Roof slab and column construction.
The Greater Toronto Airports Authority (GTAA) was building a new system to control stormwater runoff. The final structure in this new system would intercept two large diameter storm sewers and collect a mixture of fuel and water from apron and runway surfaces. The system would need to handle up to 42,000 cubic meters of runoff, resist a 14-metre head uplift, and support the equivalent weight of a Boeing 747. To meet a fast track eight-month construction schedule, much of the concrete work had to be done during winter months.
First suspended slab concrete pour and formwork tables being set.
Innovative construction techniques were needed to bring this project in on schedule and on budget. The Moore Creek Stormwater Management Facility was designed as a four-cell tank. Each cell features an automatic sedimentation flushing system comprised of a series of eight (per cell) tipping buckets, which periodically wash down the sides of the tank. The concrete mixes were specifically developed to meet the demanding schedule, cold weather construction and to achieve 75% of the design strength in five days. This was necessary to allow the formwork to be moved and reset in a fast and efficient manner.
Construction in Cold Weather
As a large portion of construction was completed during the winter months, base mixture and pouring/curing methods had to be modified. Curing compounds were applied to all slabs, walls and columns. Insulating blankets were added to wall formwork and tarping was used to control heat gain and loss ensuring that concrete met strength requirements. To further control the affects of the weather, kerosene powered glycol heating machines, propane power salamander heaters, and infrared heaters were used.
Base slab oil/water separator.
The one meter thick base slab required the construction team to develop methods and procedures for mass pouring concrete. The columns utilized a modular forming system and these forms made it possible to set and pour six columns per day. Aluma Systems provided sixty truss style form beds that could be dropped and moved to the next pour location without re-fabrication. This forming system used a prefabricated wood beam side. The construction joints utilized an extruded metal product that remained in place following the completion of the concrete pour. The use of Stayform allowed the bulkheads to be constructed in a time efficient manner. As this structure was required to be watertight, a waterproofing membrane was installed.
The success of the project was a result of the cooperation of all of the parties involved in the project. The development of several innovative and productive construction methods allowed the facility to be built in an extremely short span of time.
|Consulting Engineers||Hatch Mott MacDonald and Thornburn Penny|
|Concrete Supplier||James Dick Concrete Supply|
|Contractor||Kenaidan Contracting Ltd.|
For additional technical details on this project visit the Ontario Concrete Awards site at: www.ontarioconcreteawards.ca/01cs.htm