Farrans is the main contractor on the Govan to Partick Bridge, a fabricated steel cable-stayed opening swing bridge for Glasgow City Council. Linking Water Row in Govan and Pointhouse Quay in Partick, the bridge will restore the historic link between the two areas for pedestrians and cyclists.
Groundforce Shorco is helping with the construction of the piers at either end of the crossing by supporting the sheet-piled cofferdams in which the structures are being built. Work started on site in January 2022 and Groundforce Shorco has already delivered the equipment to support the next cofferdam on the northern bank of the river.
The cofferdam on the southern (Govan) bank of the river encloses the location for the bridge's swing mechanism. Measuring 15.5 metres by 15.5 metres, the sheet-piled cofferdam was supported by a combination of Groundforce Shorco's Super Mega Brace and modular hydraulic props.
There are four each of Groundforce's MP150, MP250 and MP375 (150, 250 and 375 tonnes capacity respectively) units assembled at four levels within the excavation. The props are around 7.2 metrs long and the span between them is 5.5 metres.
Groundforce Shorco senior engineer Ahmed Adayem said: "To deal with the heavy hydraulic loads acting on the structure, standard 508mm-diameter extension tubes were fitted to the MP150 props at the top of the cofferdam. The intermediate-level MP250 props are fitted with 610mm-diameter tubes and 813mm-diameter tubes are fitted to the MP375 props."
The permanent works in the south cofferdam is now complete and the temporary support has been dismantled. The equipment supplied by Groundforce Shorco was off hired in August as the cofferdam was disassembled.
The focus now shifts to the north bank where the second cofferdam is located ready for construction of the abutment and pier to support the moveable end of the swing bridge. This cofferdam on the north bank is the same size as the one on the south bank so the props will be configured similarly.
Design of the cofferdams and their supporting structure is complicated by the fact that this part of the River Clyde is tidal, with the water level rising and falling roughly four metres twice a day. So the depth of the excavation from the top of the sheet-piled wall to formation level is approximately 12 metres.
Fluctuations in the tidal loadings are managed by pre-loading the propping system using the integral hydraulic rams. Groundforce Shorco has supplied wireless load-monitoring to track loads in real-time and send alerts via SMS message should any load exceed the pre-set value. The system also allows the customer to keep an eye on loads and adjust the propping system accordingly.
Groundforce Shorco won the contract to supply support equipment in an open tender against stiff competition. According to Farrans site agent Luis Alves, Groundforce Shorco's design capability, coupled with its track record, were deciding factors in awarding the contract.
"We have a long-standing relationship with Groundforce Shorco having worked with them several times in the past four years," says Mr Alves. "We've recently worked with them on a couple of big dockyard projects locally so we know their capabilities.
"I have previously worked with [Groundforce Shorco major project manager] Adam Fletcher and the engineering team at Groundforce Shorco are very helpful," adds Mr Alves. "We've had a couple of design changes to accommodate this job and they have been very supportive."
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