Spencer Block
Scope of work
This Project consisted of multiple scopes of work for Western Grater including blasting, shotcrete shoring, and tie-back anchors. The shotcrete shoring consists of welded wire mesh and rebar to reinforce the shotcrete creating a stable vertical wall allowing developers to maximize land utilization. Tie-back anchors are drilled and grouted to further support the shotcrete wall system. Western Grater utilizes a hollow anchor bar system which greatly improves efficiency over traditional drilling methods.
Blasting works occurred over a 3-4 month period with a total rock volume of over 8900 cubic meters. Due to the extremely close proximity of the neighbouring heritage building, a “line drilling” method was used to ensure an accurate rock break at desired property line.
Challenges
As with most blasting operations in urban settings, much care must be taken to ensure the safety of all other workers and the general public, as well as the presence of older structures from the early 20th century that the city of Victoria is famous for. On the Spencer Block project there is an adjacent brick building built in 1908 by Sam Kee Laundry, the utmost care was taken to ensure no damage was sustained and the impact to the residents was kept to a minimum. Engineers are also involved in the monitoring of neighbouring structures to ensure all excavation perimeters remain stable and safe.
Another major challenge on this project was the local ground conditions. Due to poor environmental practices in the early 20th century, large areas of the job site contained contaminated soil at depth. The presence of this contamination creates challenges for all contractors involved, such as removal of contamination, which comes with great cost to the client and delineation of materials for the excavation contractor. These conditions also create some hurdles for WGC as the ground conditions were not conducive to bonding anchors to soils. WGC employed the use of a “grout Swivel” which allows us to drill anchors in with continuous grout flow throughout the drilling process as opposed to the traditional method of drilling with air and grouting post installation. The use of this method provided great success upon its application.