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Rural Aluminium Multiplate underpass offers considerable savings
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Customer: Southroads Invercargill
Contractor: Southroads Invercargill
Location: Tapanui, West Otago
Product: Rural Aluminium Multiplate underpass
CSP Pacific’s Rural Multiplate option

At present Southroads Invercargill, a construction company specialising in roading and civil engineering, install an underpass each week for the expanding dairy industry in their region.  So when a local farmer who was in the process of converting to a dairy operation purchased land on the other side of a highway and had to install a stock underpass to have access to all of his land, he called Rae Rennie from Southroads.

“We install concrete underpasses all the time but I had been working with Ian Rowland from CSP Pacific to produce a multiplate underpass range of sizes that would be suitable for stock use,” says Rae Rennie, Bridging Manager for Southroads Invercargill.

“We have supplied multiplate structures for projects all around the country for a variety of uses - anything from rail underpasses to culverts,” says Ian Rowland, Sales Engineer for CSP Pacific. “So it made sense to produce a smaller range, 3m span x 2m rise, 4m span x 2m rise and 5m span x 2m rise underpasses, to suit rural applications.”

With cost a factor for the farmer Rae supplied costings for both a concrete underpass and CSP Pacific’s Rural Multiplate option. It turned out that the installation of CSP Pacific’s multiplate option would save the farmer approximately $30,000.

“Installing a multiplate underpass would not suit all situations,” adds Rae. “Not all soil types and locations are suitable for this product. But in this case the multiplate option suited the site and it has meant the farmer has made a considerable cost saving.”

The ability to assemble the multiplate to the side of any installation allows Rae and his team to pick the right weather and time to excavate and lift the multiplate into place with one easy lift.

“Ian did a bloody good job for us over this installation. Actually all the CSP Pacific guys were great and were really good to deal with,” adds Rae. “Having this product range available to us just means that when the location is suitable we have another option to give our customers.”


Key benefits include:

  Manufactured from marine grade aluminium alloy
  Underpass design life of 100 years with minimal maintenance of structure required
  Three underpass structure sizes to choose from
  All structures are supplied with a generic Producer Statement PS1 based on common site conditions to facilitate the issue of a Building Consent
  Fast and economical job completion meaning a structure, depending on site conditions, can be assembled and backfilled in one week
  Can be pre-assembled off site to reduce impact on farm workings and production. Structure plates are easy to transport, handle and store
  Optional structure coatings available


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