Strengthening of reinforced concrete beam-column joints using ferrocement

Evidences from previous earthquakes have shown that failure in beam-column joints may cause disastrous collapse of structures, especially for buildings without seismic provisions. To extend the life span of beam-column joints, strengthening is required and this can be effectively achieved using ferrocement. Ferrocement is a composite material of wire mesh embedded in various mortars. It is bonded to the beam-column joints for strengthening. In this study, four 2/3 scale reinforced concrete interior beam-column joints, including one control specimen and three specimens strengthened by the proposed method, were constructed and tested under cyclic loading. The specimens were without transverse reinforcement and designed to be shear deficient, but complied with previous design codes in Hong Kong. Three types of mortar were selected as the variable parameters for the strengthening scheme while the same wire mesh was adopted. The experimental results indicated that the proposed strengthening method is effective to enhance the ultimate loading capacity, stiffness and energy dissipation. In addition, the strength of mortar has a crucial influence on strengthening.