Although cross-laminated timber (CLT) offers greatly improved directional stability against moisture changes compared to lumber, some layup dependent directional differences still remain. Furthermore, even under a purely homogeneous distributed moisture change strong deformations appear along the boundaries, which show a decrease of swelling/shrinkage towards the inside of CLT panels. Metrological determination of this behavior is still a challenging task and involves long-lasting moisture content conditioning and typically manual measurements. This limits the amount of measurable data-points and thus the gain-able insights. We apply a recently introduced computer vision technique based on optical flow from scan images to measure surface deformation fields of various CLT specimens with different layups. This allows us to measure the change of average differential swelling and shrinkage coefficients throughout the cross section and visualize them as curves with high resolution. We gain measurements for each image pixel and demonstrate good matching to previously published manual single-point measurements. Furthermore, we analyze various specimens specifically built to allow for investigations of the aforementioned boundary effects. Using the computer vision approach we are able to show how the combination of homogeneous deformations and boundary effects leads to the resulting deformations observable with manual methods.

Wood-composite materials are widely used today as they homogenize humidity related directional deformations. Quantification of these deformations as coefficients is important for construction and engineering and topic of current research but still a manual process. This work introduces a novel computer vision approach that automatically extracts these properties directly from scans of the wooden specimens, taken at different humidity levels during the long lasting humidity conditioning process. These scans are used to compute a humidity dependent deformation field for each pixel, from which the desired coefficients can easily be calculated. The overall method includes automated registration of the wooden blocks, numerical optimization to compute a variational optical flow field which is further used to calculate dense strain fields and finally the engineering coefficients and their variance throughout the wooden blocks. The methods regularization is fully parameterizable which allows to model and suppress artifacts due to surface appearance changes of the specimens from mold, cracks, etc. that typically arise in the conditioning process.

In der vorliegenden Arbeit werden, aufbauend auf die Bemessungsdiagramme für einen Biegeträger einer Dachkonstruktion mit homogenem Stabquerschnitt [ 1 ], die Erweiterung um den inhomogenen Stabquerschnitt (geschichteter Verbundquerschnitt) sowie die Implementierung der Schwingungsnachweise gezeigt. Während bei den Bemessungsdiagrammen für den homogenen Stabquerschnitt sowohl die ULS‐ als auch die SLS‐Nachweise von Relevanz waren, treten bei Erweiterung um die Schwingungsnachweise sowie aufgrund der Einflüsse des inhomogenen Querschnittsaufbaues vorrangig die SLS‐Nachweise auf. Das Schwingungsverhalten von Deckentragwerken wird wesentlich durch die Lagerungsbedingungen beeinflusst. Die Einspanneffekte im Bereich des Anschlussdetails Wand‐Decke zufolge der Geschossauflasten werden bei der Bestimmung der Eigenfrequenz berücksichtigt.

This paper presents an application of design charts for inhomogeneous cross-sections (layered composite section) and the implementation of vibration design criteria as extension of the charts for beams with homogeneous cross-sections in roof-structures according to selected European Design Standards published in [1]. While ULS and SLS criteria were nearly equally governing for the homogeneous cross-section, mainly SLS criteria are now governing due to the extension with vibrations and the influences of the inhomogeneous cross-sections. The vibrational behavior of floors is essentially influenced by the support conditions. Effects of moment restraints at the wall-floor-wall detail, activated by wall-loads from stories above, are systematically being taken into account.

This contribution deals with the influences of time and those relevant to bearing capacity on the reliability of historic timber roof structures. Furthermore the evaluation as well as damage analysis of historic roof structures are discussed. Based on this an easily comprehensible and documentable methodology temporarily only for roof structures in the area of Graz is presented and illustrated with examples.

The proportion of the load-bearing capacity of the roofing lath on the global load transfer of roof structures. In this contribution, the influence of the roofing lath on the spatial load-bearing behaviour of single areas of carpentry roof structures is pointed out. Therefore, some theoretical background on the load-bearing capacity of roof battens is presented. This is followed by the report of some structural tests and the documentation of two model calculations.