Title: Seismic Response of Reinforced Concrete Double-Deck Bridge Structures

Author(s): S. Mazzoni, F. Zayati, J. P. Moehle, and S. A. Mahin

Publication: Symposium Paper

Volume: 187

Issue:

Appears on pages(s): 235-254

Keywords: beam-column connections; bridges; reinforced concretes; seismic design.

DOI: 10.14359/5601

Date: 6/1/1999

Abstract:
A program of field a laboratory tests to study the seismic response of reinforced-concrete double-deck bridge structures has been conduced at the University of California Berkeley. The research was prompted by the poor performance of these structures during the 1989 Loma Prieta Earthquake. The program had three phases of testing. The first phase was conducted in-situ immediately after the earthquake on a section of the Cypress Street Viaduct that had not collapsed. This test showed the need for confinement in the critical beam column joint region as well as the need for a ductile lateral-load-resisting system. The second phase of testing was the proof test of a comprehensive retrofit concept for a bent of the Alemany Freeway. The test showed that a ductile system, combined with a conservatively designed beam-column connection, provides adequate structural performance under unidirectional and bidirectional lateral loading. The third phase of testing focused on the current design criteria for beam-column connections in ductile double-deck bridge structures. In this phase of testing, two one-third scale models of beam-column connections in ductile frames designed according to current criteria were tested in the laboratory. Results from this test series showed that proper detailing, without excessive amount of reinforcement, increases the load-resisting capacity of beam-column connections and relocates the yield mechanism from the joint to the column. The goal of this paper is to provide the reader with a comprehensive overview of the work.