Abstract：
In this paper, a long-span prestressed concrete frame structure is strengthened with the methods of enlarging section method and external prestressing method due to its inadequate construction quality and insufficient stiffness. The commercial software SAP2000 is firstly used to compare the retrofit performance of these two methods. And then, the cracking variations before and after strengthened are analyzed with the help of ANSYS. The results show that the enlarging section method and external prestressing method has good retrofit performance on prestressed concrete
frame.
