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Contact Interaction of a Claw Washer with Wood at Limiting Shear

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E.V. Popov, A.V. Ruslanova, V.V. Sopilov, N. Zdralovic, S.M. Mamedov, B.V. Labudin

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When designing, manufacturing and maintaining of woodworks and elements of wooden structures it is necessary to solve the problem of providing the calculation of strength, stiffness and their bearing capacity. This problem becomes particularly relevant while reconstructing and new wooden house building, as the correct choice of connection type influences the technical possibility to use wood in the elements of structures. Such types of special connectors as claw washers, gang nails, dowel connections, etc. are used for these purposes. The existing range of claw washers implies different diameters, thicknesses, and claw configurations depending on the required bearing capacity and cross-sectional dimensions of sawn timber. The accepted physical model of wood is a transtropic body. The forces transmitted in the joints of the elements of wooden structures are perceived by the total contact surface of the mating elements. However, the work of individual teeth of claw washers has been poorly studied: research on influence of geometrical characteristics of the tooth on the bearing capacity of the connector is absent; variation in thickness of the connector is not assessed. A double-sided claw washer of the Bulldog type (prototype) with the diameter of 50 mm was adopted as the object of study. Various schemes of cutting of the claw washer with predetermined dimensions (width and height) of a triangular tooth are considered. The influence of dimensions on the bearing capacity of the thickness of claw washers is estimated within 1–1.5 mm. The main criterion for the selected cutting patterns is the ability to produce the washers by single-impact stamping without additional trimming. Double-sided claw washers of 5 different types with the number of cog-teeth from 8 to 12 items on each side were studied. A differential equation of the 4th order is accepted as a mathematical model of cog-tooth action. The equation describes the behavior of a dowel on an elastic base with a fixed value of bending stiffness EI. The transition to which was carried out from the variable value EI = f(x) by searching for the equivalent width of the cross-section from the bending conditions of the element of the triangular section of a variable directed normal to the frontal surface and a constant directed normal to the lateral surface.


E.V. Popov1, Candidate of Engineering; ORCID:
A.V. Ruslanova1, External PhD Student; ORCID:
V.V. Sopilov1, Postgraduate Student; ORCID:
N. Zdralovic2, Chief Engineer, Coordinator of Projects;
S.M. Mamedov3, Candidate of Economics, Assoc. Prof.;
B.V. Labudin1, Doctor of Engineering, Prof.;


1Northern (Arctic) Federal University named after M.V. Lomonosov, Naberezhnaya Severnoy Dviny, 22, Arkhangelsk, 163002, Russian Federation; e-mail:
2Fylkesmannen i Troms og Finnmark, Statens hus, Vadsø, Troms og Finnmark County, 9811, Norway; e-mail:
3Saint Petersburg State University of Architecture and Civil Engineering, ul. 2-ya Krasnoarmeyskaya, 4, Saint Petersburg, 190005, Russian Federation; e-mail:


wood, wooden structures, anisotropy of wood, strength, deformability, claw washers, gang nails

For citation

Popov E.V., Ruslanova A.V., Sopilov V.V., Zdralovic N., Mamedov S.M., Labudin B.V. Contact Interaction of a Claw Washer with Wood at Limiting Shear. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 4, pp. 178–189. DOI: 10.37482/0536-1036-2020-4-178-189


1. Kabakov N.P. A Device for Connecting Wooden Parts in Structures. Certificate of Authorship USSR no. SU 26424 A1, 1932.
2. Khor’kov M.M. Sheet Metal Dowel for Wooden Structures. Certificate of Authorship USSR no. SU 29009 A1, 1933.
3. Labudin B.V., Popov V.D., Yakovlev V.V., Veshnyakov A.V. Nodal Connection of the Rods of Wooden Supporting Structures. Certificate of Authorship USSR no. SU 1807185 A1, 1993.
4. Agafonov S.A., German A.D., Muratova T.V. Differential Equations. Ed. by V.S. Zarubina, A.P. Krishchenko. Moscow, MSTU Publ., 2004. 352 p.
5. Ashkenazi E.K., Ganov E.V. Anisotropy of Structural Materials: Handbook. Leningrad, Mashinostroyeniye Publ., 1980. 247 p.
6. Vdovin V.M., Muhaev A.I., Ariskin M.V. To the Estimation of Stress-Strain State of Wooden Elements Connected by Pivot Glued Dowels. Regional’naya arkhitektura i stroitel’stvo [Regional Architecture and Engineering], 2013, no. 2, pp. 81–90.
7. Galakhov M.S. Connections of Wooden Structures on Glued Shearing Rings: Cand. Eng. Sci. Diss. Penza, 2002. 176 p.
8. Danilov E.V., Chernykh A.G. Methods of Joinery Timber Construction with the Claw Dowels. Nauchnoye obozreniye. Tekhnicheskiye nauki [Scientific Review. Technical science], 2014, no. 1, pp. 133-134.
9. Dmitriyev P.A. Experimental Studies of Connections of Elements of Wooden Structures on Metal and Plastic Dowels and the Theory of Their Calculation Allowing for Visco-Elastic and Plastic Deformations: Dr. Eng. Sci. Diss. Novosibirsk, 1975. 529 p.
10. Ishmayeva D.S. Rigid Joint Connections on Glued Steel Washers in Beam Structures of Glued Wooden Elements: Cand. Eng. Sci. Diss. Penza, 2014. 171 p.
11. Karelskiy A., Labudin B., Melehov V. Shear Test Elements of Wooden Structures, United Punched Metal Plate Fasteners. Stroitel’stvo i rekonstruktsiya [Building and reconstruction], 2015, no. 1(57), pp. 11–16.
12. Kritsin A.V. Calculation of Open Wooden Structures on Metal Connector Plates Allowing for Visco-Elastic and Plastic Deformations: Cand. Eng. Sci. Nizhny Novgorod, 2004. 180 p.
13. Kuznetsov G.F. Wooden Structures. Handbook for the Designers of Industrial Facilities. Moscow, Glavnaya redaktsiya stroitel’noy literatury Publ., 1937. 955 p.
14. Labudin B.V. Improving Laminated Wood Structures with a Spatially Regular Structure. Arkhangelsk, ASTU Publ., 2007. 267 p.
15. Lennov V.G. Stamped Claw Washers as a New Type of Connection of Wooden Structures Elements. Proceedings of the Gorkovkiy Engineering and Construction Institute. Gorky, 1949, iss. 1, pp. 169–181.
16. Popov E.V., Labudin B.V., Melekhov V.I. Shear Test of Elements of Wooden Structures Connected with the Use of Toothed Bulldog Washers. Safety of the Building Fund of Russia. Problems and Solutions: Proceedings of the International Academic Readings. Kursk, Kursk State University Publ., 2015, pp. 189-198.
17. Popov E.V., Filippov V.A., Melekhov V.I., Labudin B.V., Tyurikova T.V. Effect of Shear Connections Rigidity in Calculating the Ribbed Panels. Lesnoy Zhurnal [Russian Forestry Journal], 2016, no. 4, pp. 123-134. DOI: 10.17238/issn0536-1036.2016.4.136, URL: upload/iblock/101/popov_ispr._.pdf
18. Rimshin V.I., Labudin B.V., Melekhov V.I., Popov E.V., Roshchina S.I. Dowel and Washer Connections for Elements of Wooden Structures. Vestnik MGSU, 2016, no. 9, pp. 35-50. DOI: 10.22227/1997-0935.2016.9.35-50
19. Code of Practice SP 64.13330.2017. Timber Structures. Tekhekspert: Electronic Fund of Legal and Regulatory Technical Documentation, 2017.
20. Association Standard of Wooden House Construction StADD–3.2–2011. Wooden Structures. Joining Wooden Elements Using Connector Plates. Saint Petersburg, Assotsiatsiya derevyannogo domostroyeniya Publ., 2012. 40 p.
21. Xu Yun, Chernykh A.G., Glukhikh V.N. Modeling and Calculation of the Shear Bearing Capacity of Screw on the Metal Plate with Nail Plate. Stroitel’naya mekhanika i raschet sooruzheniy [Structural Mechanics and Analysis of Constructions], 2015, no. 4(261), pp. 17-23.
22. Blaß H.J., Schädle P. Ductility Aspects of Reinforced and Non-Reinforced Timber Joints. Engineering Structures, 2011, vol. 33, iss. 11, pp. 3018–3026. DOI: 10.1016/j.engstruct.2011.02.001
23. Čechavičius R. Slip of “Bulldog”-Type Toothed-Plate Connectors in SteelTimber Joints of Open-Web Girders. Journal of Civil Engineering and Management, 2004, vol. X, suppl. 1, pp. 23–29.
24. Karadelis J.N., Brown P. Punched Metal Plate Timber Fasteners under Fatigue Loading. Construction and Building Materials, 2000, vol. 14, iss. 2, pp. 99–108. DOI: 10.1016/S0950-0618(00)00015-5
25. Meghlat E.-M., Oudjene M., Ait-Aider H. Load-Slip Behaviour of Timber-toConcrete Connections Reinforced with Punched Metal Plate. Proceedings of the World Conference on Timber Engineering (WCTE 2014), Quebec City, Canada, August 10–14, 2014. Quebec, Canada, Curran Associates, Inc., 2014, pp. 813–821.
26. Product Catalog of the Company Bova Březnice spol. sro. Available at: (accessed 15.11.19).
27. Rimshin V., Labudin B., Morozov V., Orlov A., Kazarian A., Kazaryan V. Calculation of Shear Stability of Conjugation of the Main Pillars with the Foundation in Wooden Frame Buildings. International Scientific Conference Energy Management of Municipal Facilities and Sustainable Energy Technologies EMMFT 2018. Cham, Switzerland, Springer, 2019, vol. 2, pp. 867–876. DOI: 10.1007/978-3-030-19868-8_85
28. Rimshin V.I., Labudin B.V., Melekhov V.I., Orlov A.O., Kurbatov V.L. Improvement of Strength and Stiffness of Components of Main Struts with Foundation in Wooden Frame Buildings. ARPN Journal of Engineering and Applied Sciences, 2018, vol. 13, no. 11, pp. 3851−3856.

Received on November 15, 2019


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