability for strengthening like CFRP sheets, TRM jackets, steel stiffeners, steel bolts, column capital, increasing slab thickness and many other techniques. Typically, the strengthening enhanced punching shear capacity, and the increment may reach 90%. Repair specimens’ punching shear capacity, which may be more than that of the control specimen and the repairing techniques can be used for strengthening. From presented studies, it was found that using the same technique for strengthening and repairing gave better results in strengthening, so strengthening slabs before damages occur is important and enhances resistance better.