Stiffness-Mass Ratios Method for a baseline determination and damage assessment of a benchmark structure

Abstract

A new method based on ratios between stiffness and mass values from the eigenvalue problem is introduced and applied to the benchmark structure to obtain baseline modal parameters utilizing damaged state information of the structure. The benchmark problem on structural health monitoring developed by the ASCE Task Group on Structural Health Monitoring (TGoSHM) is a four-story steel building model created to compare performances of different vibrational damage identification methods. This research is focused on the evaluation of the new Stiffness-Mass Ratios Method for extraction of baseline modal parameters in conjunction with the Damage Index Method for damage assessment as applied to the SHM benchmark structure. In this investigation a shear-beam model is used to predict location and severity of damage using the Damage Index Method for all six existing damage patterns established by TGoSHM. A damage identification process is also carried out for the same six existing damage patterns for the case when undamaged state information is available. In addition, two different damage patterns are studied to locate connection damage from an unbraced frame model as part of the second phase of the benchmark problem. This research will be of interest to structural engineers and inspection practitioners who deal with structural damage identification problems and who will corroborate the feasibility of the proposed method.