Wellington: an active earthquake engineering laboratory

Earthquakes may be a way of life for Wellingtonians, but the city has been home to cutting edge engineering developments since the 1960s that have helped keep us safe. So here are four buildings that stand out as globally significant seismic engineering designs – with the wider public that see them every day largely unaware of their significance.

Jerningham Apartments (1968)

First use of ‘capacity design’

Wellington’s post-war baby boom and predictions of enormous population growth unleashed a new generation of high-rise apartments. To the casual observer these 1960s behemoths look relatively indistinguishable, but in the world of seismic engineering the large block at 20 Oriental Terrace is a global icon.

Design work on Jerningham Apartments started in 1964, with the tall structure stepped back from the street to take maximum advantage of the town plan’s height limits. Developers Wilkins and Davies were experienced hands in the Wellington apartment market, having completed Wharenui further along Oriental Parade in 1960, and Hollings & Ferner (a relatively new Wellington engineering practice) was engaged as the project’s structural engineers.

John Hollings was interested in improving the performance of concrete frame buildings in earthquakes, which typically failed in a brittle manner as movement occurred in a single storey low down, ultimately risking a ‘pancake’ collapse. He envisaged the new development as a tall building with movement evenly distributed up the height of the structure, and flexing occurring in carefully specified areas, a concept he described as ‘lead hinges’ protecting the ‘glass-like columns’ from damage.

Jerningham’s concrete columns were strengthened considerably relative to the beams so they would not fail. The connection of the concrete beams to the columns including extra steel reinforcement to allow them to flex and dissipate energy without losing integrity during a big shake. The precision of the calculations in the era before calculators or computers was extraordinary, but Hollings was still not fully satisfied as to the performance of the junction between the floors and internal columns. He had his team build a full-scale rig at the building’s base to undertake testing at the start of construction – the design passed with flying colours.

Holling’s structure had significantly better seismic performance compared to the conventional approach proposed by the developer; it was also commercially more attractive. The revolutionary design reduced the scale of the foundations required, saving $100,000 on the original cost estimate (around $8 million today). And by opting for a low-profile floor system he had fitted in an extra level of apartments for the developer – all of which helped increase the affordability of the high-rise housing needed to accommodate Wellington’s steep population growth.

The strong columns, weak beams design philosophy sounds like common-sense now, but it was a revolutionary concept at the time. It was refined by the University of Canterbury to become known as ‘capacity design’, and is now a fundamental aspect of almost all seismic design codes around the world. Meanwhile recent property listings state Jerningham has been assessed as 84%NBS – better than some apartments a third of the building’s age.

The Beehive (1979)

First use of diagonally reinforced coupling beams

In 1951 a young refugee family arrived in Wellington, sponsored by Catholic students at Victoria University of Wellington. Tom Paulay, 27, had fled Hungary three years earlier, after his two years as a cavalry officer fighting the Red Army on the Eastern Front had put him at odds with the new Communist regime in Budapest. Paulay completed his engineering degree in Christchurch and returned to Wellington, where he spent eight years as a consulting engineer, before taking a 35% pay cut to return to the University of Canterbury as a lecturer on structural design in 1961.

1960s New Zealand was a curious mix of forward-thinking confidence and lingering attachment to the Mother Country – epitomised by plans to replace the rat-infested, earthquake-prone 1871 Government Buildings at the southern end of the Parliamentary Estate. The Parliament Building’s incomplete Edwardian design was viewed as old-fashioned, and Britain’s star architect Sir Basil Spence was engaged to make the case for something more progressive. Construction on his circular, modernist tower (quickly dubbed ‘the Beehive’) started in 1969, just as Paulay was completing his doctorate on the vulnerabilities of interlinked shear walls during earthquakes.

Paulay’s research was perfectly timed: damage from the 1964 Alaska Earthquake had confirmed his hunch that the existing approach to reinforcing the beams coupling shear walls was inadequate, with the side-to-side rocking of the building stretching these links diagonally, producing large X-shaped cracks that significantly weakened the structure. The improvement Paulay landed on was simple: introduce steel reinforcement in an X-shape to mirror the stress from the building’s movement, and allow ductile steel to take the load, rather than brittle concrete.

New Zealand’s reputation for earthquake engineering was growing rapidly – Paulay’s peers would greet him at international conferences by crossing their arms over their heads, imitating his new design. A culture of co-operation between academia, the engineering profession and government was spurred on by the 1968 Inangahua Earthquake on the West Coast, the strongest felt in the capital since 1942, and encouraged by the Ministry of Work’s enthusiasm for seismic design innovation, under Chief Structural Engineer Otto Glogau.

It began a new period where we stopped copying what was coming from California and became an innovative world-leading laboratory for seismic design.The Ministry was overseeing the construction of Parliament’s new Executive Wing, and Glogau immediately requested that the new ‘diagonally reinforced coupling beams’ be included for the remainder of the building; the circular concrete lift core was modified to accommodate the new design from Level 5 upwards.

Half a century later, Paulay’s coupling beam reinforcement design is global standard practice. Yet with the steelwork encased in concrete it’s invisible to the general public: a hidden witness to the Beehive’s place in earthquake engineering history. 

The William Clayton Building (1982)

First use of lead rubber bearings

The Wellington Urban Motorway ripped a long gash though Thorndon when it was built in the 1960s. Whole streets disappeared following the government’s compulsory purchase of properties, leaving awkward slivers of land adjacent to the roaring traffic, and too far from the CBD to be attractive to commercial developers – but the perfect location for the new Ministry of Works headquarters, which was to be named after William Clayton, the architect of the 1876 Government Building at the other end of Molesworth Street.

The building was located on the site of May Street, a cul-de-sac off Tinakori Road lost under the motorway, and would have a long, low form sympathetic to the surrounding houses. It was also 100m away from the Wellington Fault – and an ideal candidate for Otto Glogau’s interest in seismic isolation. The Department of Scientific and Industrial Research’s Ivan Skinner devised sacrificial steel dampers: then a conversation in the staff tearoom prompted his metallurgist colleague Bill Robinson to hunt out a metal with better damping qualities. Two hours later Robinson had identified lead: its low melting point could turn pressure from an earthquake into heat, it had the right crystal structure to ensure ductile behaviour at low temperatures, and was cheap to buy at a high purity for consistent performance.

Robinson’s genius lay in using the combined properties of simple materials in his revolutionary ‘lead rubber bearing’, where a lead core is contained by a ‘spring’ formed by layers of rubber and steel, which allows lateral movement. The elastic properties of rubber isolate the building from the ground movement and return the bearing to its original position once shaking has stopped, the steel plates maintains the bearing’s shape, and the lead core damps the action.

The experimental bearings were tested by a second-hand Ministry of Works Caterpillar bulldozer that was modified to power a rig called ‘MASHER’ – the Machine for Simulating Earthquakes. By 1978 the concept had been proven, and 80 isolators were despatched to the construction site at the top of Molesworth Street. The building was something of a prototype, with an overly-strong structure in case the isolators didn’t work, and too little ‘rattle’ space for the building to move in a major shake (this was later rectified by Beca).

Bill Robinson died in 2011 having spent most of his working life in Wellington. Robinson Seismic (still based in Lower Hutt) is a global leader in seismic protection devices, with their lead rubber bearings (like those visible underneath Te Papa) manufactured under licence around the world; their effectiveness has been proven by countless earthquakes. The William Clayton building was refurbished and extended five years ago: one of its 1970s vintage isolators as removed for testing by Robinson Seismic and performed like it’d just rolled off the production line.

8 Willis Street (1987 / 2021)

Breakthrough in modelling fluid viscous dampers

Older Wellingtonians will remember the partially completed steelwork of the BNZ Tower (dubbed ‘Darth Vader’s pencil box’ by Ian Athfield) during the late 1970s. The Boilermakers’ Union’s strikes turned a 48 month construction programme into 11 years, and drove up costs fourfold by the time the building was completed in 1984.

The saga contributed to the Lange Government’s labour market reforms, which in turn fuelled an economic boom. Understandably the 1980s property developers weren’t keen on steel, opting for precast concrete floors made with non-union labour. Quick to install, they were manufactured offsite, lifted into place by crane, and held in situ by the adjacent beams and the building’s structural frame – like very rigid sardines in a tin.

Today central Wellington has dozens of buildings with precast concrete floors. The 2016 Kaikoura Earthquake’s long, powerful shaking hit these structures particularly hard, with flexing in the buildings’ frames damaging the edges of the concrete units. Built in 1987 on rock and to higher ‘investment grade’ standards as Trust Bank’s new home, 8 Willis Street – opposite the BNZ Tower (now the Aon Centre) fared better than many of the CBD’s buildings from the 80s and 90s, and came through the shake undamaged.

So what makes the building next to Stewart Dawson’s Corner so interesting? Many of the structural upgrades incorporated reflect lessons learned from the Kaikoura shake – more concrete to stiffen the building, and improvements to the floor units’ seating. However the building’s new tenants will quickly spot large pistons running diagonally from floor to ceiling. These ‘fluid viscous dampers’ were first developed for NASA’s Apollo moon landers, and work like giant versions of the shock absorbers in a car, stiffening the building when it starts to move.

Compared with the simple concept of base isolation, configuring the optimum damper arrangement in a relatively tall structure like 8 Willis Street is complex. Install too many dampers and you risk creating unwanted forces in the structure; too few will leave the building vulnerable during a large shake.

Previously the modelling approach would have been trial-and-error: running different configurations through a range of historical earthquakes, adjusting the damper arrangement, and rerunning the tests. The breakthrough is engineering firm Beca’s work to automate the process to determine the best damper layout – which is then tested against dozens of historic earthquake models. This world-leading approach enables a level of evaluation that would previously have been impracticable.

The optimised damper configuration means the building, now rated at 130%NBS (IL2), has significantly increased resilience to shaking than conventional strengthening work, without the complexities of costly retrospective base isolation – unrealistic for many of Wellington’s tightly packed buildings. It has also paid a large sustainability dividend, with the materials used in construction substantially reduced and thousands of tons of concrete retained, rather than sent to landfill – demonstrating a low carbon way of delivering high performance structural retrofits.

First published in Capital (Issue 77). Illustrations by Kumiko Matsumoto.

Buying sex shouldn't be criminalised: some thoughts on New Zealand's experience

Every so often our politicians declare that ‘it’s time to prosecute men for buying sex’; most recently with Caroline Spelman’s call for men to make their views clearer about prostitution. I’m one of few men who’ll own up to visiting brothels and spending time with call girls. Alas – for those getting hot under the collar with anticipation – my time spent cruising red light zones was strictly professional: I spent most of 2008 photographing sex workers in New Zealand for my dissertation, which documented how the country’s decriminalisation of sex work in 2003 had changed the industry.

New Zealand’s prostitution law reform sidestepped passing judgment on the ethics of prostitution, focusing simply on improving ‘the welfare and occupational health and safety of sex workers’. This might sound bureaucratic, but women in the sex industry are now protected by society, rather than marginalised from it. I remember the case of a bloke who’d pulled his condom off when he was in a brothel. The $400 fine the courts served him seemed paltry; but his name was published when the local newspapers covered the case. He was the bad person, rather than the ‘woman of ill repute’ he’d been visiting, which seemed pretty reasonable to me.

From 'The New Professionals' (Matthew Plummer)

My experience from the dozens I met in the industry was that sex work is remarkably mundane, and the stories I heard about the (mostly) men who paid for sex were pretty humdrum: widowers, couples who’d stopped having sex, and so on. But I can’t remember meeting sex workers who expressly disliked their job. Many were comfortable – even proud – of what they did for a living, with the main complaint being that decriminalisation had seen a slump in their earnings. This (I was told by an MP who debated the 2003 legislation) came down to basic economics, with price being a product of supply and demand. And on that basis criminalising the purchase of sex would be a nasty double whammy for prostitutes, as not only would they be at the mercy of clients on the wrong side of the law, but it would also drive down earnings: hardly the way to look after vulnerable people.

Of course the press loves running stories of women brought to the UK and forced into sex work; trafficked victims in heels and lipstick make for far more exciting copy than cases of domestic servitude or forced agricultural work. The English Collective of Prostitutes has done a comprehensive rebuttal of the girls-trafficked-into-prostitution misconception which is worth reading, and various estimates on the numbers of women being trafficked to Britain to work as prostitutes have proved to be wildly inaccurate. This doesn’t surprise me; statistics gathered by the police in New Zealand in the aftermath of the 2003 decriminalisation showed the numbers of active sex workers had been overstated by a factor of ten. The murky legal and social status of the profession makes gathering hard data almost impossible, and I can’t imagine that things are any different over here. Far better to bring it out of the shadows, with taxes paid and health and safety regulations enforced, rather than creating a needlessly dangerous underworld and wasting valuable police resources.

First published by Coffee House on May 16th, 2014

A building weakened by red tape

"I was inside the main hall when the quake hit. As the building's tower came down, the noise and dust was unbelievable. The bottles, plates and glasses were like shrapnel flying all over the place. The three chefs were preparing a lobster bisque, which went all over the floor but missed them, as did a pan of hot fat. They came out through the dust looking like ghosts. We didn't have the composure to stop and grab our wallets and car keys - we just bolted."

Alan Slade

Octagon Live owner Alan Slade was short on sentiment as he looked back at the ruined building he'd narrowly escaped from, with his concern entirely focused on ensuring his staff were all out.

After the previous September 4 quake he'd had funny mannequins attached to the emergency scaffolding that had shored up the stone walls.

"I just remember looking at one of the mannequin's legs sticking out of the rubble and I just felt sick - my joke had backfired on me."

In retrospect, it was an unusual holiday purchase. Alan Slade, owner of a thriving wedding business in Australia, was visiting Christchurch when he heard the Trinity Congregational Church on the corner of Manchester and Worcester streets was for sale.

"We owned a number of churches in Australia, but when we saw the Trinity building we couldn't believe that such a precious icon of Christchurch would be for sale," says Slade. "It was a treasure: the interior was unmatched, and the ceiling was the jewel in the crown."

He admits that buying the building was a weak moment. "My wife says it was bought by a guy with a big heart and very little brain."

The church was designed by Benjamin Mountfort, the architect behind Christ Church Cathedral and the Provincial Council buildings. What followed was a 13-year renovation that transformed the site into Octagon Live, Slade's quirky vision for a restaurant with live music performances. Mountfort's vision of "beauty though a lack of ornamentation" was preserved.

"The building's H1 historical registration meant that everything we did needed consent, which took forever. The roof had a lot of water damage: repairing that with matching timbers was a long job. We even restored the dilapidated 1871 London organ to superb recording condition. Finance held us up, as things always cost more than you'd expect, but it was worth it."

The restaurant opened in 2006 and, after a quiet first year, business grew rapidly, with a strong following built on the restaurant's food and live music.

"By the third year we were second on TripAdvisor.com's list of recommended restaurants in New Zealand. In the season before the earthquakes we were booked out every day of the week," says Slade.

With four music schools in Christchurch, the restaurant was also instrumental in nurturing young talent.

"Learning to perform for an audience - rather than at them - is a critical skill. Where else in town can you learn that? We were strongly recommended by some of the teachers, and we always had a long queue of musicians hoping to work with us."

The building's acoustics garnered rave reviews, with pianist David Helfgott stopping by every six months to play.

Behind this success was an ongoing tension over heritage issues with the city council and the Historic Places Trust.

"When you take on a building like this, you do it with your heart, not your head. You are as keen to protect it as anyone. You don't want to cut corners, and preserving the building's integrity is vital. But the Historical Places Trust suspects every owner of deviousness."

The September earthquake hit Octagon Live hard, with more than $600,000 required to rescue the building. "We were allowed to take emergency action to build a frame to hold up the tower, but the retrospective consent ended up costing $8000 - for something I'd done to save the building."

The restaurant was closed for only two months, with the local community pitching in. The Boxing Day earthquake caused yet more damage.

Even though it was the building industry's traditional holiday period, Slade had 11 workers and two cranes onsite repairing the damage the day after, and the restaurant was open a day later, with the public enjoying the mannequins that adorned the temporary braces holding up the exterior walls.

Trinity Congressional Church was significantly strengthened in 1975, explains Slade.

"The engineers at the time strongly suggested earthquake proofing the tower by temporarily removing the roof, which would have meant some damage to the wooden shutters. They were over-ruled by the Historic Places Trust.

"Just recently, the engineer from the 1975 assessment told me that the tower was severely compromised, and warned that it was unsafe. Now it has come down as predicted. We were incredibly lucky no-one was underneath it at 12.51pm, but it was the conservative attitude of the conservation movement and the Historic Places Trust that caused the danger in the first place."

Slade believes this attitude in the heritage preservation industry amplified the consequences of the Christchurch earthquake.

"Maintaining our old buildings is incredibly important, but the heritage framework in this country has worked against keeping buildings in good condition. Spirit-sapping bureaucracy stands in the way of routine jobs like replacing weak stones. Even repairing roof tiles requires consent, and the damage that three weeks' rain can do while that is processed can be enormous. Many of Christchurch's treasured buildings are now in a pile, and the narrow-mindedness of the conservationists in the council and the Historic Places Trust played a substantial part in that. Sadly they will probably never be held accountable."

With thoughts turning to rebuilding the city, Slade is confident that Octagon Live will be a key part of the new city. The structure is considered saveable by engineers and the organ should be fine.

"I do think this is the time for us to radically change our approach to protecting our heritage," he says.

"I'd be very sad if we have to replicate our old tower stone by stone. The earthquake is a tremendous opportunity to be bold and adopt modern technology - the guts of the Cathedral Spire could be made from carbon fibre, for example. It is better to preserve elements of our heritage safely, rather than taking risks to keep whole structures. But we hold on to the essence of Christchurch, and I think the new desire for a low-rise city will allow our heritage buildings to dominate once again."

At the moment, issues are tied up with the inability to access the CBD.

"My chef's knives are stuck in the restaurant's kitchen. It's a simple thing and it sounds pathetic, but it's important to him. I can't access my payroll details. We don't know how long we'll be kept out of the centre of town for. They're talking about Christmas - heavens, I'd be expecting to have my building restored and my business running by then."

First published by The Press on March 12th, 2011