This paper analyses the influence of horizontal bracing restraints provided by the friction between pallet bases and rail beams on the static behaviour and design of steel drive-in storage racks. The pallet bracing restraints are shown to significantly influence the structural behaviour of the rack, and their effect on the bending moment distribution of the uprights is studied in the paper. The 2D single upright model proposed by Godley is improved in this study by including the restraints provided by the plan flexural stiffness of the rail beams and the friction between the pallets and rail beams. The improved 2D model was found to accurately reproduce the bending moment distributions obtained using 3D advanced finite element analysis. The 2D single upright model is used to analyse 36 drivein racks under various load case combinations. The paper evaluates the influence of the pallet bracing restraints on the ultimate capacity of drive-in racks, clarifies the loading pattern(s) governing the structural design and determines the friction coefficient, or strength of a restraining device, required to prevent the pallets from sliding. It is shown that while restraints from pallets could potentially be considered in design, they would not lead to more economic structural solutions.

This paper analyses the influence of the horizontal restraints provided by pallets on the ultimate capacity of drive-in racks. The paper is based on the assumption that one can accurately determine the coefficient of friction between the rail beams and the pallets or can design a device that restrains the pallets from sliding on the rail beams. Thirty-six drive-in racks representing the global sale of an Australian manufacturer over three years are analysed for all possible loading scenarios. For the sake of computational efficiency, the simple 2D model introduced in the companion paper is used for the study. The load case(s) governing the structural design is(are) also clarified and the friction coefficient or strength of a restraining device required to prevent the pallets from sliding is determined.