Fatigue-Life Evaluation of Steel Post Structures. II: Experimentation
Publication: Journal of Structural Engineering
Volume 126, Issue 3
Abstract
Changeable message signs (CMS) are supported by cantilevered, inverted L-shaped structural components composed of a vertical post and a horizontal mast arm. The high-cycle fatigue failure of one CMS structure in southern California led to a detailed analytical and experimental study of components of CMS structures. This paper reports the results of the experimental studies and presents recommendations for future CMS construction. A companion paper documents the results of the field studies and finite-element analysis of components of CMS structures. Six cantilever specimens were tested to failure: one as-built post (AB1); two retrofitted posts (GR1 and CIP1); and three mast arms (MA1, MA2, and MA3). The specimens were tested at a stress range of 69+ MPa (10+ ksi). The fatigue life of all six specimens exceeded the AASHTO design fatigue life of 400,000 cycles for a stress range of 69 MPa. Alternate construction details; improved welding, fabrication, and quality assurance/quality control practices; additional field and wind-tunnel testing; and further laboratory experimentation are recommended.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 126 • Issue 3 • March 2000
Pages: 331 - 340
History
Received: Dec 1, 1998
Published online: Mar 1, 2000
Published in print: Mar 2000
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