Built-up I-beams with hardboard shear webs and laminated-veneer lumber flanges exhibited satisfactory performance when subjected to constant loads for up to 5 years in interior, protected exterior, and controlled cyclic humidity environments. Creep deflection was greatest for beams in the cyclic humidity environment and least for those in the interior environment. For beams loaded at the same stress level in a given environment, deflection was greater for beams made with web material having the lower shear stiffness. Except for 6-foot beams in the cyclic humidity environment, static tests on beams after long-term loading did not reveal any loss in strength or stiffness. (Author).

Twelve-foot and 6-foot I-beams with webs of two different hardboard materials and plywood were subjected to constant loads in three different humidity environments. After 17,000 hours of test, the performance of the hardboard-webbed I-beams appears to be at least comparable to that of I-beams with plywood webs. Results of this study will be useful to researchers, designers, and building code officials for judging the acceptability of wood-base materials in structural components such as I-beams. (Author).