Articles about BD90/05

The extent to which manufacturing-induced fibre mat misalignments compromise the structural integrity of pultruded GFRP road bridge decks is not properly understood. The problem is often critical at the web-flange junctions, which frequently contain the most severe misalignments and are subjected to high local moment-shear (M-V) combinations due to concentrated tyre load and also global vehicle load effects. Over the last 20 years, several GFRP decks have developed tyre load-induced damage of the top flange, due in large part to the prevalence of fibre misalignments.

Colinton Dell is a steep-sided gorge and wildlife refuge on the Water of Leith, just north of the old village of Colinton on the outskirts of Edinburgh. It extends from Colinton Parish Church towards Slateford along the Water of Leith Walkway and has an area of 10 ha (25 acres). The Dell includes mature and ancient mixed woodland and the protection afforded by the high banks and thick undergrowth makes it a natural habitat for wildlife, including numerous bird species and amphibians, voles, weasels, stoats and occasionally roe deer.

Off site production allowed us to continue with this project during the lock down.  Once restrictions were eased the existing bridge was removed and the foundations upgraded by CRL working for Kent Highways, before the new bridge was installed in June. KCC Cabinet Member for Highways and Transport, and Member for Tonbridge, Michael Payne said:
“This work was carried out to provide a strengthened and refurbished bridge to ensure it continues to be safe river crossing for the public to use. “The original deck was made from railway rails with a type of expanded metal mesh reinforcement, but unfortunately it wasn’t able to handle the number of people using it.

The DMRB was updated by Highways England just before the lockdown started. We were probably all distracted from noticing this at the time. The technical changes were substantial, especially regarding FRP bridges but the structure of the suite of documents changed. A summary of these changes can be seen at (https://standardsforhighways.co.uk/dmrb/help#new-structure)
One key change for us is the replacement of BD90/05 with CD368. CD368 updates the approach to FRP bridges. The new approach is now quite closely aligned with current European guidance documents.

The construction industry is committed to reducing the environmental impact of its activities. The Construction 2025 joint strategy from the UK Government and industry, working in partnership, sets a vision, which includes 50% lower emissions, 33% lower costs and 50% faster delivery. Using FRP composites in place of steel and concrete for bridge construction will deliver this vision now. The carbon and energy embodiment is significantly reduced at the construction stage and still further during the 100-year minimum service life.

The existing skewed reinforced concrete footbridge had come to the end of it life, so an FRP Replacement was selected to provide reduced maintenance in the tree enclosed environment over the Gutter.  Following completion of new abutments and associated retaining walls, the lightweight, preformed, replacement allowed fast and simple installation on site using a lorry mounted crane, to both transport and lift the bridge into place.  The colour scheme was selected to match the clients requirements.

Lifespan Structures FRP cycleway Bridges on Horsey Way, Eastbourne, were highly commended at the 2018 ICE South East England Engineering Excellence awards in the best infrastructure category..no mean feat when going up against much larger schemes, congratulations to all involved in the project! The new Horsey Cycleway crosses a wetlands area where two footbridges with service vehicle access were required to cross waterways on the route.  Due to the poor ground conditions the bridges needed to be lightweight to aid installation and reduce the abutment loadings.  The client, had already used an FRP composite footbridge on a previous scheme and commissioned Lifespan Structures to design and manufacture the two FRP composite Footbridges.  The bridges were both 3.0m wide  and had clear spans of 14.8m and 10.6m with respective deck weights of 5600kg and 3350kg.

600kg FRP bridge deck replaces a 2-3000kg timber bridge, delivered and put in place in just a few hours. The installation of our first generation of lightweight footbridge structures is over 3 years ago now.

Off site construction, means bridge production can continue all year round, and minimises installation times. This bridge replaces a corroded steel structure which had reached the end of its service life.

Lightweight FRP bridge deck for cycleway delivered. The 15m by 3m structure has been constructed off site and is being unloaded using a lorry mounted crane.  Low dead weights allow simplified foundations especially where poor ground conditions exist.