Located in the heart of Bristol and spanning the floating harbour, Redcliffe Bascule Bridge comprises of two fixed spans and a bascule span providing access to shops, businesses and the famous Queen Square. Fairfield Engineering Solutions collaborated with sister company Fairfield Control Systems to provide MEICA works on the long-standing bridge, which was originally constructed in the 1940s.
Fairfield’s was responsible for the detailed design from initial client team concepts for all elements of the system M&E elements to current UK standards.
Fairfields were appointed under an NEC contract, initially to The Cleveland Bridge & Engineering Company and later Alun Griffiths (Contractors) Ltd.
Fairfield Engineering Solutions has undertaken the refurbishment of several key mechanical elements which are vital to the bridge’s operational and structural integrity:
- Design, manufacture and replacement of the hydraulic nose bolt system
- Design, manufacture and replacement of the emergency operating recovery drive system
- Inspection, report and refurbishment of the differential gearbox
- Removal, inspection and refurbishment of the thruster brakes
- Removal, inspection and refurbishment of the holding brakes
- NDT inspection and refurbishment of the quadrant rack teeth
- Design and replacement of the end of travel buffers with modern sealed hydraulic units
Fairfield Control Systems was responsible for the design, installation and commissioning of a new and improved distributed control system and associated instrumentation. This complemented the new mechanical systems, being designed and provided to the latest industry standards and future proofing. The team has installed new Siemens PLCs, facilitating the implementation of new communication networks serving multiple points around bridge and in both abutments, to allow the bridge to be safely operated from the central control room from a new operator control desk.
The upgrade also allows replacement or improvement of other essential features such as the emergency stop system, traffic control, fire alarms and CCTV etc. In addition, a new overspeed detection safety system has been implemented which will help to improve overall safety when travelling and working on the bridge.
One of the key deliverables of this project was a mechanical clamping system. The existing nose bolt system had become worn, in tandem with the deflections of the bridge due to its construction, leading to excess movement at the nose end of the bridge. This in turn led to noise being generated as vehicles passed over it. A hydraulic clamping arrangement had been proposed and specified within the client’s works information. As the initial design works progressed, it became clear that replacing the existing nose bolt system with a hydraulic clamping rather than nose bolt type assembly would have little sympathy for the bridge construction techniques used and would inherently provide greater stresses and fatigue. Working with this in mind, FES engineers took the client’s key success requirements, along with inspections of the structure to design and specify a new and improved electrical operating nose locking system which met the client’s key objectives whilst removing the hydraulic requirements spanning the watercourse and reduced more specific maintenance requirements. This not only improved from an engineering perspective but also proved to be both programme and cost efficient. Our designers re-engineered the nose bolt arrangement and presented this revised solution to the client along with a substantial cost saving.
The collaborative work between Bristol City Council, Fairfield Control Systems and Fairfield Engineering Solutions provides a completed project which is more closely matched to their key requirements, sympathetic to the infrastructure whilst providing a safer and more reliable route for the general public. It allows access for larger boats, with current technology improving resilience and future proofing from that installed previously in the early 90s.