How to maximize your productivity when installing long, linear runs of trench boxes.

The shoring division of FinningCAT was recently contracted by a large, utilities contractor to supply the shoring to complete an install/relocation for Greenline Enabling Works for future Greenline LRT expansion to SE Calgary. This project included abnormally deep cuts to facilitate future Greenline Construction, some spots of the project had cuts of 9.5m inverts depths. 

This project had a lot of competition in the bidding process, which meant the margins were tight and it was necessary to think outside the box to reduce costs and shorten the time taken to complete the work. After a thorough and careful assessment of the ground conditions and different shoring methods and options, including CAD models, the GroundWorks steel system was chosen for its lightness and ease of assembly. Space at site was very tight and it was felt better to use a smaller, less costly excavator and a small crew to minimize costs.

This work was safely completed ahead of schedule and on budget using only a 30T Excavator to excavate, place and remove shoring. Once excavated and shored they were required to build a 20-way (4 wide 5 high) concrete encased duct bank. The excavation was completed using a few different methods from bulking upwards to 4.5 of material to work with a level surface equal to the elevation of the existing roadway. Once the bench was completed, they excavated a 5.5m invert straight walled trench and placed stacked GWSS trench boxes in one lineal run of approximately 70m and completed their install/concrete pour at once. The time taken to assemble the shoring boxes was minimal and delivery to site was flawless. The local Calgary shoring team worked closely with the contractor's field team to deliver truck loads as they were required. 

In the words of the contractor, “In order to complete this work using traditional steel shoring boxes, a 30T excavator would not have been large enough to place and remove the boxes. Furthermore, to maintain the schedule, double the manpower to assemble boxes would have been required.”

 The contractor commented that it was a pleasure to work with GWSS, Simon and Al on the project and that “In summary, working with GWSS on this project enabled them to first and foremost complete this install safely, on time and on budget.”