Shoring a bridge



Groundforce Shorco is supplying a range of large-capacity modular hydraulic shoring equipment to contractors building a new footbridge and cycleway over the River Clyde in Glasgow.

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 was funded through the Glasgow City Region City Deal and will restore the historic link between the two areas.

Groundforce Shorco is helping with the construction of the piers at either end of the crossing by supporting the large 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 new bridge’s swing mechanism. Measuring 15.5m x 15.5m, the sheet-piled cofferdam was supported by a combination of Groundforce Shorco’s Super Mega Brace and its modular hydraulic props.

The props employed comprise 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 7.2m long and the span between them is 5.5m.

Ahemed Adayem, Groundforce Shorco senior engineer, 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 complete and 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, like its counterpart on the south bank, also measures 15.5m x 15.5m and the Groundforce Shorco equipment will be installed here in a similar configuration.

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 4m twice a day. Consequently, the depth of the excavation from the top of the sheet-piled wall to formation level is approximately 12m.

Fluctuations in the tidal loadings are managed by pre-loading the propping system using the integral hydraulic rams. Groundforce Shorco has supplied its wireless load-monitoring system 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.”