Bruce Road, the only car access to the Whakapapa Ski Area, sits on the northwestern slopes of Mt Ruapehu and its functionality is critical to the success of New Zealand’s largest ski field - owned and operated by Ruapehu Alpine Lifts.
CSP Pacific’s FX94 type steel posts are a key factor in the company’s ability to keep the road open during the busy ski season when mishaps on this sometimes treacherous road can damage the safety barriers.
Over the years Russell Le Quesne, Director of TPP Contracting - the company tasked with maintenance of the road barrier - has looked at systems to suit the alpine conditions. Russell explains, “we have slowly, as budgets permit, been converting the standard barrier system in certain places to the bridge post system. When a snow plough or a vehicle impacts the barrier the brackets are designed to break off but still offer protection - but it means the system can be repaired that much faster so the road can remain open.”
“This particular post system is traditionally used on bridges as the cost to repair the concrete on a bridge after a collision is tremendous and the repairs themselves are sometimes very difficult,” says Jeremy Mallender, Sales Engineer – Lower North Island for CSP Pacific.
How does it work?
A concrete deck or slab is poured using 200mm unreinforced or 150mm reinforced thick concrete with cast in brackets (FX150) set in the concrete at the centres of the bridge posts - 1.905m for highway rail.
Once the concrete has cured posts are bolted to the concrete deck by using necked bolts (FX147). These bolts screw into the cylinders that have been cast 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 post and guardrail to deck.
“There are other factors as well that make using the bridge post system the best option,” says Russell.
|“1.||There is a lot of rock on the mountain and we have to drill a hole using an excavator - so if we install the posts system, it’s permanently there;|
|2.||the concrete slab helps protect the edge of the road as it can be a bit unstable in places,|
and of course the repairs to the barrier are so much easier and quicker to do.”
With a third of the barrier on the road now installed with this system Russell is happy with the safety and repair ability of the road. “It is more costly to install but it is far cheaper in the long run. Another plus is that Jeremy and CSP Pacific are just really good to deal with.”