Articles

Unreinforced Masonry (URM) buildings are vulnerable to earthquakes due to their large masses, a lack of integrity between masonry units, and insufficient deformation capacity. The most critical elements are those located at height and unrestrained against lateral loads. Examples of such elements include parapets, chimneys, ornaments and gable end walls. These unrestrained elements can fall during an earthquake and are a significant life-safety risk.

Follow the story of a commercial building that needed to be assessed and possibly seismic strengthened following the Christchurch earthquakes and subsequent regulation changes.

Tino Seismic has achieved a lot in 2020, despite the many challenges presented by Covid-19. We’ve performed seismic engineering work on a wide range of projects in 29 different cities/towns around NZ. This includes retail, industrial, office, hotel, school, restaurant, apartment, supermarket and public buildings.

During the recent Kaikoura and Canterbury earthquakes in New Zealand, it was observed that non-structural elements performed poorly, particularly in multi-storey buildings. The safety of building occupants can be put at risk due to non-structural elements falling on them. There are also significant disruption and economic losses due to poor performance of non-structural elements.

Sadly, the Christchurch Earthquake, and the CTV building in particular, underscore the fact that we live in a seismic nation and we must make sure we learn from this tragic event. The event itself sparked subsequent changes across a range of industries, from design, engineering and construction to councils and insurance. Main changes included how earthquake-prone buildings are managed in New Zealand.

“We all know New Zealand is extremely susceptible to seismic activity,” explains Dr Jing. “Unfortunately, much of our building stock is ‘earthquake-prone’. This means a building is rated at less than 34%NBS and it will have its ultimate capacity exceeded even in a moderate earthquake. If it collapses, injury or death is likely.

PROPERTY OWNERS, ENGINEERS AND COUNCILS should be aware Section C5 of the MBIE Guidelines for seismic assessment of existing buildings has been revised and is referred to as the Yellow Book, released in 2018. The initial July 2017 version is known as the Red Book.

Earthquake engineering is a field of engineering that deals with the analysis and design of structures to make buildings and civil infrastructure resistant to major earthquakes. Ultimately, this means safer communities and saving lives. As Dr John Jing explains: “A structure doesn’t need to be rigid and stronger than an earthquake. A well-designed structure can work smarter to make the earthquake weaker by dissipating its devastating energy and self-centre with little to no structural damage post the earthquake, achieving true resilience while saving build and repair costs and time.”