The vibration responses of structures under controlled or ambient excitation can be used to detect structural damage by correlating changes in structural dynamic properties extracted from responses with damage. Typical dynamic properties refer to modal parameters: natural frequencies, mode shapes, and damping. Among these parameters, natural frequencies and mode shapes have been investigated ex...

A technique is developed to model instrumented buildings with a second-generation performance-based earthquake engineering approach, producing a damage and loss estimate shortly after the cessation of strong motion. It estimates the likely locations of damage (including concealed structural damage), potentially saving the owner time and money by focusing post-earthquake safety and repair inspec...

Structural Health Monitoring (SHM) is a systematic method for nondestructive evaluation of a structure’s performance by sensing, extracting and analyzing features of the structural system. Most approaches for damage recognition in SHM focus on statistical analyses. We introduce a method to improve nondestructive evaluation for damage assessment by performing damage diagnosis using fuzzy sets. W...

The assessment of seismic performance of existing structures is becoming an important problem in earthquake engineering. Some important ructures are considerably old and, therefore, their strengths and ductilities are less than strength and ductility demands because of changes in codes and design methodologies. Such structures must be strengthened to resist future earthquakes. First, a structur...

Bridges are potentially one of the most seismically vulnerable structures in the highway system during earthquake &#10 &#10events. It is known that the seismic performance of transportation systems plays a key role in the post-earthquake emergency management. Hence, it is necessary to evaluate both physical and functional aspects of bridge structures. The physical aspects of the seismic perform...

Piezoelectric wafer active sensors may be applied on aging aircraft structures to monitor the onset and progress of structural damage such as fatigue cracks and corrosion. The state of the art in piezoelectric-wafer active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) the Electro–Mechanical (E/M) impedance technique ...

Recent structural collapses of bridges and damaging occurred on deck and dampers of suspension bridges, are driving the development of monitoring techniques for the structural integrity assessment of primary lifelines. Structural Health Monitoring combines a variety of methods for observed dynamic systems response detection of different structural systems. Among others techniques, Operational M...

The damage in epitaxial Co& films 500 nm thick grown on Si( 111) produced by roomtemperature implantation of 150 keV **Si were investigated by 2-MeV 4He channeling spectrometry, double-crystal x-ray diffractometry, and electrical resistivity measurements. The damage in the films can be categorized into two types. In lightly (heavily) damaged CoSi, the damage is in the form of point-like (extend...

This paper presents an overview and recent advances in impedance-based structural health monitoring. The basic principle behind this technique is to apply high-frequency structural excitations (typically greater than 30kHz) through surface-bonded piezoelectric transducers, and measure the impedance of structures by monitoring the current and voltage applied to the piezoelectric transducers. Cha...