本文首先介绍了改、扩建工程的设计思路,然后结合台州某实际工程既有混凝土建筑与新建钢结构建筑连接设计中遇到的一系列问题进行研究,对钢梁与原有钢筋混凝土柱连接、钢梁与原有钢筋混凝土梁连接、新老建筑地下室底板衔接处防水节点处理等关键问题进行详细地阐述,以便为今后遇到此类设计提供借鉴。 This paper first introduces the design ideas of the renovation and expansion project, and then studies a series of problems encountered in the connection design of an existing concrete structure and a new steel structure in an actual project in Taizhou. By connecting the steel beam with the original reinforced concrete column, Steel beams and the original reinforced concrete beam connection, the old and new building basement joints waterproofing node processing and other key issues described in detail in order to meet the future for such designs to provide reference.