Duration of load behavior of yellow poplar laminated veneer lumber: Effect of cyclic relative humidity

The effect of cyclic relative humidity (RH) on the duration of load (DOL) behavior of laminated veneer lumber(LVI) is presented The LVLs were commercially manufactured with rotary-peeled yellow-poplar veneers and phenol-formaldehyde resin. Three groups of 243.84 cm (96 in.) long and 8.89 cm (3.5 in.) high LVL specimens, 25 A each group, randomly selected from a large sample population, were prepared for this study Group I specimens had scarfed veneer-joints, group II had crushed-lap veneer-joints and group III had no veneer-joints and served as the control. All the LVL specimens were loaded in edgewise bending under cyclic RHs of 65% <- -> 95% at 23.9 degrees C (75 degrees F) with a 48-hour frequency for the evaluation of cyclic RH effect (change of moisture content) on their DOL performance. constant loads based on the 15th, percentile of their edgewise static bending strength distributions, evaluated at constant RH of 65% and 23.9 degrees C (75 degrees F) were used for the DOL fasts. Effects of veneer-joint types and cyclic RHs on the DOL behavior of yellow poplar LVLs are discussed.