APPLICATION OF AUTO-REGRESSIVE MOVING-AVERAGE (ARMA) METHOD FOR STRUCTURAL DYNAMIC MODAL PARAMETERS IDENTIFICATION IN TIME DOMAIN

• Main Author: Bernadus Nicholas, Ignatius
• Format: Theses
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/66697
• Institution: Institut Teknologi Bandung

Dynamic loading test is one of the testing methods to obtain structural dynamic response. Structural dynamic modal parameters can be obtained through post processing of dynamic structure response data using modal analysis method. Modal analysis method can be classified into two, namely, modal analysis in frequency domain and modal analysis in time domain. Auto Regressive Moving Average (ARMA) method is one of modal analysis method in time domain. ARMA method has advantages compared to conventional Peak Picking method, where analysis methods can use response data either from known excitation sources or from environmental excitation. In this study, the modal parameters comparison between ARMA method, Peak Picking method, and also Random Decrement Technique (RDT) method will be performed with Finite Element Model result as a validation. Natural frequency, damping ratio, and mode shapes are the structural dynamic modal parameters that will be compared. The analyzed structures are Elevated LRT Bridge with ambient excitation and Semanggi Bridge with impuls excitation. The identification process is done bt selecting and filtering the random response data, then the RDT process is done to obtain the free response data, then the structural dynamic modal parameters is obtained through ARMA analysis, and finally a comparison and validation of all methods with Finite Element Model are carried out. Based on analysis results, the natural frequency obtained with ARMA method has a smaller margin error of natural frequency from Finite Element Model compared to the results from conventional Peak Picking method and RDT method. The structure mode shape from the ARMA method is also identical with Finite Element Model result. However, structural dynamic modal parameters results from ARMA method are strongly dependent with the order value of the ARMA equation.