Would my building be safe in an earthquake?

Beril Köseoğlu / DUVAR

Millions of people have the same question in their minds after the 5.8 magnitude earthquake in Istanbul last week: Is my building safe? How can I test the safety of my home before the big earthquake that's expected to hit the city?

There are those, of course, who think neighborhood rumors are scientific facts. They might ask why they need to test the earthquake safety of their home due to various beliefs like "Our home is on hard rock," "If the contractor who constructed this building lives here too, it must be safe," or "The wall makes the correct sound when we tap on it."

Another typical story might be that a family lives in an apartment built in the '80s, in which a main column has been removed during renovations. An extra story may even have been added to the top of the building too. The family may be scared about the safety of the building, but they may not trust the official procedures for destroying and re-building at-risk homes due to fears that they'll lose their home in the process.

However, we are facing an earthquake that will happen for sure, although we don't know exactly when. The Chamber of Architects has labeled it a "big tragedy" for a long time. "It is for sure that a disaster bigger than the 1999 quake will happen," said architect Korhan Gümüş, who works on several earthquake-related projects. "But when we look at the problem, we see people who are desperate in the face of an upcoming disaster."

"We need to focus on the part of the problem created by humans," said Gümüş.

Earthquake resistant buildings in 8 questions

How can you be sure how safe your building is? How can you guarantee that your building will not collapse, blocking the way to hospitals or earthquake meeting points? Here is what you need to know about earthquake-resistant buildings:

1. Where can I apply to have to my building tested?

There are two ways to test your building's earthquake resistance: you can appeal to the municipality, district governorship, or Ministry of Environment and Urban Planning, or you can make a deal with a private firm.

A lot of the municipalities do not have earthquake laboratories, and the ultimate authority lies with the Ministry of Environment and Urban Planning. So when most citizens apply to the city, technical staff who visit the home only observe and do a kind of damage assessment. If this observation has a result of "heavy damage," the residents may be forced to leave the building.

Even if there is no heavy damage, if there are problems, the resident is asked to apply to one of the construction supervision companies licensed by the technical universities, the Chamber of Construction Engineers, or the Ministry of Environment and Urban Planning. According to the Beşiktaş Development Directorate, the only groups that can evaluate buildings in detail are those approved by the ministry.

2. Why is it important to choose the right inspection agency?

After the 1999 earthquake, inspecting the construction of new buildings and doing earthquake risk analysis for existing buildings has become a completely new industry. Experts say almost unanimously that most inspections are not performed correctly. This can mean two things: 

First, buildings that do not actually need to be demolished but have high property values are designated to be demolished because “they don’t follow the latest regulations.” This is why many people are skeptical about urban transformation and shy away from conducting the required tests through official authorities.

When we look at Istanbul in general, architect Korhan Gümüş says the aforementioned process has caused new problems: "Urban transformation, first offered as a solution, destroyed earthquake-resistant buildings before all else. Some fraudsters using university names are giving reports in exchange for money." Architect Oktay Şahin, speaking to Gazete Duvar, said, "With the new directorate, they always give the order for demolition after an official inspection. But you can always test your building with a trusted private firm."

Secondly, in the case of new buildings, the construction inspection system has a lot of faults within itself. An anonymous construction engineer speaking to Gazete Duvar said, "Many firms that carried out inspections on behalf of the Ministry of Environment and Urban Planning were abused. Municipalities would refer people to firms they knew, telling them that their reports would be approved within a day. People followed them because they were asking themselves, “Who can I go to so that my house won’t get demolished?”

Thus, the solution is to have the building tested by a good firm. 

3. How should I choose which firm should conduct an earthquake test (building performance analysis)?

If you have decided to have an earthquake resistance test, these are the things you should pay attention to: 

• Stay away from firms without a license from the Ministry of Environment and Urban Planning. Unlicensed firms are listed on the ministry's website.
• Check the references and previous work by the firm. 
• If possible, collect information about the architects and engineers who will conduct the test.
• In addition to inspecting the building, learn if the firm also does ground studies as well.
• If possible, collect information about the lab the firm uses. That's because, according to the ministry on their website, “the laboratory conducting the investigation does not have to be authorized by the ministry.”

4. How is an earthquake risk analysis conducted?

So, now you have a deal with a trustworthy firm and have called experts to your building. What now? And how many days are required for the report to be ready?

Architect Oktay Şahin sums up a typical risk analysis process as follows: "First, the primary indications are checked. A good engineer and architect can spot possible problems during a main viewing. A core drilling can also be performed if necessary."

According to your contract with the firm and the data regarding the building's history, sometimes a detailed exterior inspection without drilling the core can be sufficient. The ground, base, beams, walls, columns and static properties are inspected in detail.

However in many cases, in order for the inspection to be fully trustworthy, drilling into the core of the main columns, beams and groundwork is necessary. Afterwards these samples are tested in the laboratory for resistance, pressure and quality.

X-rays of the iron used main load-bearing parts of the buildings are checked to see their dimension, number and distance from one other. Some concrete load-bearing structures are checked to see if there is any rusting and if load-bearing units are weakened because of it.

After the earthquake resistance test, a three-dimensional simulation of the building is rendered on computer and an earthquake test report is prepared. This report tells you how resistant your building is to earthquakes, which parts carry risks, and what precautions must be taken.

Experts also warn to make sure the firm you are using also examines the type of rock or soil your building sits on.

5. Is it dangerous to take a sample from the building?

One point that people argue about when it comes to whether to have a building tested is the matter of core drilling. Does core drilling damage the building?

Architect Oktay Şahin explains this potentially life-saving activity: "Core sampling is like to taking a pathology sample in medicine. It is similar to asking for a biopsy if the primary symptoms look like cancer. This means that if a building looks problematic at first glance, questions cannot be answered and the building's safety can't be guaranteed without first taking a sample of the core."

Experts emphasize that a qualified firm can take samples without damaging the building.

6. What is the price of a building earthquake test?

In Istanbul, the price of an earthquake resistance test differs from district to district. Also, the price of the test depends on whether it will be quick, medium or comprehensive. Most of the qualified, experienced firms do not give out prices before looking at the building and determining the tests required.

7. How important is the ground below a building?

There is a incorrect belief that during earthquake resistance tests it is enough for the concrete, iron quality, and column-beam systems to just be "good." However, there are buildings that look like they are in line with the earthquake law, but are in fact not constructed in accordance with the properties of the ground. Therefore, this parameter must be kept in mind when the building is being tested. Architect Oktay Şahin says, "After the Gölcük earthquake (in 1999), there were buildings that had sunk into the ground, but their structure was still intact."

8. Are you still living on sea sand?

As Istanbul awaits the "Big Tragedy," thousands of buildings in the city have a common problem: sea sand.

Some older Istanbul residents will still remember playing with the sea shells brought by trucks for when a new house in the neighborhood was being built.

Even the famous real estate tycoon Ali Ağaoğlu said, "In the '70s, I sold most of the construction material used on the Anatolian side of Istanbul. We pulled the sand from Marmara Sea and iron from the junkyards. That was the best material in those days. It wasn't just us—all of the companies were doing the same thing. If an earthquake happens, even the army won't be able to enter the city, and whoever dies will be lucky."

Don't forget that such sand with salt in it accelerates corrosion in iron, the sea shells in the concrete create holes, the air gaps hurt the strength of the concrete, and most of the buildings built like this are over 30 years old.