1
Title
Author-s
Seismic response of FRP-upgraded exterior RC Beam-column joints
Alsayed, S.H., Al-Salloum, Y.A., Almusallam, T.H., Siddiqui, N.A.
Contact lnfo salsayed1@yahoo.com
, 00966-1-4676925, Department of Civil Engineering, King Saud
University, P.O. Box 800, Riyadh 11421, Saudi Arabia
Department Civil Engineering Department
Major citation structures
Journal of Composites for Construction
Volume 14, Issue 2, 2010, Pages 195-208
2010 Year of
Publication
Publisher ASCE
Sponsor
Type of
Publication
ISSN
URI/DOI
Journal
10900268
10.1061/(ASCE)CC.1943-5614.0000067
Full Text
(Yes,No)
Yes
Key words Beam columns; Beam-column joints; Exterior joints; Fiber reinforced polymer; FRP; Joints;
Rehabilitation; Seismic effects; Strengthening
Abstract Shear failure of exterior beam-column joints is identified as the principal cause of collapse of many moment-resisting frame buildings during recent earthquakes. Effective and economical strengthening techniques to upgrade joint shear resistance and ductility in existing structures are needed. In this paper, efficiency and effectiveness of carbon fiberreinforced polymer (CFRP) sheets in upgrading the shear strength and ductility of seismically deficient exterior beam-column joints have been studied. Four as-built joints were constructed with nonoptimal design parameters (inadequate joint shear strength with no transverse reinforcement) representing preseismic code design construction practice of joints and encompassing most of existing beam-column connections. Out of these four asbuilt specimens, two specimens were used as baseline specimens (control specimens) and other two were strengthened with CFRP sheets under two different schemes (strengthened specimens). In the first scheme, CFRP sheets were epoxy bonded to joint, beams, and part of the column regions. In the second scheme, however, sheets were epoxy bonded to joint region only but they were effectively prevented against any possible debonding through mechanical anchorages. All of these four subassemblages were subjected to cyclic lateral load histories so as to provide the equivalent of severe earthquake damage. The damaged control specimens were then repaired by filling their cracks through epoxy and externally bonding them with CFRP sheets under the same above two schemes. These repaired specimens were subjected to the similar cyclic lateral load history and their response histories were obtained. Response histories of control, repaired, and strengthened specimens were then compared. The results were compared through hysteretic loops, loaddisplacement envelopes, column profiles, joint shear distortion, ductility, and stiffness degradation. The comparison shows that CFRP sheets are very effective in improving shear resistance and deformation capacity of the exterior beam-column joints and delaying their stiffness degradation. © 2010 ASCE.