The M53 Moreton North Bridge carries the Junction 2 southbound slip road (Chester bound) over the main motorway. Recent bridge assessments had recommended a weight restriction be applied to the bridge which would restrict HGV use. Highways England therefore planned for its replacement.
The presence of asbestos permanent formwork cast into the prestressed beam pockets meant an innovative solution was required to safely demolish the infill span.
The final solution comprised the use of Mammoet’s SPMT’s to lift the infill span, rotate it through 90°, and transport to a designated offline lay down area some 300m North of the existing bridge where it could be safely demolished in a controlled environment.
Critical to the operation was the need to safely and economically remove the bridge from the SPMT’s at the lay down area to allow efficient demobilisation of the specialist transport equipment and commencement of the bridge demolition.
PaSCoE were commissioned Frank O’Gara Demolition Ltd to assist with temporary works arrangements and design the laydown area and temporary bridge abutments that would allow the lowering and support of the bridge to allow removal of the transportation equipment.
The innovative PaSCoE designed solution utilised ISO shipping containers which were internally braced and propped with a light-weight aluminium system to carry the vertical loads whilst being shielded from debris during the demolition phase. The unique solution provided an economical solution whilst also being robust enough to withstand the subsequent demolition activities.
The operation took place during the first weekend in August with the M53 opening 12 hours ahead of schedule. The bridge was broken down by the end of the following week and the demolition material transported to licensed waste disposal facilities during normal operating hours.