A63 Castle Street Hull

[jackal]

Interesting article on this challenging scheme:

Getting the project onto site has been a long process, [National Highways senior project manager Frances] Oliver concedes. Balfour Beatty was originally awarded the £75M early contractor involvement contract to work on design development and deliver the scheme in August 2014. The project cost has grown to £355M as the implications of excavating the city’s shifting foundations were counted.

Balfour Beatty project director Will Neaves explains: “We are building a 400m long underpass in very poor ground conditions. We installed diaphragm walls along the sides, a grid of tension piles across the footprint of the underpass, and a jet grout layer to form the bottom of that structure and keep the water out.”

The original cost was an estimate before the scheme was designed, at which stage no diaphragm walls were anticipated. Alongside the ground engineering challenges, National Highways points to the work required to excavate and relocate the 240 year old Trinity Burial Ground as another reason for the cost increase.

With higher costs and the need to justify the scheme in terms of value for money, National Highways and its delivery partners explored further improvements within the city centre, such as the footbridge at Princes Quay just east of the underpass.

The five year construction programme started in June 2020. Its duration reflects the challenge of working on the line of the existing road while minimising disruption and the volume of temporary works.

https://www.newcivilengineer.com/innova ... 6-03-2024/