Detailed 3D FE modeling approach for 2D and 3D beam-column joints retrofitted with fully fastened haunch retrofit solution including anchor behavior

Abstract

Fully fastened haunch retrofit solution (FFHRS) is a low-invasive method for seismic retrofitting of substandard beam-column joints. The method is quite effective provided a good performance of the anchors used for connecting the haunch elements and structural members is ensured. Therefore, to assess the performance of the joints retrofitted with FFHRS, realistic modeling of anchors connecting haunch elements to the joint members is essential. The paper presents a new numerical modeling approach for detailed 3D finite element analysis of substandard beam-column joints retrofitted with FFHRS, where bonded anchors are used to connect the haunch elements to structural members. The model includes detailed and realistic modeling of concrete, reinforcement, bond, haunch elements and anchors. A special focus is laid on the detailed modeling of anchor behavior. The model is validated against two experiments reported in the literature, by comparing the complete performance obtained in the tests and analysis in terms of load–displacement response, failure modes and forces in the haunch elements. The validated model is used to carry out parametric studies to investigate the performance of the single haunch retrofit solution and the performance of FFHRS as well as the efficacy of FFHRS in a 3D beam-column joint with transverse beams and slab.