The engineer design 40meter tall terminal and to make most of the space it was designed with single-spine roof of size five football fields.
But raising these monster roof was the biggest challenge for the engineers as one single piece of the roof weighs 6 jumbo jacks. lifting it up 40 m with tower cranes will create a problem as the cranes are so tall that they might disturb the Heathrow radar system. so it was required to conceive a design which can build the roof from ground.
The construction team assembled the roof on the ground using small cranes. Then they used a clever lifting technique to pull the roof of the ground. It is called strand jacking.
They suspend the section of the roof with steel wires. These wires are pulled by the strand jacks, powerful hydraulic rams , each lifting 185 tons.16 of these jack was used to lift the roof 40m high. It took almost a year to lift the complete roof.
Terminal 5 has much more space compared to other 4 terminals combined.