- Author
- Springer, G. S. | Do, M. H.
- Title
- Degradation of Mechanical Properties of Wood During Fire. Final Report.
- Coporate
- Michigan Univ., Ann Arbor
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
- NBS GCR 83-433, October 1983, 130 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NB80NADA1054
- Keywords
- computer programs | degradation | fire models | fire tests | mechanical properties | wood | exposure time | shear strength
- Abstract
- The major objectives of this investigation were to evaluate the decrease in mechanical properties of wood exposed to fire, and to develop a method that can be used to predict the failure time of loaded wooden structural members during fire exposure. To achieve these objectives analytical models were developed which can be used to calculate a) the temperature distribution inside the wood, b) the mass loss, c) the changes in tensile, compressive and shear strengths and moduli, d) the decrease in the safety factor and e) the time of failure. On the basis of these models, a "user friendly" computer code was written which is suitable for calculating these parameters for loaded wooden slabs exposed to elevated temperatures. Tests were conducted measuring the thermal and mechanical responses of southern pine and douglas fir during exposure to temperatures in the range of 100 to 800 deg. C. In the tests the following parameters were measured as function of exposure time: a) center point temperature, b) mass loss, c) tensile, compression, and shear strengths and moduli. In addition failure times of simply supported loaded beams were measured. The results of the model were compared to the data and reasonable agreements were found between calculated and measured values.