Development of lateral displacement sensor for real‐time detection of structural damage

Abstract

We have developed a novel sensor that enables us to measure the relative story displacement of a building structure in real time. This lateral displacement sensor (LDS) is composed of a light‐emitting diode (LED) array, which is fixed on the ceiling, and a position‐sensitive detector (PSD) unit, which is placed on the floor. We optimized the LDS to achieve high accuracy in lateral displacement measurement. The accuracy was evaluated to be 60 µm by conducting shaking table tests. Two LDSs were implemented in an actual building equipped with an active variable stiffness (AVS) system, and the building was vibrated with seismic waveforms by an exciter placed on the rooftop. The seismic displacement of the second floor relative to the first floor was measured using the LDS. Furthermore, the inclination angle of the second floor could be measured using the LDS during the seismic vibration. Using the AVS system, we realized the residual displacement of the second floor without inducing damage to the building, and succeeded in real‐time residual displacement measurement for the first time. These results indicate that the LDS is useful for the health diagnosis of a building structure. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Measuring the interstory drift of buildings by a smartphone using a feature point matching algorithm

“…It can be concluded that the precision of the smartphone is lower than Kanekawa et al, 6 Matsuya et al, 7 and Matsuya et al, 8 but higher than Islam et al, 5 and Dai et al 10 The advantages of using a smartphone include the low cost, convenience, and large measurement range. However, they also have a relatively low precision and sampling rate.…”

“…4 As these disadvantages impact the ability to accurately monitor displacement, many instruments have been developed to monitor interstory drift directly. These include the laser-based method, 5 a laser light source and phototransistor array, 6 a light-emitting diode array and position-sensitive detector unit, [7][8][9] and consumer grade digital cameras. 10 However, these methods require professional instruments, which significantly affect the cost.…”

Impact of Standard Deviation and Reflectance of the Measured Surface on Laser Diode-Position Sensitive Detector System

“…Due to its wider spectral range, higher detection precision, higher response rate and simpler processing circuit, position sensitive detector (PSD) has received extensive attention in recent years and is widely used in a variety of measurement systems [1][2][3][4][5]. Typically the PSD is combined with the laser diode (LD) to detect micro-displacement, which is the so-called LD-PSD triangulation system.…”

Experimental study on lateral displacement measurement using air-coupled ultrasound transducers

“…In particular, measuring relative lateral displacement in a building structure has attracted much attention because of its capability for direct damage assessment (Nitta, et al, 2006, Matsuya et al, 2010, 2011. Figure 1 shows relative lateral displacement between a lower floor and an upper floor in a building during an earthquake.…”

“…The seismic forces are applied to any vertical position of the building and displace the floors relatively inside the building because each floor is recognized as a concentrated mass. Since permanent deformation of building elements results in residual displacement, a direct displacement measurement method is an even more powerful tool for structural health monitoring compared to the conventional accelerometer which, in principle, cannot follow low-frequency movements (Matsuya, et al, 2011). Also, by combining numerical simulation and real-time lateral displacement information, a precise assessment of a building structure can be given.…”