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With the reported increasing number of collapses occurring in major infrastructures, health selleck chemicals monitoring of civil structures has become of significant importance. Structures must satisfy strength and serviceability criteria throughout their stipulated design life. However, after a natural disaster, such as an earthquake, the strength and serviceability of the structure may become questionable due to possible damage induced in it. In addition, to prevent catastrophic failures, gradual deterioration of structures with time, environmental corrosion, lack of maintenance, accidental overloading and excessive usage all require periodic evaluation during the life span of the structures.Concrete structures have been used extensively in civil infrastructural systems.

However, compared to metallic or other composite structures, non-destructive evaluation (NDE) technologies of concrete structures are relatively undeveloped [1]. Inhibitors,Modulators,Libraries Many types of structural health monitoring (SHM) techniques have been reported in the literature, based on either the global or the local monitoring of Inhibitors,Modulators,Libraries structures [2]. Some researchers have proposed methods based on the global static response of structures, such as the static displacement response technique [3] and the static strain measurement technique [4]. The main limitation of the static response techniques is that their application on large structures is not feasible in practice. The static displacement technique involves applying static forces to the structure at specific nodal points and measuring the corresponding displacements which is expensive and tedious task for real size structures.

In global dynamic techniques, the structure is subjected to low frequency excitations and the first few mode shapes and their corresponding natural frequencies Inhibitors,Modulators,Libraries are extracted. The main drawback of these techniques is that they rely on a small number of low order modes, which, being global in character, are not Inhibitors,Modulators,Libraries very sensitive to the presence of localized damages. Another limitation of these techniques is interference from ambient vibration noise, which happens to be in the low frequency range, typically less than 100 Hz [2].Another category of damage detection techniques are the so-called local methods, which rely on the localized monitoring of the structures.

Some common techniques in this category are the ultrasonic Brefeldin_A wave http://www.selleckchem.com/products/BI6727-Volasertib.html propagation technique, acoustic emission, magnetic field analysis, electrical methods, dye penetrant testing, impact echo testing and X-ray radiography [5]. However, these techniques share many drawbacks which prevent their use for health monitoring of large civil structures [2,6,7].Due to the increasing number of infrastructures and the need of monitoring inaccessible areas, manual monitoring becomes less interesting and not applicable for most projects.