Pile hitch gives hospital headache

25th August 2005

Pile drivers have struck unexpected problems at Tauranga Hospital's construction site and other snags have surfaced with the new carpark lift and staircase.

Test pile-driving for the $110 million Project Leo hospital extensions came to a halt on Tuesday afternoon when contractors were unable to penetrate a layer of hard material 4.5m down.

Another method was trialled yesterday morning that involved boring two 150-diameter and two 250-diameter holes 5m into the ground to penetrate this layer and then driving the piles into the ground.

James Crawford, the project leader for the hospital upgrade, said engineers were now carrying out a structural analysis before deciding on the best method for driving the remainder of the piles.

"In the piling area, the core sample suggested sandy soil with clay that was soft and firm, but anything in the ground is an unknown until you get to it.

"We know what the strata of the soil is, but localised areas can hit hard pans," he said. "We may need to pre-bore each hole - drill all to 1.5m to start with."

The piling trial, which is being held at peak times to allow Project Leo to assess how this activity will impact on hospital clinics, is based on a geotech survey that involved core drilling across the site to a depth of 11m, using a wide grid.

Now that test piling has started, areas within those grids have exposed hard pans, and once the test piles are in place a test of their structural load capacity will be necessary.

"We don't anticipate any increase in cost or in time for completion," Mr Crawford said.

In all, 350 or so piles must be driven into the ground. This is estimated to take six weeks and is likely to begin in early September.

There are also teething troubles with the lift up from the new Clarke St carpark, and its neighbouring staircase.

The lift has failed several times since it opened, and the shuttle bus has been pressed back into service intermittently.

Mr Crawford said this was not unusual for a newly commissioned lift - part of a $700,000 scheme to get air ambulance patients from the helipad to the emergency department. Part of the problem was the impatience shown by the public - the door close button had been worn out by repetitive use.

He said the doors were designed to close slowly, and to stay open longer than a conventional lift, to enable the medical staff ample time to wheel the trolley and patient out of, or into, the lift.

"People are pushing the button several times in a bid to try and get the doors to close more quickly. This has resulted in the button jamming." And vertical railings were being added to the balustrade on the adjacent stairwell, which hasn't opened yet.

Mr Crawford said the original railings complied with resource consent for use by staff but more work was required.