Prevention of premature failures of plate bonded flexurally strengthened RC slab using end anchor and connector

Flexural strengthening of reinforced concrete (RC) slab using externally bonded plate is found to be the most common and popular in retrofitting of deficient structure. However, premature failures due to plate end debonding of steel plate and shear could be the major drawbacks of the system to obtain the highest flexural capacities. The aim of this research was to propose a comprehensive strengthening technique to eliminate premature failures of flexurally strengthened RC slab. In the experimental programme, five full scale RC slabs including un-strengthened control slab and flexurally strengthened slabs using steel plates were fabricated and tested. The strengthened slabs were further strengthened with end anchor and embedded steel bar connector to eliminate premature end peeling and shear failure respectively. Theoretical and numerical models were also provided to design and to analyse the structural behaviour of steel plate strengthened slabs. Results showed that end anchor and embedded connectors prevented premature end peeling and shear failure of flexurally strengthened RC slabs completely and allowed the slab to fail by flexure with the maximum strength and ductility, whereas, their corresponding strengthened slabs without end anchor and embedded connector failed with premature plate end debonding and shear respectively. Both premature failures were found to be brittle in nature. The proposed theoretical model predicted the capacities of strengthened slabs satisfactorily. The results based on the numerical analysis were found to be comparable with the experimental findings.