Precautions and protective measures were undertaken
The project involved the construction of an extension to the existing Ste Anne’s Elementary School located in Ottawa, Ontario. Due to the poor existing ground conditions encountered at site a soil improvement program was required prior to beginning construction. Geopac, the Canadian subsidiary of Menard, proposed a ground improvement approach consisting of Rapid Impact Compaction (RIC) using the GeopacTOR© to compact the soil with the objectives of improving the bearing capacity, controlling settlement, and mitigating liquefaction. The soil improvement was necessary to support the future slab-on-grade and footings of the school addition.
Before ground improvement works were started, the site was stripped of topsoil and other deleterious material, and roughly graded. The soil profile in the area consists of sand and fill overlying stiff silty clay till. The water table was found to be near the surface, approximately 1 meter below the working platform.
Based on Geopac’s design, the 1700 square meter platform was compacted in four phases using a 9 ton hydraulic hammer falling repeatedly from a 1.2 meter height. The number and spacing of the phases allowed for proper compaction at depth for the site. The ground improvement program occurred directly beside Ste Anne’s School. Due to the project’s proximity to the existing school structure, several precautions were undertaken to ensure that the integrity of the school remained sound. Protective measures included a pre-construction survey of the building, monitoring of the school for movement during works, and particle velocity measurements.