M7.8 earthquake: UK team arrives in Turkey to assess buildings

UK structural and civil experts have arrived in Turkey to assist in the investigation into why so many buildings collapsed during the strong earthquake last month.

On February 6, a 7.8-magnitude earthquake near the Syrian border in southern Turkey was followed by several strong aftershocks. 

Due to building collapses, the area lost more than 50,000 people.

Why did so many buildings collapse during the quake?

Following the destruction, Turkey's building codes and construction methods have come under criticism.

Work with their Turkish colleagues has revealed that while the quake's power had much to do with the scale of destruction, examples of poor construction are also evident. This includes large pebbles mixed in concrete, which weakens its strength.

The research is being carried out by the Earthquake Engineering Field Investigation Team (EEFIT)- a group of industry experts and academics who have assessed major earthquakes over the last three decades. 

Turkish structural engineers collaborating with the team have already identified a few issues.

For example, samples of concrete obtained from a fallen building in Adiyaman have revealed that it includes 6-centimeter-long stones. These were employed to bulk out the concrete and came from a nearby river.

"That has some serious implications on the strength of the concrete," said Professor Emily So to BBC News, who is the director of the Cambridge University Centre for Risk in the Built Environment and will be co-leading the investigation.

Additionally, it was discovered that the steel bars that should have strengthened the concrete were smooth rather than ridged. As a result, the concrete won't stick to them, weakening the structure.

Many older structures fell during the earthquake in Turkey, although some more recent ones also did. After a significant earthquake in Iznit in 1999, new building rules were implemented. According to Prof. So, these relatively more modern buildings should have withstood the quake better.

The EEFIT team is also analyzing the nature of the mighty quake, which caused very high horizontal and vertical ground shakes.

With many buildings looking like they 'sunk' in many regions, it is likely that a process called liquefaction also occurred during the event. This is when solid ground loses its strength and turns fluid-like due to strong shaking.

Were the buildings earthquake-resilient?

As the building sways back and forth, dampers and other structural elements incorporated in the design can act as shock absorbers. Additionally,  Rubber bearings, which are installed underneath a building and absorb earthquake energy, can also be installed. Yet all of this comes at a price.

The cost of cleaning up and reconstructing after the earthquake in Turkey might be more than $100 billion, according to the United Nations.

According to the EEFIT team, their findings, which will be published in the upcoming weeks, could aid in developing new building regulations. In this way, similar devastations caused by future earthquakes may be prevented.