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).
Around 1m3 of Shotcrete was sprayed by specialist contractor Gunite & Shotcrete Services, who completed the project in one day.
Date added: 12/04/2022