In a city located in a first-degree earthquake zone such as İzmir, urban transformation means far more than merely renewing an ageing building stock; it is a direct guarantee of life safety. The 1999 Marmara and 2020 İzmir earthquakes painfully showed how great a risk buildings that received no engineering service or had completed their economic life can pose. So what are the elements that keep an earthquake-resistant building standing?
Soil Investigation Is the Starting Point of Everything
A sound structure begins with sound ground. The geological-geotechnical soil investigation carried out before the permit reveals the bearing capacity of the soil, the risk of liquefaction and its settlement behaviour. A foundation designed without this data cannot be considered safe, no matter how high the quality of the superstructure. On weak soils, raft foundations, pile foundations or ground-improvement methods are brought into play.
Reinforced-Concrete Quality and Reinforcement Details
In a design compliant with the Turkish Building Earthquake Code (TBDY 2018), the concrete class should generally be at least C25/30 and the reinforcement B420C ribbed steel. However, workmanship is just as critical as material quality:
- Stirrup confinement: Closer stirrup spacing at column-beam joint regions provides ductile behaviour during an earthquake.
- Concrete cover: Sufficient concrete cover must be provided to protect the reinforcement from corrosion.
- Lap lengths: Reinforcement splices must comply with the lap lengths stipulated in the code.
A Regular and Symmetrical Structural System
Irregularities in plan and in elevation (soft storey, short column, the shift of the mass and stiffness centres) cause earthquake forces to concentrate at certain points. The collapse of many buildings whose ground floor is entirely opened up into shops through "soft-storey" failure is the best-known example of this. Balanced placement of shear walls increases the building's stiffness and limits lateral drift.
The Right Steps in Urban Transformation
Risky-building assessment is carried out by licensed organisations and the report is recorded in the Ministry's system. The process consists of the stages of consent, design approval, demolition and reconstruction. Working with an experienced contractor and inspection firm at all of these stages secures both legal safety and structural quality.
As İdeal Yapı, in our urban transformation projects we take the current earthquake code as the basis at every stage — from soil investigation to turnkey delivery — building structures in which not only today's generation but also future generations can live safely.