型钢开口肋-UHPC轻型组合桥面新结构静力与疲劳性能

Research on Static and Fatigue Properties of New Structure of Section Steel-UHPC Lightweight Composite Deck with Open Rib

为解决传统正交异性钢桥面疲劳开裂、铺装层破损难题,研究团队于2010年研发成功钢-UHPC轻型组合桥面体系,并在中国的钢桥上获得了规模化的应用。鉴于UHPC层大幅度提高了钢面板的局部刚度,为简化施工和降低造价,可对传统正交异性钢桥面进一步优化。为此,提出了型钢开口肋-UHPC轻型组合桥面结构,首次应用在某大跨度拱桥主梁结构中,以实桥为背景展开了桥面方案比选和有限元计算。在此基础上,进行了型钢组合桥面关键部位负弯矩条带静力试验,对UHPC裂缝进行观测和宽度验算;对型钢组合桥面抗疲劳性能做了计算与分析,并针对桥面纵横肋重要连接焊缝开展了负弯矩条带疲劳试验。研究结果表明:负弯矩区UHPC表现出优良的受弯拉韧性,抗拉强度是实桥应力的1.4倍;型钢组合桥面通过新型的纵横肋连接构造,将所有连接焊缝均置于低应力区,将非焊接型钢母材置于高应力区,以达到提高桥面抗疲劳能力目的,型钢组合桥面包含10个钢结构疲劳细节,所有疲劳细节计算应力幅均在常幅疲劳极限以下;型钢组合桥面纵横肋新型连接焊缝在设计疲劳应力幅下等效加载4840万次才发生疲劳破坏,疲劳强度满足实桥应用需求。综上表明,型钢组合桥面具有优良的静力与疲劳性能,加工制造简便,建设成本低,是一种具有竞争力的新型桥面方案。

To solve the problems of fatigue cracking and pavement damage in orthotropic steel decks(OSD),the author's research team successfully developed a steel-ultra-high-performance concrete(UHPC)lightweight composite bridge deck system in 2010,which has been widely applied to steel bridges in China.Because the UHPC layer significantly improves the local stiffness of the steel deck,the OSD can be further optimized to simplify construction and reduce costs.Therefore,a hot-rolled section steel-UHPC lightweight composite deck with an open rib(HSD)is proposed in this paper and applied to the girder of a long-span arch bridge for the first time,and different deck schemes and finite element calculations based on a real bridge are compared.On this basis,a negative bending moment strip static test of the HSD was carried out,the crack development of the UHPC was observed,the crack width was calculated,the fatigue resistance performance of the HSD was calculated and analyzed,and a negative bending moment strip fatigue test was carried out for the important connection welds between the longitudinal and transverse ribs in the HSD.The research results show that UHPC in the negative moment area shows good flexural tensile toughness,and the tensile strength is 1.4 times that of the real bridge;HSD connects the longitudinal ribs and the diaphragm in a novel way;by placing all the necessary connecting welds in the low-stress area and non-welding hot-rolled section steel in the high-stress area,the fatigue resistance of the bridge deck is improved.HSD contains 10 key fatigue details,and the calculated fatigue stress amplitude of each fatigue detail is below the constant amplitude fatigue limit;fatigue failure of the connecting weld between longitudinal and transverse ribs in HSD occurred after 48.4 million equivalent loading times under the design fatigue stress amplitude;the fatigue strength meets the requirements of real bridge applications.In summary,the HSD exhibits good static and fatigue behavior,simple processing and manufacturing,low construction costs,and is a new competitive bridge deck scheme.