Fully installed cross-lot internal bracing
Embedded plate connections along north wall
Cross-lot internal bracing facing east
Mass excavation proceeding beneath internal bracing
28 Chestnut Street SOE Design
SOE for Life Science Office and Laboratory Space
GeoEngineers’ Construction Design team partnered with Trevi Icos Corporation of Charlestown, MA, to provide excavation support design for the 28 Chestnut Street development in Somerville, MA. The 200,000-square-foot project delivered state-of-the-art life science office and laboratory space. GeoEngineers’ scope included the design of a slurry wall and an internally braced support of excavation system.
Approach
- Designed support of excavation (SOE) for a 400-by-125-foot excavation reaching depths of up to 26 feet to accommodate the project’s basement and underground parking levels.
- Implemented a 30-inch-wide slurry wall system with one level of internal bracing; internal wales supported the long sides, and external wales reinforced the short sides and corners.
- Addressed challenges such as variable rock elevations, proximity to large utilities (dual 90-inch force mains within 50 feet of the site), and coordination around proposed structural elements.
- Provided construction-phase support by revising designs to accommodate as-built conditions, reconfiguring bracing, adjusting construction sequencing, and evaluating alternate equipment surcharges.
Results
GeoEngineers delivered comprehensive design calculations and detailed drawings for the project’s temporary support of excavation (SOE) system. The final design package included typical plans, cross sections, material specifications, and construction sequencing details for the braced slurry wall system. These deliverables provided clear guidance for the contractor, supporting safe and efficient excavation and construction of the project’s below grade structure.
