The third of a total 11 wharf concrete pours was completed at Port Otago's $21 million multipurpose wharf extension yesterday, with the project completion date still on target.
The wharf concrete pours, using about 60 truck-loads, begin about 3.30 am through to about 9.30am, uses about 300 cubic metres of concrete, weighing 720 tonnes, to encapsulate the reinforced steel.
Port Otago civil engineer Andy Pullar said a “major milestone” was achieved in late April by contractors HEB Construction on the wharf extension, with the final large diameter tubular steel pile, which holds up the concrete deck, driven to depth.
A specialist concrete mix was required, given the 750mm depth of the wharf slab, which generated a lot of heat, plus the need for a higher strength concrete. The 138 piles were on average about 32m each in length and were driven, by a combination of vibrating and impact hammer, into the bedrock, before being filled with concrete.
“There's still some pile driving to be completed on the public fishing jetty and sheet piling of the existing wharf. However, these are driven by the vibrating hammer with the noise generated not expected to be noticeable beyond the site,” Pullar said.
The project, to extend the wharf by 140m, was advancing ahead of schedule with overall completion in October still on target, he said.
“The public fishing jetty is in the final stages of design with a slight change in position proposed from the earlier consented position,” Pullar said.
For safety reasons, it would be realigned back from the wharf face to the end of the Boiler Point walkway, but with a “T head” to provide more fishing space, to access a water depth of about 5m.
*Simon Hartley is senior business reporter and assistant chief reporter for the Otago Daily Times.