GLOSSARY

Cantilever

A cantilever is a structural member, such as a beam or slab, that is supported at only one end and projects freely past its support.

SIMPLE SPAN VS. CANTILEVER (ELEVATION, SCHEMATIC)supported at both ends:sags most in the middlefree endsupport at one side only:droops most at the tip,highest stress at the supportback span
A cantilever projects past its support and is anchored back into the structure. It deflects most at the free end and works hardest at the support, which is why drainage, cracking and added loads near the tip deserve attention. Schematic.

Cantilevers let a structure reach out without columns below, which is useful for overhangs, canopies, balconies and facades. The member resists the load by bending, with the greatest stress at the support, so it must be anchored back into the structure.

Where they appear in parking

  • Slab or double-tee edges that extend past the outer columns.
  • Entrance canopies and pedestrian overhangs.
  • Facade supports and architectural screens.
  • Solar canopies on top decks. See solar canopy.

What to watch

  • Deflection and bounce at the free end. See deflection.
  • Drainage, so water does not run back toward the support or pond at the tip.
  • Cracking near the support, where water and salt can reach the reinforcing steel.
  • Added loads later, such as signs, planters or equipment, which need an engineer’s review.

The Parkonomics view

A cantilever is an elegant way to avoid a column. Treat it as a structure that is working hard at all times, and check with an engineer before hanging anything new on it.

Related terms: Deflection, Clear-Span Construction, Solar Canopy, Structural Systems of Parking, Post-Tensioned Concrete, Wind Loads