As part of regular maintenance on the roads in the region, the South Taranaki District Council (STDC) required the services of Inframax and their team of contractors and suppliers to lift the safety level of four bridges by installing new guardrail with leading and trailing end terminals – all supplied by CSP Pacific.
“We were awarded the tender to upgrade four bridges for the STDC which is part of their bridge maintenance programme,” explains Wayne Snellgrove from Inframax Hawera. “I have no hesitation, when awarded contracts like this, in getting the team together – ourselves, Ian Murphy Fencing and CSP Pacific. We have all worked together so long we have developed a winning team – it just works well every time.”
“There was nothing particularly tricky about the installation on three of the bridges as they required standard guardrail with two X-350 Terminal Ends and Trailing End Terminals per bridge,” says Ian Murphy from IG Murphy Fencing – the road barrier installer on the project. “However the fourth bridge was a bit more involved.”
“The fourth bridge already had a balustrade which had been removed by Total Services (1998), specialists in removing concrete balustrade, and another important part of the team,” explains Ian. “To avoid damage to the concrete structure of the bridge, in the event of a collision, we used a specially made bridge post system which includes a necked bolt by CSP Pacific.”
How does it work?
The existing concrete plinth, left after the concrete balustrade has been removed, is core drilled and a special insert is epoxied into the deck. This is similar to the threaded sockets used with cast in brackets on new builds.
Once the epoxy has cured, slightly shorter posts (FX94) are bolted to the concrete deck by using socketed necked bolts (FX150-5 r3 and FX147). These bolts screw into the sockets that have been epoxied into the deck. When the guardrail is impacted the post rotates backwards and the heads of the bolts shear off. The guardrail deflects and behaves as it would with ground planted posts. To repair, simply unscrew the section left in the socket, replace the guardrail – and post, if badly damaged, and insert two new bolts to hold the post and guardrail to the deck.