ADVANCED GRADING FOR IMPROVEMENT AND RELIABILITY OF ROUND TIMBER DESIGN VALUES

This project is the last piece of the round timber production puzzle for WholeTrees Structures' SBIR-funded research initiatives: improved selection and grading procedures for round pole timber, building on ASTM visual grading rules for poles and piles, but for structural spanning applications. This research project is based on a solid body of prior work (Wood et al. 1965; Goodman et al. 1981; Wang et al. 2001) correlating in-field nondestructive valuation (NDE) with tested bending strengths and the modulus of elasticity (MOE). WT proposes to refine and implement a cost-effective selection and grading methodology for commercial production. USDA secretary, Tom Vilsack, has urged the Forest Service to "develop new markets" for forest by-products that encourage healthy timber management. WholeTrees® Architecture & Structures (WT) has successfully commercialized a line of round timber structural systems for the non-residential construction industry. The company is creating value from the abundant cullings of well-managed forests with ongoing structural testing of branching round timbers, and subassembly connection tests (2012 Phase II SBIR); development of a software-based grading system for branched round timber, (SBIR Phase I 2013), and perhaps most importantly, successful entry into commercial markets.This research project will optimize the selection and grading of round timber used for spanning to reduce costs and improve product safety, performance and reliability. This research project will: 1) build on previously demonstrated effective Non-Destructive Evaluation (NDE) techniques; 2) further correlate NDE with destructive testing; and 3) develop a cost-effective set of grading procedures for manufacturing as Phase I proof of concept.