Creep Buckling of Small, Slender Wood Columns Under Cyclic Environment
Keywords:Douglas-fir, columns, creep, cyclic environment, relative humidity, temperature, deflection, failure, duration of load, buckling
AbstractCreep buckling of small, slender Douglas-fir columns was studied under two types of cyclic environmental conditions. Three load levels were used for an environment with severe changes (Type A), while one load level was used for a less severe one (Type D). Experimental data show in both cases an increase of deflection during the low humidity cycle and recovery during the higher humidity cycle. The reduction of deflection during the wet cycle was more pronounced in Type A than in Type D cycling. Time to buckling failure was nearly one order of magnitude less, at the same load level, in Type A as compared to Type D. Small initial deflections did not appear to have a significant effect on time to failure. The relationship between load level and time to failure under Type A cycling was similar to published data for beams of similarly small size.
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