PSI - Issue 55

Dulce Franco Henriques et al. / Procedia Structural Integrity 55 (2024) 214–221 Henriques et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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safety in relation to the class. Its wane and biological degradation lead to the consideration of an effective (residual) section of 8.5 x 13 cm. With the data collected, it is possible to carry out a structural analysis. If the decision is made to retain this beam in the structure, it will likely require reinforcement.

Table 2. Visual Strength grading of the beam V1 according to BS 4978:2007. Key VSG Measurement of characteristics versus VSG standard criteria

GS SS

cross-section SC1 has a larger knot area:

TKAR SC1 = 21,5 / 137,5 = 0,16 < 1/2

Knots

X

MKAR SC1 = 5,75 / 32 =0,18 < 1/3

(cm)

Slope of Grain

Slope of grain ≈ 0

X

Rate of Growth Fissures

Ring width average = 75/2 = 3,57 mm < 6 mm

X

Not through the thickness and not longer than 1.5 m

X

4. Conclusion This study underscores the criticality of conducting thorough diagnoses of structural timber conditions in historic buildings. A variety of diagnostic methods are available, some of which are well-established, while others are still in the developmental phase. The Visual Strength Grading (VSG) methodology is a proven and reliable approach, especially when used in conjunction with Non-Destructive Testing/Stress-Diagnostic Testing (NDT/SDT) methods. Its application to in-service timber members should be grounded in fundamental features such as knots, grain slope, and growth rate, with other defects and characteristics analyzed on an individual basis. The case study demonstrated that data gathered through visual inspection, penetration resistance testing, and VSG can effectively support the structural analysis of existing buildings. This is since data has been obtained from a variety of methodologies, which have been meticulously correlated and integrated. Acknowledgements The authors are grateful for the Foundation for Science and Technology's support through funding UIDB/04625/2020 from the research unit CERIS / Instituto Politécnico de Lisboa (IPL) for the financial support to the WOODINSITU project (ref. IDI&CA/WOODINSITU) and to the TEC-TIMBER project (IPL/2019/TEC TIMBER_ISEL) / Spybuilding - Inspecção de Edifícios, Lda. for promoting the application of the inspection methodology to a real building. References BS 4978:2007. Visual strength grading of softwood - Specification. British Standards Institution. London. Cabaleiro, M., Branco, J., Sousa, H., Borja Conde., 2018. First results on the combination of laser scanner and drilling resistance tests for the assessment of geometrical condition of irregular cross - sections of timber beams. Mat. and Struct. Vol. 51(4). 10.1617/s11527 - 018 - 1225 - 9. Cruz, H., Yeomans, D., Tsakanika, E., Macchioni, N., Jorissen, A., Touza, M., Mannucci, M., Lourenço P. B., 2015. Guidelines for the on - site assessment of historic timber structures. International Journal of Architectural Heritage, 9:277 - 289. DOI: 10.1080/15583058.2013.774070.