MGI Construction Corp. is serving as the lead subcontractor on a large demolition, earthworks and new construction project located in Toronto that can be easily seen from Highway 401.
It is the transformation of a former Home Depot warehouse into a mixed use industrial and commercial property.
The company first demolished the initial structure and then performed all the earthworks, including soil rehabilitation. They are now constructing the shells for the new buildings.
“We took down more than one million square feet of warehouse space,” says Lou DeVuono, senior site superintendent with MGI. “We demolished two of the original three buildings on the site.”
Once everything was demolished, all the contaminated material was moved off site and any remaining material had to be reengineered to native (undisturbed soil) up to subgrade of the new building footprints.
A project this size required a large fleet of equipment. MGI purchased several Hitachi excavators, a John Deere 700 dozer, a Rubblemaster crusher and a McCloskey stacker.
Wheel loaders loaded demolition debris onto trucks that carried the material to the crusher. The crushed material was then separated and repurposed or removed from the site.
“We only used soil from here at this project,” says DeVuono. “We didn’t need to import any.”
A major part of the earthworks portion of the project includes the installation of all the storm, sanitary and watermain systems.
The other major part includes the creation of the new building footprints.
“We created new footprints for the buildings that are to be constructed onsite,” says DeVuono. “The 900,000-square-foot warehouse that we demolished ran north south with doors on two sides, but the new building runs east west with doors on the north and south sides and the existing parking lot had to be removed.”
The company has moved nearly 30,000 cubic metres of earth and expects to move another 6,000 to 7,000 cubic metres by the time they complete the project at the end of November, says DeVuono.
“A lot of engineering had to be done,” he explains. “Material was excavated to native and all the buildings were then engineered with existing native soil up to the subgrade.”
Instrumental in the grading process were the Trimble grade control features on the dozers and excavators.
Whether you’re building a highway or a parking lot, using machine control on a dozer just makes good sense
— Scott Crozier
Trimble’s Civil Engineering and Construction Division
Hitachi excavators come equipped with the Trimble GCS900. This 2-D grade control system helps MGI improve their excavation productivity and accuracy. It uses an angle sensor, dual axis sensor and laser catcher to measure the relationship between the body, boom, stick and bucket. It then guides the operator to the desired depth and slope by determining where the bucket teeth are and should be. Operators view on a 10-inch screen where their bucket is relative to the 2-D surface.
The use of grade control has translated into big gains.
“It increased our productivity dramatically,” says DeVuono.
“There’s less guesswork. We no longer need a person to run around the site laying out stakes. The surfaces we need to cut or fill are already in the machine; curb lines and elevation changes are built into the grade control system. With it, we are able to move faster and be more accurate with our cuts and fills.”
Their John Deere 700 dozer and John Deere 850 dozer are both equipped with Trimble machine control.
“Whether you’re building a highway or a parking lot, using machine control on a dozer just makes good sense,” said Scott Crozier, general manager of Trimble’s Civil Engineering and Construction Division.
“We see dozer operators getting to grade 35 to 40 per cent faster with grade control than without. The technology takes the guesswork out of grading, which makes the operator’s job easier and the end result more accurate, and it means companies like MGI can operate more efficiently and take on more jobs.”
Although using grade control to this degree is new to the company, the technology itself isn’t new to them. They have worked with their Trimble-equipped John Deere 850 dozer for two construction seasons.
“We see the benefit of having the systems incorporated into the equipment, and as our fleet grows, the amount of advanced technology we use will grow too.”