Because tunnel forms are preassembled in a factory-type setting, the uncertainty that often surrounds equipment fabricated on site is eliminated. The factory setting usually implements a quality assurance program to guard against imperfections or flaws in workmanship and materials. Also, because tunnel formwork is made of steel, the quality of the resulting concrete surface is superior and may require no additional finishing.
The tunnel forms have a number of safety features.
• Since they are preassembled in a factory setting, the system should have predictable strengths and quality assurance.
• The forms are not dismantled between lifts, and thus remain the same as when first used.
• Guard rails are provided at the slab edges.
• Supervised craning operations provide safety below.
• Workers positioning or stripping forms underneath are secure due to the all-steel and rigid tunnel form system.