Title:
Bond Slip of Bridge Column Reinforcement Anchored in Cap Beams
Author(s):
S. Sritharan, J. M. Ingham, M. J. N. Priestley and F. Seible
Publication:
Symposium Paper
Volume:
180
Issue:
Appears on pages(s):
319-346
Keywords:
Bonding; bond slip; bridge anchorages; bridge structure; caps
(supports); cyclic loading; seismic loading; slippage
DOI:
10.14359/5883
Date:
10/1/1998
Abstract:
Until recently, bridge design specifications in California permitted longitudinal column reinforcement to be terminated in monolithic cap beam/column joints with straight bar development not extending fully up the joint height. Since the development length could be construed not to comply with AC1 3 18 requirements, it was suspected that the anchorage length provided for the column bars was insufficient to develop the full moment capacity of the column at the joint interface. Considering that this detailing was widely used in bridges in California, an experimental investigation was initiated at the University of California, San Diego, where response of a bridge knee joint incorporating as-built reinforcement details was examined under simulated seismic loading. Following inadequate performance of the test unit, the behavior of the knee joint was investigated based on the experimental readings, giving consideration to bond slip of the longitudinal column reinforcement. The response of the test unit indicated that the bond conditions developed when anchoring the longitudinal reinforcement of circular bridge columns is unlike that developed along the beam reinforcement anchored into building joints.