Rack structures show a peculiar seismic behavior highly influenced by their dry semi-rigid connections; their assessment is also mandatory in a design-by-testing strategy that current codes require.

Designing rack structures for static loads means knowing the connection static stiffness and ultimate moment only. However, a nonlinear analysis is required to evaluate the seismic response carefully, considering P-delta effects, joint pinching behavior, and moment-rotation curve. Additionally, upright-to-beam joints in racks are the leading cause of energy dissipation during seismic motion; consider this behavior critical in capacity design.

This paper presents a series of nonlinear dynamic and pushover analyses, showing that the joint nonlinear moment-rotation curve and its pinching behavior can substantially modify the structure's seismic response. Also, neglecting the nonlinear behavior of joints can lead to results not always on the safe side.