New bridge first in UK to combat risk of flooding
Hanson supply concrete and asphalt for construction of the new Pooley Bridge in Cumbria
A NEW stainless steel and concrete bridge, the first of its kind in the UK, has opened to pedestrians and vehicles in Pooley Bridge, Cumbria.
Replacing its 250-year-old stone predecessor, which was destroyed during severe flooding as a result of Storm Desmond in 2015, the new single-span bridge has been designed to withstand extreme weather conditions and is in keeping with its location at the northern end of Ullswater, on the edge of the Lake District National Park.
Hanson UK worked with contractors Eric Wright Civil Engineering Ltd to create a bespoke concrete mix for the lower arch of the steel bridge, which was designed and constructed to provide structural strength, and also supplied and laid the asphalt to complete the project.
The steelwork for the new bridge was manufactured off site in two sections and fabricated and welded on an adjacent piece of land, where the concrete lower arch was installed to allow the whole structure to be lifted into place over the river Eamont.
The high early strength concrete mix included Hanson Regen GGBS (ground granulated blast-furnace slag) cement replacement, enhancing the durability of the concrete whilst adding to its sustainability credentials.
The use of this by-product to replace one tonne of Portland cement reduces the embodied CO2 of the concrete by around 780kg. Its use in large pours also helps to minimize the production of heat, reducing the risk of thermal cracking.
In total 1,200 cubic metres of concrete containing Regen were supplied by Hanson’s nearby Penrith concrete plant to create the lower arch, bridge deck, bridge abutment and walls, highway approach retaining walls and several temporary works.
‘Concrete supply to this project was always going to be a challenge due to the location, unique characteristics of the bridge and the tight deadline,’ said Nick Graham, technical sales officer at Hanson Concrete.
Technical services manager Terry Balmer added: ‘Our technical team was involved early in the design stage due to the complex concrete requirements, especially for the high-quality visual concrete that makes up the deck composite, and this partnership working was fundamental to the success of the project.’
To complete the project, Hanson supplied 275 tonnes of asphalt from their nearby plant at Shap, which was laid by the company’s specialist contracting team. This included 130 tonnes of Tufflex surface course, chosen for its durability and high resistance to cracking.
In addition to the complex nature of the bridge, the final abutment work, concrete arch and composite deck – as well as the asphalt – were all supplied under the added pressure of the COVID-19 pandemic and the associated issues entailed with furloughed staff and social distancing protocols.