Title:
Seismic Repair and Strengthening of a Severely Damaged Concrete Frame
Author(s):
Dan R. Stoppenhagen, James O. Jirs, and Loring A. Wyllie, Jr.
Publication:
Structural Journal
Volume:
92
Issue:
2
Appears on pages(s):
177-187
Keywords:
beams (supports); columns (supports); damage; ductility; earthquake-resistant structures; frames; reinforced concrete; repairs; stiffness; strength; Construction
DOI:
10.14359/1157
Date:
3/1/1995
Abstract:
A repair technique designed to strengthen and repair reinforced concrete frames with heavily damaged columns was tested experimentally. A two-thirds scale model of two bays and two stories of an exterior moment-resisting frame with heavily damaged columns was repaired and strengthened by completely encasing the damaged columns. The damage was characterized by heavy shear cracking and spalling of the concrete in the window space between the spandrel beams. In addition to repairing the damage to the columns, the new columns were designed to increase the lateral capacity of the frame and to shift the mode of failure from shear in the columns to flexural hinging in the beams. Test results of the frame under statically applied cyclic lateral load indicated that the columns were successfully repaired, and that the governing failure mechanism of the frame was successfully shifted from column shear failure to flexural hinging of the beams. The results also showed that the encased columns behaved monolithically, and that the lateral strength of the frame was substantially increased.