Olympic underpass pushed through

A new link to London's Olympic Park has been completed on schedule in just 28 days using a pre-constructed concrete box section, tunnelling techniques and hydraulic rams.

Contractor Skanska employed a ‘jacked box' method to push through the underpass to the Olympic Park without affecting traffic flow on the six lane carriageway of the A12 above.

The concrete box forming the underpass was constructed in three sections and measures 50 m in length. With a height of 8m and a width of 11,5 m the complete unit weighed 3500 tonnes. Tunnelling techniques were used to excavate the ground ahead of the box while a series of hydraulic rams then pushed the box into the excavated tunnel face.

Olympic Delivery Authority chairman John Armitt said, "The delivery of this critical engineering project on time is a significant achievement given the complexities and challenges involved. It is a testament to the hard work and ingenuity of our workers and engineers working round the clock to construct the new underpass beneath a busy dual carriageway, without causing any disruption to motorists."