钢-超高性能混凝土组合桥面系中栓钉连接件的疲劳性能研究

Fatigue Performance Research of Headed Studs in Steel and Ultra-high Performance Concrete Composite Deck

针对钢-超高性能混凝土(UHPC)组合桥面系中栓钉连接件疲劳性能研究不足的状况,采用精细数值模型和模型疲劳试验,对岳阳洞庭湖大桥的钢-UHPC组合桥面系中栓钉连接件的疲劳性能进行了研究。在精细数值模型分析中,建立了岳阳洞庭湖大桥的多尺度有限元模型,提取了栓钉剪应力的影响面,基于中国《公路钢结构桥梁设计规范》的标准疲劳车,计算得到了栓钉等效疲劳剪应力幅。在模型疲劳试验中,取桥面系的正弯矩和负弯矩板带,设计了1组2个梁式足尺疲劳试件,其中正、负弯矩试件中的栓钉分别在119.5MPa和72.0MPa名义剪应力下经历了200万次疲劳加载。再考虑了影响面大小、车流量和设计年限等因素对等效疲劳应力幅进行修正,并对栓钉的疲劳寿命进行了评估。结果表明:试件在经历200万次疲劳加载后应变仍保持平截面,未发生明显界面疲劳破坏,可保守取119.5 MPa和72.0 MPa作为正、负弯矩板带试件中栓钉的疲劳强度;洞庭湖大桥组合桥面系中的栓钉连接件具有足够的疲劳承载力安全储备,能够满足120年的设计寿命要求。

Aimed at the paucity of research on the fatigue performance of headed stud connector in the steel and ultra-high performance concrete（UHPC）composite deck,by numerical simulation and fatigue experiments,the fatigue performance of headed stud connector in the steel-UHPC composite deck in Dongting Bridge in Yueyang was investigated.In numerical simulation,the multi-scale finite element model（FEM）was first established,the influence surface of the headed stud was then obtained,and the equivalent fatigue shear stress was obtained based on the standard fatigue vehicle in Chinese specifications for design of highway steel bridge.In fatigue experiments,two fatigue specimens were designed taking the plate strip of the composite deck inareas of sagging and hogging moment respectively.The specimens were loaded for 2 million cycles under nominal shear stress of 119.5 MPa and 72.0 MPa.The equivalent fatigue shear stress range was modified due to the size of influence surface,the traffic flow and the design period,and the fatigue lifetime of the headed stud was evaluated.The results show that after loading for 2million cycles,the specimens are in plain section and there is no obvious bonding failure phenomenon.Hence the fatigue strengths of the headed stud in sagging and hogging moment are safely taken as 119.5 MPa and 72.0 MPa respectively.The stud connector in composite deck of Dongting Bridge satisfies a design lifetime requirements of 120 years with enough safety margin.