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精轧螺纹钢筋作为竖向预应力构件在混凝土连续梁桥中已获得广泛应用,但由于精轧螺纹钢筋预应力损失过大而形成的箱梁腹板裂缝已经成为该类桥在运营过程中的重要病害。针对这一问题,许多学者从设计方面和施工工艺方面开展了相关研究,提出了通过合理钢筋排布、优化施工方法等措施减小预应力损失。分析了由于施工因素而导致的预应力损失并提出了针对性的改进措施。此外,鉴于现阶段对于竖向张拉力无法实现有效监控,在结构动力学理论基础上,结合模型试验建立了竖向张拉力和外露端长度以及一阶振动频率的参数模型来实现对精轧螺纹钢筋张拉力的无损检测,研究成果应用于宁夏中宁黄河大桥改扩建项目。
As a vertical prestressed component, the finished rolled rebar has been widely used in concrete continuous girder bridges. However, the cracks in the box girder web formed due to the excessive prestress loss of the finished rolling rebar have become the key points in the operation of such bridges Important disease. In response to this problem, many scholars from the design aspects and construction technology carried out relevant studies, proposed by reasonable arrangement of steel reinforcement, construction methods and other measures to reduce the loss of prestress. The loss of prestress due to construction factors is analyzed and the corresponding improvement measures are put forward. In addition, in view of the fact that the vertical tension can not be effectively monitored at this stage, based on the structural dynamics theory, the model parameters of vertical tension and exposed length and the first-order vibration frequency Non-destructive testing of tensile strength of steel, the research results applied to Ningxia Zhongning Yellow River Bridge expansion project.