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Evaluierung eines Modells zur Schätzung des Verankerungswiderstands von Baum- und Stockankern und Test eines smarten Frühwarnsystems für Ankerversagen

Projektleitung
Stampfer Karl, Projektleiter/in
Laufzeit:
01.01.2021-30.06.2023
Programm:
BMNT - Beauftragung
Art der Forschung
Angewandte Forschung
Mitarbeiter*innen
Hönigsberger Ferdinand, Projektmitarbeiter/in
Euler-Rolle Mathea, Projektmitarbeiter/in
Beteiligte BOKU-Organisationseinheiten
Institut für Forsttechnik
Gefördert durch
Bundesministerium für Nachhaltigkeit und Tourismus, Stubenring 1, A-1012 Wien, Österreich
Abstract
Tree and stump anchors are the most common type of anchors used in timber harvesting with cable yarders and winch-assisted harvesting systems. Anchor failure presents a serious risk to occupational safety and accidents connected to anchor failure are often associated with severe damage to man and machine. Therefore, selection of suitable anchors is a critical task in operation planning, and has, due to climate change related stress of trees and thus decreasing tree stability, become a more difficult one. Selection of anchors is a considerably complex decision, as anchorage of tree and stump anchors is affected by terrain, tree dimensions, vitality, soil type, soil moisture, force application point and magnitude of applied force. Therefore, it has been tried to boil down this considerably complex decision to rules of thumb or simple formulas, most of them in relation to the diameter of breast height. A recently developed static model may allow to provide a more reliable estimation of the anchorage of tree- and stump anchors through comprehensive assessment of the factors determining anchorage. Further, contrary to previous models, it is applicable to both cable yarding and winch-assisted machinery cases. The goal of the present project is to evaluate the developed model’s accuracy during empirical field tests and to investigate if anchor failure can be predicted through monitoring of changes in the position of the anchor (movement in horizontal and vertical direction, tilt, rotation). To this end, tree and stump anchors shall be brought to failure with a tractor-mounted winch in ways that represent typical load cases in cable yarding and winch-assisted timber harvesting. The pull force required for anchor failure is measured with a load shackle and recorded alongside changes of anchor position. Data is then merged with tree and soil characteristics and compared to the estimate of the model. Further, positioning data is analysed in relation to tree and soil parameters to investigate if anchor failure can be predicted from this data and if this could find application in a smart, low-cost early warning system.
Schlagworte
Forsttechnik; Forstwirtschaft;
Anker; Holzernte; Sicherheit;
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