Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Reliability of timber structures under long term loads
Abstract The strength of timber is significantly reduced under sustained load. Existing experimental data give a reasonable estimate of the strength reduction as a function of time under constant load. In practice, however, the load level is variable in time. For this situation the strength reduction must be estimated on the basis of so called damage theories. In engineering design, effects of load duration are accounted for by a strength reduction factor, $ k_{mod} $, which depends on the type of load acting on the structure. The loads are classified in terms of their duration time. In a load combination the value of $ k_{mod} $ is based on the load with shortest duration. For several reasons the scientific basis to determine $ k_{mod} $ is rather uncertain. In this paper a probabilistic analysis is made with the purpose to calibrate $ k_{mod} $ for timber structures under combination of permanent load and snow load. The analyses are based on Swedish data for snow. A theoretical model proposed in [1] describes the damage accumulation. The analyses show that $ k_{mod} $ is of the order 0.8 for geographic locations with heavy snow loads as well as for locations with moderate snow loads. The factor $ k_{mod} $ was also found independent of the two practically relevant load combinations studied. The results can be used as recommendations for appropriate choice of $ k_{mod} $ in engineering design.
Reliability of timber structures under long term loads
Abstract The strength of timber is significantly reduced under sustained load. Existing experimental data give a reasonable estimate of the strength reduction as a function of time under constant load. In practice, however, the load level is variable in time. For this situation the strength reduction must be estimated on the basis of so called damage theories. In engineering design, effects of load duration are accounted for by a strength reduction factor, $ k_{mod} $, which depends on the type of load acting on the structure. The loads are classified in terms of their duration time. In a load combination the value of $ k_{mod} $ is based on the load with shortest duration. For several reasons the scientific basis to determine $ k_{mod} $ is rather uncertain. In this paper a probabilistic analysis is made with the purpose to calibrate $ k_{mod} $ for timber structures under combination of permanent load and snow load. The analyses are based on Swedish data for snow. A theoretical model proposed in [1] describes the damage accumulation. The analyses show that $ k_{mod} $ is of the order 0.8 for geographic locations with heavy snow loads as well as for locations with moderate snow loads. The factor $ k_{mod} $ was also found independent of the two practically relevant load combinations studied. The results can be used as recommendations for appropriate choice of $ k_{mod} $ in engineering design.
Reliability of timber structures under long term loads
Svensson, S. (Autor:in) / Thelandersson, S. (Autor:in) / Larsen, H. J. (Autor:in)
1999
Aufsatz (Zeitschrift)
Englisch
Reliability of timber structures under long term loads
| British Library Online Contents | 1999
Reliability of timber structures under long term loads
| Springer Verlag | 1999
SCIENTIFIC REPORTS - Reliability of timber structures under long term loads
| Online Contents | 1999
Reliability of timber structures under long term loading
| British Library Conference Proceedings | 1999