Heat Straightening Rolled Shapes
Publication: Journal of Structural Engineering
Volume 126, Issue 7
Abstract
The process of heat straightening damaged rolled shapes is based on a logical extension of the straightening of plates. When damaged, some plate elements are bent about their strong axis, some about their weak axis, and some about both. The overall effect on a rolled shape is damage that is a combination of one or more of the following fundamental damage categories: (1) Category S denotes primary bending about the major or strong axis; (2) Category W denotes primary bending about the minor or weak axis; (3) Category T denotes torsion or twisting of a member about its longitudinal axis; and (4) Category L denotes localized damage to plate elements in the form of bulges, buckles, and crimps. The purpose of this paper is to examine the behavior of rolled shapes during heat straightening with the focus on Category S and Category W types of damage. For repair of such damage, simple heating patterns are used in combination. The use of vee, line, and strip heats are illustrated for both Category S and Category W damage. Over 300 heats were applied to 30 rolled shapes to document the behavior of heat-straightened angles, channels, and wide flange beams. The experimental data suggested that the amount of straightening during one heating cycle is a function of vee angle, magnitude of jacking force, shape of the cross section, and stress distribution due to jacking. A mathematical formula to predict the amount of straightening per heat was developed. The form of this formula was to modify the formula for a single plate element by including a load factor, shape factor, and stress factor. This approach produced reasonable agreement with the experimental data.
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References
1.
Avent, R. R. (1989). “Heat-straightening of steel: Fact and fable.”J. Struct. Engrg., ASCE, 115(11), 2773–2793.
2.
Avent, R. R., and Brakke, B. C. (1996). “Anatomy of steel bridge heat-straightening project.” Transp. Res. Rec. 1561, Transportation Research Board, Washington, D.C., 26–36.
3.
Avent, R. R., and Fadous, G. M. (1989). “Heat-straightening prototype damaged bridge girders.”J. Struct. Engrg., ASCE, 115(7), 1631–1649.
4.
Avent, R. R., Fadous, G. M., and Boudreaux, R. J. (1991). “Heat-straightening of damaged structural steel in bridges.” Transp. Res. Rec. 1319, Transportation Research Board, Washington, D.C., 86–93.
5.
Avent, R. R., Mukai, D. J., Robinson, P. F., and Boudreaux, R. J. (2000). “Heat straightening damaged steel plate elements.”J. Struct. Engrg., ASCE, 126(7), 747–754.
6.
Hicks, C. R. (1982). Fundamental concepts in the design of experiments, 3rd Ed., Holt, Rhinehart and Winston, New York.
7.
Holt, J. E. (1955). “Flame straightening: A friend in need.” Welding Engrg., 40(10), 44-46, and 40(12), 30–31.
8.
Holt, R. E. (1965). “Flame straightening basics.” Welding Engrg., 50(9), 49–53.
9.
Holt, R. E. (1971). “Primary concepts in flame bending.” Welding Engrg., 56(6), 416–424.
10.
Horton, D. L. ( 1973). “Heat curved mild steel wide flange sections: An experimental and theoretical analysis.” MS thesis, University of Washington, Seattle, Wash.
11.
Roeder, C. W. (1985). “Use of thermal stress for seismic damage repair.” Final Rep. on NSF Grant CEE-82-05260, University of Washington, Seattle, Wash.
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Received: Apr 6, 1999
Published online: Jul 1, 2000
Published in print: Jul 2000
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