A concentrated load is a force applied over a small area, such as a wheel, a jack, or a post, rather than spread evenly across a floor.
Codes require structures to resist both uniform loads, which govern beams, girders, and columns, and concentrated loads, which govern the local strength of slabs and decks. In a parking garage, the concentrated load is what decides whether a slab can resist a point load punching through it.
What the codes require for garages
- Passenger vehicle garages: 3,000 pounds applied over a 4.5 by 4.5 inch area, representing a jack during a tire change, under the 2024 IBC and ASCE 7-22. This is checked separately from the 40 pound per square foot uniform load.
- Mechanical parking structures without slabs or decks: 2,250 pounds per wheel for passenger vehicles.
- Heavy vehicles: garages that accommodate vehicles over 10,000 pounds gross vehicle weight rating must be designed for vehicle loads from the locally adopted roadway or bridge code, such as AASHTO LRFD.
Electric vehicles
EVs are heavier than comparable gasoline vehicles, largely because of their batteries, which prompted concern about garage capacity. Charles Pankow Foundation research concluded that current uniform design loads remain adequate in nearly all modeled scenarios. For owners, the practical issues sit at the edges: older structures designed under earlier codes, decks with deterioration, and vehicles that cross into the heavy class, such as loaded delivery vans. A condition assessment, not a rumor, should decide whether a facility posts weight limits.
Related terms: Factored Load, Service Load, Column Capital
Further reading: EV Charging coverage on Parkonomics