• punching shear1995 · Seoul, South Korea

  Sampoong Department Store collapse

  502 dead. A flat-slab roof punched through its supporting columns after a rooftop AC unit was relocated and the columns were undersized for the revised loads.

• foundation1173–1372 · Pisa, Italy

  Leaning Tower of Pisa — settlement

  Built on 3 m of fine sand over weak clay. Differential settlement on the south side caused the tower to tilt; engineers stopped construction for almost a century to let settlement plateau.

• liquefaction1964 · Niigata, Japan

  Niigata earthquake — liquefaction

  M 7.6 earthquake. Saturated sand below buildings turned into a viscous fluid; entire apartment blocks tilted over without breaking apart, becoming the textbook image of soil liquefaction.

• detailing2021 · Surfside, Florida

  Champlain Towers South partial collapse

  98 dead. Decades of saltwater corrosion of insufficient pool-deck reinforcement caused punching shear failure at column heads, triggering a progressive collapse.

• water pressure1959 · Fréjus, France

  Malpasset Dam — uplift failure

  423 dead. A double-curvature arch dam failed when uplift water pressure on a left-abutment shear plane exceeded the rock's shear strength.

• detailing1981 · Kansas City, USA

  Hyatt Regency walkway collapse

  114 dead — the deadliest structural collapse in US history at the time. A fabrication change to a hanger-rod connection doubled the load on the fourth-floor walkway support, which tore loose during a crowded tea dance.

• overload1968 · London, UK

  Ronan Point progressive collapse

  A small kitchen gas explosion on the 18th floor blew out a load-bearing precast wall panel, and the corner of the 22-storey tower collapsed all the way to the ground — the textbook case of disproportionate collapse.

• lateral buckling1978 · Hartford, USA

  Hartford Civic Center roof collapse

  The 90 m space-frame roof collapsed under snow and ice load just hours after a packed basketball game — a compression-member buckling failure hidden by over-confidence in a novel computer analysis.

• resonance1940 · Washington, USA

  Tacoma Narrows Bridge — aeroelastic flutter

  "Galloping Gertie" tore itself apart in a 64 km/h wind — not from wind pressure, but from torsional flutter: a self-feeding aeroelastic instability that static wind design does not capture.

Editorial summaries for educational reference. Sources are cited per entry. Each case is well-documented in public engineering literature.