The strength of the timber found in covered bridges can vary considerably, not only because of age and condition, but also because of species and grade. For evaluation purposes, it is necessary that the design values for existing wood members be determined with as much accuracy as possible. The current practice is to assign wood values for strength and moduli from existing specifications, but oftentimes these values are inaccurate for the specific condition and can result is an unreliable assessment of the structure. This could be hazardous where the type, source, and grade of the existing wood are uncertain. This study will develop methodologies for species identification and approximated field grading of timbers.
The objective is to develop methodologies for easier identification and design value estimation in grading of wood species onsite.