Experimental Investigation of Pallet Sliding in Steel Racking Systems via Shake Table Testing

Pallet racking is a long-established material handling solution that optimizes warehouse space through multi-level pallet storage and ensures time efficiency through the absence of any mechanical fasteners between the goods and the supporting steel structure. This however could lead to potentially vulnerable situations since heavy pallets are stored at high load-levels, with only the force of gravity and friction keeping them in place. Recent earthquakes have highlighted these risks, with pallet sliding and fall-offs causing operational disruptions and structural collapses; such failure modes are not adequately addressed by current seismic design codes for racks. The ERIES project RACKSLIDE addresses this knowledge gap through an extensive experimental campaign that investigates pallet sliding on two rack configurations with diverse structural characteristics. Test specimens, that depict small portions of the actual frames, are designed and constructed by industry experts and then installed on an innovative 9 degrees-of-freedom shake table system. By using as input motion, the load-level accelerations, evaluated by numerical modelling of the entire system, the proposed setup allows to assess sliding phenomena on the uppermost levels of high-rise racks. Afterwards, the experimental results are compared with blind predictions from numerical analyses, leveling the ground for future model calibrations and code applications.