中文摘要：

为整治既有线小跨度低高度钢筋混凝土梁普遍存在的竖向刚度不足的病害，应用Ansys有限元数值模拟计算分析，研究体外预应力加固技术的适用性，并对体外预应力钢绞线和体外预应力精轧螺纹钢筋方案进行方案比选；通过现场实测数据与理论分析的对比验证，结论为：体外预应力精轧螺纹钢筋加固技术可有效恢复小跨度低高度钢筋混凝土梁竖向刚度，具有经济高效、施工便捷、对铁路运输基本无干扰等特点，值得推广。

英文摘要：

To overcome the defects of existing reinforced concrete beams with low height, small span and insufficient vertical stiffness, ANSYS FEM numerical simulation calculation and analysis is employed to assess the applicability of external reinforcement technology, and the program with prestressed strand ant that with finishing rebar are compared. The comparative verification of the measured data and theoretical analysis concludes that the external prestressed reinforcement with finishing rebar can effectively recover the vertical stiffness of reinforced concrete beams with low height and small span and prove to be cost-effective, convenient in construction with almost no interference to the traffic and worth promoting.