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为解决正交异性钢桥面结构中的疲劳开裂问题,提出了一种新的结构体系——超高性能混凝土(UHPC)-钢轻型组合桥面结构,并应用于佛陈新桥。重点研究钢桥面受力最复杂的横隔板弧形切口位置的受力状态,基于传统沥青铺装和UHPC铺装两幅桥(佛陈新桥)的对比试验,选用35t和45t三轴车分别作为标准车和超重车分3个工况加载(正U肋、骑U肋、U肋间),得到弧形切口位置最不利的受力状态。通过试验数据校订有限元模型,采用《公路桥涵设计通用规范》中的550kN标准车进行加载,计算出不同工况下弧形切口位置2个主要疲劳细节的热点应力,并对其进行疲劳评估。研究结果表明:在同一工况下,2种结构(沥青铺装的钢桥面和UHPC-钢轻型组合桥面结构)中横隔板弧形切口各疲劳测点的应变分布规律相同;与沥青铺装层不同,UHPC层能与钢桥面协同受力,轻型组合桥面结构各疲劳测点的应变值明显低于传统沥青铺装钢桥面结构,实测的平均降幅为20%左右,最大降幅达到46.4%;疲劳评估中,UHPC幅各疲劳测点的热点应力幅(最大值为62.92 MPa)都低于疲劳极限值(69 MPa),确保佛陈新桥UHPC幅横隔板弧形切口在设计基准期内不开裂。
In order to solve the problem of fatigue cracking in the deck structure of orthotropic steel, a new structural system, ultra-high performance concrete (UHPC) -steel lightweight composite deck structure, is proposed and applied to Fushan Bridge. Focusing on the stress state of the most complicated cross-section arc-shaped incision position of the steel bridge deck, based on the comparison test of the traditional asphalt pavement and UHPC pavement two bridges (Fu Chen Bridge), 35t and 45t tri-axle vehicles As a standard car and overweight car loaded in 3 working conditions (positive U ribs, riding U ribs, U intercostal), the location of the arc incision the most unfavorable force state. The finite element model was calibrated by the test data and loaded with 550kN standard vehicle in “Code for Common Design of Highway Bridges and Culverts” to calculate the hot spot stress of the two main fatigue details of the arc-shaped incision under different working conditions, and the fatigue assessment was carried out. The results show that under the same operating conditions, the strain distribution of each fatigue test point of the arc-shaped incisions in two kinds of structures (asphalt pavement steel deck and UHPC-steel lightweight composite deck structure) Different layers of pavement, UHPC layer can work together with the steel deck, light composite deck structure fatigue test point strain value was significantly lower than the traditional asphalt pavement steel deck structure, the measured average decline of about 20%, the maximum The decrease of 46.4%. During the fatigue assessment, the hot stress amplitude (maximum value of 62.92 MPa) at each fatigue test point of UHPC amplitude is lower than the fatigue limit value (69 MPa) The benchmark period does not crack.