District 11, P.O. Box 85406, San Diego, CA 92186-5406


San Diego - Coronado Bridge
Seismic Retrofit Project

March 1999


The San Diego-Coronado Bridge built with an eye to appearance as well as transportation service, has become a symbol of the San Diego area-just as the Golden Gate and San Francisco-Oakland Bay Bridges symbolize that area around the world. Its distinctive towers and graceful curve are a striking landmark in the harbor area. In 1970, it received the Most Beautiful Bridge Award of Merit from the American Institute of Steel Construction. The bridge was financed by a California Toll Bridge Authority $47.6 million bond issue which has since been repaid from toll revenue. It is one of nine State-owned toll bridges. Construction started in February 1967, and the bridge was opened to traffic on August 3, 1969 during the celebration of the 200th anniversary of the founding of San Diego. It is notable among the world's great bridges for the number and size of its concrete towers. There are 30 towers and over the channel they reach a height of 200 feet. They were designed with a curved cap to echo the mission arch shape associated historically with regional architecture. The towers rest on 487 prestressed reinforced concrete piles. The piles, 54 inches in diameter and with walls 5 inches thick, were driven and jetted into the sand and clay of the bay bottom up to lengths of 100 feet. The mud was removed from inside the piles, which were then filled with concrete. Clusters of up to 44 piles were used under some towers. Girders of the steel superstructure are painted blue to harmonize with the predominant color of the sky and bay. Beginning at the toll plaza in Coronado, traffic ascends at a 4.67% grade, curving gracefully 90 degrees toward San Diego. This 2,850-foot section is the longest in the U.S. using curved steel plate girders. The shipping channels are spanned by the world's longest continuous three-span box girder, 1,880 feet. The roadway is of orthotropic steel plate design and serves as the top flange of the box girder. Its spans are third longest of their kind in the country. This design saves steel and provides a slender superstructure with a smooth exterior, all braces and stiffeners being inside the box girder. The steel superstructure was fabricated and erected in the San Francisco Bay Area. Girders were barged down the Pacific Coast and lifted into place by the largest barge crane in the West, the "Marine Boss."Precast prestressed concrete girders of up to 165-feet in length were manufactured in Long Beach. These are among the longest of their kind in use in the country. The roadway has five lanes. The center lane is a switch lane with a moveable center divider, which is used to provide three lanes for peak-hour traffic when demand warrants. The 34-inch-high concrete barrier railings are low enough to permit an unobstructed view from vehicles on the roadway. Wide at the bottom and narrow at the top, the railings are safety-designed to redirect the wheels of a vehicle back to the roadway with little or no damage. The 7-lane toll plaza, with an architecturally designed canopy on sculptured pedestals, received special landscape attention, including extensive lighting to enhance the appearance. Traffic volume on the bridge has grown at a healthy rate, permitting several toll reductions. The basic auto toll is $1 for westbound passage. Commute books cost $24, to provide a reduced toll of 60 cents to the regular commuter. The California Department of Transportation employs a force of 65 persons to operate and maintain the bridge. The total traffic volume in 1971 was 8,631,436 vehicles. In the year 1996, the average daily traffic was 66,000. During the summer, volumes increase to over 69,000 vehicles a day.



The San Diego - Coronado Bridge was opened to traffic on August 1969. In 1973, modern seismic bridge design practices were introduced that incorporated lessons of bridge performance learned from the 1971 San Fernando earthquake. As a direct result of the earthquake, the San Diego- Coronado bridge was retrofitted in 1977. Results of the 1989 Loma Prieta Quake in the San Francisco Bay area, identified a need for more strengthening than was implemented in the 1970's retrofitting project. As of December 1996, the retrofit strategy has been finalized. The strategy does not adversely impact the aesthetics of the bridge and manages to preserve the important murals in Chicano Park.

At this time, studies to determine the structural integrity of the bridge are completed. Caltrans is now finalizing the contract plans for the last three contracts. The project is scheduled to be completed in four stages. The first contract was awarded to American Bridge Company of Long Beach, California for $3.1 million.


Beginning late October 1995, Caltrans began meeting with artists, community representatives, agencies, and elected officials to keep them appraised of the status of this important retrofit project. Caltrans will continue to share information as it is received and solicit assistance from the community throughout the retrofitting process.


October 1995 begin environmental studies, community meetings
May 1996 open-house public meeting
December 1996 announcement of strategy decision
Winter 1997 begin construction
Fall 1999 complete final design of the project

Project Schedule