The specialist team of scaffolders at Sky Scaffolding Midlands Ltd have successfully delivered a technically chellenging hydrodemolition containment project on Bermuda Bridge, spanning the A444 between Coventry and Nuneaton.
This project required access and containment for hydrodemolition works to an existing bridge parapet and bridge strengthening works above a busy open carriageway near Griff Roundabout in Nuneaton, and required cantilever suspended scaffold to access the side of the bridge, similar to the Willes Road Project.
Project Background
The existing Bermuda bridge was constructed in 1974 and was designed to accommodate vehicles. However, for some time only pedestrians and cyclists can access the bridge.
The Bermuda Connection scheme focuses on opening up the existing bridge to two-way traffic, delivering additional highway capacity and improved connectivity between West Nuneaton and Griff Roundabout.
Design Considerations
The scaffold design developed by Sky Scaffolding and Layher Technical Department for this project consisted of 2.57m wide support towers erected along both parapets, supporting 780mm aluminium beams at 2.57m centres. 1.09m wide access scaffolds were then suspended over the side of the bridge from the extended beams.
The portal-frame solution to this project meant that the scaffold was free-standing with no additional kentledge required to the support scaffolds for counter-balance.
Hydrodemolition Containment
The existing concrete parapet beams were to be demolished uing hydrodemolition. This process produces a significant amount of debris that had to be contined from the open carriageway below.
The walls and roof were clad using shrinkwrap, with close fitting 18mm plyboard installed to the base and sides of the suspended access platforms. The platforms were then sealed by the demolition contractor to contain the water run-off.
Phased Installation
The support scaffolds were installed with a short beam between them that did not extend over the open carriageway. This meant that the scaffold on top of the bridge could be completed without lane closures on the busy carriageway below.
The beams were then extended over the carriageway during night-time lane closures on th A444 between Coventry and Nuneaton.
Careful consideration at design stage had to be given to the stability of the freestanding structure during the various phases of its installation.
