Study of Story Drift Limits in Steel Buildings Subjected to Seismic Forces

Traditionally, the design of steel buildings for seismic forces initiates with the definition of the lateral force resistant system (LFRS) and the dimensioning of its components for the strength limit states. In addition, construction codes require to limit the inter-story drift to values that range between one to two percent of the story height. This requirement usually controls the LFRS’s design in configurations in which the story lateral rigidity depends on the combination of flexural and axial deformations of the structural components such as in steel moment frames. In general, drift control is meant to limit the damage in non-structural components of buildings and to limit lateral displacements to admissible values, so the structure remains stable during a seismic event. This paper presents studies conducted to determine the reasonableness of inter-story drift limits specified in different construction codes around the world. Studies are focused on LFRS’s for steel structures, including the lateral stiffness contribution of non-structural components such as division walls and facades. As a result of the study, new criteria for establishing drift limits in steel buildings are proposed, considering the structural integrity of the building and limiting non-structural damage during a seismic event.

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