无黏结预应力混凝土楼板开洞改造施工技术研究

Research on Opening Retrofitting Technology of Unbounded Prestressed Concrete Slabs

随着无黏结预应力混凝土楼板的广泛应用,在房屋改造项目中出现大量需对原预应力混凝土楼板进行开洞改造的情况。由于开洞施工过程中,预应力筋的放张与重张均引起楼板受力的显著变化,同时开洞导致楼板传力路径的变化,因此无黏结预应力混凝土楼板的开洞改造施工组织设计存在较大的技术难度。以长沙市某高层裙楼改造项目为工程背景,通过施工过程安全性分析、施工工序合理安排、优化预应力筋放张工艺等技术措施提高了施工方案的安全可靠性,保证了项目无黏结预应力混凝土楼板开洞施工的顺利完成。

With the wide use of unbonded prestressed concrete slab,there are more and more cases appeared that structural opening need to be carried out for the existing unbonded prestressed concrete floor in building retrofitting projects. In the structural opening construction process,relaxation tendons and tensioned tendons will lead to significant change of floor stress,and the opening will lead to changes in load path,so the construction organization design of structural opening of unbonded prestressed concrete floor is hard to be prepared. Taking a Changsha podium building retrofitting project as an engineering background,the safety and reliability of the construction planning is improved by means of the technical measures which are construction process safety analysis,reasonable arrangements for the construction process and optimization technology of relaxation tendons,it ensures the construction of floor openings project successful completion.