This research investigated the seismic behavior of a shipping container as a structural system, including the seismic response modification factor (R), and other aspects of the plastic behavior of a container wall panel.
As more people choose shipping containers as a sustainable, modular, and affordable building material, structural designers often find there is a lack of detailed technical information regarding shipping containers, especially for the container's seismic behavior. Minimum performance requirements are available for shipping containers in the ISO 1496 codes “Series 1 freight containers – specification and testing”, and there has been some experimental research conducted to verify the elastic properties of containers. Current structural guidance for shipping container structures is given by the International Code Council's "ICC G5-2019 Guideline for the Safe Use of ISO Intermodal Shipping Containers Repurposed as Buildings and Building Components." This document recommends a seismic R of 2, and based on a literature review, this recommendation appears to be based primarily on expert opinion. This recommendation may not be verified by testing or detailed numerical modeling. This author has not been able to find any investigation into the plastic behavior of shipping containers, particularly as they are used in habitable structures.
This research investigated the seismic response modification factor for a shipping container as a structural component. Testing was performed by cutting a 40-ft long High-Cube (9.5-ft. tall) shipping container wall into 8-foot-long sections, then cyclically loading specimens per ASTM E2126 method C (CUREE).
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Overall, results indicate that (1) the container wall panel has a much higher shear capacity than the minimum standard given in ISO codes by a factor of three at a minimum, (2) corrugated wall stiffness is roughly similar to other literature, (3) proper detailing is critical to ensure maximum ductility and wall shear capacity, and (4) a seismic response modification factor of 4 is supported by these results, though more extensive testing is warranted to support general guidance for shipping container structures.
