Structural behavior of glubam I-joists: Fid-Bau Portal

Structural behavior of glubam I-joists

Tang, Z. / Shan, B. / Li, W.G / Peng, Q. / Xiao, Y.

Highlights • A new type of I-joist made with glued laminated bamboo (glubam) was fabricated and tested in the paper. • Finger joints were used between web material or flange material to fabricate glubam I-joists to desired spans, and two types of web-to-flange connections were used to connect web and flanges in this investigation. • In terms of load carrying capacity, glubam I-joists outperformed other engineered bamboo or timber I-joists with similar dimension. • Analytical methods for predicting the deformation capacity and load carrying capacity were developed.

Abstract Glubam, a new type of engineered bamboo composites, is a promising structural material characterized by outstanding mechanical performance and environmental friendliness. In this study, glubam I-joists, with the spans ranging from 2.4 m to 7.5 m, were prepared and tested to evaluate their structural behavior. The glubam I-joists were lengthened by finger joints, and two kinds of connections were used to connect the web and flanges. Four-point bending tests were conducted to examine the failure modes, load-deflection relationships and load carrying capacity of glubam I-joists. Test results indicated that the dominant failure modes of glubam I-joists included shear failure at the finger joint in the web, bending failure at the finger joint in the bottom flange and lateral buckling. Correspondingly, the load carrying capacity of glubam I-joists was governed by the bending strength, shear capacity and critical bending moment. Glubam I-joists have relatively higher mechanical performance compared with other engineered bamboo or timber I-joists with similar dimension, and the bending capacity of the glubam I-joist with continuous web-to-flange connection meets the requirement specified in Chinese code. Based on the experimental findings and existing methods, theoretical methods were proposed for predicting the stiffness and load carrying capacity of glubam I-joist and were also validated by the test results.