中文摘要：

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62.92MPa）都低于疲劳极限值（69MPa）,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。

英文摘要：

To solve the problem of the fatigue cracks in orthotropic steel deck（OSD）bridge deck,a new composite bridge deck system,light-weight composite steel bridge deck with ultra-high performance concrete（UHPC）layer was proposed and applied to the Fochen new bridge.The stress state at cutout in crossbeam,which bears the most complex stresses in OSD,was mainly investigated.Based on the comparative tests between the two parallel separate bridges（Fochen New Bridge）with traditional asphalt pavement and UHPC layer respectively,35 tand 45tthreeaxle trucks were selected as the standard and over-load trucks,which were examined under three loading cases：over-rib loading,riding-rib wall loading and in-between-ribs loading.The most adverse stress state on cutout at welded rid-to-diaphragm could be obtained.Then,the finite element model was established based on the field test data.A 550 kN standard truck in GeneralCode for Design of Highway Bridge and Culverts was loaded to calculate the hot spot stresses in two fatigue details at the cutout point under different loading cases,and its fatigue performances were evaluated.The results show that the stresses of fatigue measuring points on cutout at welded rid-to-diaphragm in two kinds of structures（OSD with asphalt pavement and UHPC layer）have the same distribution law under the same load case.However,unlike the asphalt pavement,UHPC layer is the component of the main structure,and it has a great influence on the global behavior of the deck system.Therefore,the strains of light-weight composite steel bridge deck at fatigue measuring positions are obviously less than those of traditional OSD in the same position.The measured average amplitude is decreased by about20%,and the maximum amplitude is decreased to 46.4%.In the fatigue evaluation,the hot spot stress range（the maximum is 62.92 MPa）of light-weight composite steel bridge deck on cutout at welded rid-to-diaphragm is below the limited state value（69 MPa）,which ensures that the cracks on cutout at welded ri