Earthquake Reminds of the Need to Increase Social Communication

On 26 September 2019 at 13:59:24, an earthquake struck the Istanbul Silivri offshore area (Marmara Sea) with a magnitude of 5.7 and a depth of 11.9 km. This earthquake, the largest since the Marmara Earthquake in 1999, has prompted us to reconsider the places where we live. Why is the Marmara Earthquake and Istanbul so important? I visit many cities across our country due to business. During these visits, I frequently hear complaints such as "Everything happens in Istanbul, what is so special about there?" Although my family is from Elazığ, we have been living in Istanbul for almost 80 years. We are Istanbul residents. According to the 2017 Annual Report of the Revenue Administration, tax liabilities totalling TRY 760,214 billion accrued throughout the country last year, including amounts carried forward from previous years. TRY 625,512 billion of this amount was collected. For Istanbul: accrual: TRY 326,234 billion, collection: TRY 275.34 billion, collection rate: 84.40%, Istanbul's share of total accrual: 44.4%. For this reason, Istanbul is extremely important. However, Istanbul receives less funding relative to this tax rate. In this case, it can be said that investments made in Istanbul are insufficient. Technically, Istanbul's growth is not adequate. If a Marmara earthquake of magnitude 7 or higher occurs, loss of life and property would be catastrophic. There is a serious risk for our country. Horizontal expansion should begin immediately and Istanbul's growth should be facilitated starting from neighbouring provinces. Iron and concrete determine the skeleton of a reinforced concrete structure. Iron producers are well-known and can be inspected before use in formwork. However, ready-mixed concrete is not. Because it is not actually ready. It is prepared and shipped upon order. Therefore, concrete must be kept under strict control from its fresh state to its hardened state. Adequate laws, standards and regulations exist for concrete design. Ready-mixed concrete facilities are highly advanced and the margin of error in machine production is minimized. Despite this, there are a total of 8 components involved, such as cement, water, aggregate [sand, stone dust, crushed stone 1 (5-12), crushed stone 2 (12-20)], chemical additives and mineral additives. Because human factors are involved at every stage, unfortunately concrete cannot be adequately controlled. The people who produce ready-mixed concrete and those who place it in the formwork are different. As in developed countries abroad—and some in Turkey—ready-mixed concrete producers should place the concrete they produce into the formwork and cure it. This would remove human factors. Subcontractors should establish an organization under the ready-mix concrete company. This arrangement is expected to become more widespread in the future. Revisions have been made to the building supervision law. Accordingly, inspection of chip concrete samples by concrete laboratories has become necessary and is now required. This is an extremely appropriate decision. However, the design of fresh concrete does not end with perfect design; replacement and maintenance processes must be carried out on-site within required standards. Even though excellent standards and regulations are in force, unfortunately implementation problems exist; such as bad faith, avoiding consequences, economically and politically influential people benefiting from the situation. This affects basic income distribution negatively. Only morality, social self-control and laws can solve the problem. 2019 was declared 'pedestrian priority traffic year'. According to the law, vehicles must yield to pedestrians. Social responsibility and awareness must spread. For example; when a front vehicle driver allows a citizen to cross at a pedestrian crossing, the rear vehicle driver must take appropriate measures. He or she must adjust braking distance accordingly, not honk and behave properly. Pedestrians should also cross only at designated pedestrian crossings and should not cross in the middle of the road or jump through landscaped areas.

Developing conscious social self-control will enable us to become more civilized in cleanliness, health, education and human relations. After these observations, let's examine "What We Can Do?" for our structures. A-) Concrete Cover

Most buildings in our country are reinforced concrete. The durability of reinforced concrete depends on the steel reinforcement within it. In other words, if reinforcement inside a concrete building is damaged by corrosion and loses its continuity, the structure collapses. The better the concrete surrounds the steel, the longer the structure's lifespan. Unfortunately, to preserve net floor area (m²) in buildings, even rust allowance was reduced. Consequently, some elements became vulnerable to corrosion. Also, to save space, these surfaces were not plastered. Gypsum was applied directly to them. Corrosion has begun to occur in new buildings as a result of direct contact between gypsum and concrete. Although concrete primer is sometimes applied before gypsum, homogeneous application is not done everywhere. In fact, even on many surfaces other than ceiling flooring, concrete primer is not used. Regardless of costs involved, the cost of a lost life is invaluable. Therefore, the structural formwork system should be reviewed. Deformed molds from excessive use should not be reused. The type of release agent must be observed. In short, rust allowance must be provided and variety should be increased. There are many examples of covers abroad. Using only plastic covers may be insufficient.

B-) Adjacent Structures

In some adjacent buildings, no gaps were left between the structures. As a result of oscillations during an earthquake, both reinforced concrete frames strike each other at full force. Structural cracks occur as a result of this impact. Another drawback is the occurrence of waterproofing problems. Initially, zero or just 1-2 cm separations can later be observed reaching 5-15 cm after an earthquake. Water entering the building—from both the building facade and roof—negatively impacts living comfort. Water ingress causes damage to gypsum, blistering in paint and corrosion in the structure. As known from various research, the incidence of diseases such as COPD, asthma and bronchitis has increased. Where there is a dilatation gap in the structure, such areas must be repaired with bitumen-polyurethane based products. The interior of these gaps should not be filled with rigid, cement-based products. Because rigid material will crack as a result of movements during the earthquake. *Note: The screed application specified in article 9 in the graphic is valid for horizontal planes. On vertical surfaces, closure should be considered with heat insulation and so forth. C-) Basement Floors It is necessary to address closed car parks and basements again. The height of the basement should not exceed: basement height / building height = 1/6. So if the basement height is 3 m, the building height should not exceed 18 metres. This rule can be violated if required reinforcement and concrete quality are correctly selected during the design phase. Basement floors are usually overlooked because floor owners do not directly see them. The pergola to be constructed in the garden, the colour of exterior paint, or the tree to be planted sometimes leads to greater debate. "Even if we bury our heads like an ostrich, the structure exists". Steel reinforcement of reinforced concrete surfaces should not be left exposed. Some areas are not plastered; only lime or gypsum is applied. This is extremely dangerous. Even without corrosion in the environment, it initiates corrosion and increases its rate. If there is a crack in reinforced concrete, it should be monitored for progression. If it is covered, detection becomes impossible. Proper waterproofing must be done from the positive side. In separate basement floors, insulation should be done by opening the building perimeter. However, this application is not performed because it is costly. Basement floors are statically important. Where possible, water insulation should be done externally, not internally. Internal waterproofing is not very effective. Because even if you prevent water from entering the structure, you cannot stop iron corrosion in the concrete. As shown in the photo, a small head trench was constructed to prevent water spreading and to direct it away. However, these methods will not prevent iron melting in the concrete due to corrosion. The pan method shown in the photo on the right is a frequently used system. Here water can be collected in one location and channelled from there, but corrosion in the steel cannot be prevented. D-) Asmolene Flooring No public building (generally) is constructed using asmolene foam. To complete work faster, the private sector uses asmolene foam even for multi-storey buildings. The foams used are very sensitive to temperature as they have no density.

Some problems arising in structures constructed using asmolene foam are as follows:

1) It is not suitable for use in earthquake zones as the frame is not fully formed. 2) It should not be used without reinforced concrete shear walls. 3) Due to the low rigidity of these beams, horizontal displacement between floors increases greatly and transmits very large second-order moments to the columns. 4) Heated air expands and rises. Due to the contact surface of heated air, the foam also produces harmful gases. 5) During fire, these foams will immediately ignite and burn. 6) Due to oscillations from earthquakes etc., ceiling plaster can fall. Sometimes even the foam is dislodged and falls. If children are present, injuries and property damage can occur.

Asmolen Flooring Examples

Since 2018, earthquake regulations (Turkey Earthquake Building Regulations—TBDY) have changed. Dr. Mehmet Nuray Aydınoğlu from Boğaziçi University Kandilli Observatory and Earthquake Research Institute commented on the limitations imposed on the load-bearing asmolen flooring system; these comments should be read from authoritative sources. In the concluding section, Dr. Mehmet Nuray Aydınoğlu stated that for DTS (Earthquake Design Class) = 1,2 and NMS (Building Height Class) ≥ 6, asmolene flooring buildings with load-bearing walls in both directions must satisfy the overturning moment condition stated in section 4.3.4.6 Equ. (4.3). Otherwise, asmolene flooring systems (see Table 3.3 for NMS definition): • (a) Cannot be used for buildings with DTS = 1,2 and NMS ≥ 6 (Hn, max = 17.5 m), • (b) Can be used for buildings with DTS = 3,4 and NMS ≥ 7 (Hn, max = 17.5 m).

In Conclusion

The above topics can be illustrated by numerous additional examples. According to research, a building without water insulation loses 66% of its load-bearing capacity after 10 years. Thus, an 80×60 cm column that can carry 100 tonnes of load initially can only carry 34 tonnes of load if no water insulation is applied. If so, a solution must be sought for apartments and residential complexes in accordance with empathy and social understanding. When an earthquake occurs, conditions on the 1st floor are the same as on the 8th floor. The damage status of the structure and its oscillations during the earthquake may differ depending on the storey. However, at the time of the earthquake, psychology and fear are the same. All residents, whether on the ground floor or top floor of the building, must deal with the building's problems. Waterproofing, corrosion, cracking and concrete damage are common issues for all floor owners.