Report to the Structural Engineering Institute of ASCE.

This report provides a better understanding of parking garage live loads and recommends an appropriate value for design. Based on a load survey conducted in nine parking garages in Chicago and Champaign-Urbana, Illinois, and Cambridge and Boston, Massachusetts, statistical analyses were carried out of the equivalent uniform distributed loads. These produce the maximum column axial loads and beam midspan moments that the building is expecting to experience during its lifetime. The dynamic amplifications resulting from vehicle motions on the decks and ramps were also investigated, and results suggest a possible reduction of the design live load from the current value of 50 psf, as stipulated in the ASCE-7 and Uniform Building Code, to 40 psf, but with no allowance for reduction according to bay area.