A Method for Sensitivity Analysis and Frequency Updating of Shear Buildings

Determining the sensitivity of vibratory characteristics of a dynamic system (frequencies and mode shapes) due to changes in its mass or stiffness properties is of significant importance. The original algorithms developed were on the basis of the first order sensitivity analysis. However, due to the limitations of these methods, extensive studies performed to develop more efficient methods for this purpose. The second order sensitivity analyses based methods are among the developed algorithms. Both the first and second order sensitivity analyses algorithms lead to acceptable results for only small changes in mass and stiffness of dynamic systems. In this paper, a new method for frequency updating of shear systems is presented based on shear building properties. The method is simple and needs less computation time compared to other methods. An iterative algorithm is developed by which the frequencies of the modified shear system can be determined to the desired accuracy. Since the tuning of the dynamic characteristics of the shear building systems has an important role in controlling their response against external loading, especially earthquake loading, this method can perform efficiently in frequency updating of the system. The performance of the proposed method is investigated using some numerical examples.