Bog_2

The Bognor Northern Relief Road is part of a wider project to open up land for major housing development. As part of the scheme, HOCHTIEF built a 485m long, 16-span concrete viaduct over the Barnham to Bognor Regis railway and the Lindsey Rife flood plain.

Key features:

  • 485m, 16 span concrete viaduct
  • 15m wide deck: 176 precast concrete beams up to 30m long
  • In situ piers comprising columns up to 8m high
  • Piling in poor ground

As the site was in a flood plain, we installed sand bags at the Lidsey Rife and its two tributaries during foundation works. We raised the cut-off level for the piles by 1.5m to avoid having to carry out deep excavations in poor ground, increasing safety and reducing the risk of contaminating nearby watercourses. We also carefully monitored pile positions to ensure that they met the requirements for the pier columns, avoiding the need to pre-install casings, saving time and costs. We built the piles and pier columns for the 16 deck spans concurrently, optimising the programme.

The main deck consists of 176 precast concrete beams, each up to 30m long. Due to their size, delivery of the beams to site was a critical issue for West Sussex Country Council. We planned the beam transportation collaboratively, altering several junctions along the delivery route and completing a trial delivery run well in advance to ensure its success. Our comprehensive planning with key stakeholders enabled this critical operation to run smoothly. The beams were lifted into place using a 300t crane, with those spanning the railway installed during a night rail possession.

The new relief road opened in 2016 and reduces traffic congestion on the local road network.