The Bleaton Hallet Bridge which crosses the Black Water is a vital link between the A93 and Alyth and is situated north of Bridge of Cally in Perthshire Scotland. The bridge was severely damaged by Storm Frank on 30th December 2015 when stormy weather brought heavy rain fall and flooding to the north of England and Scotland, causing widespread disruption to transport and infrastructure.
The collapsed 35 tonne bridge needed to be removed using a crane, but before this could be done, the boulders and collapsed abutment sections needed supporting before the removal to prevent them from falling into the river. Sprayed concrete was proposed as the best method to do this but EA concerns about pollution in the watercourse were high priority. There was no way to protect the watercourse using sand bags due to the sloping rock face into the water, and safety concerns about actually placing the protection. The best solution was to use Shotcrete 530 due to its environmentally friendly properties and neutral PH on initial set. There was very little rebound as the material was sprayed in much wetter than normal in order to penetrate and flow behind the boulders and rock in an attempt to ‘glue’ them together before attempting to lift the bridge. The material was allowed a full week to set before the bridge was lifted. During the course of the works it started to snow heavily. This is not a problem for Shotcrete 530 (see specification on our data sheet for temperature parameters).
We asked John Aveling of Gunite & Shotcrete Services Ltd who completed the contract how long it took to carry out the work required using our material.
“This contract was only a one day operation due to the low volume of material required for the works, (specified at 1.00cum) although it did take a full day to get to site and a full day back as it was 20 miles past Perth, Perth and Kinross. The actual spraying operation only took two hours in total (one hour per side plus time to reposition the crane/basket arrangement)”