Decay in Mine Timbers–Part III : Species-Independent Stress Grading

A pin-injecting Pilodyn and a James V-meter stress-wave measuring instrument were used to estimate crushing strength and modulus of elasticity (MOE) of mine props. Both nondestructive testing instruments can be used to sort or grade mine props. The timber sampling included 26 species or species groupings ranging from spruce and aspen to oak and hickory. Test material was selected to include a wide range of decay levels. Dynamic MOE derived from stress-wave measurements generally gave the best estimates of crushing strength and static MOE for samplings of all species combined, hardwoods only, softwoods only, and sorts of maples, oaks, and pines. Results indicate that species-independent machine stress-rating systems can be a viable supplement or alternative to visual grading.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member