Client: A E Yates.
Location: Preston, UK.
Project summary
The aim of the improvement works at both Wild Boar and Yoad Pool were to improve the safe operation, access and maintenance of the outfall tidal flap valves.
Wild Boar included a winch system to lift the outfall tidal flap valve, design of a concrete headwall to accommodate the winch and flap, stepped access to the outfall to allow for maintenance and operation with a gate and safety handrail to prevent public access. A footpath with steps to provide level access to the headwall with additional steps on the existing bund. Earthworks creating a suitable surrounding in accordance with the geographical area and tidal water, while the design accounted for the site’s location within Flood Zone 3 and the tidal nature of the River Wyre, including appropriate sheet piling measures.
The works at Yoad Pool also included a winch system, stepped access, safety handrails and a concrete headwall. Earthworks provided a suitable surrounding for the tidal water whilst in keeping with the immediate area. The design accounted for the site’s location within Flood Zone 3 and the tidal nature of the River Wyre, including appropriate dewatering measures during construction.
Successes
- Through design progression the carbon footprint was significantly reduced.
- Worked collaboratively with the contractor and Environment Agency (EA) to develop suitable permanent and temporary designs for construction on the embankment and within live tidal waters.
- Delivered the design within the timescales set by the EA, ensuring minimal impact on local wildlife, the surrounding environment, and seasonal tidal flows.
- Developed an accessible maintenance route for personnel, incorporating all necessary safety measures for working adjacent to tidal waters.
- Selected durable and sustainable materials to maximise the longevity of the scheme and improve the effectiveness of future maintenance.
- Produced comprehensive structural calculations covering all elements of the structural design, including EA requirements.
- Successfully incorporated the structural design requirements into both the temporary works and final permanent design.
Challenges
- Excavation within the riverbank on a tidal flowing river.
- Limited site access.
- Presence of existing services and structures.
- Partial demolition of the existing structure.
- Steep slope and challenging topography above the flap valve, required long-reach excavators.
- Working at height.
- Provision of suitable edge protection.
- Risks associated with working in or near tidal water.
- Presence of nearby members of the public and landowners.
- Traffic management and liaison for site access and construction activities.
- Protection of existing structures and services throughout the works.
