Seismic Retrofit of Reinforced Concrete Coupling Beams Using Steel Plates
Kent A. Harries, William D. Cook, and Denis Mitchell
Appears on pages(s):
beams (supports); earthquake-resistant structures; load tests; reinforced concrete; shear properties; walls; Construction
Existing beams coupling reinforced concrete walls are often found to be deficient. Common deficiencies include inadequate overall capacities, particularly shear capacities that are insufficient to develop flexural yielding of the beams. This research examines the use of steel plates to improve the shear resistance of reinforced concrete coupling beams in moderate seismic zones. Full-scale reversed cyclic loading tests of shear-deficient reinforced concrete coupling beams were carried out. The retrofit measures involved attaching thin steel plates on one side of the coupling beams to enhance their shear performance. A number of different ways of attaching the plate were investigated. Tests with the steel plate attached only with epoxy demonstrated a need for further connection to improve the hysteretic response. Additional specimens were constructed to investigate the influence of connecting the plate with both epoxy and bolting. The purpose of testing these retrofitted specimens was to develop a procedure for designing the plate connection details such that significant stresses are developed in the plate. The reversed cyclic loading responses of the retrofitted specimens are compared with a control specimen representing the deficient coupling beam before retrofit.