Originally conceived as a simple retaining wall repair and roadway reconstruction project, Stadium Way in Tacoma, Washington, was expanded to address past poor construction methods and slope stability hazards that had significantly impacted the roadway. NV5 provided geotechnical services to support retaining and shoring wall design for new walls and the restoration/strengthening of existing walls; slope stability analyses for two areas of interest on the marine bluff between Schuster Parkway and Stadium Way; and a geotechnical data report for the roadway design.
The scope involved historical research of the area through the City of Tacoma web-based and hardcopy archives, extensive geotechnical explorations, geotechnical instrumentation, geologic studies, and numerical analysis of the slopes to support the design and construction of the restoration of the Schuster Parkway retaining wall and stabilization of Stadium Way. We provided a complete team that included geotechnical and structural engineers to support cost effective repair, replacement, ground improvement, and landslide stabilization options.
The project involved atypical wall designs for existing walls that were as much as 80 years old and showing signs of deterioration.
During the Stadium Way reconstruction project, we identified areas of poor fill placement and landsliding areas that were affecting the roadway. We provided cost effective ground improvement recommendations that included a combination of compaction grout and stone columns in order to reduce construction costs and minimize impacts to residents. During the compaction grouting phase, the grout take was significantly more than anticipated due to poor ground conditions and voids. We monitored construction costs on a daily basis and modified the program and grouting criteria so that the required level of improvement was achieved, while keeping the additional costs to less than 10% of the estimated budget.