高速铁路下承式系杆拱桥桥面形式的研究

通过有限元分析,对采用结合梁桥面和整体钢桥面两种桥面形式的下承式钢系杆拱桥的竖向刚度、系梁和拱肋的内力、桥面系统的内力和自振特性进行对比分析。计算结果表明:两种形式的竖向刚度基本上相等;系梁和拱肋的内力后者略优于前者,并且不均匀降温对前者更不利;端部横梁都存在较严重的应力集中,方案一对温度荷载很敏感;日照引起的局部温差能较大的增加方案一混凝土桥面板的拉应力值;方案二的纵梁、加劲横梁和桥面板的组合应力都较低。提出整体钢桥面为适合于我国新建高速铁路下承式钢系杆拱桥的合理桥面形式。

STUDY ON DECK TYPE OF THROUGH STEEL TIED ARCH BRIDGE ON HIGH SPEED RAILWAYS

Using the finite element method,the vertical stiffness,internal forces of tie beams,arch ribs and deck system,natural frequencies,and dynamic performance under high-speed train of through steel tied arch bridges with two different deck-type schemes,combined deck scheme and orthotropic deck scheme,are studied in this paper.Numerical results show that,the vertical stiffness of two schemes is almost the same,the internal forces of tie beams and arch ribs of the orthotropic-deck scheme is better than those of the combined-deck scheme,non-uniform temperature depression bring more internal forces for the combined-deck scheme,serious stress concentration is found at the end of end-cross-beam for both combined-deck and orthotropic-deck schemes,the combined-deck scheme is sensitive to temperature,local difference in temperature under sunlight can lead to the tensile stresses of deck increasing obviously for the combined-deck scheme,the combined stresses value of longitudinal tie beam,stiffening cross and deck slab for the orthotropic-deck scheme is less than those for the combined-deck scheme.In conclusion,the orthotropic-deck scheme is better than the combined-deck scheme,and it is suitable for through steel tied arch bridges in newly built double line high speed railway.