Sudden collapse describes which observation?

• A. Non planar irregular fracture
• B. Planar shear requiring at least one tap
• C. Sudden crack in column and noticeable collapse
• D. Thin planar crack crosses column

Answer: (C)

Sudden collapse is shown by a rapid development of a crack in the column followed by an observable failure of the structure. This captures the idea of abrupt, catastrophic loss of strength where the column suddenly cannot carry load, leading to immediate collapse. The other patterns describe more gradual or localized damage rather than an instantaneous, full-scale failure: non-planar irregular fractures are jagged and don’t inherently imply immediate collapse; planar shear that requires a tap reflects a controlled, initiated shear event rather than a spontaneous collapse; a thin planar crack crossing the column indicates a small flaw that hasn't triggered a full failure.