Boscastle Flood Defence Project 

Environment Agency contractors Carillion carried out the whole operation which took a day to complete. The bridge was brought into the heart of the village in two pieces on articulated lorries, before being lifted into place by a giant crane.

The new lower bridge is an important part of the £4.6 million flood defence scheme, as it spans a channel specially widened to help reduce flood risk to local residents, homes and businesses near the harbour.  It will carry traffic as well as pedestrians and will replace the existing bridge.

The £200,000 Bridge was built off site by Cornish Concrete Products, based in Truro. Once in place, a temporary central support was driven into the river bed to support the two parts of the span (which weighs 20 tonnes) until they were joined together and properly reinforced.

The complexity of the procedure meant that one part of the bridge had to be lowered and secured in place before the lorry could make a repeat trip for the second section. Once the whole new deck was in position, additional works was necessary to weather-proof and secure the new bridge, which crosses the river near the site of the old bridge in the lower harbour area.

The installation of the bridge was the final part of the flood defence scheme for Boscastle and is an essential element of the scheme.

BASF Admixtures

Typically precast concrete producer Cornish Concrete Products uses BASF’s advanced technology admixture Glenium ACE 333 in all of its products as it delivers of increased working time and high early strength. For the Boscastle Bridge project the dosage was tweaked to approximately 0.6% by weight of cement for C60 concrete. The cement used in the bridge was shipped into Truro and the coarse and fine aggregate used in the concrete was local granite recycled from the china clay industry.

Glenium ACE 333 is an innovative second-generation range of polycarboxylic ether polymer superplasticizer developed for the pre-cast industry. The particular configuration of Glenium ACE 333 has a longer working time than Glenium ACE 30 whilst still accelerating cement hydration for early stripping.  Rapid adsorption of the molecule onto the cement particles, combined with an efficient dispersion effect, exposes increased surface of the cement grains to react with water.

As a result of this effect, it is possible to obtain earlier development of heat of hydration, rapid development of the hydration products and, as a consequence, higher strengths at a very early age.  

Glenium ACE 333 is a key element of BASF’s Zero Energy System, which utilizes the innovative technology of Rheodynamic concrete. The Zero Energy System has been developed to help precast concrete producers rationalise the production process, save on energy costs and improve quality of product and working conditions.