Knights Brown’s works comprised the investigation, design and refurbishment of a steel and concrete road bridge over Langstone Harbour, a designated SPA, SSSI and RAMSAR. This dictated both when and how the works could be undertaken.

The bridge is one of only three major routes on and off Portsea Island and the northern part of Langstone Harbour is one of only a few sites in northern Europe that is key for over-wintering birds.

Due to the potentially devastating impact to the road network and the numerous environmental and ecological constraints the scheme underwent a two-stage procurement model with a six-month collaborative planning, design and approvals phase between Knights Brown, Portsmouth City Council, Ramboll and our specialist painting subcontractor, SCA.

We worked with Portsmouth City Council’s team to develop safe and effective methods to undertake the bridge inspections with respect for the tidal nature of the works and available working windows. Bird netting was erected under the bridge to prevent any birds or bats roosting/nesting prior to the works. We produced the methodology for all the MMO licences and relevant environmental consents, which were approved at first time of asking.

The main elements of the construction work that followed included the erection of scaffolding and encapsulation to the underside of the bridge to prevent contamination to Langstone Harbour, grit blasting of steel beams and preparation of steelwork, structural steelwork investigation works, application of a corrosion resistant paint system, sealant to the joints and bridge inspection and testing works.

The project won a 2018 National Considerate Constructors Scheme Bronze Award.