APPLICATION OF IBRAHIM TIME DOMAIN METHOD IN BRIDGE MODAL PARAMETER IDENTIFICATION THROUGH AMBIENT TESTING

• Main Author: ANTHONY SUGIANTO, YOEL
• Format: Theses
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/83084
• Institution: Institut Teknologi Bandung

Structural Health Monitoring (SHM) is performed to determine the actual condition of the structure during its operational life against the damage that may occur to the structure. One of the most used methods for structural health monitoring is modal parameter estimation, which is usually performed using FFT-based algorithms, such as the well-known spectral density peak retrieval method. The drawback of this frequency domain modal analysis is the inability to obtain mode shapes, damping ratios, and to distinguish between physical and non-physical modes. Therefore, a time domain method is used to obtain modal parameter estimation. This paper presents the results of modal parameter estimation on two bridges in West Java, namely Pasupati Bridge, which is a continuous-span prestressed bridge, and Cisangkuy Bridge, which is a simply supported steel girder bridge. The bridge response was measured under unmeasured and uncontrolled loading using an EZDYN triaxial accelerometer. The acceleration response was processed using operational modal analysis (OMA) with the Ibrahim time domain method, and modal parameters such as natural frequency, damping ratio, and mode shape were obtained. A finite element method, based on limited information obtained from field surveys, was also used for comparison with the OMA results. The OMA and the finite element model show that both provide satisfactory results, which confirm each other to some extent, for both the natural frequencies and the vibration modes of the various vibration modes identified.