The investigation team aims to determine why some structures survived while others collapsed. British structural and civil engineers traveled to Turkey to help investigate the damage caused by the severe earthquake that struck last month. They collect geological information and conduct extensive analyzes of the causes of collapse of many buildings.
Large stones placed in the concrete, which reduce the strength of the material, are one of the bad construction examples that emerged in their work with their Turkish colleagues. However, some of the destruction was caused by the intensity of the earthquake.
In some places the displacement on the ground was greater than anticipated for the structures. Turkey is also conducting its own extensive research on earthquakes.
The Earthquake Engineering Field Research Team (EEFIT) is conducting the study.
The panel, made up of leading academics and industry experts, evaluated the major earthquakes that have occurred over the past three decades.
They will combine their findings with research conducted by Turkish teams and other construction experts to learn from the earthquake and find ways to make building construction more resilient.
Professor Emily So, co-leader of the study and head of the Risk Center in the Built Environment at the University of Cambridge, says it's crucial to get the whole picture, rather than focusing on just one asset or one structure.
“The success of buildings that are still standing and working perfectly is just as important as the destroyed structures of their neighbors.
Having this distribution and overview is crucial to understanding what can be learned from this earthquake.
Several severe aftershocks followed the 6-magnitude earthquake that struck southern Turkey on February 7.8 near the Syrian border.
More than 50.000 people lost their lives in the region due to building collapses. After the demolition, Turkey's building codes and construction methods came under criticism. The EEFIT team is currently conducting a technical assessment of the building stock in the area.
Turkish structural engineers collaborating with the team have already identified several problems.
6 cm long stones were found in concrete samples taken from a collapsed building in Adıyaman. These stones were used to pile the concrete and came from a nearby river.
According to Professor So, the strength of concrete is seriously affected by this.
It was also discovered that the steel bars that were supposed to reinforce the concrete were straight, not protruding.
As a result, the concrete does not stick to them and weakens the structure once again.
Many old structures were destroyed during the earthquake in Turkey, but some more recent structures were also destroyed.
After a major earthquake in Iznit in 1999, new construction rules were introduced and Prof. "I believe it's really important that we recognize these and run tests to understand why these new rules-built buildings are collapsing in this way," he told BBC News.
Analyzing the nature of the earthquake is another task for the EEFIT team. Co-leader of the expedition from UCL in London, Dr. According to Yasemin Didem Aktaş, the earthquake was very severe. According to him, even aftershocks were comparable in size to a major earthquake.
The earthquake brought along significant ground movements.
During an earthquake, the ground vibrates both vertically and horizontally.
The vertical component of movement is usually much smaller and insignificant compared to horizontal movement. However, very important vertical accelerations were also seen in this event.”
Liquefaction is a process that occurs in some regions. A collapsed or sinking building is a sign of this because it turns solid ground into a heavy liquid similar to very wet sand.
Dr. Aktaş continued his words as follows: “I believe that the nature of the events had a great impact on the damage we saw.
However, buildings can be made earthquake resistant.
Ziggy Lubkowski, the leader of the seismic team of the design and engineering company Arup, which sent engineers to Turkey for research, said: “We want to minimize the loss of life when designing structures.
“The basic principle of construction is to allow some degree of damage inside the structure. This damage ensures that the building still stands upright but does not collapse by absorbing the force of the earthquake.”
It is possible to include elements such as dampers that act as shock absorbers when the building is swaying, and rubber bearings placed under buildings that absorb earthquake energy.
But all this is expensive. According to Ziggy Lubkowski, these increases in structural cost can be “between 10 and 15%,” depending on the type of structure.
“Still, if you really think about it, a building's hardware expenses often exceed its structural expenses. So the additional structural costs are not that high after all.”
According to the United Nations, the cost of cleaning and rebuilding after the earthquake in Turkey could be more than $100 billion.
According to the EEFIT team, the findings, which will be published in the coming weeks, could help develop new construction rules to prevent earthquakes with the same level of destruction in the future.
Source: BBC/News
Günceleme: 14/03/2023 17:58