Fundamental modeling issues on benchmark structure for structural health monitoring

The IASC-ASCE Structural Health Monitoring Task Group developed a series of benchmark problems, and participants of the benchmark study were charged with using a 12-degree-of-freedom (DOF) shear building as their identification model. The present article addresses improperness, including the parameter and modeling errors, of using this particular model for the intended purpose of damage detection, while the measurements of damaged structures are synthesized from a full-order finite-element model. In addressing parameter errors, a model calibration procedure is utilized to tune the mass and stiffness matrices of the baseline identification model, and a 12-DOF shear building model that preserves the first three modes of the full-order model is obtained. Sequentially, this calibrated model is employed as the baseline model while performing the damage detection under various damage scenarios. Numerical results indicate that the 12-DOF shear building model is an over-simplified identification model, through which only idealized damage situations for the benchmark structure can be detected. It is suggested that a more sophisticated 3-dimensional frame structure model should be adopted as the identification model, if one intends to detect local member damages correctly.