Finite element analysis on the damage detection for RC frame beams by the Vibration Mode Slope Change Rate

According to the mechanism of the relative change rate of mode shape (RD), a new damage identification quantity called the Vibration Mode Slope Change Rate (RD´) is put forward. The new quantity is analyzed with the fundamental principles of function differential method. By means of SAP2000, Finite element analysis on the damage detection for two-span RC. frame beams is carried out, which are preset damages in edge support, mid span and the mid support, it can be seen that the misjudge is serious. The comparison analyses between RD and RD´ indicate that RD´ can effectively avoid the careless judges and misjudge in the damage identification of frame beams.