The Colonnade Residences

GEI Consultants provided geotechnical and environmental consulting services associated with the construction of a 20-story residential building in downtown Boston. From initial investigations through construction, the size-restricted site called for experienced engineers.

Nearly the entire site was excavated to a depth of 40-feet immediately adjacent to an occupied hotel, a subway tunnel, a high-rise residential/commercial building, and old brick row houses supported on timber piles. GEI provided geotechnical consulting including foundation design, specifications preparation, excavation support, submittal review, and monitoring construction and its potential effects on the adjacent century old buildings.

GEI’s expertise in dewatering and in foundation behavior and protection was also utilized when the sheeting did not provide as tight a water barrier as intended. GEI monitored and evaluated the impacts of the actual pumping rates and drawdown on adjacent buildings. GEI provided the owner with guidance during selective subsequent jet-grouting and injection of fast-acting chemical grouts and deep dewatering well installation and operation.

Our environmental services included a groundwater and soil chemical testing precharacterization program that assisted the owner in obtaining financing, and allowing the contractor to directly load and haul the approximately 12,000 cubic yards of material excavated during foundation installation. During excavation, GEI monitored the excavated materials for compliance with disposal facility requirements. On a monthly basis, GEI monitored the dewatering treatment system for compliance with dewatering requirements.

GEI also assisted the owner with obtaining permits from the City of Boston, the Massachusetts Department of Environmental Protection, the Massachusetts Water Resources Authority, and the Boston Water and Sewer Commission.

Throughout this process, GEI has been an integral part of the solutions that have helped to get the project out of the ground.