The tunnel formwork system uses an accelerated method of curing the concrete. Typically, automatically controlled heaters are placed inside the tunnel formwork to accelerate the concrete curing process. After about 14 hours, the concrete reaches a sufficient compressive strength for the formwork to be removed. Other factors attributed to shortening construction time include:
• The use of metal skin plates provides a smooth finish, thus eliminating shoring and finishing of the concrete walls and slabs.
• The floors and walls are cast monolithically, therefore reducing time and cost as well as the need for two separate forming systems.
• Faster learning cycle: Once workers become familiar with the cycle, the time for each cycle will be reduced.