United States Department of Agriculture Nondestructive Evaluation of Wood Second Edition Forest Forest Products General Technical Report July Service Laboratory FPL–GTR–238 2015 Abstract Conversion Table This report summarizes information on nondestructive test- English unit Conversion factor SI unit ing and evaluation of wood. It includes information on a inch (in.) 25.4 millimeter (mm) wide range of nondestructive assessment technologies and foot (ft) 0.3048 meter (m) their uses for evaluating various wood products. board foot 0.0023597 cubic meter (m3)) (nominal) Keywords: Wood, timber, nondestructive testing, feet per minute 0.005080 meters per second nondestructive evaluation (ft/min) (m/s) pound (lb) 0.448 newton (N) pounds per square 0.0069 pascal (Pa) inch (lb/in2) in4 4.162 × 10–7 m4 July 2015 Ross, Robert J. (Ed.). 2015. Nondestructive evaluation of wood: second edition. General Technical Report FPL-GTR-238. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 169 p. A limited number of free copies of this publication are available to the public from the Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI 53726–2398. This publication is also available online at www.fpl.fs.fed.us. Laboratory publications are sent to hundreds of libraries in the United States and elsewhere. The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. The use of trade or firm names in this publication is for reader information and does not imply endorsement by the United States Department of Agriculture (USDA) of any product or service. 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Ross Forest Products Laboratory Contents Preface ..................................................................................................................................................... iii Preface to the First Edition .......................................................................................................................iv Chapter 1—Nondestructive Testing and Evaluation of Wood ...................................................................1 Chapter 2— Static Bending, Transverse Vibration, and Longitudinal Stress Wave Nondestructive Evaluation Methods ..........................................................................................................5 Chapter 3—Ultrasonic-Based Nondestructive Evaluation Methods for Wood .......................................21 Chapter 4— Proof Loading ......................................................................................................................53 Chapter 5—Sounding, Probing, Moisture Content, and Resistance Drilling Techniques .......................59 Chapter 6—A Review of the Piezoelectric Effect in Wood .....................................................................67 Chapter 7—Nondestructive Testing in the Urban Forest .........................................................................77 Chapter 8— Acoustic Assessment of Wood Quality in Trees and Logs ..................................................87 Chapter 9— Laser Scanning of Logs and Lumber ................................................................................103 Chapter 10—Ultrasonic Veneer Grading ...............................................................................................109 Chapter 11—Machine Grading of Lumber ............................................................................................115 Chapter 12— Inspection of Timber Structures Using Stress Wave Timing Nondestructive Evaluation Tools ....................................................................................................................................141 Chapter 13— Use of Laser Scanning Technology to Obtain As-Built Records of Historic Covered Bridges .....................................................................................................................................149 Appendix—Proceedings of the International Nondestructive Testing and Evaluation of Wood Symposium Series ..................................................................................................................................167 ii Preface This edition of Nondestructive Evaluation of Wood builds upon the first edition with important new content: • Ultrasonic nondestructive testing methods (Chapter 3) • Piezoelectric effect in wood (Chapter 6) • Urban tree assessment (Chapter 7), reflecting significant research and technology transfer advances • Laser scanning of logs and lumber (Chapter 9), reflecting the importance of scanning systems in the wood manufacturing industry • Updates on mechanical grading methods for structural lumber (Chapter 11) • Use of laser scanning technologies for evaluation of historic, covered timber bridges (Chapter 13) • An appendix providing information to access digital copies of all proceedings from the International Nondestructive Testing and Evaluation of Wood Symposium Series The objective of this book is the same as that of the first edition—to serve as a primary reference on non- destructive evaluation of wood. Sections of the book originally appeared in technical journals, research reports, and proceedings from various symposia. For example, the chapters on ultrasonic nondestructive testing methods, the piezoelectric effect in wood, and the use of laser scanning technologies for evalua- tion of bridges were originally published as USDA Forest Products Laboratory (FPL) reports. I worked with several well-respected technical authorities in preparing this edition. I thank the technical contributors to this edition: • R. Bruce Allison, PhD, Adjunct Professor, University of Wisconsin–Madison; and Allison Tree, LLC, Verona, Wisconsin, USA • Brian K. Brashaw, PhD, Program Manager, Forest Products Marketing Unit, USDA Forest Service, Madison, Wisconsin, USA • Peter Carter, CEO, Fibre-gen, New Zealand • William Galligan, Consultant, USA • Gregory Schueneman, PhD, Project Leader, USDA Forest Products Laboratory, USA • C. Adam Senalik, PhD, P.E., Research General Engineer, USDA Forest Products Laboratory, USA • Edward Thomas, Research Computer Scientist, USDA Forest Products Laboratory, USA • Xiping Wang, PhD, Research Forest Products Technologist, USDA Forest Products Laboratory, USA I also acknowledge Professor (retired) Roy F. Pellerin, Washington State University, for his valuable contributions to the first edition ofNondestructive Evaluation of Wood. Financial support from the USDA Forest Service for this second edition of Nondestructive Evaluation of Wood is gratefully acknowledged. This edition of Nondestructive Evaluation of Wood is dedicated to Roy F. Pellerin and John R. Erickson, my good friends and colleagues. Roy F. Pellerin is a pioneer in the field of nondestructive testing and evaluation, leading the successful nondestructive evaluation research program at Washington State University for nearly 40 years. His technical accomplishments are numerous, and his leadership of the International Nondestructive Test- ing and Evaluation of Wood Symposium Series has resulted in the worldwide development and use of nondestructive evaluation. He is an inspiration and source of knowledge to a generation of graduate students, scientists, and engineers working in the field. iii John R. Erickson (1934–2014), P.E., Director and Research Engineer, FPL, was an internationally recognized leader in the wood science profession. He conducted research on wood harvesting and utilization issues with wood and guided the FPL through numerous changes. He initiated new research initiatives at FPL in recycling, green technologies, biotechnology, and ecosystem manage- ment. Under his leadership, FPL provided critical technical support to the Forest Service, wood prod- ucts industry, and various government agencies, including the Department of Defense, Department of Energy, National Park Service, and Department of Housing and Urban Development. John was a strong supporter and advocate for the nondestructive evaluation field; after retiring from the Forest Service he joined the staff at Michigan Technological University, where he worked on the develop- ment of advanced tree and log nondestructive assessment and grading technologies that have been widely adapted for use. John was a well-respected scientist, worldwide, and he served the public in a professional manner for over 40 years. His reputation is impeccable. Nondestructive Evaluation of Wood, Second Edition is available in digital format from the USDA Forest Service Forest Products Laboratory website. Special thanks to Jim