3D打印混凝土配筋桁架梁力学及疲劳性能试验研究OA

To reveal the mechanical behavior and fatigue damage evolution mechanism of reinforced 3D-printed concrete(3DPC)structures,this paper presents a systematic experimental investigation on the mechanical and fatigue performance of reinforced 3DPC truss beams.By comparing the mechanical responses of four typical truss configurations,namely parallel chord,trapezoidal,tension-compression optimized,and shape-optimized,under static loading,the influence of configuration on load-bearing capacity,deformability,and failure mode was analyzed.The results show that all truss beam configurations exhibited ductile flexural failure characterized by multiple cracking,similar to under-reinforced concrete beams,while notable differences were observed in their load-bearing efficiency,ductility,and material utilization.Subsequently,fatigue tests were conducted on the parallel chord configuration under different stress amplitudes.The results reveal that fatigue performance is controlled jointly by the 3DPC matrix and its interface with reinforcement,the presence of transverse constraints,and the properties of the steel reinforcement.The failure mode transitions from fatigue fracture of the reinforcement at low stress ranges to interface debonding at medium and high stress ranges.Based on the test results,a fatigue damage model suitable for reinforced 3DPC truss beams was proposed based on stiffness evolution,and a fatigue life prediction formula was established,providing a theoretical basis for performance assessment and fatigue design of these structures.