Seismic Investigation/Below-Water Load Test for a 100-Year-Old Pier

Broadway Pier, owned and operated by the San Diego Unified Port District (District), was constructed in 1913 as San Diego's first major concrete pier. In 1930, the pier was extended 200 feet (61 meters) further into San Diego Bay to its current length of 1,000 feet (305 meters). Over the years, the pier was renovated and upgraded several times, the most significant being in 1989 when the deteriorated outer portions of the 1913 pier were removed and replaced with a new structure supported on batter piles. The facility has been used to support a transit shed, general-purpose vessel berthing, military facility, cruise ships, and a place of public assembly. In 2007, the District decided to construct a new building on Broadway Pier to convert it to a modern dual-purpose facility to meet the need for a downtown location for public assembly over the water and to support the cruise ship industry. The facility is known as the "Port Pavilion at Broadway Pier." (Reference 1). During the preliminary design phase for the new facility, it became apparent that the pier might not meet requirements of the California Building Code to support the building structure. Findings of an initial seismic evaluation indicated numerous deficiencies, the most critical being brittle batter pile connections to the pier deck and questionable lateral capacity of a 1930 extension that had a unique pile-to-deck connection. This paper summarizes the seismic investigation for the outer 1930 extension of the pier, the construction of which was considerably different than the original 1913 pier construction. Specifically, the paper will describe the seismic analyses and the details and findings of the below-water load test using engineer-divers, which resulted in significant seismic retrofit savings to the District, leading to successful execution of the building project.