Everybody is happy including the fish

For the property developer of a site at the end of Blacks Road in Greenhithe to have access to the whole of his site, with the intention of creating 40 residential sections, the installation of a culvert or bridge to span a stream running through the middle of his land was required. With the Auckland City Council placing huge ecological value on the stream, various options were considered taking into account a variety of factors.

“Providing the fish passage through the culvert was a key issue when reviewing culvert options for the stream,” said Mike Lee from Airey Consultants Ltd. “The bottom of the stream had to remain open. We considered a traditional concrete structure but it would have been very costly and time consuming for all.”

With height of any structure another requirement, Airey Consultants settled on a Multi-plate™ Steel Arch from CSP.

“We were involved right from the beginning of the project with Airey Consultants and J W Neill Contractors to choose the right shape of structure,” says Mo Yang, Product Support Engineer for CSP. “There is limited head room and with the requirement to retain a natural stream bed an 8.2m long 6.0m span 2.4m rise galvanised Steel Multi-plate™ arch was ordered.”

“This was quite a complicated bit of engineering as we also had to install a very large retention tank and we needed a specific height to assist with the approaches to the culvert from both sides,” says Paul Cato, Director of J W Neill Contractors Ltd.