Groundforce Shorco has supplied a number of its most advanced hydraulic shoring equipment to contractor Sir Robert McAlpine to be used at the £50m redevelopment of Glasgow’s School of Art.
The project involves construction of a brand new five-storey building in Renfrew Street, directly opposite the famous Grade A listed art school building designed by Charles Rennie Mackintosh.
The substructure of the brand new building requires temporary propping in the course of the construction of the double storey basement in an excavation measuring approximately 60m x 34m x 10m deep.
McAlpine opted for a propping solution over structural steel since it offered some great benefits of speed of installation and the potential to watch loads, said Groundforce technical sales manager Mark Whitmore. The price was roughly the identical.
The support structure comprises nine hydraulic props in total; six on the upper level and 3 raking props on the lower level. Because the site slopes quite steeply, all props also are on a vertical incline, meaning that Groundforce needed to make it possible for the tip bearing plates, that are designed to allow lateral articulation, were rotated 90° to fit the relationship detail at the capping beam.
As there has been a necessity to measure the effect of the basement excavation at the surrounding buildings, wireless load monitoring system was used, which uses electronic load pins to log prop loads and transmit readings to a central server via GPRS. This information is then displayed within the style of charts and graphs on a safe website which the customer, and some other authorised users, can access at any time.
Using the modular hydraulic system together with active load monitoring allowed Groundforce and McAlpine to be fluid with the design requirements which provided flexibility to alter aspects of the design to house changes to the development sequence. The wireless load monitoring system enabled McAlpine to adopt an observational option to the lower level propping, so it may significantly reduce the selection of struts required.
Among the many props is 150-tonne capacity. Each of the others are 250-tonne capacity MP250 hydraulic units with 610mm diameter steel tube extensions. “With the 2 upper level central props, that have a the relatively long span of around 31.5m, we needed to specify our 1220mm-diameter Super tubes,” Mr Whitmore said.
Delivery started in the course of the first week of May 2012 with the full duration expected to be around five to 6 months. However progress was quicker than SRM had anticipated with the lower level of props scheduled for removal mid August with the higher level removed during September.
“I’ve worked with smaller equipment, like hydraulic manhole braces, regularly before, but this can be a whole different order of scale” says McAlpine construction manager Peter Unwin. “Instead of handling units weighing 250-500 kg, you’re handling pieces weighing 16 or 18 tonnes. But it’s very user-friendly and everything’s gone very smoothly.”
When completed the hot building, designed by The big apple-based Steven Holl Architects and Glasgow practice JM Architects, will house various studios and teaching facilities in addition to workshops, communal areas and exhibition spaces.