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Mabey and Ekspan complete Bristol viaduct support works

Bromley heath viaduct image credit ekspan

Mabey and Ekspan have completed support works to a 105m viaduct in Bristol. 

Situated on the busy A4174 ring road, the Bromley Heath Viaduct five-span structure carries approximately 55,000 vehicles and 500 cyclists a day, and is one of Bristol’s busiest commuting routes. 

Appointed by South Gloucestershire Council to carry out the works, Mabey and Ekspan simultaneously lifted 16 beams making up the deck of the viaduct in order to avoid any structural damage through excessive beam displacement.

Mabey was approached by Ekspan and was tasked with designing a bridge propping and jacking solution that could facilitate this maintenance work and offer the necessary structural support and clearance - all with less than 0.5mm of room for error. 

Mabey Hire UK chief executive Gordon Macdonald said that early collaboration was a great aid to the project’s award winning sucess.  

“Early contractual involvement meant we were able to collaborate with Ekspan from the off to develop a temporary works solution which would combine our expertise in propping and monitoring and ultimately deliver the viaduct improvements as quickly, safely and efficiently as possible,” he said. ”Receiving the ’Large Project of the Year’ award is a true testament to Ekspan’s clear brief and flexible working nature.” 

Rough and uneven ground conditions also made the works more challenging for Mabey, who deployed their Mass-50 modular shoring and propping system to support the 16 viaduct beams. 

Each Mass-50 unit is capable of supporting loads of up to 500kN on a single leg, and was originally designed for façade retention and structural alterations in buildings.

Ekspan project manager Spencer Goff said that Mabey’s Mass-50 Units allowed other renovation work to continue safely and minimise disruption.

He said: “Mabey’s innovative Mass 50 propping system allowed us to carry out bearing replacement work on the viaduct safely and efficiently, and in turn, helped us to minimise disruption for commuters using the A4174 Bristol ring road.”

The Mass-50 units were combined with Mabey’s Hymat jack systems to lift and prop the viaduct beams. 

Also in use was a real-time monitoring system. This ensured that displacement between two adjacent beams did not break the 0.5mm limit. The sensors also recorded the project data in real time with warnings sent via text message to operators if movement exceed the maximum levels permitted.

“The use of real-time displacement monitoring was especially valuable, enabling us to keep track of any shifts in movement and rest assured that the Council’s requirements were being fulfilled,” Goff added.

After a year of refurbishment, the Bromley Heath viaduct is now open to the public.  

The Mass-50 units were also used in the construction of two new bridges, providing additional crossing and seating for audiences over the world-famous Barry Burn at the 147th Open at Carnoustie.

The 147th Open at Carnoustie.

Mabey built the two new bridges, providing additional crossing and seating for audiences over the world-famous Barry Burn at the 147th Open at Carnoustie.

The Mass-50 Units used in the viaduct renovation have been used in many projects, even at the British Open in Carnoustie. There units were used to construct two new bridges, providing additional crossing and seating for audiences over the world-famous Barry Burn at the 147th Open.

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