高速公路特大型桥梁与跨大堤桥设计方案研究

Research on the Design Scheme of Super-large Bridges and Cross-embankment Bridges

针对特大型桥梁及跨大堤桥的施工难度大、稳定性及耐用性要求高等问题,依据濮阳至阳新高速公路黄河特大型桥梁跨大堤桥的水文地质特征,设计了预应力混凝土连续梁、波形钢腹板预应力混凝土组合梁桥两种方案,并从施工难度、桥梁稳定性、桥梁耐用性、结构受力、造价、后期维护量等方面比对分析。结果显示:波形钢腹板预应力混凝土梁式桥将混凝土与钢材料相结合,能显著降低大跨径混凝土梁式桥腹板开裂及跨中下挠风险,桥梁自重也减轻15%,地震力降低,造价少,工期短。但其施工工艺复杂,对施工控制和质量要求非常高,后期维护难度大,维护成本高,施工技术不成熟,两种设计方案的差距主要是结构合理性、工期及工程造价、施工难度及后期维护上,综合考虑相关因素,濮阳至阳新高速公路黄河特大型桥梁跨大堤桥应选择预应力混凝土连续梁设计方案。但要处理好跨中下挠及结构抗震问题,于梁端、塔端分别以消除裂缝、扭转或限制扭转的牵引张拉设备提高斜拉索的施工质量及安全。

In view of the difficulties in construction,high requirements for stability and durability of super-large bridges and cross-embankment bridges,and based on the hydrogeological characteristics of the Yellow River super-large cross-embankment bridge on Puyang-Yangxin Expressway,two schemes of prestressed concrete continuous beams and prestressed concrete composite beams with corrugated steel webs are designed.The comparative analysis on the maintenance amount in the later period shows that the combination of concrete and steel materials in the prestressed concrete beam bridge with corrugated steel webs can significantly reduce the risk of web cracking and midspan deflection of long-span concrete beam bridges,reduce the dead weight of the bridge by 15%,reduce the seismic force,reduce the cost and shorten the construction period.However,the construction technology is complex,the requirements for construction control and quality are very high,the later maintenance is difficult,the maintenance cost is high,and the construction technology is not mature.The gap between the two design schemes mainly lies in the structural rationality,construction period and project cost,construction difficulty,and later maintenance.After comprehensive consideration of relevant factors,the prestressed concrete continuous beam design scheme should be selected for the Yellow River super-large cross-embankment bridge on Puyang-Yangxin Expressway.However,it is necessary to deal with the midspan downwarping and structural anti-seismic problems.At the beam end and tower end,traction tensioning equipment to eliminate cracks,twist or limit twist should be used to improve the construction quality and safety of stay cables.