Strengthening Unreinforced Masonry

Wellington, New Zealand

Resilience Project

Background

The capital of New Zealand, Wellington is home to more than 400,000 residents, who draw on a long history of resilience in a beautiful but sometimes harsh harbor at the southern tip of the country’s North Island. Potentially destructive earthquakes, rising seas, and the city’s famous winds have kept Wellingtonians acutely aware of their vulnerability, honing their famous Kiwi ingenuity. Today, Wellington is a city ready to innovate for resilience and preparedness in order to create tangible benefits for its communities, from stabilizing its fragile water supply to upgrading its energy systems.

Threatened by multiple active fault lines, Wellington has historically responded to earthquakes after the event, through response and recovery efforts. But in 2011 the New Zealand region of Canterbury suffered a devastating earthquake, in which 185 people lost their lives and many thousands were injured.  In November of 2016, Wellington itself was hit by a magnitude 7.8 earthquake, causing the city’s building stock to suffer extensive damage – it was eventually calculated that two thirds of the more than US $600M in building insurance claims nationwide occurred in Wellington.  These shocks and the timely publication of the Wellington Resilience Strategy prompted the City and Government to switch focus into resilience and risk reduction rather than response and recovery.

Structural failures, such as building collapse and falling masonry, are the leading cause of fatalities in a seismic event.

While no lives were lost in the city in the 2016 event, Wellington’s Mayor took the stance that the city had ‘dodged a bullet but was not bulletproof’ and saw the recovery process as an opportunity.  Given the city’s focus on resilience thanks to the efforts of Chief Resilience Officer Mike Mendonça and the city’s Resilience Strategy, both political and public will aligned to drive a commitment to making the city’s overall building stock more resilient in the face of future seismic shocks. After all, it’s not earthquakes that kill people, its falling buildings and their elements.  The city committed to securing unreinforced masonry parapets and facades (URM), shortening regulatory timeframes for structurally strengthening older buildings and implementing measures that allow the city to more rapidly assess its risk following seismic events.  Some of these commitments addressed risks and put in place solutions that had never been previously budgeted.

Unreinforced masonry refers to buildings where some element of the structure is made of brick, cinderblock, tiles, or other material that is not braced by a reinforcing material, such as rebar. These elements are vulnerable to collapse in an earthquake.

The Action

Unreinforced Masonry

Wellington cataloged 113 unreinforced masonry buildings which had the potential to injure or kill hundreds  of people if an earthquake struck during busy periods, as those buildings are concentrated in popular tourist, university, and café areas.

The first step was legislative; Wellington City Council worked with the central government to introduce a special legislation that required owners of unreinforced masonry buildings to secure street-facing parapets and façades within 18 months for the most vulnerable buildings in Wellington.

However, seven months into the period allotted for making the upgrades to these buildings, few building owners had made any progress, indicating that a more comprehensive approach was required. Wellington City Council discovered the problem wasn’t a lack of willingness to make improvements, more a lack of understanding how to start.  Developing a case management approach to working with each of the building owners, City Council helped drive compliance by taking a ‘case management’ approach, by introducing financial incentives, launching a public information campaign, and linking building owners to experienced contractors. Building owners and other actors in the private sector were also educated on ensuring the historic value of the city’s architectural heritage is preserved.

As a second phase of the earthquake prone buildings program, Wellington City Council is now working to accelerate compliance with earthquake codes to minimize the risk of building collapse.

Structural Integrity

The City has learned a lot about earthquake risk in the last ten years.  This has prompted a change in regulation.  New Zealand has a code of compliance for the seismic strength of buildings where a new building is required to meet 100% of a code.  The code aims to ensure preservation of life in a moderate earthquake.  Many older buildings score poorly against this code, and where a building scores 33% or less (usually older buildings) it must be modified within a specified timeframe.

Under new regulations, for certain buildings such as schools, hospitals, buildings along high traffic routes and emergency services routes will have to complete work required under this code within a shortened timeframe, typically 7.5 years, or face prosecution.  This affects around 200 building owners in Wellington, with another 400 working to meet the code on a 15 year timeline.  Cost is met by building owners, with an advisory service and some funding available from the City.

Better Intelligence

Parallel with these efforts to improve the physical integrity of buildings and facades, Wellington City Council has also sought to increase the speed at which it can assess how any further earthquake affects critical buildings in the city. To do this, the city aims to have accelerometers (a device which measures acceleration forces from events like earthquakes) installed in 400 buildings around the city.  The aim is to have some of the information available publicly, and the City has brokered partnerships with the Universities of Auckland and Tokyo to assist with data analysis and structural assessments to inform decision making about evacuations and building safety following seismic events.

<p>400 accelerometers will be installed in buildings across Wellington, so that building safety can be evaluated within 30 minutes of a seismic event.</p>

400 accelerometers will be installed in buildings across Wellington, so that building safety can be evaluated within 30 minutes of a seismic event.

The Impact

In the face of inertia, financial constraints, and limited timeframes the City was able to deliver on a very public campaign to improve building façade integrity and public safety. Within 18 months of the introduction of legislation and associated support mechanisms all 113 unreinforced masonry buildings have completed the required upgrades.

The City’s resilience team, and by extension the City Council, developed new ways of working with the community that has earned them a reputation for flexibility, resourcefulness and inclusiveness – executing within a challenging public policy scenario, creating strong relationships with building owners, and using multiple levers to achieve their goals.

Thanks to the clear and consistent public information campaigns and engagement that supported the project, the Council raised public awareness and created public demand for access to information about earthquake code compliance and a private sector push for compliance above the minimum standard.  Property managers from government buildings, banks and university voluntarily choose to occupy only buildings that meet 80% of code or more.  Other major employers and homebuyers are following suit creating marketplace demand for increased safety standards across the city.  Wellington used clear, consistent, and informative messaging to enlist the help of the community and private sector to create a marketplace for building safety and created demand for a safer city that is better able to whether times of crisis.

The accelerometers and university partnerships have reduced the time it takes to understand the extent of shaking following a seismic event from six weeks to 30 minutes.

Within 18 months of the 2016 earthquake and the subsequent release of Wellington’s Resilience Strategy, the city is a less vulnerable place.  Scientists are currently recalculating complex models to show the expected reduction in fatalities due to these interventions.  The City Council also has a strong foundation on which to continue to strengthen the city’s built environment and improve its resilience thanks to key innovations that led to the success of this work: Adopting a case management approach that put people, rather than legislation or infrastructure, at the center of its objectives.

This Project is Part Of the

Wellington Resilience Strategy

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