Fulton Bridge Lift-over

As heavy lifts go, it was one small step for a Christchurch bridge, but one big leap for the company that did it. Hugh de Lacy reports. 

Shoving Auckland’s 2,300-tonne Stanley Street railway bridge sideways 17 metres in 2003 was a technological triumph for Auckland-based HTC, but hoisting a slightly lighter earthquake-damaged Christchurch bridge just 200mm last December was an even greater one.

The earlier shove, to position the pre-fabricated rail-bridge on its Stanley St/Beach Road/Strand site, was achieved by the then-standard method of deploying hydraulic jacks whose movements were synchronised by workers using walkie-talkies, and sometimes whistles, at each of two pulling points and eight lifting and lowering points.

The lifting of Christchurch’s 1,600-tonne Bridge Street bridge 11 years later was, in contrast, performed with a single touch-screen display module controlling the operation of no fewer than 72 separate hydraulic rams, each with a lift capacity of 100 tonnes.

The 2011 quakes in Christchurch had caused the two-lane concrete Bridge Street bridge across the Avon River to slump as much as 200mm, forcing its closure and cutting Bexley and South New Brighton residents off from their direct route to the central city.

One lane of the bridge was re-opened, for city-bound traffic only, in August 2012, and for the next 12 months commuters had to make a five-kilometre detour to return home.

The rail-bridge job, completed over Auckland’s 2003 anniversary weekend, was at that time the highlight of HTC’s achievements, but last year’s Christchurch lift was a landmark project, the first of its kind in Australasia. 

HTC shelled out a million dollars in 2013 to buy five Syncmaster synchronised lifting systems from Queensland high-pressure hydraulic tool manufacturer Durapac, and Christchurch’s Bridge Street bridge project marked the first time such a system was used in Australasia.

The Syncmaster units can be set up to create and control no fewer than 128 lifting points – accurate to 0.5mm - through the single touch-screen, giving a level of precision and control that greatly reduces both the risk and the cost of heavy-lift operations.

Lead contractor Fulton Hogan had been engaged by the Stronger Christchurch Infrastructure Rebuild Team (SCIRT) to repair the Bridge Street bridge for its owner, Christchurch City, and HTC was sub-contracted to come up with a way of lifting it back onto the level, plus a bit more to allow for repairs.

The quakes had badly skewed the bridge by twisting the abutments, and it had slumped by varying degrees between 8mm and 200mm.

After levelling the bridge, the system was used to lift it high enough for temporary packing to be placed between the bridge and the abutments and to allow for the abutments themselves to be repaired. All repairs will not be completed for some months yet, due to the complexity of piling required.

Once the abutments are repaired the bridge will be lowered back on to them, and on to the two mid-river piers that support it.

“We had six lifting positions across the width of the bridge at the abutments, and on the two piers we were able to fit a whole bunch of very small, low-height rams,” HTC’s Christchurch branch manager, Daniel Brice, told Contractor.

“On the abutments, Fulton Hogan had to put in temporary structures going down about 38 metres into the ground to give the stability for the lift-off.”

Once all 72 rams were in place, each was connected to a hose that ran onto the deck of the bridge and into the synchronised lifting system.

HTC had a team of five of its own staff on the job, supplemented by Stuart Smith, an engineer who had been involved in the building of the bridge in 1980 and was lured out of retirement to advise on its repair.

HTC began setting its gear up on-site on December 5; the lift itself began eight days later, and was completed by December 16.

“We did the actual lift over a 24-hour period – just over – which is what we’d planned for,” Brice said.

Fulton Hogan had been working on and around the bridge long before HTC came on-site: it had renewed the smashed wastewater infrastructure along Bridge Street, digging trenches up to 3.5m deep, de-watering by spear and pump, and installing a new PVC main pipe and the laterals to the houses.

It had sunk the piles to take the hydraulic lifts at the abutments, re-built the abutments themselves, and repaired and upgraded the services that run under the bridge. 

HTC was involved in the conventional lifting of a number of other Christchurch bridges in recent times, but the Bridge Street job drew a small crowd of onlookers when Fulton Hogan opened up the worksite a few days before to media and industry visitors.

The exposure resulted in a surge of industry inquiries not only from Australasia but around the world, giving the company confidence in the value of its big capital investment.

For transport between projects, the five Durapac lifting systems can be loaded into a single container, turning the whole of Australasia into HTC’s target market.

The computer that runs the system keeps each hydraulic ram operating within a pre-set tolerance of the others, and also monitors weight and subsidence at each lifting point, pausing the operation if anything gets out of kilter.

HTC has a total staff of 25, and was launched as the Hydraulic Tool Company from a Howick garden shed in 1982 by Roy Huskinson, the father of the present managing director, Robb Huskinson.

The older Huskinson is a fitter by trade, and he started out selling a range of high-quality, high-pressure hydraulic tools, especially those of the Japanese manufacturer Riken Kiki.

As the business grew, Huskinson found himself increasingly involved in the operational stages of heavy-lifting projects using the equipment he was marketing, so the company’s focus expanded to include the planning and executing of heavy lifts.

One high-profile job that equipment was supplied for was the raising of Parliament’s House of Representatives to enable base isolator bearings to be installed within the brick piers, rendering the building safer in an earthquake. 

Robb Huskinson took over the managing director’s role from his father in 2005, and though heavy lifts are part of HTC’s overall business strategy, the distribution and rental businesses remain vigorous, with more than 1,000 product lines offered from bases in both main islands.

The company also hires most of the equipment it sells because renting helps HTC test how the tools last in the real world while helping the repair division stock the right spare parts. As well as sales and hire divisions, HTC provides on-site and laboratory calibration services for a wide range of torque tools.