Moment-Rotation Behavior of "Pinned" Connections in Low-Rise Metal Buildings

Abstract

Low-rise metal building systems are widely used in the United States and worldwide as complex production facilities and warehouses, retail stores, shopping centers, schools, libraries and medical facilities for their cost effectiveness, easy fabrication and quick turnaround times. In most cases, the current practice is to assume zero rotational stiffness (“pinned”) for the base-plate-foundation connection of web-tapered columns in low-rise metal buildings for both serviceability and strength design. The underlying reason for this assumption is the lack of design guidelines and experimental data. On the other hand, prior research indicates that this approach may result in a significant underestimation of the rotational stiffness of the connections, and thereby, increase the cost of the structure. The objective of this paper is to study the rotational stiffness of column base-plate connections in low-rise metal building systems through testing of eight full-scale base-plate connections with varying base-plate dimensions, number of anchor rods, anchor rod diameters, gage distances, and tapers of the column sections.