Seismic retrofitting of damaged exterior beam–column joints using fibre reinforced plastic composite–steel plate combined technique

Abstract

A conventional gravity load design philosophy for reinforced concrete (RC) structures has been slowly replaced by seismic design since the 1970s. But, till recently, capacity design and ductile detailing were not strictly implemented in practice in many developing countries which are prone to seismic hazard. In the present study, performance of exterior beam-column joints designed based on ductile and non-ductile philosophy has been studied under cyclic load. It is found that although the incorporation of ductile detailing has considerably improved the seismic behaviour of the structural component, it could not assure the damage propagation in a safe zone. Moreover, in both specimens, the main damage has been concentrated in the joint zone irrespective of ductile detailing. Further, the damaged specimens were adequately repaired and suitably retrofitted using fibre reinforced plastic and steel plate and tested again under the same cyclic load. The retrofitted 'NonDuctile' specimen, as proposed in this study, could not only be able to regain its original performance (in terms of strength deterioration, stiffness degradation, energy dissipation), but has also shown improved performance in comparison to the original ones which is ideally desirable as well. Further, the retrofitted 'Ductile' specimen has shown a promising aspect of the proposed retrofitting strategy for seismically damaged components.

Numerical simulation of performance of near-surface mounted FRP-upgraded beam–column sub-assemblages under cyclic loading

“…only column upgrading, only beam bottom upgrading and both beam top and bottom upgrading). Furthermore, energy dissipation from the 'BF' sub-assemblages is comparable with that obtained from the 'Ductile' sub-assemblages with similar geometry and subjected to similar type of loading as reported in the literature Sasmal et al, 2013). The concise observations on the seismic performance of upgraded beam -column sub-assemblages are presented in Table 4, which can provide a clear picture to the readers for developing the efficient and optimum upgrading schemes using NSM bars.…”

Rehabilitation of earthquake damaged external RC beam‐column joints by joint enlargement using prestressed steel angles

“…For these reasons, a large number of rehabilitation techniques for earthquake-damaged RC beam-column joints have been reported in earthquake-prone countries such as USA, New Zealand, and Japan, but these techniques possess their own practical limitations and cause various difficulties in practical implementation at the joint, such as requiring intensive labor, artful detailing, and increased dimensions [12]. In the last two decades, several techniques for seismic retrofitting of undamaged non-seismically detailed RC beam-column joints have been used, including reinforced or prestressed concrete jacketing [18][19][20][21][22][23], steel jacketing and the addition of external steel elements [24][25][26][27][28], and fiber-reinforced polymer composite jacketing [29][30][31][32][33][34][35][36][37][38][39][40]. Various rehabilitation procedure has also been used to repair and improve earthquake-damaged beam-column joints, including crack injection with epoxy resin and partial core replacement with high-strength cement paste or mortar [41][42][43][44][45], complete core replacement with new concrete [46][47][48], and partial core replacement with high-strength mortar [32,49].…”