San Diego-Coronado Bridge

One of the first things newcomers notice about San Diego is the dramatic curve of the Coronado Bridge spanning the bay between the city and the island of Coronado. Opened in 1969, the bridge is both functional and beautiful to look at. The distinctive towers and graceful curves of the bridge earned it the "Most Beautiful Bridge" Award of Merit from the American Institute of Steel Construction in 1970.
All of the braces and stiffeners for the bridge are contained in box girders, giving it a smooth exterior. The concrete piles are driven over 100 feet into the bay in order to support the span. The views from the bridge are breathtaking and virtually unobstructed—a significant distraction for drivers. The drive across provides a nice panorama of San Diego's skyline and the huge Navy ships lining the harbor. Built as a toll bridge, there is no longer any charge to use it.

The orthotropic design used in the 2.12-mile long bridge originated in Germany during World War II in the construction of battleships. The structure uses the world's longest continuous box girder to conceal the braces, joints, and stiffeners normally visible in other bridges providing a vertical clearance of 200 feet over the shipping channels, and giving the exterior a sleek, smooth appearance. The 90-degree turn mid-span serves to make the bridge long enough to achieve a 4.67 percent grade, allowing the bridge enough height to clear an empty aircraft carrier.

Under the roadway is a steel-mesh catwalk built to facilitate bridge maintenance. Caltrans conducts routine inspections to detect concrete flaking and exposed bare metal surfaces. Painting the bridge is a never-ending job. A four-person crew works year-round to keep it protected from corrosive ocean breezes. The blue color was chosen to blend with sky and sea.

In the 1976 the bridge was retrofitted with special rods to protect against earthquake damage.

There are five lanes of traffic available on the bridge with the center lane reserved for a safety median and a reversible lane that provides three lanes during rush hours. The "zipper" used to accomplish this reversal is an engineering feat in itself.

Facts At A Glance

Construction start date: February, 1967
Opened: August 3, 1969
Cost to build: $47.6 million
Length: 2.12 miles
Channel span: 1880 feet
Vertical Clearance: 200 feet

Information from the following websites:

http://www.sddt.com/Community/Landmarks/Landmarks.cfm?Landmark_ID=31
http://www.dot.ca.gov/hq/esc/tollbridge/Coronado/Corofacts.html
http://www.SignOnSanDiego.com