An environmental result for local businesses and residents in Hampshire

The Redbridge Causeway spans the tidal part of the river Test, to the west of Southampton and is part of the A35 dual carriageway. The 1960’s causeway is situated in an environmentally sensitive area with challenging logistical conditions. It required a complete refurbishment. In 2021 Hampshire County Council (HCC) approved a £15.8 million budget to repair damaged concrete and improve the stability of the structures.  

The project’s design and delivery required innovative solutions to address the unique challenges of working in a tidal zone containing seven designated areas of special interest. Critical works needed careful planning to avoid disturbance to surrounding habitats. 

Our team led an extensive 18-month Early Contractor Involvement (ECI) period, creating an integrated team that included HCC, designers and our supply chain. This collaborative approach emphasised early identification of risks and opportunities through tools such as 3D models, strategic planning and a shared risk and opportunity register (R&O).  

Repairs were completed in small, controlled phases, meaning there was no need for heavy-duty propping or a cofferdam, minimising the impact on the tidal environment. Fixed scaffold arrangements and pontoons allowed for intrusive repairs without disrupting traffic or compromising marine ecosystems. Concrete repairs and cathodic protection addressed chloride attack damage caused by road salts in the marine environment. 

The results were: 

Following the success of the Redbridge Causeway, M Group is continuing in collaboration with HCC to deliver the +£30m Botley Bypass.