Encontrados 12 documentos, a visualizar página 1 de 2

Characterization of cross sections from old chestnut beams weakened by decay

This work aims to experimentally assess the material properties of old chestnut (Castanea sativa Mill.) cross sections weakened by decay. Specimens were taken from critical zones of twenty floor beams, mostly corresponding to their ending parts, in contact with granite masonry walls. These specimens were compared with clear wood specimens taken from non-decayed parts . The experimental campaign comprised of vi...

On the use of NDT data for reliability-based assessment of existing timber stru...

The objective of this paper is to address the possibilities of using non-destructive testing (NDT) data for updating information and obtaining adequate characterization of the reliability level of existing timber structures and, also, for assessing the evolution in time of performance of these structures when exposed to deterioration. By improving the knowledge upon the mechanical properties of timber, better a...

Methodology for safety evaluation of existing timber elements

Tese de doutoramento em Engenharia Civil ; The past decades have seen a renewed interest in timber research related topics. As instance, timber engineering is not only confined to the design of new construction with innovative wood based products, but also an increasing awareness for the preservation of existing timber structures is visible in nowadays society. Therefore, arises the need for a better understan...

Glulam mechanical characterization

The glued laminated timber (glulam) mechanical properties may be evaluated through the determination of the key mechanical properties of the lamellae that compose that element. Simple bending and tension parallel to the grain tests were performed in order to assess the strength class of three glulam elements. Regarding the bending tests, 8 samples were taken from a glulam beam and assessed. Values for the resis...

Reliability analysis of a timber truss system subjected to decay

Assessing the safety of existing timber structures is of paramount importance for taking reliable decisions on repair actions and their extent. The results obtained through semi-probabilistic methods are unrealistic, as the partial safety factors present in codes are calibrated considering the uncertainty exhibited by new structures. In order to overcome these limitations, and also to include the e ects of deca...

In situ measured cross section geometry of old timber structures and its influe...

Old timber structures may show significant variation in the cross section geometry along the same element, as a result of both construction methods and deterioration. As consequence, the definition of the geometric parameters in situ may be both time consuming and costly. This work presents the results of inspections carried out in different timber structures. Based on the obtained results, different simplified...

Effectiveness and subjectivity of visual inspection as a method to assess bendi...

Besides the difficulty of assessing an existing timber structure on site, the efficiency and accuracy of visual inspection is often compromised by its subjective nature inherited by the level of expertise of the inspector. This often leads to conservative predictions of the mechanical properties, even with the use of specific visual grading norms. The main objectives of this work are to assess the effectiveness...

Characterization of old chestnut beams sections weakened by decay

The objective of this work was to experimentally assess the material properties of old chestnut (Castanea sativa Mill.) sections weakened by decay. Specimens were taken from critical zones of twenty floor beams, mostly corresponding to the ending parts in contact with granite masonry walls. These specimens were compared with clear wood reference specimens taken from undecayed parts of the same old beams. The ex...

Assessment of strength and stiffness variation within old timber beams

The mechanical properties of timber elements vary significantly along its extent due to natural variability of wood cellules and presence of defects. In this work, the variability of stiffness and strength properties of old chestnut (Castanea sativa Mill.) floor beams with more than 100 years, was experimentally assessed and mechanical properties were correlated. Visual inspection, non-destructive and destructi...

Inspeção e diagnóstico estrutural do armazém da estação de Foz Tua