Abstract:
Project: Gilmore Place Towers - Dawson Street & Gilmore Avenue, Burnaby, BC, Canada
Developer: Onni Group
Geotechnical Engineering Consultant: GeoPacific Consultants Ltd.
Geotechnical Monitoring Consultant: Municon West Coast Monitoring Ltd.
ABSTRACT
Excavation and shoring work adjacent to the above-grade Gilmore train station and elevated guideway supporting caissons was undertaken in 2019 for the Gilmore Place development, which will be home to the tallest tower in Western Canada standing at 64 storeys or 216 m tall. A perimeter secant pile cut-off wall was constructed to a depth of up to 37 m below ground surface and consisted of 900 mm diameter drilled piles spaced 750 mm on-center, tied back with soil anchors. Each pile was filled with concrete with a specified strength of 10 MPa at 28 days, with every 4th pile reinforced with a W610 steel section. Additional secant piles and a bracing/jacking system was also constructed to support the free-standing guideway caissons within the excavation. Soil conditions at the site consisted of mineral fills, overlying bog/swamp deposits of compressible peat, organic silt, and firm low plastic silt up to 7 m below ground surface, overlying very dense glaciated till-like soils including a bedding of glaciofluvial sand and gravel containing a confined aquifer, overlying tertiary bedrock at depth. A robust, automated instrumentation program was installed to monitor movements of the shoring walls and train infrastructure in real time, and to provide immediate alerts to the design and construction team should movements exceed predetermined thresholds established by the design team. Monitoring instrumentation consisted of a robotic total station, in-place inclinometer systems, tiltmeters, strain gauges, displacement gauges, and anchor load cells. Excavation and shoring for Phase 1 of the development was successfully completed in December, 2021. The monitoring program indicated movements of the guideway, station, and supporting piers were below maximum movement tolerances and enabled safe completion of shoring activities without disruption to train and passenger movement.
Abstract: Theme 2