Assistance with Bridge Demolition & Rebuild
EDS has recently been involved in a major local project to assist in the demolition of a listed bridge structure that spans the Afon Taff.
The bridge sustained structural damage during storms in recent years and also posed a flood risk to adjacent houses. It was therefore decided that the bridge would be demolished, while preserving as much of the original masonry as possible for refurbishment. This project highlights our multi-disciplinary functionality, incorporating both our underwater and above-water expertise.
The river runs through the heart of Pontypridd, with residential areas on both sides of the bridge. In 2022, EDS was commissioned to build a flood/training wall, and these current works will mean the area becomes even more flood resilient in the future. The project consists of three phases, utilising our own NATO pontoons, our rescue and safety-trained staff, our underwater engineering proficiency, and our construction knowledge for cladding structures along the river bank.
Phase 1 – To provide machinery access for the demolition stage and ensure works were carried out safely for all operatives
Key Challenges:
- Providing a platform capable of sustaining the weight of the machines required to demolish the three-span arch structure
- Preventing material from entering the river
- Transporting the material from the bridge to the roadside
- Maintaining the safety of all machine operatives from the demolition contractor
Solutions:
- Our own floating NATO pontoons were used as an access platform for machinery and operatives, with an approved temporary works design
- A silt curtain system was placed downstream in a staggered fashion to prevent moving sediment
- A safety boat team monitored plant and pontoon movements
- Separate pontoons transported skips from the deck to the client’s access point
Phase 2 – To construct foundations for concrete abutments required to support the new bridge structure
Key Challenges:
- Installing sealed formwork on an undulating river rock bed
- Limited space behind the shutters to install steelwork
- Ensuring no pollution of the watercourse during concrete works
Solutions:
- Steel formwork was placed and tied into the existing structure to provide support, with a temporary works design prepared for this
- The formwork was built to the correct specification to take the volume of concrete required for the abutment. Shutters were placed in a sequence that allowed access for installing restraining bars
- Timber was placed at the base of the shutters so the existing riverbed profile could be scribed to create a seal
- Restraining bars were covered with plastic so they could be released once the concrete was set. The concrete foundation was brought above water level and handed to the client for abutment construction
Phase 3 – Clad the RC structures along the river bank
We are proud to have been part of this project and look forward to seeing the positive impact the new bridge will bring to the local community.
Key Challenges:
- Limited access when working adjacent to the watercourse and public highway
- Summer temperatures potentially affecting the drying of concrete (micro-cracking)
Solutions:
- Stone for cladding was reused from the demolition, adding environmental value
- NATO pontoons were used as working platforms for operatives and materials
- All works were carried out under a traffic management plan
- Stonework was built in accordance with the design specification
