Experimental analysis and finite element simulation of the flexural performance of glued laminated bamboo beam string structures

Abstract

To address the low flexural stiffness and limited deformation of glued laminated bamboo (GLB) beams, this study introduces the beam string structure (BSS) system, aiming to investigate the effects of strut configuration and rise height on their flexural performance. Static tests were conducted on eight full-scale specimens, which were explicitly categorized into two configurations: (a) Straight BSS, varying in strut number (single vs. double) and strut length (130 mm vs. 160 mm); and (b) Arched BSS, varying in rise height (50 mm, 100 mm, and 150 mm). Simultaneously, a numerical model incorporating tension-compression asymmetry and Extended Finite Element Method (XFEM) damage mechanisms was established, and theoretical formulas covering the entire loading process were derived. Results indicate that the BSS system significantly improved the mechanical performance of GLB beams. Among the straight configurations, the double long-strut type (TLSSB2S) exhibited optimal performance, with ultimate load capacity and energy dissipation increasing by 52.9% and 64.6%, respectively, compared to the pure beam. Conversely, for the simply supported arched configurations, both load capacity and stiffness showed a degradation trend as rise height increased. Numerical and theoretical predictions agreed well with experimental data, validating the effectiveness of this system for engineering applications.