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The Northridge, California Earthquake of January 17, 1994: Performance of Highway Bridges

I.G.Buckle

NCEER-94-0008 | 3/24/1994 | 132 pages

About the Report:

TOC: The table of contents is provided.

Notes: The photographs and corresponding captions included in this report can be viewed online

Keywords: Northridge, California Earthquake, January 17, 1994, Highway Bridges, Damage, Seismic Performance, Bridge Geometry, Failure Modes, Local Geological Conditions, Geotechnical Aspects, Gavin Canyon Undercrossing, Bull Creek Canyon Channel Bridge, Balboa Boulevard Overcrossing, Fairfax-Washington Undercrossing, Retrofitted Bridges, La Cienega-Venice Undercrossing, State Route 14/I-5 Separation and Overhead, State Route 14/I-5 North Connector Overcrossing, and Earthquake Engineering.

Abstract: During the Northridge earthquake of January 17 in Los Angeles, California, seven highway bridges suffered partial collapses and another 170 bridges suffered damage ranging from minor cracking to the slumping of abutment fills. This report thus contains a detailed summary of the performance of eight bridges that suffered major damages. These bridges are as follows: 1) Gavin Canyon Undercrossing; 2) State Route 14/I-5 Separation and Overhead (Southbound); 3) State Route 14/I-5 North Connector Overcrossing; 4) Bull Creek Canyon Channel Bridge; 5) Mission-Gothic Undercrossing; 6) Balboa Boulevard Overcrossing; 7) Fairfax-Washington Undercrossing; and 8) La Cienega-Venice Undercrossing. Damage sustained by these and other bridges can be categorized as follows: abutment back-fill settlement and erosion; abutment and shear key structural damage; flexural failures in plastic hinges with inadequate confinement; pounding and unseating at hinge seats and girder supports; shear failures in short single columns, piers, multi-column bents, columns with flares and other accidental restraints, and columns in skewed bridges. It is observed that of those bridges with collapsed spans, all were designed and constructed from the mid-sixties to the mid-seventies. None were "new" in the sense of being built to current codes. Most had been retrofitted with cable restrainers, where appropriate. Some bridge columns in the epicentral region had also been strengthened with steel-jackets. Whereas several cable restrainer units failed, none of the steel-jacketed columns showed distress despite strong ground shaking in some cases.