First Trials to Set Up a Microwave Reflectometric Tool for the Survey of Historic Timber Structures

Timber structures can be degraded during their life both by structural problems and by biological degradation factors like fungi and insects. The occurrence of those biodegradation agents could lead to a loss of their structural integrity, in the absence of appropriate maintenance. An early assessment of the decay is even more important when the wooden structures are part of historical buildings, in the interest of conservation of cultural heritage.

This article presents an application of microwave reflectometry for the in situ evaluation of timber structures. The measurement system allows detecting anomalies inside the material in a non-destructive and non-invasive manner.

The reflection coefficient is measured by means of a vector network analyzer (VNA) using a double-ridge antenna which transmits the continuous-wave (CW) microwave signal and receives the signal reflected by the material under investigation.

Measurements on laboratory models demonstrated the feasibility of the method. Results obtained on timber beam sections, compared with the findings of traditional investigation methodologies, demonstrate the potentiality of microwave reflectometry, suggesting its possible usefulness during the diagnostic phase as a non-invasive tool for preliminary screening.     

Direct Displacement-Based Design of Glulam Timber Frame Buildings

We introduce a direct Displacement-Based Design methodology for glued laminated timber portal frames with moment-resisting doweled joints. We propose practical expressions to estimate ultimate target displacement and equivalent viscous damping, and we demonstrate that these expressions provide prior values that are close to those obtained a posteriori using a more refined model. Applied to case studies, the method yields base-shear forces lower than those obtained using the force-based approach of Eurocode 8. This is due to the high dissipation capacity of the specific connection technology, which apparently is conservatively accounted for in the q-factor of Eurocode 8.     

Timber exploitation during the 5th–3rd millennia BCE at Arslantepe (Malatya,Turkey): environmental constraints and cultural choices

A considerable amount of charcoal remains from the archaeological site of Arslantepe (Eastern Anatolia) has been analysed. The anthracological assemblage comes from seven archaeological periods, ranging from the Late Chalcolithic 1–2 (mid-5th millennium BCE) to the Early Bronze Age III (late 3rd millennium BCE). The woody taxa exploited by the local communities appeared to have only minor changes throughout the investigated periods. For the evaluation of wood use practices, charcoal was chronologically grouped according to depositional context. The categories of depositional context identified differentiate between the uses of wood for structural parts of buildings, object manufacture, fuel, refuse, and wood found in outdoor areas or in burial contexts. Communities at Arslantepe, characterized by different cultural and socio-economic traits, appeared overall to select timber depending on its use: hydrophilous plants prevail in building material, with the exception of the 2900–2500 BCE period when environmental constraints probably motivate the dominance of woodland-steppe plants. The differential occurrence of taxa in the diverse depositional contexts highlighted cases of under/overestimation of remains, in particular in relation to the woods for construction. Finally, taxa have been attributed to different ecological groups. The interpretation of results and the comparison with other available palaeoenvironmental data point out that climatic factors play only a secondary role in the choice of wood exploitation in the area. Human choice may vary even with constant environmental records.     

Establishing the Middle Sea: The Late Bronze Age of Mediterranean Europe (1700–900 BC)

Journal of Archaeological Research - The Late Bronze Age (1700–900 BC) represents an extremely dynamic period for Mediterranean Europe. Here, we provide a comparative survey of the...