Pedestrian Bridge, Helical Screw Pile Foundations, Heritage Site, England

Overview

Delivering a robust bridge foundation solution within a tight schedule

The Chester House Estate is a nationally significant heritage site, being one of the few places in the country that can demonstrate over 10,000 years of human activity.

The new bridge was required across the River Nene, replacing an old burnt-out structure that connects Chester House Estate to the Wellingborough embankment and is key to the future Greenway active-travel project. The previous bridge had been closed to the public for the past 15 years.

The project was quite challenging due to the nature of the area, which is a floodplain and includes the scheduled monument at Chester House. The steep, sloping banks of the River Nene also needed to be taken into consideration.

Working within a tight timescale, we were asked to propose a screw pile solution that would ensure the project stayed within the programme of works so that the new bridge could open in time for the first birthday celebration at Chester House and the half-term week.

Solution

Turnkey foundation solution for pedestrian bridges

Helical Screw piles installed to 9.5m to successfully bridge the river

Prior to any work starting, our team conducted a point load test to check the integrity of the ground and to ascertain the depth required to ensure strong and stable foundations were installed.

Our site survey and ground tests provided the empirical data showing that six RADIX Extendable 76mm Screw Piles with helical extensions would be required, installed to a depth of 9.5m on either side of the river, with 450mm left exposed to create the necessary ramp for wheelchair access. A bespoke structural steel grillage was installed on top to provide the complete foundation solution required to support the new steel bridge.

Once installation began, the whole project on the north and south banks of the river was completed in only 3 ½ days, and the bridge itself could be placed and secured on top immediately. Our screw piling team used the latest ground screw machines and augers designed for extendable screw piles.

This project is just a small part of a wider initiative to improve accessibility throughout North Northants to see the Chester Farm Estates attractions while working towards their commitment to going carbon-neutral.