A565 Cambridge Road, Southport – Roundabout (Carriageway Inspection)

Client: Sefton Council
Completion Date: 2015
Duration: 2 months
Location: Cambridge Road, Southport, Merseyside

Project Overview

A565 Cambridge Road Roundabout, junction with Park Crescent and Park Ave

Following numerous attempts to rectify a depression within the carriageway over the years, Sefton MBC decided to find out once and for all why the carriageway kept sinking.

In May 2015 Dowhigh where instructed to install a road closure to Park Avenue, and set up 3 way temporary traffic signals to control the flow of traffic, whilst a section of the roundabout was investigated.

Worse case scenario was the discovery of a damaged United Utilities brick culvert almost 5m below ground level. A 7m x 4m excavation commenced including a hydraulic frame and heavy duty sheet piles using a 20t 360 degree excavator. At 1.3m we located a water main running directly over the line of the culvert, a temporary works design was performed and a steel RSJ was installed over the water main together with the use of 6 ratchet straps to support the water main whilst the investigation continued.

As the excavation neared a depth of 5m, our workforce discovered old timbers what we believe where used to support the headwall (tunnel), whilst they installed the brick culvert. The timbers had rotted hence causing the road above to sink.

The excavation was reinstated, and the road was reopened within a 2 week period.