Following nine months of early contractor involvement comprising numerous design workshops, planning meetings, design discussions and client comfort sessions, we finally demolished Woodlands Lane bridge over the M3 just outside Farnborough using exploives on the weekend of 18th/19th November 2016.
The original remit from the client representatives was impractical and frought with risk. During the feasibility study period, we were able to convince Highways England that the safest, most practical and economical method to demolish the bridge was by explosives, which had been expressly excluded during the tender period.
Three weeks before the blowdown, we were able to carry out some pre-weakening of the structure and also complete 80% of the drilling for the explosive charges. During the weekend closure, we started by laying the road protection over the motorway surface in the form of Crane mats covered with a layer of crushed concrete to absorb the impact of the deck collapsing. Then we completed the drilling and charged all the piers with explosives. At 5:00am on the morning of the 19th, the detonation occurred, removing the piers completely and allowing the full length of the 90m deck, with a 45 degree skew, to simply collapse ont the protection below completely within its original footprint.
Having successfully dropped the bridge, our Explosive Engineers left us to clear up the pile of 4000 tonne pile of concrete rubble. With a fleet of ten Excavators ranging from 23 tonnes up to 50 tonnes and up to fifteen Tipper Lorries at anyone time, we cleared all the arisings off the road and back to the project recycling facility. The road protection was lifted and the road handed back to the client three hours ahead of programme.