大跨斜拉桥型钢组合桥面的结构设计与方案比选

Structural Design and Scheme Comparison of Structural Steel Composite Deck of Long-span Cable-stayed Bridge

摘要:

为取消正交异性钢桥面板，提出了一种新的型钢开口肋-UHPC组合桥面板，即采用T型钢替代加工复杂的U肋。以某双塔双索面大跨斜拉桥为背景，通过整体与局部受力分析相结合的方式，研究了新型组合桥面在大跨斜拉桥领域应用的可行性与优势，并与传统的正交异性钢桥面进行了在结构受力和技术经济性层面的对比。结果表明：在大跨斜拉桥的横向简支受力状态下，两种方案的整体受力性能较为接近；在正常使用极限状态下，新型组合桥面中UHPC层的最大纵、横向拉应力分别为7.96、6.92 MPa，均满足抗裂需求；在整体和局部受力分析中，新型组合桥面方案中的钢顶板应力较原方案均有较为明显的改善，最大应力分别下降了16%、81.9%；新型组合桥面的各疲劳细节应力幅均远在规范疲劳强度限值以下，表明新型组合桥面具有优异的疲劳性能，且具有较高的安全储备。新型组合桥面方案的桥面板重量与正交异性钢桥面方案的基本持平，但每平米造价减少约34.4%，表明新型组合桥面在大跨斜拉桥领域有较好的应用前景。

Abstract:

To cancel the orthotropic steel deck (OSD), a new type of structural steel open rib - UHPC composite deck is proposed, that is to use T-shaped steel instead of complex U-ribs. Taking a double-cable double-plane long-span cable-stayed bridge as the background, through the combination of overall and local mechanical analysis, the feasibility and advantages of the application of the new composite deck in the field of long-span cable-stayed bridges are studied, and the comparison with the traditional OSD is carried out in terms of structural mechanical performance and technical economy. The results show that the overall mechanical performance of the two schemes is relatively close under the transverse simply supported state of the long-span cable-stayed bridge. Under the normal usage limit state, the maximum longitudinal and transverse tensile stresses of the UHPC layer in the new composite deck are 7.96 MPa and 6.92 MPa, respectively, which all meet the crack resistance requirements. In the overall and local mechanical analysis, the stresses of the steel top plate in the new composite deck scheme are obviously improved compared with the original scheme, and the maximum stresses are reduced by 16% and 81.9% respectively. The stress amplitudes of each fatigue detail of the new composite deck are far below the fatigue strength limit in the specification, indicating that the new composite deck has the excellent fatigue performance and higher safety reserve. The deck weight of the new composite deck scheme is basically the same as that of the OSD scheme, but the cost per square meter is reduced by about 34.4%, indicating that the new composite deck also has a good application prospect in the field of long-span cable-stayed bridges.