Reinforced Wood I-Joists with Web Openings

摘要

Prefabricated wood I-joists with web openings are commonly used in light-frame wood construction. The capacity and the failure pattern of such I-joists in the presence of a circular web opening were experimentally investigated on 100 specimens with various sizes and locations of web openings and two different span lengths of 3.66 m (12 ft) and 6.10 m (20 ft). The control I-joists, i.e., I-joists without any opening, failed in flexure in the midspan, whereas most of the I-joists with an opening failed in a brittle and sudden shear mode. The presence of an opening reduced the capacity up to 54% compared to I-joists without web openings depending on the size and location of the opening. Subsequently, to prevent brittle failure and improve capacity, the I-joists were reinforced using two perpendicular OSB collar layers with a variation in the reinforcement length. The effectiveness of reinforcing the web around openings was investigated on another 100 specimens. After reinforcement, brittle premature failure of I-joists was prevented with an increase in capacity up to 27% compared to the I-joists with openings. Analytical models to calculate the capacity of unreinforced and reinforced I-joists with openings are proposed, validated with results from previous research, which prove to be more accurate compared to existing models from the literature. (C) 2017 American Society of Civil Engineers.