caa a22 4500 463216857 CHVBK 20180405153159.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1007/s00226-007-0154-5 doi (NATIONALLICENCE)springer-10.1007/s00226-007-0154-5 Duration of load revisited [Elektronische Daten] [Preben Hoffmeyer, John Sørensen] A duration of load study representing 13years of testing was recently terminated. Preliminary results have been published over the years. This paper represents the final account of the study, which was focused on the influence of moisture content on time to failure for structural timber subjected to bending under constant load conditions. Two constant moisture conditions (MC=11 and 20%) and one condition of varying moisture (MC between 11 and 20%) were applied. A total of 816 Norway spruce boards of dimensions 44×95×1,800mm3 were included. Eight groups of non-destructively matched samples were formed. Four groups were subjected to short-term strength tests, and four groups were subjected to long-term tests. Creep and time to failure were monitored. Time to failure as a function of stress level was established and the reliability of stress level assessment was discussed. A significant mechanosorptive effect was demonstrated both in terms of increased creep and shortening of time to failure. The test results were employed for the calibration of four existing duration of load models. The effect of long-term loading was expressed as the stress level SL50 to cause failure after 50years of loading. SL50 was found to be of the order 0.60 for MC = 11%, 0.50 for MC = 20% and 0.44 for MC varying between 11 and 20%. The test results revealed no evidence of a threshold stress level. A reliability based calibration of load-duration factors was performed using probabilistic models of loads and of the short-term and long-term strengths. For permanent and imposed library loads, reliability-based estimation of the load duration factor gave almost the same results as direct, deterministic calibration. Springer-Verlag, 2007 Hoffmeyer Preben Department of Civil Engineering, Technical University of Denmark, Building 118, 2800, Kgs Lyngby, Denmark aut Sørensen John Department of Civil Engineering, Aalborg University, Sohngaardsholmsvej 57, 9000, Aalborg, Denmark aut Wood Science and Technology Springer-Verlag 41/8(2007-12-01), 687-711 0043-7719 41:8<687 2007 41 226 https://doi.org/10.1007/s00226-007-0154-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00226-007-0154-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hoffmeyer Preben Department of Civil Engineering, Technical University of Denmark, Building 118, 2800, Kgs Lyngby, Denmark aut NATIONALLICENCE 700 1- Sørensen John Department of Civil Engineering, Aalborg University, Sohngaardsholmsvej 57, 9000, Aalborg, Denmark aut NATIONALLICENCE 773 0- Wood Science and Technology Springer-Verlag 41/8(2007-12-01), 687-711 0043-7719 41:8<687 2007 41 226 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer