Investigation of Shear Stiffness of Spine Bracing Systems in Selective Pallet Racks

This paper presents a general analysis on the shear stiffness of spine bracing systems of selective storage racks in the down-aisle direction. Unlike the architectural steel structure, the bearing capacity of bracing connection in the spine bracing systems of steel rack structure is weaker than that of bracing members. Firstly, destructive tests of spine bracing connection in single entry racks have been conducted. In the tests, a portion of column web around bolt holes is damaged due to the pull force of connecting bolts. Based on the experimental results, the finite element shell model of tested bracing connection is developed, and the emulation method is also used to analyze the deformation behavior of spine bracing connections in double entry racks. The calculating results indicate that, with better mechanical behavior and less local deformation, the tensile stiffness of bracing connection in double entry racks is much larger than that of bracing connection in single entry racks. From the trial calculation, the simplified models using elastic plastic beam elements are proposed. These simplified models can be adopted in the overall deformation analysis of selective pallet racks subjected to horizontal loading. Through the comparative analysis of single entry racks and double entry racks which have four bays and eight floors, the lateral deformation of double entry racks is considerably less than that of single entry racks, showing the large different effect of spine bracing systems on two rack lateral behavior.