The background

Bishopsford Road Bridge, spanning the River Wandle collapsed during heavy rainfall in 2019 after attempts to strengthen it failed.

The damaged bridge was demolished in summer 2020 to make way for a £2.7million replacement to be built. The chosen contractor, Land & Water, called in Selwood’s pumping solutions teams to assist with overpumping the river so the building works could take place.

The challenge

Construction of the bridge required rotary piling to take place to remove soil and rock around the structure which connects the deck of the bridge to the ground, and reinforced concrete works were carried out to build the abutment. Cofferdams were installed to enable the relevant section of the river to be drained to create a working area.

Each of the north and south sides of the bridge needed to be dry for a four to six-week period in turn, and it was essential that the pumping setup that could be relied upon to be running 24 hours a day.

The site was in a built-up area where noise and disruption had to be kept to a minimum while works were taking place along with having limited working area so the footprint of the pumps had to be relatively small.

The solution

Following a detailed site survey Selwood’s team recommended a solution involving four Selwood D100 four-inch Super Silent pumps – two each side of the bridge.

To enable access, water was pumped out from the cofferdam and back into the river on the opposite site. Work began on the south of the bridge where the piling and concrete works were completed before progressing to the north side to repeat the operation.

Each side had a duty pump backed up by a standby to guarantee 24 hour running, ensuring pumping would take place even in the event of an equipment failure.

The super silent canopies reduced the noise on site, and silt traps were provided to avoid pollution of the river.

The result

Careful planning of the project enabled the working areas to be drained quickly and safely, with filtered liquid being introduced to the river. The use of super silent pumps meant the customer was able to meet the minimal noise requirement, avoiding disruption to people in the local area.

The operation was carried out on time and within budget. The customer is very happy with how the job is going and our equipment makes it easy to complete the project.