新型钢-混组合桥塔构造型式研究

Study on Structural Type of New Steel-concrete Composite Bridge Pylon

摘要:

针对传统钢-混组合桥塔的钢壁板单侧约束易发生局部屈曲、加劲肋构造复杂、施工难度大等问题，提出了两种新型的钢-混组合桥塔构造型式：加劲肋外置型外包钢中空混凝土组合桥塔、双钢板-UHPC（Ultra-High Performance Concrete）组合桥塔。以某峡谷千米级铁路悬索桥的组合桥塔为工程背景，拟定两种新型组合桥塔的构造尺寸，通过有限元建模分析了提出的新型组合桥塔构造受力性能，并且从施工和经济层面对比分析了两种新型组合桥塔与原桥四肢格构式钢管-混凝土组合桥塔的技术经济指标。研究结果表明：两种新型钢-混组合截面桥塔均能满足规范中对大跨度悬索桥主塔静力和稳定性的设计要求，且具有构造简化、受力性能优以及施工难度降低等优势；外包钢中空混凝土组合桥塔、双钢板-UHPC组合桥塔在材料成本上相比原设计钢管混凝土桥塔分别提高约13%、19%，但考虑到构造简化带来的施工造价降低以及UHPC材料的高性能，建造和后期运营维护成本大幅降低。

Abstract:

In view of the unilateral constraints of the steel panels of the traditional steel-concrete composite bridge pylon, it is easy to have local buckling, complicated stiffener structure and difficult to construct. Two new types of steel-concrete composite bridge pylon are proposed, which are the stiffened ribbed outer clad steel hollow concrete composite bridge pylon and the double steel plate - UHPC (Ultra-High Performance Concrete) composite bridge pylon. Taking a composite pylon of a canyon kilometer-level railway suspension bridge as the engineering background, the structural dimensions of two new composite bridge pylons are proposed. The structural mechanical properties of the proposed new composite bridge pylons are analyzed by finite element modeling, and the technical and economic indexes of the two new composite bridge pylons and the original four-limb lattice steel tube-concrete composite bridge pylons are compared and analyzed from the construction and economic levels. The research results show that the two new steel-concrete composite section pylons can meet the design requirements of the static and stability of the main pylon of the long-span suspension bridge in the specification, and have the advantages of simplified structure, excellent mechanical performance and reduced construction difficulty. The material cost of the outer clad steel hollow concrete composite bridge pylon and the double steel plate - UHPC (Ultra-High Performance Concrete) composite bridge pylon is about 13 % and 19 % higher than that of the original designed concrete-filled steel tube bridge pylon respectively. However, considering the reduction of construction cost brought from the structural simplification and the high performance of UHPC materials, the cost of construction and later operational maintenance is greatly reduced.