Latest reports from Fonterra indicate of the 22 suppliers in Kaikoura District three couldn’t supply from their farm dairies and of the 98 in the epicentre district of Culverden only one dairy shed had been written off.
Canterbury dairy shed builder Craig Walker said on the whole the building codes for farm dairy construction proved robust, with the greatest problems in large farm dairies being rotary platforms coming off their rollers.
“Because they are rigid they do not like being moved sideways.
“We learnt a lot from the Darfield quake in 2010.
“They now put a lot more stays around the platform pedestal to keep it in place, with more than one stay at every point.
“Any farm dairies built in North Canterbury after that quake would have had that done and would have come through okay.”
The high profile loss of Don Galletly’s farm dairy near Waiau was one most builders believed could not have been avoided, given the farm’s proximity to the quake epicentre.
A movement over past years from 100% steel rotary platforms to reinforced concrete platforms might also have made reinstating some dairies to operational level more difficult.
“The move was to make the platform quieter and more appealing for cows but it has meant a heavier platform is added on top of the building’s foundation.”
He noted farm dairies with DynaBolted platform constructions on them tended to have the platform rigging ripped out, compared to designs where the rigging was embedded in the foundation concrete.
Walker said it was unrealistic to expect farms in earthquake-prone zones to also have a smaller, standby herringbone dairy for events like this.
“But I think it may encourage a few more farmers not to put all their apples in one basket with one large shed and possibly consider splitting their operation into two.”
Long-time farm dairy builder Don Chapman said he had one client very close to the epicentre who was able to prise the platform back onto its rollers and was up and running in 24 hours despite the proximity to the destroyed Galletly operation.
He felt on the whole building codes for dairy construction were tight enough and had tightened since the last big quake.
“Whether they tighten again, that remains to be seen.”
He had heard older dairies around the more traditional dairying area close to Kaikoura had suffered more damage, a claim supported by Fonterra’s figures.
“And it could be that if they are older sheds they have not stood up to this as well as newer designs.”
He suspected there might be some business ahead helping reconstruct dairies but it came with a sense of grim pleasure.
“This is not something you would wish on anyone. This has come at the peak production period and even if the damage is only minor, it is still a major disruption to these businesses.”
Walker had supplied some concrete silo platform moulds to a Kaikoura farmer so more silos could be installed, enabling that farmer to milk his neighbour’s cows through his dairy until repairs could be done.
“But, overall, we are not expecting to see a great deal of work from this. It will be more a case of patching things up than complete rebuilds.”
Waikato Milking Systems upper South Island sales manager Chris Barclay said in the aftermath no “golden engineering rule” had materialised on quake-proofing dairies.
“In some cases the platforms have fallen off but been all right otherwise but that does damage all the milking equipment below it.”
His company had equipped the Benton farm dairy featured in NZ Farmers Weekly on November 21.
The dairy was able to be back and running 20 hours after the quake. House removal jacks enabled the platform to be re-positioned and held in place.
“But that still needs a lot of work doing to it to get it back to where it was.”
He said lessons were learned in Darfield around silo construction, with reinforced pads reducing silo losses.
