Development and validation of a metallic haunch seismic retrofit solution for existing under-designed RC frame buildings

Seismic Retrofit of Defective RC Beam-Column Joints

“…The introduction of Fiber Reinforced Polymer (FRP) made possible the introduction of various retrofitting methods to increase the shear strength of non-seismically detailed RC beam-column joints. A retrofitting approach that was experimentally examined by Pampanin, Christopulos [27], Said and Nehdi [28] and Sharbatdar, Kheyriddin [29], was to mount diagonal metallic haunches on the beam-column to protect the panel zone. This way of retrofitting mobilizes the part of the beam and column immediately adjacent to the panel zone of the joint and aids the joint in withstanding the shear force input which procrastinates the shear failure of the joint.…”

Seismic Performance of Exterior RC Beam–Column Joints Retrofitted using Various Retrofit Solutions

“…According to a previous investigation (the Korea National Emergency Management Agency 2011) in Korea, concrete beam-column joints designed without consideration of earthquake load have certain material and geometrical characteristics: low concrete strength; plain steel re-bars; inadequate or no transverse reinforcement in beam-column joints; and insufficient anchorage detailing leading to lack of concrete confinement (Santersiero and Masi 2015;Pampanin et al 2002;Engindeniz et al 2005). When such concrete buildings are subjected to earthquake loading, the beamcolumn joints (in particular, the corner and exterior joints) could fail in brittle manner, which might trigger partial or entire collapse of the buildings (Rashidian et al 2016;Petrone et al 2016).…”

“…In the analysis by Del Vecchio et al (2016), the anchorage effect of beam bars and the shear contribution of the FRP strengthening system were delicately accounted for, and the analysis results showed a good agreement with the test results in terms of strength, global deformation, crack pattern, strength and stiffness degradation, and pinching. Pampanin et al (2006) experimentally investigated the effectiveness of various haunch retrofit solutions on the seismic response of the reinforced concrete beam-column joints. The haunch elements were used including diagonal axial elements and they were hinged or welded to the steel plates at both ends to form haunch elements.…”

Experimental Study on Structural Performance of RC Exterior Beam-Column Joints Retrofitted by Steel Jacketing and Haunch Element under Cyclic Loading Simulating Earthquake Excitation

“…Moreover, the haunch retrofit solution (HRS) using haunch elements was proposed by Pampanin et al [8] and several comprehensive tests were performed by Genesio [9] using postinstalled anchors for optimization of the HRS. The main principle of HRS was to relocate the plastic hinge away from the vulnerable panel zone thus enhancing the global response of RC beam-column joints without seismic reinforcement details by altering the hierarchy of strength suitably.…”