Seismic design of storage systems is a specialized field that requires an in-depth understanding of standards, seismic loads, and the behavior of steel structures. Camrack shares its expertise here to explain the principles governing the design of industrial pallet racking and the requirements to ensure the safety and compliance of installations.
SAFETY • STABILITY • COMPLIANCE
The objective of seismic design is to ensure user safety by preserving the integrity of the storage system during an earthquake. The National Building Code of Canada requires structures to be designed to withstand a major seismic event with a 2% probability of occurring over a 50-year period, which corresponds to an approximate return period of 4,750 years based on seismological data collected across the country’s various regions.
Unlike a design based solely on gravity loads, seismic design also takes into account the lateral forces generated by ground motion during an earthquake.
Modern design philosophy is based on the principle of energy dissipation. Certain system components are intentionally designed to deform in a controlled manner to absorb seismic energy—particularly bracing and connectors—while the main structural elements, such as columns and beams, must remain within their elastic range to preserve the overall stability of the pallet racking system.
This approach, known as capacity-based design, is prescribed by CSA S16, notably in Annex N, which applies to steel storage systems.
STANDARDS AND COMPLIANCE
Without limitation, the main applicable codes and standards for pallet racking design include the following:
Design and construction of steel structures.
North American Specification for the Design of Cold-Formed Steel Structural Members.
Design and construction of steel storage systems.
User’s Guide for Steel Storage Racks.
The seismic loads used for design are derived from the project site’s seismic hazards. These values represent the likely intensity of ground motion during an earthquake and vary depending on geographic location. In Canada, they are determined from data published by Natural Resources Canada, which provides the seismic parameters used in the National Building Code. These values can be obtained using the online seismic hazard calculation tool by simply entering the site address or coordinates. The main parameters provided include spectral accelerations for different periods as well as peak ground acceleration, which are then used to establish the seismic forces applied to the storage system.
