Performance-based structural health monitoring through an innovative hybrid data interpretation framework

The utilization of Structural Health Monitoring (SHM) for performance-based evaluation of structural systems requires the integration of sensing with appropriate data interpretation algorithms to establish an expected performance related to damage or structural change. In this study, a hybrid data interpretation framework is proposed for the long-term performance assessment of structures by integrating two data analysis approaches: parametric (model-based, physics-based) and non-parametric (data-driven, model-free) approaches. The proposed framework employs a network of sensors through which the performance of the structure is evaluated and the corresponding maintenance action can be efficiently taken almost in real-time. The hybrid algorithm proposed can be categorized as a supervised classification algorithm. In the training phase of the algorithm, a Monte-Carlo simulation technique along with Moving Principal Component Analysis (MPCA) and hypothesis testing are employed for simulation, signal processing, and learning the underlying distribution, respectively. The proposed approach is demonstrated and its performance is evaluated through both analytical and experimental studies. The experimental study is performed using a laboratory structure (UCF 4-Span Bridge) instrumented with a Fiber Brag Grating (FBG) system developed in-house for collecting data under common bridge damage scenarios. The proposed hybrid approach holds potential to significantly enhance sensor network design, as well as continuous evaluation of the structural performance

Modal analysis of multi-reference impact test data for steel stringer bridges

A comparative study on the postprocessing of experimental modal data from a full scale steel stringer bridge for damage identification is presented. The bridge was tested before and after removal of one of the bearing plates at one abutment. Frequency Response Functions, measured crt different spatial locations, are used to post-process the data using a Complex Mode Indicator function(CMIF) algorithm. Dynamic properties of the bridge show major differences between the two cases. In addition modal flexibility of the bridge is calculated for the measured degrees of freedom. Modal flexibility of the bridge shows good agreement with static instrumentation results under truck loading. The induced damage is successfully quantified for this loading case. The ''after-removal'' condition data was also post-processed at Los Alamos National Laboratory using the Eigensystem Realization Algorithm (ERA) in order to provide a distant check and correlation for the results. This paper briefly describes the two different algorithms and presents the results in both modal and flexibility space. Further the principal focus of this paper is the post-processing algorithms and one damage index, although a number of different damage identification indices are being used for varying levels and types of damage as part of the ongoing research project

Modal analysis of multi-reference impact test data for steel stringer bridges

A comparative study on the postprocessing of experimental modal data from a full scale steel stringer bridge for damage identification is presented. The bridge was tested before and after removal of one of the bearing plates at one abutment. Frequency Response Functions, measured crt different spatial locations, are used to post-process the data using a Complex Mode Indicator function(CMIF) algorithm. Dynamic properties of the bridge show major differences between the two cases. In addition modal flexibility of the bridge is calculated for the measured degrees of freedom. Modal flexibility of the bridge shows good agreement with static instrumentation results under truck loading. The induced damage is successfully quantified for this loading case. The ''after-removal'' condition data was also post-processed at Los Alamos National Laboratory using the Eigensystem Realization Algorithm (ERA) in order to provide a distant check and correlation for the results. This paper briefly describes the two different algorithms and presents the results in both modal and flexibility space. Further the principal focus of this paper is the post-processing algorithms and one damage index, although a number of different damage identification indices are being used for varying levels and types of damage as part of the ongoing research project