In Situ Compression Stress-Deformation Measurements along the Timber Depth Profile

Abstract:

The paper presents a novel concept and a prototype of a diagnostic tool for in-situ assessment of timber in existing structures and buildings. The device enables direct determination of conventional compressive strength and modulus of deformation in arbitrary depth along timber profile. The measurement of the stress-deformation relationship is performed in a prepared hole of a very small diameter by means of a special small size symmetrical loading jack. Testing and verification of the new device behaviour during loading of wood along the fibres has been carried out on fir which is the most frequent wood species in European buildings. The comparison of stress-strain diagrams acquired by means of the new device with those measured in compliance with the European standard for testing of wood shows a very good correlation including the determination of the compressive strength values. This semi-destructive method causes a very gentle damage and can be also used for the assessment of historic timber structures.

• Periodical: Advanced Materials Research (Volume 778)
• Pages: 209-216
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.778.209
• Online since: September 2013
• Authors: Miloš Drdácký, Michal Kloiber
• Keywords: Compression Strength, In Situ Testing, Nondestructive Testing (NDT), Small Size Loading Jack, Wood

References

[1] Rinn, F., Schweingruber, F., Schär, E.: Resistograph® and x-ray density charts of wood komparative evaluation of drill resistance profiles and x-ray density charts of different wood species. Holzforschung – International Journal of the Biology, Chemistry, Physics and technology of Wood, Vol. 50(4), 1996, pp.303-311.

DOI: 10.1515/hfsg.1996.50.4.303

[2] Kasal, B., Tannert, T.: In situ Assessment of Structural Timber. State of the Art reports. Springer, 2011, 124 pp.

DOI: 10.1007/978-94-007-0560-9

[3] Bethge, K., Mattheck, C., Hunger, E.: Equipment for detection and evaluation of incipient decay in trees. Arboricultural Journal, Volume 20, Issue 1, 1996, pp.13-36.

DOI: 10.1080/03071375.1996.9747095

[4] Kasal, B., Drdácký, M., Jirovský, I.: Semi-destructive methods for evaluation of timber structures. Structural Studies, Repairs and Maintenance of Heritage Architecture VIII. C.A. Brebia, Editor. Advances in Architecture. WIT Press. Southampton, 2003, p.835.

[5] Drdácký, M., Jirovský, I., Slížková, Z.: On the Structural Health and Technological Survey of Historic Timber Structures. Proceedings of the International Conference: The Conservation of Historic Wooden Structures, Florence, Vol. I, 2005. pp.278-284.

[6] Borský, P.: Kostel Nanebevzetí Panny Marie ve Vranově nad Dyjí – Stavebněhistorický průzkum (Church of the Assumption of the Virgin Mary in Vranov – Architectural and historical Survey, October (2009).

[7] Kloiber, M., Tippner, J., Hrivnák, J., Praus, L.: Experimental verification of a new tool for wood mechanical resistance measurement. In: Wood Research 57(3): 2012, Slovakia. ISSN: 1336-4561, pp.383-398.

[8] Kloiber, M., Kotlínová, M.: In-situ evaluation & non-destructive testing of historic wood and masonry structures, RILEM Workshop, 10-14 July 2006, Prague, Czech Republic. pp.56-65.