Underpinning and relevelling large commercial buildings has been proven viable with the successful relevelling of a large three-storey building damaged in last February’s big earthquake in Christchurch, New Zealand. The magnitude 6.3 quake - which killed 185 people in New Zealand’s second-largest city - was followed by a series of aftershocks that further weakened buildings in the devastated central city.
A collaborative effort between Piletech and Enerpac, in responding to the needs of the owners of the three-storey building, resulted in the structure being safely jacked back into position with millimetre precision using the Enerpac Synchronised Hydraulic Lifting System and a battery of Enerpac 50 and 100 tonne jacks, with a combined lifting capacity of 800 t.
The Enerpac synchronous system, available through Enerpac Integrated Solutions, is being employed globally for challenging lifts of up to tens of thousands of tonnes, ranging from ships, buildings, bridges and wharves through to mining draglines, ball mills, turbines, petroleum drilling platforms and exploration machinery and loading/unloading facilities. Applications include relocation of the Shanghai Concert Hall, lifting the Prado Museum in Madrid, lifting the San Francisco Bay Bridge and even the recent U2 concert’s giant climbing stage.
Piletech designed and installed screw piles both inside and outside the building which provided the support for temporary steel jacking frames. The Enerpac Synchronised Hydraulic Lifting System provided the ability to individually control the jacking points, ensuring that the building was not subjected to further stresses. The relevelled building is now supported by new screw pile foundations which have been proven to perform exceptionally well throughout all the seismic events.
Believed to be the first relevelling of a building of this size in Christchurch, it brings new hope to owners of large buildings that would otherwise be facing the demolition ball. The Piletech/Enerpac team is currently assessing several more significant building relevelling projects within the city with lifting capabilities of up to 12,800 tonnes.
The lift went right to schedule and as planned, saving many hours or even days of hard work.
“The ability to control all aspects of the lift is a huge step forward in helping rebuild Christchurch safely and without further damaging the building,” said Jonty Petorius of Piletech.
Piletech’s wide experience in screw piling is complimented by Enerpac’s wealth of worldwide experience in heavy lifting. Screw piles can be put in just about anywhere; even piling through windows is possible, as is coming down from a second story to install screw piles.
The Enerpac synchronised lift systems are available for monitoring up to 64 points. The entire lift can be controlled by one person by touch screen, safely away from the building being lifted.
“There are virtually no limits to what can be lifted, only your imagination,” said Enerpac New Zealand Territory Manager Neville Stuart. “The ability to control so much force with the touch of a finger is impressive.”
The Enerpac technology is designed to provide optimum control and stability during the lift and ongoing safety, by protecting the structures’ integrity during the lifting and manoeuvring.
“Not only does the PLC controlled lift provide minute control - down to 1 mm or less during the lift, measured over hundreds of cylinders arranged in clusters - but it can also account for variation in load over the floor or keel of the structure,” said Enerpac.
“This means system operators can maintain outstanding control over huge numbers of cylinders to apply exact force as it is needed in particular parts of a structure as it is hosted for weighing, balancing or prior to skidding into position for launch.”