Live load design moments for parking garage slabs considering support deflection effect

This paper develops a simplified, but effective, algorithm to obtain critical design moments for clamped and/or elastically supported parking garage slabs. Maintaining the uniformly distributed load concept generally adopted in the design of building structures, this paper introduces the equivalent vehicle load factors which can simulate the vehicle load effects without conducting additional sophisticated numerical analyses. After choosing a standard design vehicle of 2.4 ton following the investigation of small to medium vehicles made in Korea, finite element analyses for concentrated wheel loads were conducted by referring to the influence surfaces. Based on the obtained member forces, the equivalent vehicle load factors for slabs which represent the ratios of member forces under vehicle loads to those under uniformly distributed loads were determined. In addition, the relationships between the equivalent vehicle load factors and sectional dimensions were established by regression, and those are used to obtain the design moments by vehicle loads. The member forces calculated by the proposed method are compared with the results of four different approaches described in current design codes with the objective being to establish the relative efficiencies of the proposed method.