Building New Zealand one structure at a time

Photo / NZ Herald

A new book looks at the great engineering feats that shape and reflect the Kiwi character.

As the National Government puts its foot down on major works around the country - from Auckland's motorway to Kopu Bridge and a national cycleway - a look back at what New Zealand engineers have bulldozed, built and invented reveals the scale of our can-do ingenuity.

Politics, economics, attitudes to the environment, and brute imagination have shaped our material world as much as terrain, machines and sweat. At the fulcrum of all these forces and constraints stands the engineer.

Know your country? Look again.

Maori built over 6000 pa from the 15th century, later adapting their design for musket warfare. Today, traces are visible on cow-grazed slopes. Maungakiekie, Auckland's One Tree Hill, once had three known pa with more than 170 terraces, and was home to up to 5000 Nga Marama people.

The Paterangi chain fortress in Waikato, now destroyed, was so formidable that government forces went around it, rather than trying to penetrate its elaborate defences.

Auckland's Great South Road, the first major roading project of the colonial age, started as a war route: built to carry troops and supplies in the campaign against the King movement.

In his new book, Big Ideas: 100 Wonders of New Zealand Engineering, author Matthew Wright is interested in what our built environment reveals about us.

"The landscape and environment has been challenging to two peoples," he says, "both of whom have met those challenges in their own ways."

British settlers were lured to New Zealand by the promise of a bigger, better, more prosperous Britain: with all its benefits but none of its social ills. Science and engineering was to tame nature.

Opening the North Island main trunk line in 1884, Premier Robert Stout declared: "It is by works of this class that nature is conquered and made subservient to men."

Public protests about a hydrostation at Lake Manapouri in the 1960s reveal a sea-change in environmental attitudes.

Today the debate is around electrifying railway, but when colonial treasurer Julius Vogel conceived of a national trunkline in the 1870s, he had something quite different in mind. The railway was part of a wider policy, writes Wright, "to attract new settlers, draw the provinces together, break Maori and 'kick start' the whole economy". (Vogel's grand scheme was frustrated by high costs and politics; it would be decades before rail connected New Zealand's main centres.)

Some of the engineering achievements in the book were ecologically or financially disastrous; others were more profitable, better attuned to their surrounds. But Wright is most impressed by the cleverness they reflect.

"They underscore just how innovative and capable Kiwis really are."

Landscape engineering and rail

CENTRAL NORTH ISLAND

Even BY 19th-century standards, the voracious scale of bush-clearance across the central North Island to remake it in the likeness of pastoral Europe was shocking.

Settlers took their axes and fire to the dense forests. Writes Matthew Wright: "For a few heady years, the North Island burned. By the 1880s, scorched stumps and debris littered the central North Island from Norsewood to Eketahuna and west to Taranaki."

Parliamentarian James Inglis darkly declared the "wholescale denudation" would "exact its retribution in widespread ruin and desolation".

Later, the invention of mechanical dairying machinery would lead to a proliferation of dairy farms, realising the dream of pastoral prosperity.

Meanwhile, the rugged volcanic landscape stretched railway engineers. One of the most striking shows of ingenuity was the 7km Raurimu spiral.

The 132m vertical gap it was built to traverse was the last major engineering challenge of the North Island main trunk line. The spiral, which includes a double loop and two tunnels, allowed a more gradual slope.

Kelly Tarlton's underwater world

AUCKLAND

Kelly Tarlton was a renowned diver and shipwreck-explorer. The aquarium he designed and built "stands as a monument to [his] imagination and enthusiasm", writes author Matthew Wright.

The 110m transparent underwater tunnel in Kelly Tarlton's Underwater World was a world first, giving visitors an unprecedented diver's-eye view of a simulated coral reef.

Tony Crang, the engineer who worked on the ambitious project with Tarlton, says the pair toured aquariums around the world, gleaning as much as they could.

The first challenge, says Crang, was developing disused stormwater sewerage tanks on Auckland's waterfront into the aquarium - which necessitated lifting the road above about one metre and digging down below the tanks.

Tarlton had pioneered the use of Hamilton jet engines as underwater excavators, and his jet pumps were used to clear sludge from the tanks. Construction was geared around tidal flows, in six-hour shifts, 24 hours a day.

The second challenge was the acrylic tunnel. The pair worked out the best design was "lobster back": sections joined at wide angles.

The tunnel's highest point has 2m of water above it, and passes through two tanks.

Shipping costs for pre-curved acrylic were too high, so Tarlton imported flat sheets of 7cm-thick acrylic and heat-moulded them into the correct curve. Craftsmen spent hours polishing and wrapping the 31 curved sheets, which were lowered one by one through a hole in the roof of the present shark tank.

Tarlton died from heart complications only seven weeks after the aquarium's January 1985 opening, a day after greeting the 100,000th visitor.

It remains a popular Auckland attraction.

Sky Tower

AUCKLAND

When the Sky Tower's space-age spire pierced the Auckland skyline in 1997, detractors tagged it the "hypodermic needle". (A comment recorded by The Dominion at the time: "A huge phallus, just what Auckland needs to symbolise its preoccupations".)

For others, it was Auckland's missing heart, a spirit-lifting monument to ambition. At 328m (37 buses end on end), the $74 million tower was the tallest building in the Southern Hemisphere.

Its 24m over the Sydney Tower was widely viewed as a display of transtasman rivalry, but architect Gordon Moller denies this. He says the motive was to make the viewing deck high enough to see out to the Manukau Heads, while the 92m of the steel mast was needed for the various aerials and transmitters.

Moller says the tower was built with two things in mind: "The experience you get when you go up it, which is to understand the city; and we saw it as a landmark.

"I was also keen to create something that was beautiful."

It generated as many engineering challenges as it did controversy. An especially dense concrete was mixed to achieve the required rigidity.

The eight legs stand on a colossal foundation "raft", 2.5m thick and 24.5m across. The raft, which forms the floor of the ticket office, acts much like a yacht's keel as a counterweight to the massive wind pressure on the tower. The pod (housing the restaurants) is designed to move up to 50cm in each direction; the mast up to 2.5m each way.

Erecting the mast and pod was a major operation. The mast was too heavy for a helicopter, so a crane was placed level with the highest viewing deck. The mast was brought up in sections, then a luffing crane was used to lower the first crane. The second crane was then disassembled and sent down on the lift.

Grafton Bridge

AUCKLAND

Grafton Bridge, with its elegant concrete sweep, connects Aucklanders not only with the other side of the inner city gully, but also with their past.

When it was closed for strengthening last year, Auckland commuters wondered how they'd do without it: a heavily used crossing over the motorway and link between the inner city and the hospital.

But when it was built 99 years ago the bridge was lampooned as "Myer's Folly". (Sir Arthur Myer was the mayor of the day.) Ratepayers resented bearing the expense - about $4.65 million in today's terms.

Engineers were excited, though. The bridge, at 97.6m, was the world's largest single span of steel-reinforced concrete - the new wonder material of its time.

The sturdy-looking false piers - leg-like structures - were added not for structural reasons, but to reassure those who doubted the new material would hold.

Death has always been close to the bridge. Symonds St cemetery spreads under and beside the bridge - the gully was then known as Cemetery Gully. And the bridge soon become a site for suicide jumps. Barriers were added in the 1930s. After they were removed in 1996, there was a five-fold increase in suicides from the bridge, prompting their quiet reinstallation in 2003.

The main challenge in strengthening the bridge, says Auckland City Council project manager Graham Long, has been getting at it. As well as scaffolding, cherry pickers and abseilers have been used. The motorway beneath has been temporarily closed overnight to allow access for workers.

The strengthening, which will increase the weight limit from 13 tonnes to 44 tonnes, is set for completion in October.

A few of the main piers have been strengthened with piles bored into the ground; bearings and joints have been repaired; a strip of carbon fibre has been glued to the deck beams; epoxy resin has been injected into 805m of cracks. The last step will be a waterproof coating.

Public transport advocates hope the council will persevere with a planned weekday 7am to 7pm ban of all traffic but buses, emergency vehicles, motorcycles, bicycles and pedestrians.

Manapouri Power Station

FIORDLAND

In every way, Manapouri power station was an extreme event. The biggest hydroelectric station in the southern hemisphere, Manapouri is entirely underground. Its dramatic and contentious construction, from 1964 to 1972, was forged in the collision of two forces.

On one side was industry, represented by the Australian company Consolidated Zinc Pty; on the other side was New Zealand's emergent environmental movement.

In 1963, the New Zealand Government granted the company exclusive right to use power generated from lakes Manapouri and Te Anau to run an aluminium smelter in Bluff (now owned by now Rio Tinto Aluminium). The original plan was to raise Lake Manapouri to the level of Te Anau, drowning the original shoreline and its primeval forest.

Protests spread. The "Save Manapouri" campaign, which picked up steam in the late 1960s, is seen by some as the birth of the modern environmental movement.

It marked a shift in attitudes towards nature: from something to be mastered, to something to be conserved. Manapouri was a flashpoint for the 1972 general election, and a founding issue for the Values Party, precursor to the Green Party.

Finally, a compromise did save Manapouri, and in a mind-boggling feat of engineering, a redesigned station was hacked out of solid rock below the lake.

Almost 1.4 million cu m of rock has been excavated in all. The main machine cavern is the size of a football field and over 30m high, accessed via a long spiral tunnel. A 160km transmission line was built across remote, rugged terrain to Bluff.

From 1997 to 2002, a second tail-race was added (tail-races carry the water), boosting generation. The tunnel-boring machine used was 500m long and weighed 1500 tonnes, advancing an average 10m a day.

Matthew Wright says that, to him, the station sums up the essence of New Zealand's engineering spirit: "A combination of boldness with innovative attention to detail, displayed here with exquisite care for the environment."

The Beehive

WELLINGTON

The politicians who now decide which new engineering works will be funded are doing so in a structure that was radical in its time: the Beehive.

The legend goes that British architect Sir Basil Spence sketched the idea for Parliament's Executive Wing on a napkin during a Wellington dinner party. The earliest preserved drawing by Spence, who died in 1976, was presented to Parliament in 1964.

It drew mixed reactions. But a new building was urgently needed: the main parliamentary building was cramped; and other accommodation was dilapidated and leaking. Work started on the Beehive in 1969.

Its 14 floors - 10 above ground - were built in stages over 10 years. Rooms and office radiate from a central core. Its decor was classic 1970s: brown carpet, exposed concrete, and New Zealand woods.

A grand double-storey entry foyer features wall panels of New Zealand macrocarpa, Takaka marble-clad columns, a backlit translucent onyx wall at one end, and opaque glazed walls at the other.

The core has marble floors, stainless steel mesh wall panels, and translucent glass ceilings.

The Prime Minister's office is on the ninth floor, while the civil defence headquarters are in the basement.

In the 1990s, there was talk of moving the Beehive on rollers to a new location behind Parliament and building the second wing of Parliament as per its 1911 design. But the idea was too expensive and was shelved.