Retrofitting of Reinforced Beam-Column Joints Using Hybrid Laminates

Thousands of reinforced concrete structures are constructed annually and a large number of these deteriorate or become unsafe before their design life. In buildings, the major part that fails is the beam-column joint connections. The behaviour of reinforced concrete moment resisting frame structures in recent earthquakes all over the world has highlighted the consequences of poor performance of beam column joints. In the last two decades, use of advanced composite materials such as Fiber Reinforced Polymers, (FRP), in strengthening reinforced concrete, (RC), structural elements have been increasing. Researches and design guidelines concluded that externally bonded FRP could increase the capacity of RC elements efficiently. This paper aims to study the performance of reinforced concrete beam-column joints strengthened by hybrid laminates. This paper presents an experimental program conducted to study the behaviour of RC beam-column joints strengthened with hybrid laminates. The program consists of a total of 4 specimens with overall dimensions of beam equal to (100 x 100 x 900-mm) and column equal to (100 x 150 x 1100-mm). The beam-column joints are to be tested under cyclic seismic loading up to failure to examine its behaviour. Different fiber directions, locations of combinations of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) laminates were attached to the beam-column joints to predict the best strengthening scheme. The test specimens were casted for estimating the load vs displacement, frequency vs amplitude, ductility, stiffness characteristics.