Evaluation of Bridge Beam-Column Joints Under Simulated Seismic Loading

Document Name: 99-S07
Author(s): Clay J. Naito, Jack P. Moehle, and Khalid M. Mosalam
Publication: Structural Journal
Volume: 99
Issue: 1
Keywords: beam; column; joint
Date: January 1, 2002

The 1989 Loma Prieta earthquake and subsequent studies resulted in higher design requirements for transverse reinforcement in reinforced concrete bridge beam-column joints constructed in California. The resulting reinforcement details can be congested and difficult to construct. An experimental investigation examined four large-scale interior joints with details typical of those required in California. The experimental program included tied square cross-section columns and spirally reinforced circular cross-section columns. Both conventional and headed joint reinforcement configurations were investigated. Experimental results show that current design requirements produce joints that remain essentially elastic to relatively large drifts, whereas the columns develop inelastic rotations adjacent to the joints. The use of headed reinforcement within the joint regions was shown to be effective in reducing congestion and thereby improving construct-ability while maintaining comparable structural behavior.