8. Damage to Steel Buildings

The Committee of Steel Structures of AIJ conducted earthquake damage reconnaissance over cities where severe ground shaking was recorded among Miyagi Prefecture and Fukushima Prefecture. Tsunami damage reconnaissance was also performed along the coastlines of Iwate, Miyagi, and Fukushima. The observed damage to steel buildings is categorized into that caused by ground motion and that caused by tsunami. Steel buildings exhibited excellent seismic performance. Buildings that used older cladding construction methods sustained damage to their claddings even though their structural performance was excellent. In some older buildings, severe ground motion caused damage to structural members and connections, which are the same modes of damage observed from past earthquakes. A unique feature is the damage caused by tsunami. In the most extreme cases, buildings were displaced from their original location and completely destroyed. In other cases, fracture of connections and members caused the building to tilt or collapse. In buildings whose claddings were completely washed away by tsunami, structural damage was minor. The extent of tsunami damage varied substantially depending on the locality of tsunami attack.