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

Maurizio Piazzais Full Professor at the Department of Mechanical and Structural Engineering at the University of Trento and a member of a number of international and national technical committees. His research activity is mainly devoted to the themes of steel, composite steel -concrete, timber -concrete and timber structures. As regards the latter theme and in particular the existing timber structures, the research areas deal with traditional connections, mechanical characterisation, static and seismic behaviour, rehabilitation procedures as well as fi re resistance. Mariapaola Riggiois an architect and has a PhD in Structural Engineering. She is a member of the RILEM technical committee AST for the ' In-situ assessment of structural timber ' . She has carried out research activities in fi elds typical of structural rehabilitation, initially at the University of Calabria (UNICAL) and currently at the University of Trento. Her research and professional interests are mainly focused on the appraisal and restoration of existing structures. AbstractIn order to assess the safety of old timber structures and eventually to select appropriate strengthening strategies, the evaluation of mechanical properties of the material is of key importance. Visual strength-grading coupled with the use of nondestructive in situ testing allows these properties to be determined. Nowadays, the defi nition of both nondestructive testing (NDT) procedures and criteria for the results interpretation are almost exclusively in charge of the producer. In Italy, effort has been made to develop codes for grading timber on-site, and also by means of NDT. The aim of this paper is to highlight the diffi culties and shortcomings that still occur in the assessment of traditional timber members following the criteria established by the legislation in force in Italy. The presented results can be helpful for the building surveyor who is in charge of the inspection of existing timber structures. Indeed, the paper gives some indications on the effectiveness of the grading criteria applied on historical timbers, as well as on the level of accuracy of some nondestructive methods.

This paper summarizes the test recommendations for selected non-destructive testing (NDT) techniques as developed by members of the RILEM Technical Committee AST 215 "In situ assessment of structural timber". The recommendations cover visual inspection, moisture content determination, species identification, digital radioscopy, and ground penetrating radar. The paper includes a matrix of common NDT to assess structural timber. The discussion of each technique is intended to provide users with sufficient information to understand the theoretical basis, typical equipment set up, and basic capabilities and limitations

This paper summarizes the test recommendations for selected semi-destructive testing techniques as developed by members of the RILEM Technical Committee AST 215 "In-situ assessment of structural timber". The recommendations cover resistance drilling, core drilling, glue line test, tension micro-specimens, screw withdrawal, and several hardness tests. The paper includes a matrix of common non-destructive testing to assess structural timber. The discussion of each technique is intended to provide users with sufficient information to understand the theoretical basis, typical equipment set up, and basic capabilities and limitations

This paper reviews the official documentation (standards, guidelines and procedures) available for the assessment of heritage timber structures. The subsequent discussion does not catalogue all relevant technical literature. Instead, it intends to convey the state of background knowledge, recommendations and code rules using some illustrative examples. A specific focus is given to visual inspection as a fundamental first step for all different scopes and levels of assessment. The objectives of this review are to: 1) highlight the gaps and limitations in the currently available tools as well as the need for standardization; 2) contribute to the definition of an ontological approach, Highlights • A review of the methodological, normative and operational tools for the assessment of heritage timber structures. • A critical discussion of the gaps and limitations of current assessment tools. • An introduction to a proposed inspection form for heritage timber roofs.

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