Next

In conversation with John Barrett

Posted on

In conversation with John Barrett

What is your name and what job roles did you do at Leada Acrow?

I’m John Barrett and I had numerous positions during my career at Acrow. I was with them for more than 20 years, from 1963 until 1984, starting as an apprentice then developing the business internationally and, eventually, progressing to deputy managing director.

What is your most memorable project?

My most memorable project is the Tongariro Hydro Scheme in New Zealand. It was a six miles tunnel in the rock for an Italian client, Codelfa Cogefar.

Back in 1977, New Zealand had increased its demand for power by more than 8% each year. Most of this was from the North Island with its rapidly expanding population and industrial development.

To meet this demand, the New Zealand government had engaged engineering consultants, Sir Alexander Gibbs and Partners, of London, to investigate the possibility of producing more power from existing hydro-electric stations on the Waikato River. From investigations carried out, the Tongariro Power Development was formed.

The eight hydro-electric stations on the Waikato River had a generating capacity of more than one million kilowatts. The Tongariro Power Development was to increase its annual power production by 16% whilst adding 300,000 kilowatts of generating capacity at Tokaanu and Rangipo locations.

Codelfa Cogefar New Zealand Limited had been established for many years and made an important contribution to the scheme, having been engaged in major civil engineering work and, in particular, tunnelling projects.

Acrow-Carpenter, as it was known in New Zealand, played its part – it was engaged to design and manufacture the forms for the Rangipo Headrace Tunnel.

The contract was for two forms, each 13.5m in length by 4.5m diameter, with hydraulically operated travellers carrying a 4.5m length of form capable of telescoping through previously assembled forms. Each set of forms consists of arch forms from which the side forms are hinged. The side or ‘wing’ forms locate on the kerb forms which then incorporate the rails for the traveller. Hydraulic rams raise and lower a 4.5m length of form on lifting beams, incorporated in the top of the traveller, and another set of rams activate the side forms. The traveller was powered by hydraulic motors, and through chain drives from the motors to the rail traveller wheels could be moved fore and aft within the forms. All hydraulics were controlled from the console and made for rapid stripping, moving and re-positioning of each section of form. Each 13.5m length of form, complete with traveller and kerb forms, is in excess of 30 tons in weight.

Before the start of this project, there was a trial erection of the first form carried out at Acrow-Carpenter’s works in Auckland.

What is your favourite memory?

My favourite memory is very easy – growing the business!

What advice would you give to Leada Acrow for the next 80 years?

My advice to Leada Acrow for the future is that the customer is first and not reliant on you. You are reliant on the customer. A business’s success is not only because it has been established for many years but, more importantly, how it’s looked after its customers’ needs.