Bracing of Wood Composite I-Joists to Resist Lateral Buckling from Walking Loads

Abstract

Lateral buckling of unbraced beams during construction may be an important cause of fatalities and injuries. Temporary bracing to restrict lateral buckling is a potential preventive approach, but has received little study. Lateral acceleration, lateral displacement, and rotation of wood composite I-joists were measured under different bracing conditions while participants traversed the joists. Five different bracing stiffnesses and two different bracing placements were examined. Lateral displacement and rotation increased near the midspan of the joist, while acceleration remained consistent. Greater lateral displacement and rotation were found with increasing participant weight and lack of construction experience. Construction experience was found to be a significant factor in the amount of joist motion. A safety platform similar to the testing methods discussed may have potential as a training tool to expose workers to partially braced joists. The relationship of lateral displacement and rotation with bracing stiffness was nonlinear. Bracing placement had little effect upon lateral displacement and rotation. Increased bracing stiffness reduced lateral displacement and rotation at a decreasing rate, indicating that bracing stiffness can be optimized to reduce cost.