Spectacular blast as old Taupo road bridge destroyed
The 63-year-old Mohaka bridge, on the Napier-Taupo highway, came to a spectacular end today as explosions sent it plunging 40 feet to the riverbed below.
After the ﬁrst of a series of three blasts by a Ministry of Works demolition squad the northern section of the bridge lay crumpled on the riverbed. A further section was to follow early this afternoon. The ﬁnal section will be blasted tomorrow.
The Ministry of Works explosives expert, Mr J. Gerrard, said: “It was a perfect blast. We cut the bridge just as we had calculated and everything went just right.
The old wooden structure – one of the ﬁrst bridges to span the Mohaka – has been replaced by a new high-level concrete and steel bridge which was opened late last year.
About 20 Ministry of Works employees, Press photographers and newsmen saw the old bridge crash to the riverbed with a thundering explosion which echoed through the valley.
The ﬁrst explosion was held up brieﬂy as the Labour Department’s safety inspector,
Mr W. J. Keough inspected the scene to make sure safety requirements had been fulfilled.
The demolition was supervised by a Ministry of Works bridge specialist, Mr S. Drinkrow.
Earlier, a team under Mr J. Franklin had stripped the bridge of Bailey bridging, decking and stringers to make it as light as possible for the demolition. They will later salvage the timber from the riverbed for future bridge maintenance work.
For the first blast the shot firer, Mr Gerrard, inserted nine plugs of gelignite into the wooden span on top of the northern pier.
He lit a four-minute fuse, climbed down a 40ft ladder, and sought safety on the riverbed about 200 yards away.
Spectators at various vantage points about the steep valley watched apprehensively as blue smoke from the burning fuse curled towards the charge.
Exactly four minutes after the fuse was lit the explosion blasted through the valley and the northern section fell to the riverbed with a roar.
Immediately, the squad began to plug the centre section with gelignite, and it was expected that it would also be blown down to the riverbed early this afternoon.
PIERS TO BE LEFT
Mr Drinkrow said the remaining southern section would be demolished tomorrow. He said the two piers would be left for possible emergency use in the future. “In the event of hostilities or an earthquake, we may need to throw a Bailey bridge across the piers in the future,” he said.
FIRST SECTION OF MOHAKA BRIDGE COLLAPSES
Photo caption – THE FIRST SECTION of the Mohaka bridge to be blasted begins its plunge to the riverbed below this morning. The demolition is being carried out in three stages – the last tomorrow.