乌江特大桥超高性能混凝土组合桥面铺装方案研究

Study of UPHC Composite Deck Pavement for Wujiang River Bridge

为研究不同桥面铺装方案的疲劳性能和经济性,以遵余高速乌江特大桥(主跨680 m钢桁梁悬索桥)为背景,采用有限元法建立钢桁梁节段模型,分析1.0倍设计荷载下,16 mm厚钢板+35 mm厚GA10+40 mm厚SMA13(方案1)、16 mm厚钢板+45 mm厚UHPC+30 mm厚SMA10方案(方案2)、14 mm厚钢板+55 mm厚UHPC+30 mm厚SMA10方案(方案3)正交异性钢桥面板疲劳构造细节处的应力幅值,并对方案2和方案3造价进行比较。结果表明:在1.0倍设计荷载下,沥青混凝土铺装方案(方案1)各构造细节最大应力幅值满足设计规范要求,但应力安全储备较低;组合桥面铺装方案(方案2和方案3)各构造细节最大应力幅值接近,均低于500万次常幅疲劳极限;与沥青混凝土铺装方案(方案1)相比,组合桥面铺装方案(方案2和方案3)各构造细节最大应力幅值降幅12.4%~57.6%;相比于方案2,方案3结构恒载增加0.84%,同等安全储备下综合成本增加127.8万元。综合疲劳性能和经济性,该桥采用方案2。

The fatigue performance and economy of diverse pavement options are studied.A finite element model of a steel truss girder segment was established based on the Wujiang River Bridge of Zunyi-Yuqing Expressway,a steel truss girder suspension bridge with a main span of 680 m.Under the 1.0 times of design load,three types of pavement were designed,including the 16 mm-thick steel plate covered with 35 mm-thick GA10 and 40 mm-thick SMA13(option 1),the 16 mm-thick steel plate covered with 45 mm-thick UHPC and 30 mm-thick SMA10(option 2),and the 14 mm-thick steel plate covered with 55 mm-thick UHPC and 30 mm-thick SMA10(option 3).The stress amplitude at the fatigue details of the orthotropic steel deck was analyzed,and the costs of the option 2 and option 3 were compared.As per the study,in the case of asphalt concrete pavement(option 1),the maximum stress amplitudes at each fatigue details can meet the code requirements,but the stress safety margin is narrow.Whereas in the case of composite deck pavement(option 2 and option 3),the maximum stress amplitudes at each fatigue details approximate each other,but all lower than the constant amplitude fatigue limit of 5 million numerical cycles.Compared with the asphalt concrete pavement(option 1),the composite deck pavement(option 2 and option 3)can lead to reduction of the maximum stress amplitudes of each fatigue details by 12.4%to 57.6%.Compared to option 2,option 3 results in the increase of dead load and comprehensive costs,by 0.84%and 1.278 million RMB under the same level of safety margin,respectively.Option 2 was finally selected and implemented on the Wujiang River Bridge,because of the relatively more outstanding fatigue and economic performance.