Bracing Requirements for Lateral Stability
Publication: Journal of Structural Engineering
Volume 110, Issue 8
Abstract
The forces induced in braces depend on the magnitude of initial imperfections (lateral bending and twist) and magnitude of applied loads. A method for calculating these forces is presented here. Shear stiffness of attached deck is taken into account. Calculations show that, for beams which derive their lateral stability mainly from the stiffness of the attached deck, additional bracing against rotation or lateral deflection is not able to achieve an important increase in the load capacity of the systems. In those cases, bracings employed merely to straighten the initial imperfections need not be very strong. In cases where decking cannot be counted on to stabilize the roof system, bracings should be designed for stiffness (sufficient to enforce a higher buckling mode) and checked by the methods presented here for required strength. The results are of value to designers of large flat wood roof systems;
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References
1.
Barsoum, R. S., and Gallagher, R. H., “Finite Element Analysis of Torsional and Torsional‐Flexural Stability Problems,” International Journal of Numerical Methods in Engineering, Vol. 2, 1970, pp. 335–352.
2.
Flint, A. R., “The Influence of Restraints on the Stability of Beams,” The Structural Engineer, Vol. 29, Sept., 1951, pp. 235–246.
3.
Hancock, G. J., and Trahair, N. S., “Finite Element Analysis of the Lateral Buckling of Continuously Restrained Beam‐Columns,” Civil Engineering Transactions, Inst. Engineers, Australia, Vol. CE20, No. 2, 1978, pp. 120–127.
4.
Hancock, G. J., and Trahair, N. S., “Lateral Buckling of Roof Purlins with Diaphragm Restraints,” Civil Engineering Transactions, Inst. Engineers Australia, Vol. CE21, No. 1, 1979, pp. 10–15.
5.
Kitipornchai, S., and Richter, N. J., “Elastic Lateral Buckling of I‐Beams with Discrete Intermediate Restraints,” Civil Engineering Transactions, Inst. Engineers Australia, Vol. CE20, No. 2, 1978, pp. 105–111.
6.
Mutton, B. R., and Trahair, N. S., “Stiffness Requirements for Lateral Bracing,” Journal of Structural Division, ASCE, Vol. 99, No. ST10, Oct., 1973, pp. 2167–2182.
7.
Nethercot, D. A., “Buckling of Laterally or Torsionally Restrained Beams,” Journal of Engineering Mechanics Division, ASCE, Vol. 99, No. EM4, Aug., 1973, pp. 773–791.
8.
Nethercot, D. A., and Rockey, K. C., “The Lateral Buckling of Beams Having Discrete Intermediate Restraints,” The Structural Engineer, Vol. 50, No. 10, Oct., 1972, pp. 391–403.
9.
Nethercot, D. A., and Trahair, N. S., “Design of Diaphragm‐Braced I‐Beams,” Journal of Structural Division, ASCE, Vol. 101, No. ST10, Oct., 1975, pp. 2045–2061.
10.
O'Connor, C., “Imperfectly Braced Columns and Beams,” Civil Engineering Transactions, Inst. Engineers Australia, Vol. CE21, No. 2, Sept., 1979, pp. 69–74.
11.
Schmidt, L. C., discussion of “Lateral Bracing Force of Steel I‐Beams,” by C. Massey, Journal of Engineering Mechanics Division, ASCE, Vol. 89, No. EM3, June, 1963, pp. 218–224.
12.
Zahn, J. J., “Lateral Stability of Beams with Initial Imperfections,” Journal of Engineering Mechanics Division, ASCE, Vol. 109, No. 3, June, 1983, pp. 821–835.
13.
Zahn, J. J., “Lateral Stability of Wood Beam‐and‐Deck Systems,” Journal of Structural Division, ASCE, Vol. 99, No. ST7, July, 1973, pp. 1391–1408.
14.
Zahn, J. J., “Shear Stiffness of Two‐Inch Wood Decks for Roof Systems,” USDA, Forest Service Research Paper FPL 115, Forest Products Laboratory, Madison, Wisc., 1972.
15.
Zahn, J. J., “Loss of Torsional Stiffness Caused by Beam Loading,” Journal of Structural Engineering, ASCE, Vol. 110, No. 1, Jan., 1984, pp. 47–56.
16.
Zuk, W., “Lateral Bracing Forces on Beams and Columns,” Journal of Engineering Mechanics Division, ASCE, Vol. 82, No. EM3, July, 1956, pp. 1032‐1–1032–16.
Information & Authors
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Published In
Journal of Structural Engineering
Volume 110 • Issue 8 • August 1984
Pages: 1786 - 1802
Copyright
Copyright © 1984 ASCE.
History
Published online: Aug 1, 1984
Published in print: Aug 1984
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