Building framework structure damage detection method

The invention discloses a building framework structure damage detection method. The method comprises the following steps of: firstly, testing a framework structure before being damaged to obtain a structural modal parameter (omega 0, phi 0); then, testing the damaged structure, and performing modal analysis to obtain a modal parameter (omega D, phi D); establishing a first-order modal parameter sensitivity equation S1D'=delta f and a second-order modal parameter sensitivity equation S1D'+S2D''=delta f; calculating first-order and second-order modal parameter sensitivities by adopting an improved modal truncation method; and solving a unit damage coefficient Di (i is 1, 2...n) by using a first-order and second-order sensitivity equation-based mixed iteration solving method so as to fulfill the purpose of simultaneously identifying the number, position and size of damages of the whole building structure. The method is suitable for damage detection of the building framework structure, saves the calculation workl