From The Wire

Ross, amongst others, has asked me about wire rope crash barriers.

One of our favourite engineers has sent me some video links of drowsy drivers straying into the barrier on Centennial Highway.
Check them out Here

This has been a killer stretch of road. (Map)

I think they speak for themselves.

The Zen of Amco's Revisited

This Amco barrier has taken a swipe.
It has done it's job well.

Beyond it is a steep bank, and a creek.
If a truck went over here it is doubtful if the driver would survive.

It is on a tight sweeping bend on the Hiwi's, on State Highway 4.

The marks would suggest a truck has hit it, the rail has deflected the tires and despite a bit of red paint and indicator glass, all has ended well.

We will have to repair this.

Straighten the rail, and realign and ram the posts. No big deal.

But somebody got a hell of a fright.

The Zen of the Amco

Amco crash barriers are simple but effective.

The metal rail is quite springy, and bolted to posts. The head of the bolt passes through a slot allowing for some stretching of the rail.

The ends as pictured are loosely bolted in place. Should you hit this it will slide down the rail, the posts will shear at ground level (They have a fist sized hole drilled in them) and the end will act like a potato peeler, curling, and feeding the rail through.

The first couple of posts are sitting in a metal sleeve which is quite deep in the ground.

This is done so the posts break in the impact and don't just uproot. The cable spreads the force of the impact, as does the brace at ground level.

We are often replacing dinged crash barriers, There is generally a bit of broken plastic, indicator lenses etc. Often a car can drive away a bit battered, but mobile.

It's certainly better than hitting a rock bank or going into the river.

Today we replaced a guardrail at a corner with a deadly and macabre history.
It had been damaged by a semi that jack-knifed, fortunately with no injuries.
In 1995 a car left the road on this corner, killing an asian couple, when the vehicle landed in a small but flooded stream.
A police dive team searching the stream found another car with two men in it that had left the road 4 days before.
The two men had been away on a bit of a jaunt, and had not been missed.
There is a little a little memorial plaque behind my two work-mates, placed by the family of the asian couple, and two of the crosses commemorate the earlier crash.
This corner did not have a guardrail then, and has since been widened, and given better visibility.
When you look at the tiny stream, it is hard to believe that it turned killer.