Construct - Issue 50

Project

STRESS REDUCTIONON INNOVATION AND EXPERTISE WERE ESSENTIAL FOR THE COMPLEX AND TECHNICALLY CHALLENGING WORKS ON ONE OF THE OLDEST SUSPENSION BRIDGES IN THE WORLD

In February 2022, FM Conway began works to stabilise Hammersmith Bridge, the iconic green and gold Grade II* listed Thames crossing. Opened in 1887, it saw more than 130 years of continuous use before it was closed to motor vehicles in 2019. Now, the bridge is again open to pedestrians, cyclists, and e-scooters thanks to repair works carried out by FM Conway. After years of service to pedestrians and moving vehicles, including horse-drawn carts, cars and lorries, the historic bridge had developed fractures in the cast iron pedestals. These are critical components of the suspension system, and the deterioration meant essential repair works were required.

This made the stabilisation programme carried out by FM Conway of utmost priority. As a first step, the small fractures in the pedestal structures that support the bridge’s weight had to be strengthened. The FM Conway team created a high strength concrete mix and tested it rigorously over a six-month period before using it in all four cast iron pedestal cavities, the first of many bespoke solutions developed for the works. “Throughout the stabilisation, we were working to tolerances of within maximum deviation +/-0.05 millimetres. Working with such small margins on a large project was challenging and rewarding in equal measure,” explains Sam Goddard, project manager at FM Conway. “Some of the Daver bars were seized in place, meaning we had to drill them out, working from each side to meet at a central point. We used specialist metrology techniques to calculate the exact drilling points, due to the risk of potentially drilling and damaging the existing saddle.” The next step was to replace the seized Victorian - era cast iron roller bearings with new elastomeric bearings. These are designed to reduce friction and enable smooth, low-wear movement. This was a complex job that required a tailored fix. It involved lifting the bridge off its pedestals using hydraulic jacks to allow the installation of new elastomeric bearings.

LOCATION

Shepherd’s Bush

Kensington

Hammersmith

Earl’s Court

HAMMERSMITH BRIDGE

R I

Fulham

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M E

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