Paper Title
MODAL BEHAVIOR OF MODULAR TIMBER BEAMS: INFLUENCE OF SEGMENTATION AND CONNECTORS ON DYNAMIC STIFFNESS

Abstract
As demand grows for sustainable and modular infrastructure solutions, timber-based structural systems are increasingly favored for their low environmental impact and construction flexibility. This study investigates the modal behavior of modular timber beams designed for portable bridge applications, emphasizing the effects of segmentation and mechanical connectors on dynamic stiffness. Through a combination of Experimental Modal Analysis (EMA) and Finite Element Modal Analysis (FEMA), the first vertical bending mode was identified and compared across ten full-scale beam specimens, encompassing both continuous and segmented configurations with and without reinforcement. Results reveal that increased segmentation and connector quantity significantly reduce natural frequencies, indicating a degradation in dynamic stiffness due to joint flexibility and local discontinuities. Notably, continuous beams exhibited vertical bending modes at higher frequencies and later mode orders, while segmented beams displayed these modes earlier due to constraint-induced suppression of lateral deformation. Furthermore, comparative analysis between EMA and FEMA revealed consistent frequency trends, though discrepancies emerged due to idealized boundary conditions and material heterogeneity. These findings provide valuable insight into the dynamic performance of modular timber systems, offering guidance for the design and optimization of mechanically connected beam structures in portable bridge applications. By isolating the influence of segmentation and connector placement on frequency response, this study contributes to the advancement of modular timber engineering for high-performance, vibration-sensitive structures. Keywords - Modular timber beams, segmentation, dynamic stiffness, Experimental Modal Analysis (EMA), Finite Element Analysis (FEA), mode shape, connector design, natural frequency.