This paper summarizes the test recommendations for in situ assessment of structural timber using stress wave measurements as developed by members of the RILEM Technical Committee AST 215 "In-situ assessment of structural timber". In the first part, the basic principles, the equipment, and the practical application of stress-wave-based testing using the time-of-flight method are described. A detailed testing procedure provides hands-on information on the execution of in-field stress wave testing. A typical example is given to demonstrate step-by-step on how to evaluate stress wave readings and the health state of the inspected timber member. The latter part of the paper gives a short overview of the use of acoustic tomography and ultrasonic echo methods

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This paper presents a comparative study using static and ultrasonic testing for the determination of the full set of orthotropic material properties of wood. In the literature, material properties are typically only available in the longitudinal direction, and most international standards do not provide details on the testing of the other two secondary directions (radial and tangential). This work provides a comprehensive study and discussions on the determination of all twelve orthotropic material properties of two hardwood species using static testing and an alternative testing approach based on ultrasonic waves. Recommendations are given on the execution of the tests and the interpretation and calibration of the results.

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In this first part of a two-part paper, the use of two existing algorithms developed for global nondestructive evaluation to locate and evaluate localised damage in timber beams is investigated using a finite element model. These damage localisation algorithms were found, through this investigation, not to be effective in locating multiple damage scenarios and unable to evaluate the severity of damage. Hence, modifications on damage index algorithm as well as a hybrid algorithm are proposed to overcome the problems. In this study, Experimental Modal Analysis (EMA) was used as a tool to extract mode shapes for calculating the damage index in the proposed method which utilises changes in modal strain energy between the undamaged and the damaged timber beam model. The Modified Damage Index method normalises the mode shape curvature and the hybrid algorithm combines the modified index algorithm and changes in flexibility algorithms which reflect the changes of natural frequency and mode shape. Analytical evaluations were performed to compare and verify the ability of existing and modified damage localisation algorithms in locating single and multiple damage in timber beams. The Modified Damage Index algorithm and the hybrid damage algorithm are also used in the companion paper to validate the effectiveness of the methods to