A404(M) Bridge Removal

A404(M) Bridge Removal

Civils Demolition of Motorway Bridge over live railway

Spanning over Great Western Railway, the A404(M) Motorway Bridge had reached the end of its operational life, spalling concrete deck and extensive corrosion had compromised the structural integrity.

Coleman & Company was commissioned by Birse Civils to develop a scheme to remove the bridge while maintaining the flow of motorway traffic and having minimal disruption to Network Rail’s operations.

Major demolition was limited to weekend and midweek night closures of four hour periods. All cranes had to be set up, demolition works completed and all equipment cleared to allow the Motorway and Rail Network to be reopened on time. High risks were involved when removing a structurally defective bridge under immense contractual liabilities. These were overcome by Coleman & Company’s expertise, professional abilities and management controls within the organisation.

A scheme was developed to remove the bridge in stages. This involved deconstructing the bridge in longitudinal strips working in harmony with the existing structure, allowing Birse Civils to slide the new bridge in behind each stage of demolition.

Due to structural and operational constrains, no heavy cranes or plant could work off the bridge structure, resulting in multiple plant working concurrently to remove up to 100 Tonnes of concrete per hour overnight and still return the railway and highway to use at the end of the shift.

Cranes of up to 1000 tonnes capacity, working at 40m lift radius used specially commissioned lifting equipment successfully removed 1200 tonnes of concrete and 600 tonnes over the duration of the project. Throughout the works as-built information proved to be inconclusive and contained numerous errors this, along with changing Client requirements, meant Coleman and Company had to adapt and modify design and methodology to overcome the issues while adhering to the formal approval procedures and stringent contractual programme constraints.

Coleman & Company rose to this complex and unique civil demolition project to provide bespoke equipment, management and staff to successfully complete this demanding project.

The challenges of this civil demolition project tested the limits of the all persons involved from planning to operations and pushed the boundaries of concept and application.

A unique project carried out under demanding conditions completed within set time limits without accident or major incident.