Often, when diagnosing on site and assessing load-bearing timber elements, the architect or engineer is faced with timber members appearing totally or with portions very much decayed. Fissures and splits across the wood section may be very wide and deep, may be multiple and thus the cross-section will look partialised. In addition, decay due to rot and insects attack may aggravate the health situation. Punctual and area diagnostic tools such as drill penetration resistance, sonic tests including tomography, high- frequency GPR radar investigations, IR thermography with their image diagnostic capabilities may effectively and rapidly delimit the extent of such decayed areas. Nonetheless, the question may remain on the mechanical response of the remaining material when undergone to load. Since a few years, availability of measuring techniques exploiting optical principles allows through inexpensive full-field monitoring of geometry changes in sample surface to easily obtain accurate maps of displacements, deformations and tension along the 3 principal directions. Firstly used in mechanical engineering and composite material testing, their use for testing of structural elements and construction materials is gradually spreading. Instead, application of DIC (Digital Image Correlation) on timber specimens is still very scarce. In order to enhance the surface’s displacement spatial resolution, an up-to-now compulsory method requirement is the preparation of the investigated surface by a white coating spotted by a distribution of speckles of appropriate size. In the present work, cross-sectional slices from a historic timber beam are undergone in the lab to compression testing in elastic field while monitored by DIC. Specimens are partialised and in different health status. Moreover, the investigated face of the specimen has not been previously prepared by coating, introducing a novelty in the method procedure. Through the discussion of obtained strain maps at different load levels, it will be provided a new insight into local response of historic timber across the beam section.
Colla, C., Gabrielli, E. (2015). On the response of historic timber beam cross-section when loaded in compression. Wrocław : DWE.
On the response of historic timber beam cross-section when loaded in compression
COLLA, CAMILLA;GABRIELLI, ELENA
2015
Abstract
Often, when diagnosing on site and assessing load-bearing timber elements, the architect or engineer is faced with timber members appearing totally or with portions very much decayed. Fissures and splits across the wood section may be very wide and deep, may be multiple and thus the cross-section will look partialised. In addition, decay due to rot and insects attack may aggravate the health situation. Punctual and area diagnostic tools such as drill penetration resistance, sonic tests including tomography, high- frequency GPR radar investigations, IR thermography with their image diagnostic capabilities may effectively and rapidly delimit the extent of such decayed areas. Nonetheless, the question may remain on the mechanical response of the remaining material when undergone to load. Since a few years, availability of measuring techniques exploiting optical principles allows through inexpensive full-field monitoring of geometry changes in sample surface to easily obtain accurate maps of displacements, deformations and tension along the 3 principal directions. Firstly used in mechanical engineering and composite material testing, their use for testing of structural elements and construction materials is gradually spreading. Instead, application of DIC (Digital Image Correlation) on timber specimens is still very scarce. In order to enhance the surface’s displacement spatial resolution, an up-to-now compulsory method requirement is the preparation of the investigated surface by a white coating spotted by a distribution of speckles of appropriate size. In the present work, cross-sectional slices from a historic timber beam are undergone in the lab to compression testing in elastic field while monitored by DIC. Specimens are partialised and in different health status. Moreover, the investigated face of the specimen has not been previously prepared by coating, introducing a novelty in the method procedure. Through the discussion of obtained strain maps at different load levels, it will be provided a new insight into local response of historic timber across the beam section.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
