15th Avenue-Leary Way Bridge Seismic Retrofit
Seattle Department of Transportation
Seattle, Washington
Exeltech conducted a seismic vulnerability study, developed planning-level cost estimates and strategies, designed modifications to strengthen the existing bridge and make the bridge less vulnerable in the event of an earthquake, and prepared final Plans, Specifications & Estimates. The work was completed in three phases: Phase 1 – Project Definition Report; Phase 2 – PS&E; and Phase 3 – Engineering Support during Construction. Construction is scheduled to begin in the summer of 2023.
Project deliverables included the Basis of Design Report, Seismic Vulnerability Study & Retrofit Strategies Technical Memorandum, Bridge Condition Summary Report, Cultural Resources Report, Environmental Overview Technical Memorandum, Project Definition Report, construction schedule, and bid documents.
Exeltech’s subconsultant partners conducted geotechnical engineering and analysis to support the development of retrofit alternatives; prepared a public outreach plan; and conducted a cultural resources assessment and topographic survey. Conceptual design recommendations and preliminary cost estimates for minimal, optional, and extensive approaches to seismic retrofit of the bridge were presented to the City at a workshop conducted in October 2019.
The 15th Ave/Leary Way Bridge was built in 1959 with significant retrofits in 1976 and 1993. The bridge carries four lanes of 15th Ave NW in the north south direction over Leary Way. Improving the seismic performance and resiliency of the 15th Ave NW/Leary Way Bridge will help protect public safety, improve infrastructure sustainability, and maintain access to north Seattle neighborhoods. Each span of the bridge is supported by steel rocker bearings. The 48'-8" wide bridge consists of five 70-ft-long simply supported spans for an overall length of 350'.