6 March 2020
New Pyramid Bridge construction tested by flood waters
The new Pyramid Bridge faced one of its toughest tests in last month’s flooding and passed with flying colours.
Only two spans of the new bridge were in place when record breaking flooding from the Mataura River struck the first week in February. Flood waters came within half a metre of the bridge spans.
Gore District Transport Manager Peter Standring said the flood was a good test of the bridge piers and its design.
“It showed the bridge is high enough for a significant flood.”
Mr Standring said even if water tops the piers once the bridge is finished, it shouldn’t be too much of a worry.
“It’s (the bridge) designed to withstand the side-load of flood waters.”
A trench box was the only casualty of the floods. The contractor had plenty of warning and moved heavy machinery to higher ground. However, the 2 tonne metal box was swept away by flood waters. An aerial search found it beached a few kilometres downstream.
While construction work has been tracking along nicely, a week’s delay during the floods will have a knock on effect.
Mr Standring said the latest challenge thrown up by the flood was a new gravel bar downstream of the bridge. The bar has caused the river to pond and the water level was now too deep for earthworks on the approaches to the bridge.
“We are working with Environment Southland to find a solution.”
No date has been set for the bridge’s opening at this stage.