Widening the existing A465 along the steep edges of the Clydach Gorge is widely recognised as a unique and massively challenging project. For the Saleyard River Crossing, the delivery team engaged in close collaborative relationships between the designer, principal contractor, their supply chain and the Client. Essential for successful delivery, this collaboration allowed the long-sought utopia of a precast composite bridge deck to become reality with the following benefits:
- Improving safety – minimizing work at height and minimising the numerous hazards of fixing reinforcement on site on thin permanent formwork such as slips, trips and falls
- An independently assessed saving of over £500k in construction costs through reduced steelwork and temporary works
- Faster deck construction with up to 226m2/day of precast deck installed
- Higher quality product using digital technology for quality assurance
Significant challenges were overcome throughout the delivery process to enable successful delivery. The key challenges were:
- Devising a new precast deck stitch detail to resolve longstanding Technical Approval Authority concerns with the traditional loop stitch detail
- Development of a design taking full advantage of the increased spans of precast decks; reducing steel beam support requirements and costly edge cantilever formwork
- The adoption of a higher level of Quality Assurance throughout design and construction using digital technology to meet necessary tight tolerances
The best practice adopted and lessons learned have since been shared across the industry through Highways England Lean Maturity Assessments (HELMA) and industry presentations leading to precast bridge decks being adopted on several other schemes.
