Estimating strengths of wooden supports

A method of locating regions of unsound wood in a wooden support comprising the steps of:

• a) estimating the strength of the wooden support by transmitting gamma rays parallel to a neutral axis through a cross section of the wooden support, detecting the gamma rays transmitted through the wooden support, determining the average density of the gamma rays transmitted through the wooden support, determining the average density of the gamma rays in rows parallel to the neutral axis, assessing the amount of unsound wood in each row, and calculating the strength of the wooden support, and conducting one or both steps of b) and c):
• b) (either before or after step a), determining the density of sound wood of the wooden support, directing gamma rays approximately normal into the surface of the wooden support, detecting the gamma rays that are backscattered approximately 180 degrees, comparing the measured rates with those of the sound timber to estimate the thickness of wood;
• c) repeating step a), but in rows substantially orthogonal to the neutral axis.

A device for estimating the strength of a wooden support and/or for locating regions of unsound wood in a wooden support comprising a frame adapted to be positioned around the wooden support, at least one gamma ray source and at least one gamma ray detector, the gamma ray source and detector positioned on the frame to transmit and detect gamma rays through a wooden support parallel to a neutral axis of the wooden support, computation means arranged to receive a signal from the at least one detector, determine the average density of the gamma rays in rows parallel to neutral axis, assess the amount of unsound wood in each row, and calculate the strength of the wooden support.

A method of estimating the strength of a wooden support comprising the steps of transmitting gamma rays parallel to a neutral axis through a cross section of the wooden support, detecting the gamma rays transmitted through the wooden support, determining the average density of the gamma rays in rows parallel to the neutral axis, assessing the amount of unsound wood in each row, and calculating the strength of the wooden support and wherein the method further comprises making two cross section measurements at different points on the wooden support, one measurement being a reference measurement taken through wood that is assumed to be sound and the other measurement taken through wood to be analysed.