中文摘要：

为保护故宫古建筑,采取现场勘查与归纳分析相结合的方法,以故宫古建大木结构的梁为对象,研究了它们的典型残损问题。基于这些木梁典型构造和受力特点,对木梁所表现出来的各种类型的典型残损问题进行了归纳和汇总,从构造、受力、材料等角度探讨了残损问题的主要根源,结合传统方法和现代技术,提出了加固残损木梁的方法或建议。结果表明：故宫古建木梁的典型残损问题有开裂、梁头变形、糟朽、加固件破坏等,产生这些问题的主要原因与木材及铁件材料性质、木梁构造、施工工艺、外力作用等因素相关,采取传统和现代的方法均可实现木梁的有效加固。

英文摘要：

To protect ancient buildings in the Forbidden City,beams in the Forbidden City were taken as example to study their structural health problems by survey as well as analysis methods.According to constitution characters and bearing performances of these beams,their typical structural health problems were discussed.By considering factors such as beam constitution,material property,load and so on,causes for the problems were discussed.Typical as well as modern strengthening advices were proposed.Results show that typical structural health problems of these beams include crack,rot,deformation of beam end,rust of iron strengthening material and so on; main causes of these problems relate not only to construction process as well as bearing performances of beam,but also material properties of wood and iron; by traditional as well as modern techniques,the beams can be effectively strengthened.