Experimental and Analytical Study on the Short-Term Behavior of Locally Bonded Connections in Bamboo-UHPC Composite...

The synergistic application of ultra-high-performance concrete (UHPC) and bamboo scrimber provides innovative solutions for sustainable structural engineering. In this study, the structural response mechanism of the combined beams under the steel plate-screw composite connection system was systematically investigated by designing three shear connection gradient specimens (TS200/300/400) to address the key scientific issues of the mechanical behavior of the bamboo-UHPC interface. Based on the unidirectional compression tests of bamboo-UHPC composite shear connections and four-point bending tests of composite beams, the damage modes, load-mid-span deflection relationship, bending stiffness, bamboo-UHPC slip and normal lift were evaluated for all the composite beams with the shear connection gradient as a parameter. The results showed that the flexural performance of the composite beams went through three stages: elastic behavior, damage development and final damage. The interfacial slip and interfacial lift-off have more obvious asymmetric spatial distribution characteristics, and increasing the shear joint degree can delay the separation between the UHPC and the bamboo layer, thus enhancing the structural integrity. Typical features of the final damage are the bending damage of ultra-high-performance concrete and bamboo fiber damage. This study highlights the potential of UHPC-bamboo composite beams for sustainable construction and emphasizes the importance of optimizing shear connection for improved performance.