New Zealand to Ease Strengthening Rules on Quake-Prone Buildings

New Zealand is changing the way it assesses earthquake-prone buildings in an attempt to reduce costs and confusion for owners.

The government is implementing clearer definitions to identify buildings that pose a genuine risk to human life in medium and high seismic zones, Building and Construction Minister Chris Penk said Monday in Wellington. The new regime, which will require a law change, will more than halve the number of properties needing earthquake strengthening and save the nation NZ$8.2 billion ($4.7 billion), he said.

Since 2017, engineers have applied a rule that requires a structure to be at least 34% of the New Building Standard, which has seen 8,000 properties earmarked for strengthening or demolition. That has meant expensive and at times lengthy remediation work, or even closure, for apartment blocks, commercial towers and iconic properties such as the Chateau Tongariro, a 96-year-old tourist lodge in the central North Island.

“While well intentioned, the current system for assessing and managing seismic risk in buildings places an overwhelming financial burden on building owners,” said Penk. “For many buildings, the price of strengthening runs from hundreds of thousands to several million dollars. As a result, these buildings are often left empty and become derelict, making them even more dangerous to bystanders in an earthquake.”

New Zealand sits on the Pacific Ring of Fire, a belt of volcanic and seismic activity that rings the Pacific Ocean. A devastating earthquake in 2011 killed 185 people in the South Island city of Christchurch and gave rise to the tougher standards nationwide on all buildings. Capital city Wellington, which sits on a fault line, has been rattled by several tremors in recent years that have forced building closures and refits.

The new system will drop the 34% of NBS rule and provide specific definitions of an earthquake-prone building, Penk said.

They include concrete buildings three storeys or higher, and those constructed with unreinforced masonry, he said. Auckland, Northland and the Chatham Islands will be removed from the regime entirely to reflect the low seismic risk in those areas. The South Island city of Dunedin is upgraded to a medium seismic hazard area.

Unreinforced masonry buildings under three storeys in small and rural towns will no longer require remediation but owners must secure the facade before the building can be removed from the earthquake-prone register, Penk said. This reflects fewer pedestrians at risk in those centers, he said.

The changes will reduce the number of properties registered as earthquake prone to about 2,900 from 5,800 under the current regime. Of the remainder, just 80 will need a full refit while 1,440 will need cost-effective remediation and 840 won’t need any work other than on their facades.

To ease financial stresses, owners will be able to apply for extensions of up to 15 years to complete seismic work, Penk said.

Photograph: New Zealand earthquake damage; Photo credit: Cameron Spencer/Getty Images AsiaPac