Application of three types of outer-jacketing structures for adding story around the existing building

In order to perfect decision-making system and technique measure of outer-jacketing structure for adding story around existing building, combined with actual project practice, three types of outer-jacketing structures for adding story are introduced. They are prestressed concrete outer-jacketing frame structure for adding story, outer-jacketing frame structure for adding story with encased prestressed steel-truss-concrete composite beam for first floor of new-added structure, and prestressed steel-concrete composite outer-jacketing frame for adding story. Characteristics of these outer-jacketing structures were compared and analyzed. The results show that using the method of prestressed steel-concrete composite outer-jacketing frame for adding story, the weight of the first floor can be carried by the structure itself during construction, in addition, the structural whole cost is lower and the construction period is shorter than using other schemes. So prestressed steel-concrete composite frame structure should be firstly chosen in outer-jacketing structure reconstruction for adding story around existing building.