Is your home earthquake-resistant? This simple test provides 80 percent accurate results...

The risk of an expected earthquake in Istanbul is increasing every day.

Earthquakes experienced in many provinces have also increased citizens' earthquake anxiety.

Following the 4-story building that collapsed in Bahçelievler, the roof of another building in Bahçelievler also collapsed. A building had also collapsed in the same area last month, resulting in 1 fatality.

Following these developments, citizens have begun searching for answers to the questions: Is my home earthquake-resistant? How can I tell if my home is earthquake-resistant?

So, how can you tell if your home is earthquake-resistant? Here is the answer....

IS YOUR HOME EARTHQUAKE-RESISTANT?

Dr. Hafez Keypour, a faculty member at Istanbul Aydın University Faculty of Engineering, stated, "People should remove the plaster on the columns in the basement of the building and check for cracks. One of the simplest things that can be done is the Schmidt test. This test provides up to 80 percent accurate results.”

WHAT IS A CONCRETE (SCHMIDT) HAMMER USED FOR?

In a study signed by İbrahim İlhan from the TMMOB Chamber of Civil Engineers, the use of the Schmidt hammer process is explained as follows.

In our country, the rebound concrete (Schmidt) hammer is widely used to determine concrete compressive strength. Its popularity stems from being cheap, easy, and impressive. However, it is observed that the purpose of the tool is misunderstood and errors are made in its use.

WHAT IS A CONCRETE HAMMER?

The definition of the Schmidt hammer is given as, "a non-destructive testing tool used to test the uniform distribution of concrete and to estimate its compressive strength."

The test hammer strikes the concrete with a certain force and rebounds according to the hardness of the surface it strikes. The Rebound number R is measured by the sensing mechanism and displayed on the needle located on the tool. As can be understood from its working mechanism, the tool primarily measures surface hardness, and finding the compressive strength does not go beyond an estimation.

In fact, these tools only provide information about the properties of the concrete surface being tested (up to a depth of approximately 30 mm).

In TS 3260, published in September 1978, the method was called the method for determining concrete surface hardness and approximate concrete strength, and it was explained in all its details. We can explain the purposes of the concrete hammer as follows:

To check whether the concrete is distributed uniformly,

To compare the concrete of different elements in the structure with each other.

Another way of using it is to estimate the concrete compressive strength by utilizing surface hardness. The logic here can be explained as: the harder an object is, the higher its strength. However, it is impossible to find concrete strength using only a concrete hammer. Hammer values are of little use unless they are calibrated with results obtained from core samples that possess the properties of the surface where the measurements were taken.

HOW IS MEASUREMENT PERFORMED WITH A CONCRETE HAMMER (SCHMIDT HAMMER)?

The concrete hammer is only suitable for non-porous concrete. The surface to be measured must be clean, smooth, and dry. For this, the concrete surface must be cleaned of substances such as paint, oil, and dust to make it smooth. The cleaning process can be done with the abrasive stone provided with the hammer. Under no circumstances should measurements be taken over plaster. At least 10 readings should be taken from each sample surface, and there should be a minimum of 20 mm between each reading point. Also, one should not get closer than 40-50 mm to the edges. Readings are taken as follows:

The surface is cleaned with an abrasive stone,The impact rod is released by applying light pressure,

The concrete hammer is placed perpendicular to the test surface,

The hammer is pressed slowly against the test surface until the impact is triggered,

After triggering, the impact rod is locked by pressing the button located on the bottom side,

The rebound number R is read from the indicator,

The above steps are repeated until 10 separate readings are taken for each test surface.

After taking 10 readings, the largest and smallest values are ignored, and the arithmetic mean of the remaining 8 readings is taken. Thus, an average R value representing that test surface is obtained.

The found R value is substituted into the conversion curve representing that test surface to find the concrete compressive strength corresponding to the R value.

What should not be forgotten here is that the concrete strength you find will only be correct if the sample concrete used in the preparation of your conversion curve represents the concrete to be tested. Otherwise, errors that can reach 60-70 percent can be made.