Push-out test on bolt connectors of H-section steel-laminated bamboo lumber composite structure
This study presented an extensive experimental investigation focusing on elucidating the performance characteristics of a novel steel-bamboo composite structure.This composite structure was composed of H-section steel components integrated with side-pressure laminated bamboo lumber and interconnected through bolt connectors.With a series of designed static push-out tests,the research endeavored to unravel the intricate yield modes and failure mechanisms inherent within this innovative composite connection.Central to the investigation was the meticulous examination of the effects of varying bolt diameters and bamboo thicknesses on the mechanical properties and structural behavior of the steel-bamboo composite structures.One key observation gleaned from the experimental results was the discernible influence of laminated bamboo lumber thickness on the yielding behavior of the composite structure.Specifically,it was observed that specimens featuring thicker laminated bamboo lumber tend to exhibit a two-hinge yielding mechanism.In such instances,the formation of two distinct plastic hinges facilitated by the bolts in the laminated bamboo lumber hole and the H-section steel flange hole.Conversely,specimens with thinner laminated bamboo lumber tend to undergo one-hinge yielding,wherein the bolt formed a singular plastic hinge in the H-section steel flange hole while maintaining rigidity in the bamboo component,leading to a different failure mode characterized by bamboo splitting before bolt fracture.Furthermore,the investigation delved into the influence of bolt diameter on crucial performance metrics such as yield load,ultimate load,shear slip stiffness,and ductility.It was established that increasing bolt diameter correlates positively with the enhanced yield load,ultimate load,and shear slip stiffness,with negligible impact on ductility.The results indicated a progressive enhancement in the specimen's resistance to deformation with an increase in bolt diameter,which was characterized by notable plastic deformation in shear resistance.Conversely,a reduction in bamboo thickness was found to adversely affect the yield load,ultimate load,and ductility,with no significant impact on shear slip stiffness.Drawing upon established theoretical frameworks such as Johansen yield mode Ⅲ s and Eurocode 5,this study proposed an empirically derived equation for estimating the shear bearing capacity of steel-laminated bamboo lumber connections,duly accounting for the rope effect.Notably,the calculated shear bearing capacity closely aligned with experimental findings,with an error of 12.92％,thus validating the proposed analytical model.In summation,this study not only sheds light on the mechanical behavior of steel-bamboo composite structures,but also offers valuable insights for informing the design and optimization of such innovative construction systems in practical engineering applications.
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