Pacific Spirit Properties is constructing a new residential / commercial development on a waterfront property in Sechelt, BC. The proposed development will consist of two 6-storey concrete residential structures situated over a common level of parking structure and retail units.
Besides compressibility of the organic near surface soils, one of the main geotechnical challenges facing this site is the possibility of liquefaction of underlying saturated native sands and gravels during the design earthquake, which could result in vertical and lateral foundation movements. Opposed to the deep pile option which was eliminated due to its high cost, the owner chose to remove the peat and restore grade using clean structural fill, followed by ground improvement and building support on conventional shallow footings. Menard Canada successfully offered the execution of Vibro Compaction ground improvement for compaction of the imported fill materials and deeper native granular soils. A suitable triangular compaction point grid spacing was selected to achieve soil densities specified in the Engineer’s CPT performance specification. While working in close proximity to an adjacent hotel, a survey and vibration monitoring program was carried out by the Engineer. At a distance of approximately 3m, measured vibrations were generally in the order of 5 to 10mm/sec, values that are below the published potentially damaging velocity. Menard Canada completed the ground improvement work ahead of schedule with exceptional results relative to required CPT resistance values.