大跨度双线铁路钢桁梁斜拉桥受力特性研究

【作者】 谢晓慧；

【导师】 张晔芝；

【作者基本信息】 中南大学 ， 工程力学， 2010， 硕士

【摘要】 某新建铁路跨长江大桥设计为(81+135+432+135+81)m五跨两塔连续钢桁梁斜拉桥,通行两线铁路,采用正交异性板整体钢桥面结构,整体钢桥面参与主桁共同作用,受力复杂。斜拉桥在纯铁路桥梁中的应用较少,到目前为止,国内外还没有建成这种大跨度铁路专用斜拉桥的实例。本文对该桥的受力性能进行了研究,主要完成了以下工作：1、采用空间板梁法建立全桥空间有限元模型,对该桥在恒载、最不利活载及附加力作用下的受力性能进行了分析。结果表明：该桥受力合理,刚度和强度均满足要求。2、对混凝土道碴槽板是否设置断缝进行了对比研究。结果表明：将混凝土板在节点横梁上方设置断缝,可释放该处混凝土板的峰值拉应力,但对离断缝0.5m以外的混凝土板和全桥的钢结构应力几乎无影响。3、对混凝土板的合理浇注顺序进行了研究。结果表明：混凝土板的浇注顺序主要影响混凝土板自重作用下的应力,主跨跨中区域的混凝土板拉应力最大,应最后浇注,使该区域混凝土板在自重作用下不产生拉应力。4、研究了混凝土道碴槽板对桥梁刚度及受力状态的影响。结果表明：考虑混凝土道碴槽板抗力后,桥梁的竖向刚度及横向刚度分别提高了约1.8%和7.5%,桥面系钢构件的应力有较明显的降低,主桁杆件受力变化不大；增加混凝土板的厚度或宽度,桥梁竖向刚度和主桁杆件的受力变化较小,桥梁横向刚度增加和桥面系钢构件的应力降低较明显。本文的研究成果为该桥设计提供了依据,对其他类似桥梁也有参考价值。更多还原

【Abstract】 Hanjiat Yangtze River Railway Bridge is a double tower, five-span continuous steel truss cable-stayed bridge with span arrangement (81+135+432+135+82) m. The bridge allows two lines railway. Orthotropic monolithic steel deck is adopted, which works together with the main truss. So far, cable-stayed bridges have seldom been applied in railway bridges. There is no railway cable-stayed bridge with span as long as Hanjiat Yangtze River Railway Bridge at home and abroad. The mechanical behavior of the bridge was studied in this paper. Main work of this paper is as follows:1.Space finite element model of the full bridge was established adopting SPB(Space Plate-Beam)method. The mechanical characteristics of the bridge under dead load, worst-case of living load and additional forces were studied. The results show that the working condition of the bridge is reasonable and the stiffness and strength meet the requirements.2.The effects of the break joints in concrete slab were studied. The results show that the break joints of the concrete slab above cross beams at chord joints, can effectively decrease the peak tensile stress of the concrete slab nearby the break joints, but they have no effect on the stress of the concrete slab 0.5m away from the break joints and the steel structure.3.The reasonably pouring sequence for the concrete slab was studied. The results show that, the pouring sequence of concrete slab mainly affects the self-weight stress of the concrete slab. The tensile stress of the middle midspan area is largest. Therefore, the reasonably pouring sequence is to pour the concret slab in this area at last, so that the self-weight of the concrete slab would not creat tensile stress in this area.4. The effects of the concrete slab on the bridge stiffness and mechanical behavior were studied. The results show that, the concrete slab can increase the vertical stiffness and the lateral stiffness of the bridge by 1.8% and 7.5% respectively, effectively decrease the stress of the steel decks, but little change the stress of of the main trusses.With the thickness and width of the concrete slab increased, the lateral stiffness of the bridge increased and the stress of the steel decks increased, while the vertical stiffness and the stress of the main trusses changed little.The research results in this paper not only service design of Hanjiat Yangtze River Railway Bridge but also provide references for other similar structures.更多还原