混凝土置换法在某短肢剪力墙高层住宅加固中的应用

Application of Concrete-replacing Method in Reinforcement of a High-rise Short-leg Shear Wall Residential Building

某新建的17层短肢剪力墙结构住宅楼,结构封顶后发现该房屋第七层的混凝土强度明显偏低,取芯试验显示混凝土强度不足C15,远达不到C25的设计要求。根据第七层剪力墙的轴压比情况,现场采用免支撑混凝土分段置换方法,以高强度自密实混凝土分段置换全部原七层剪力墙混凝土,对此结构进行"加固"。通过预先制定置换顺序和分段置换量,严格控制施工质量,取得了良好的加固效果。结合该工程实例,给出了短肢剪力墙结构用免支撑混凝土置换加固的技术要点。

A 17-story residential building of short-leg shear wall structure was under construction. After the main structure had been completed, the detection personnel found that the concrete strength of shear wall in 7th floor was obviously low. And the core tests showed that the concrete strength in 7th floor was less than C15, far less than the design strength of C25. According to the condition of axial compression of the shear wall in 7th floor, the structure was to be retrofitted through the unpropped concrete-replacing method. It meant that all of the original concrete shall be segmentally replaced by high-strength and self-compaction concrete. The replacement order and segmental displacement and also the construction quality were under strictly control during the whole process, and ultimately the strengthening method had achieved good effect. Through this project example, this paper presents the essential points of the use of unpropped concrete-replacing method.