The catalogue of risk

Clay Technology magazine
,
17 May 2018

A new methodology to establish the connection between construction material and a building’s habitability after an earthquake hopes to promote superior city planning. Khai Trung Le reports.

Looking to glean insight into which types of buildings are likely to suffer enough damage during an earthquake to affect habitability, researchers from Universidad Politécnica de Madrid (UPM), Spain, are creating a visual catalogue to help identify uninhabitable buildings after seismic activity. 

The UPM team states that although there are numerous studies that classify buildings according to its seismic vulnerability – the tendency to suffer damage after an earthquake – as well as methodologies to identify damage, there has been insufficient attention to how construction materials and building foundations, so called urban modifiers, affect the vulnerability of buildings. Their work was released in the paper, Urban modifiers of seismic vulnerability aimed at Urban Zoning Regulations, published in the Bulletin of Earthquake Engineering.

Speaking to Clay Technology, UPM researcher Sandra Martínez Cuevas said, ‘This information would be very valuable for councils and regions that are located in seismic risk areas since it would allow them to predict which buildings would remain habitable.’ It would also prove useful in constructing new buildings and upgrading resistance to seismic activity of existing cities.

Damage control

The city of Lorca, Spain, was chosen for the exploratory study, due to the visibility of damage that remains since the 2011 earthquake. Satellite radar data analysed by the University of Western Ontario, Canada, found the earthquake resulted from slippage on a shallow fault bordering a water basin roughly 3km south of the city. 

During the magnitude 4.4 earthquake, 10 people were killed due to cave-ins and falling debris.

Over 800 buildings were classified by material – concrete or masonry – and whether the foundation was hard or soft, and the type of damage suffered in 2011.

A correlation analysis was conducted to establish links between urban modifiers and habitability, creating an index of discrimination. Following this initial analysis, the team paired urban modifiers information with each type of ground and structural typology.

From this information, a scale of habitability was applied. Cuevas said, ‘In other words, we could say with 70% reliability which buildings would be uninhabitable in Lorca if an earthquake with the same characteristics occurred as it happened in May 2011.’

Cuevas continued, ‘This first graduation of the urban modifiers in relation to the damage will allow us to initially influence the urban regulation in the city of Lorca, give recommendations for urban planning, and reduce the damage of possible future earthquakes.’

To read Urban modifiers of seismic vulnerability aimed at Urban Zoning Regulations, visit bit.ly/2HZOUct