Sultangazi retaining wall collapse, Istanbul
What happened
On 15 October 2026, during rain that had started the previous morning, a large section of a retaining wall collapsed at the Small Industrial Site in the 50. Yıl neighbourhood of Sultangazi, Istanbul, crushing a parked car.
What reports confirm
- Rain began in Istanbul the previous morning. A retaining wall at the Small Industrial Site in the 50. Yıl neighbourhood of Sultangazi collapsed. (IHA News)
- As rainwater accumulated, cracking sounds came from the wall and small pieces of stone began to fall; shortly after, a large section gave way. (IHA News)
- A car parked in front of the wall was crushed by concrete and stone debris. No one was nearby and no injuries were reported. (IHA News)
- Not reported: the wall type, height, age, design, drainage, or any official cause. (IHA News)
Cause: No cause published. Wall type and drainage details not reported.
Likely mechanism, general engineering
General engineering, not a finding about this event
A retaining wall is normally designed for the earth pressure of drained backfill, and if water cannot escape, the water pressure behind the wall adds to the soil pressure and can greatly increase the total lateral load the wall has to carry. That is why walls have a free-draining blanket or drainage layer behind them, a filter to stop fines clogging it, and weep holes or a drain pipe to let the water out, and why those need to keep working for the life of the wall. Saturation can also soften the backfill and the foundation soil and weaken masonry or poorly bonded stone. The source does not say how this wall was built or drained, so none of this is a finding about this wall.