大跨度矮塔斜拉桥索梁锚固区受力分析

Analysis on Mechanical Behavior of Cable-Beam Anchorage Zone of Long-Span Low-Pylon Cable-Stayed Bridge

摘要:

以汉江上的某矮塔斜拉桥为研究对象，采用三维有限元方法对索梁锚固处的受力特性进行分析。模型中按照实际情况施加三向预应力，边界荷载根据全桥整体计算结果进行模拟，重点讨论了锚固区的集中应力效应和剪力滞效应。研究结果表明：索梁锚固区的最大主压应力出现在锚垫板下与斜拉索套管相交的孔道边缘处；在桥梁斜拉索的拉力影响之下，超宽箱梁可能会因为梁上剪力滞的存在而产生包括混凝土开裂、钢结构屈曲失稳等不安全因素，应该在桥梁设计过程中予以足够重视。研究成果可为类似桥梁拉索梁锚固的设计和施工提供参考。

Abstract:

Taking a low-pylon cable-stayed bridge over Hanjiang River as a research object, the three-dimensional finite element method is used to analyze the force properties at the cable-beam anchorage zone. The three-dimensional prestress is applied in the model according to the actual situation. The boundary load is simulated based on the overall calculation results of the whole bridge. The concentrated stress effect and the shear lag effect in the anchorage zone are discussed particularly. The study result shows that the maximum principal compressive stress of cable-beam anchorage zone appears at the edge of the duct which intersects the stayed cable sleeve under the anchor plate. Under the influence of the tension of the bridge stayed cable, the ultra-wide box girders may experience unsafe factors such as concrete cracking and buckling instability of steel structures due to the existence of shearing force lag on the girders, which should give the sufficient attention in the process of bridge design. The research results can provide the reference for the design and construction of the cable-beam anchorage of similar bridges.