A soft or weak story wood-framed building is a multi-story wood structure where the first story is substantially weaker and more flexible than the stories above due to lack of walls or frames at the first floor.

Non-ductile concrete buildings are structures that contain brittle concrete elements (columns, beams, walls, and connections) that tend to perform poorly during earthquakes due to the limited amount of provided reinforcing steel.

During the 1994 Northridge Earthquake in the Los Angeles area, many steel moment-resisting frame structures experienced unexpected brittle damage to their beam-to-column connections.