The self-supporting retractable roof designed by Dessau is a truly unique technological solution.
On August 27, 2010, Dessau and EllisDon submitted an expression of interest to Quebec’s Régie des installations olympiques (Olympic Facilities Authority) with regard to replacing the roof on Montreal’s Olympic Stadium. Dessau’s singular proposal involves a self-supporting retractable roof.
Mechanisms to Open and Close the Roof
This self-supporting roof design is tailored specifically to Montreal’s Olympic Stadium and makes a retractable roof a feasible option for the stadium. The plan involves adding a basic mechanical system that uses gravity and potential energy from compressed air accumulating in pressurized reservoirs.
The proposed means of activating the different roof retraction phases will eliminate the need for sensor technologies. What’s more, the concept offers a major advantage over other retractable roofs that require electric motors and high-capacity electromechanical equipment that is expensive to install, operate and maintain.
The basic principle behind the proposed system consists of continuously accumulating low power energy with compressed air at 100 PSI in four large reservoirs. The system also includes counterweights to balance the weight of the loads.
This stored energy (compressed air at 100 PSI) will deliver enough power to activate the cables of the roof-retraction mechanisms. Yet, it will remain very stable. Unlike other retractable roof technologies, this solution will not generate sudden major power demands. Moreover, the stored energy will help reduce the facility’s energy costs.
Regularized power demands save energy, which translates into substantially lower electrical costs compared to conventional retractable roofs of this size, which are often powered by electric engines with several thousand horsepower. This exemplary use of electricity is an excellent sustainable development initiative.
Pistons activated by compressed air (operating pressure of 15 PSI or 1 atmosphere) act as counterweights and help ensure that the two roof sections open and close in a stable manner. These compressed air pistons are located in the sills. The vertical height of these sills provides a sufficiently long stroke length so that the guide rails and roof halves can deploy sequentially, with the roof halves running along the rails. The mechanism was designed so that the guide rails are completely enclosed in the roof when it is closed.
A fifth system, located in the tower, is made up of compressed air pistons and counterweights with a proportional tension control system using pulleys. Creating two degrees of tension in the cables, it compensates for variations in the length of the four pairs of cables that connect the roof sections to the tower during roof retraction.
Eleven copyrights in 34 countries exist for this retractable roof design, which is the property of Delaney Technologies Inc.