随着我国经济的高速发展和人民生活水平的不断提高，许多既有建筑已不能满足新功能的要求，需要进行改造处理。为了扩大使用面积、节约费用，在短期内施行加层改造是一种有效的改造方法。近年来在既有建筑加层改造的工程实践很多，但对加层改造后整栋结构受力性能的研究还较少，甚至造成下部结构的受力性能及其安全性存在隐患。为此，本文对增层设计及施工过程中遇到的相关技术问题进行研究分析。 本文采用SAP2000有限元分析软件对四层加两层结构与一次性新建六层结构进行静力弹塑性分析。由数值模拟计算分析结果得出：增层结构的周期相比一次性整体结构有所增加；其基底剪力比一次性整体结构要小同时位移增大；增层结构的薄弱层在一层，相比一次性结构薄弱层在二层偏于不安全；增层结构的塑性铰的数量比一次性整体结构要多，且柱子上塑性铰出现的也较早。以上分析结果均表明增层结构的整体性能很明显弱于一次性新建结构。本文针对以上问题拟定了三种加固方案（对原结构中柱采用加大截面法进行加固）并分别对其进行建模分析，得到了在多遇、罕遇地震作用下增层加固结构的变形、位移、层间位移角等参数以及性能点和塑性铰，通过这些参数与一次性新建结构进行分析对比，找出了与一次性新建结构各方面最相似的加固方案，建议工程实际中类似工程一般可取对原结构中柱进行加大截面法加固，从一层到四层中柱每边加宽60 mm并配以植筋14mm的纵筋间距200mm排列。 上述研究成果对进一步研究直接增层结构相对薄弱环节的加固方面和完善混凝土结构加固设计规范以及砖混结构房屋加层技术规方面有一定的参考价值，并可供同类工程的设计与施工参考。

With the rapid development of China's economy and the improving of people's living standards, many existing buildings have not been able to meet the requirements of the new features and need to handle. In order to expand the area and save cost, it is an effective method that adding layer to transform in the short term.There are a lot of engineering practices. The stress performance research of whole structure is less to add layer after transforming and it leads to hidden trouble of the mechanical properties and safety of infrastructure. In this paper,the author research and analysis technical problems in the process of design and construction . The author analysis the four plus two layer structure and one-time new six-story structure using finite element analysis software SAP2000. The results are as follows by the numerical simulation calculation.The cycle of the add layer structure is more than the one-time new six-story structure. The base shear of the add layer structure is less than the one-time new six-story structure but the displacement is more. The weak layer of the add layer structure is on the first floor and it is not safe. The plastic hinge of the add layer structure is more than the one-time new six-story structure and the plastic hinge in pillar appears earlier. The above analysis results show that the overall performance of the layer structure is better than the new structure in one-time. Three kinds of reinforcement scheme is worked out aiming at the problem above(using enlarging section method to the column in original structure).The author gets the deormation, displacement, the interlayer displacement angle and the plastic hinge in the add layer structure under the action of earthquake and the rarely meeting earthquake and carries on the analysis comparison with the the new structure in one-time.The author finds out the reinforcement scheme Similar to one-time all aspects of the new structure.The suggestion is that reinforcing the column of original structure by enlarging section method in the similar practical engineering. Widen the 60 mm per side and planting bar with a 14 mm longitudinal reinforcement which the spacing is 200 mm in the column from one to four layers. The above research results are conducive to research the weak layer of the layer structure and reinforced concrete structure design code and the adding layer technique of brick structure.It provides the reference for the design and construction of similar projects.