Comparative Calculations for Eccentrically Compressed and Compressed-Bent Wooden Components (According to Building Regulations SNIP II-25–80 and to the Theory of Strength of Materials)

Complete text of the article:

Download article (pdf, 0.6MB )

UDС

539.3+624.011

DOI:

Abstract

The differences in the physical phenomena underlying static calculations for compressed-bent and eccentrically compressed components make experts doubt about the validity of the current standards. The author has performed comparative calculations for restrained struts based on approximate solutions of differential equations of deflection curve by the strength of materials formula and the recommended formula in Building Regulations. Such calculations are needed due to new engineering developments providing rigid fixing for the ends of wooden components. The calculation theory of compressed-bent and eccentrically compressed bars using strength of materials equations involves the use of the formulae both at the elastic stage and beyond. At the same time, the edge-stress calculation is complicated by the influence of deformations and the need to use variable modulus of elasticity. The author shows that the calculation by standards can be simplified by introducing a constant modulus of elasticity for the limit states of the second group (10,000 MPa) and to calculate the limit states of the first group, reduced to 4500 MPa. The formula can be applied within the entire load range. The author has determined the validity range of the calculation for eccentrically compressed struts by the formula adopted in the Building Regulations for stability analysis of central struts.

Authors

K.P. Pyatikrestovsky, Doctor of Engineering, Principal Researcher Central Research Institute for Building Structures named after V.A. Kucherenko

Affiliation

Central Research Institute for Building Structures named after V.A. Kucherenko

Keywords

eccentrically compressed components, compressed-bent components, wood, calculation methods, exact calculations, approximate calculations, practical calculations.

References

1. Kochenov V.M. Eksperimental'no-teoreticheskie issledovaniya derevyannykh konstruktsiy [Experimental and Theoretical Studies of Wooden Structures]. Moscow, 1938. 239 p. 2. Labudin B.V., Matveev R.P., Sanzharovskiy R.S. Kriterii ustoychivosti szhato-izognutykh sterzhney, usilennykh titanovymi elementami [Criteria of Compressed-Bent Bars Sustainability Reinforced by Titanic Elements]. Lesnoy zhurnal, 2006, no. 5, pp. 141–146. 3. Labudin B.V., Matveev R.P., Sanzharovskiy R.S. Ustoychivost' szhato-izognutykh sterzhney, usilennykh titanovymi elementami [Stability of Close-Bent Rods Reinforced by Titanic Elements]. Lesnoy zhurnal, 2006, no. 3, pp. 146–151. 4. Mirolyubov I.N., Engalychev S.A., Sergievskiy N.D., Almametov F.Z. Kuritsyn N.A., Smirnov-Vasil’ev K.G., Vashina L.V. Posobie k resheniyu zadach po soprotivleniyu materialov [Study Guide to Solving Problems on Strength of Materials]. 5th ed. Moscow, 1985. 399 p. 5. Pyatikrestovskiy K.P. K voprosu o vybore moduley uprugosti pri raschete derevyannykh konstruktsiy na prochnost', ustoychivost' i po deformatsiyam [On the Selection of Elastic Moduli at Strength, Buckling and Deformation Analyses of Wooden Structures]. Stroitel'naya mekhanika i raschet sooruzheniy, 2012, no. 6, pp. 73–79. 6. SNiP II-25-80. Stroitel'nye normy i pravila. Chast' II. Normy proektirovaniya. Derevyannye konstruktsii [Building Regulations II-25-80. Part II. Design Standards. Wooden Structures]. Moscow, 1982. 65 p. 7. Soprotivlenie materialov [Strength of Materials]. Ed. by Pisarenko G.S. 5th ed. Kiev. 1986. 775 p. 8. Soprotivlenie materialov [Strength of Materials]. Ed. by Smirnov A.F. 3rd ed. Moscow, 1975. 480 p. 9. Timoshenko S.P. Soprotivlenie materialov [Strength of Materials]. Moscow, 1960. 379 p.