|Bridges & Structures|
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Chislehurst Road Bridge Reconstruction
Client: London Borough of Bromley
Contractors Designers: Aecom
Form of Contract: NEC – Option B
Dates work carried out: 2011 - 2012
Chislehurst Road Bridge carries the single carriageway A208 over Network Rail’s four track Victoria to Ramsgate mainline railway between Bickley and St Mary Cray Stations.
The existing bridge is in a poor condition and has been subject to numerous inspections. The results of which have significantly reduced the load carrying capacity of the bridge restricting weight to 7.5 tonne vehicles, causing the diversion of a bus route and numerous occasions where large HGV’s have to reverse back down the long approaches to the bridge causing further disruption. The only remaining option for the London Borough of Bromley was to rebuild the bridge.
Our works involve the demolition of the existing 33m single span post tensioned concrete beam road-over-railway bridge and construction of a replacement integral steel composite bridge over the railway.
A key requirement is that the bridge remains open to pedestrians and that existing utilities remain uninterrupted. This has called for a rather challenging and innovative construction method.
Our method is based on a robust access/protection deck able to contain all the loads from demolition of the existing deck and construction of the new bridge. The protection deck below the existing bridge deck is strong enough to carry the entire load of the old deck. This has given Network Rail significant confidence in our method resulting in works that would have taken place during possessions can now be carried out while the railway is operational offering savings in time and cost.
The railway is not allowed to be disrupted during the reconstruction so the lifting operations are at night during 2 hour ‘white period’ possessions.
The footpath will remain open over the bridge for the full period of the site works other than for safety critical works associated with the crane lifts of the rail protection deck and new bridge beams. However these are scheduled to take place during very early hours of the morning to further reduce disruption.
Each half of the bridge will be demolished and reconstructed sequentially allowing one side to remain open.
Whilst the first half of the bridge is being demolished service and utility diversions can take place during the re-build on that side reducing the down time.
Due to the fact that the bridge is a significant crossing for through traffic and local residents the attention to PR and Communications on this project are paramount. HOCHTIEF are working closely with the London Borough of Bromley to ensure that all affected parties are informed promptly and accurately. We have used various methods of communication to inform residents including direct mail, dedicated website, door-to-door contact with residents in very close vicinity to the bridge, twitter, email and via telephone.