ACCELERATION-IMPEDANCE BASED MONITORING TECHNIQUE FOR PRESTRESSED CONCRETE GIRDER

摘要

PURPOSE: An acceleration-impedance based monitoring technique for a pre-stressed concrete girder is provided to improve the efficiency of a safety test by sensing local damage through a piezoelectric sensor and determining the damage through the vibration signal measurement of a structure. CONSTITUTION: An acceleration-impedance based monitoring technique for a pre-stressed concrete girder comprises the following steps: installing an accelerometer for measuring the vibration signal of a PSC(Pre-Stressed Concrete) girder bridge and installing a piezoelectric sensor in the anchorage of a tendon for measuring impedance; determining frequency domain for easily measure the variation of an impedance signal and the frequency response ratio of an acceleration signal which measured on two spots beforehand; alarming damage occurrence by periodically measuring the variation of the acceleration signal frequency response ratio; monitoring the variation of the impedance signal within the frequency domain when alarming the damage occurrence; and determining whether the damage is caused by the tension reduction of the tendon or the degradation of flexural rigidity such as cracking according to the variation of the impedance signal. [Reference numerals] (AA) Step 1: Damage alarm; (BB) Step 2: Damage classification;