Structural damage quantification in shear buildings using mode shape slope ratio

Abstract

Mode shape-based techniques are very popular among researchers since the last two decades and varying levels of success have been achieved towards identifying damage using structural mode shapes. This study presents a novel formulation to establish the expression of damage severity in the form of mode shape slope. The derived closed-form solution directly correlates the percentage damage intensity with the derivatives of the changes in mode shapes in shear buildings, the most common class of civil structures. Numerical experimentation involving a 16-storey two-dimensional shear building has been performed to show the applicability of the proposition in damage quantification. First three mode shapes are used for this purpose. A detailed parametric study comprising of location as well as noise sensitivity has also been carried out to test the robustness of the proposition. Further, the derived expression has been applied to quantify damages in multiple locations. A relatively shorter structure of eight-storey shear building has also been considered to check the efficiency of the proposed algorithm in structural damage quantification. However, if any mode depicts a very low slope value at the damage location, that particular mode could not be used for damage quantification. Finally, an extensive experimental program on a three-dimensional six-storey miniature model of a shear building ensures its practical applicability under real measurement condition in a laboratory environment. Therefore, this novel mode shape slope-based damage quantification technique can be widely applicable to be appropriate for various circumstances.