•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.
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, relating the scope of the assessment, information required and necessary procedures, (3) identify guidance for the different scopes of the assessment. The variety of timber species, architectural typologies and structural solutions, together with the varied response of these structures to climatic and other natural and man-made hazards, warrant a multifaceted and integrated assessment methodology that accounts for the hierarchical nature of timber structures behaviour and the multitude of agents affecting such behaviour. A review of existing standards and guidelines illustrates the need for a tool to consistently record the assessment process and the final decision taken, which will serve to constitute the knowledge base for the development of the next generation of more integrated and heritage specific guidelines.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Historical timber-framed wall system was investigated under cyclic loads.•Damage progression and post-elastic behaviour was analysed by image-based tracking method.•Plastic deformations and local ...damage occurred in some joints.•Observations are important for the design of strengthening or repair interventions.
The scope of this paper is to analyse local phenomena associated with the damage progression and post-elastic behaviour of a historical timber-framed wall system under cyclic loads. It was assessed on series of points identified on the wall by processing time-resolved sequences of images. Dedicated methodology of image-based tracking method was developed to analyse local phenomena, such as relative displacements, rotations and deformations in the wall. It was possible to deduce that plastic deformations and local damage occurred in some joints. This type of observation is important for the design of rigorous strengthening or repair interventions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The building and construction sector is a major contributor to human environmental impact on the planet. It follows that the sector's contribution is also crucial for transition towards a low carbon ...society and circular economy (CE). Mass timber products, are one of the sustainable alternatives to traditional building materials and have led to the recent revolution in timber construction. While environmental benefits of mas timber manufacturing and construction is well documented the end-of-life (EOL) and the post-EOL options for mass timber buildings, their environmental benefits and CE potential are discussed much less. Short history of construction technology involving prefabricated mass timber panels compared to traditional building types results in virtually no documented cases of panelized mass timber structures reaching the EOL stage and no practical examples of incorporating CE concepts in such projects. In this study, a two-step systematic literature review was used, to define and classify 23 CE-based governing principles from six categories in the construction industry, and to use those principles to analyze the state-of-the-art circular approach in mass timber research. The study covered a total of 90 papers, of which 68 focused on the general construction industry and 22 specifically on the mass timber construction. Results of this review suggest substantial gaps in knowledge and pressing research needs for the development of holistic approaches to prepare the mass timber construction for circular economy.
•A two-phase review for circular economy (CE) in mass timber research was conducted.•23 governing principles for CE in construction industry were defined and classified.•State-of-the-art of mass timber research was analyzed using 23 CE principles.•Research gaps in CE implementation for mass timber construction were identified.•Future research recommendations for CE in mass timber construction were discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The goal of this work was to understand and model the combined effect of time, geographical location, and exposure on the physical-chemical mechanisms of wood weathering in structures. Series of ...wooden samples were exposed to natural weathering in seven locations varying in climatic conditions, including Italy and north Germany. The set of samples was exposed for 4 years, collecting representative samples each year. Four exposure directions (north, south, east, and west) were investigated. Measurements of samples included: photogrammetry, near and mid infrared spectroscopy, color, gloss, roughness, and elemental composition (x-ray fluorescence spectroscopy). Results showed that the surface degradation mechanisms caused by weathering were affected by the site of exposure. The wood samples weathered in the Italian sites, in Udine and Macerata, were most degraded. The most significant changes were observed in samples exposed to the south direction. The original algorithm for calculation of "the weathering indicator", by merging the multi-sensor data and linking these to the surface performance indicators was developed. Finally, the subjective visual assessment by the expert person was compared with parameters obtained by measuring the weathered surfaces with various sensors. A good correspondence between weathering indicator W
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and subjective quality index was established.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
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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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
AbstractA full-scale 2-story mass timber building was tested on the University of California San Diego Natural Hazards Engineering Research Infrastructure (UCSD-NHERI) uniaxial shake table during the ...period from June 2017 to September 2017. The main objective of the experimental program was to test the performance of mass timber building designs with different seismic lateral force–resisting systems. The focus of this study is on a building configuration designed using self-centering post-tensioned cross-laminated timber (CLT) rocking walls with U-shaped steel flexural plate energy dissipators. The shake-table tests were designed to subject the building to a series of earthquake ground motions of increasing intensity, ranging from a service-level earthquake to 1.20 times the maximum considered earthquake intensity. Between each ground motion, low-amplitude white-noise excitations were applied to the building, which responded as a quasilinear system. In this paper, two output-only operational modal analysis methods are used to estimate the modal parameters (frequency, damping, and mode shapes) based on acceleration data collected during the white-noise shake-table tests. The correlations of observed damage and repairs performed during the experimental program with changes in estimated modal features are reported. The modal parameters estimated from the testing program are also compared with a linear finite-element model that is used to validate the modal identification results and study the performance of the two system identification methods for CLT rocking structures.
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.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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