17 April 2019

Bristol start ECI on Redbridge Viaduct
Hampshire County Council - Redbridge Viaduct, Southampton - Works Package 2 - Concrete Repair and Cathodic Protection Works

CRL Bristol has recently been appointed as the contractor to undertake the ECI work on the Redbridge Viaduct for the ultimate client Hampshire County Council.

The Bristol team are currently working with Skanska on the ECI phase of the scheme. Particular areas of development are the repair sequence and the need for temporary works, as well as the ICCP design, access solutions and logistics planning to deliver the works.

A target cost will be developed which is expected to be about £1M. Works are planned to start at the end of June.

Project Background

The Redbridge Causeway comprises four bridges taking the A35 over the River Test. These are Redbridge Viaduct, Redbridge East, Redbridge West, and Redbridge Road. All four bridges are in varying states of deterioration, with the worst areas concentrated around the marine spans. This project involves repair and long term protection of the bridges.

Work Package 2 involves works to the marine sections of Redbridge Viaduct. There are three key parts to this: 1) Piers 9-16, marine Pile Bents, 2) Piers 7-8, east channel leaf piers & Piers 17-19, west channel leaf piers. 3) Land piers 1-4 around Test Lane.

Piers 7-8 & 17-19 are within the River Channels. Piers 9-16 are adjacent to a mud flat area known as the south island. The River Test is tidal in this area, and the south island becomes flooded during high tide.

All piers require extensive concrete repairs, with up to 20 stages required on some of the bents.

Two types of CP system are to be installed, discrete anodes on the column bents and a mesh overlay system on leaf piers.

Plan of the Site

Piers 7-8 & 17-19 are within the River Channels. Piers 9-16 are adjacent to a mud flat area known as the south island. The River Test is tidal in this area, and the south island becomes flooded during high tide.

The site compound for the works will be situated to the north of the viaduct, on the “North Island”. This island supports the section of carriageway linking Redbridge East and Redbridge West. This will be used for material storage and an area to launch barges etc. from when carrying out marine works.

Environmental Restrictions

The area to the north of the bridges is a Special Protection Area (SPA), Site of Special Scientific Interest (SSSI), Special Area of Conservation (SAC), and a RAMSAR site.



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