LRFD Factors for Pultruded Wide-Flange Columns
Publication: Journal of Structural Engineering
Volume 136, Issue 5
Abstract
Fiber-reinforced polymer (FRP) pultruded profiles are produced by a number of manufacturers worldwide in similar, but nonstandard, wide-flange, I, angle, and tubular profiles. At present there is no American National Standards Institute approved design code in the United States for structural design with pultruded FRP profiles. Manufacturers of pultruded profiles each provide their own design equations, design methods, material properties, and safety factors for their pultruded products. There is a need for standardization of production and design of pultruded profiles to enable mainstream use of these profiles in structural engineering practice. The purpose of this paper is twofold: (1) to provide appropriate resistance factors ( factors) for wide-flange pultruded columns that are compatible with ASCE 7 load factors and (2) to provide a unified analytical equation for local and global buckling of concentrically loaded axial members, which may be appropriate for a future design code. The resistance factors are provided for different target levels of structural reliability, , and for different nominal design properties of the pultruded materials. The resistance factors were determined using Monte Carlo simulation based on the results of 75 tests of full-scale pultruded columns that have been reported in the literature. In addition, resistance factors and structural reliabilities were calculated for the design equations provided by the manufactures in their design codes. The paper demonstrates that a unified design equation for pultruded columns can be developed for LRFD with reliability indices that are similar to those used for conventional materials. The paper also shows that markedly different reliability indices are obtained for the different manufacturer-provided equations even though identical allowable stress design safety factors are recommended by all manufacturers.
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Acknowledgments
Partial support for the first author was provided by the Department of Civil and Environmental Engineering at the University of Wisconsin-Madison and the Department of Civil Engineering at the University of Minnesota.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 136 • Issue 5 • May 2010
Pages: 554 - 564
Copyright
© 2010 ASCE.
History
Received: Oct 28, 2008
Accepted: Aug 24, 2009
Published online: Oct 8, 2009
Published in print: May 2010
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