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Application of fiber Bragg grating sensing technology in tunnel excavation model test
Published in Airong Chen, Xin Ruan, Dan M. Frangopol, Life-Cycle Civil Engineering: Innovation, Theory and Practice, 2021
H. Song, H. Pei*, J. Jing, Z. Zhang, F. Zhang, H. Zhu
Traditional tunnel and soil deformation monitoring mainly include angle measurement and distance measurement technology represented by instruments such as convergence meters and inclinometers. These instruments firstly measure the angle change and then calculate the horizontal displacement. The inclinometer is the most effective device to measure horizontal soil displacement. Traditional intelligent inclinometers include resistance strain gauges, servo accelerometers, rigid strings, and electronic gauges. However, the accuracy and convenience of these traditional instruments need to be iproved (Bernini et al. 2002; Metje et al. 2008; Shen & Zhong 2011). Portable in-clinometers and fixed inclinometers are inclinometers for soil deformation monitoring that are currently used in many projects. A portable inclinometer requires manual operation of the instrument to complete the measurement.
Operational deformations in long-span bridges
Published in Fabio Biondini, Dan M. Frangopol, Design, Assessment, Monitoring and Maintenance of Bridges and Infrastructure Networks, 2020
James M.W. Brownjohn, Ki-Young Koo, Andrew Scullion, David List
Noise performance of accelerometers is relatively straightforward to describe. The QA750 accelerometer is reported as having ‘resolution/threshold’ better than 1 μg, while our own studies (Brownjohn & Botfield, 2009) have shown that broadband noise floor (0–100 Hz) is 3 μm/s2/√Hz or better. In terms of displacement, these figures convert to 2.5 mm resolution and 0.75 mm/√Hz noise at 0.01 Hz and to 0.25 μm and 0.075 μm/√Hz noise at 1 Hz. For the Nivel220 inclinometer, in the range setting used here, the resolution is 1 μrad and accuracy 47 μrad (no noise value is quoted by Leica). For the QA750 horizontal accelerometers used in both bridges to indicate tilt, output due to main span rotation θ is resolved gravity (g) component g sinθ, so resolution is 1 μrad and noise 0.3 μrad/Hz.
Assessment of MEMS-based sensors for inclination measurements
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
The encased MEMS-based accelerometers were installed at a tower-like structure to measure the inclinations under real environmental conditions. Also a reference system based on high quality inclinometers with a range of ±3° and an accuracy of 0.3m° was installed. The inclinations in orthogonal horizontal directions of the structure N1, N2 and the temperature were recorded (see Figure 15). The temperature variation can be clearly seen. However, if considering the inclination of the reference sensor, it is also evident, that a drift effect is overlaid in the measured inclinations of the MEMS-inclinometer. The drift seems to be a linear up to day 75, after which the temperature decreases and the growth of the deviation is reduced. The question arises whether the drift reduces after a certain period or the reduction is due to the lower temperature level.
Identifying damage in a bridge by analysing rotation response to a moving load
Published in Structure and Infrastructure Engineering, 2020
David Hester, James Brownjohn, Farhad Huseynov, Eugene Obrien, Arturo Gonzalez, Miguel Casero
Inclinometers have been widely utilised in industrial applications such as automotive, aerospace and electronics. With recent improvements in sensor technology, they have also been used in bridge SHM applications. Haritos and Chalko (1996) installed inclinometers at the support locations of Fuge’s Bridge to obtain a better understanding of its boundary conditions. They concluded that the behaviour of bearings at the abutments corresponds more closely to ‘pinned’ than ‘fixed’, for which the bridge was originally designed. In a similar study, micro-electro-mechanical systems (MEMS) inclinometers were installed on Ferriby Bridge in the UK to investigate the long-term transverse inclination of elastomeric bearing due to temperature effects (Hoult, Fidler, Hill, & Middleton, 2010; Stajano et al., 2010). Shoukry, Riad, and William (2009) instrumented a steel bridge built according to the AASHTO LRFD bridge design specification (American Association of State Highway and Transportation Officials, 2012), to evaluate the long-term performance of the bridge deck and compare the measured bridge response with the theoretical approaches proposed in the LRFD code.
A novel mechanical inclinometer device to measure acetabular cup inclination in total hip arthroplasty
Published in Journal of Medical Engineering & Technology, 2020
B. H. van Duren, M. Al Ashqar, J. N. Lamb, H. G. Pandit, C. Brew
An inclinometer or clinometer is a device used for measuring angles relative to gravity. Inclinometer based devices offer a more accurate means of determining inclination angle than freehand and MAG techniques while being more cost-effective than navigation systems. Mechanical devices, bubble inclinometers, and electronic devices have been used in determining intra-operative cup inclination [2,22,27–30,32]. However, the use of inclinometers, though showing promising results, has not been fully explored and the devices described are not without limitations; the majority of devices described cannot be autoclaved and need to be placed in sterile containers or bags and the mechanical devices raise some concerns with regard to their practicality.
Bearing behaviour of shallow foundations for wind energy converters on sandy soils under cyclic eccentric loads
Published in International Journal of Geotechnical Engineering, 2023
The cyclic deformations of the model footing were measured with four displacement transducers and an inclinometer (see Figure 12). The four displacement transducers have a measurement range of 50 mm and 100 mm (each in two pieces) with an accuracy of 0.1 mm and 0.2 mm, respectively. The inclinometer has an accuracy of 0.15°. All sensors were thoroughly calibrated before the start of the tests. The rotation was captured through inclinometer as well as the settlement difference measured by displacement transducers. A good agreement can be achieved between the rotations captured by the two ways. In the following contents, only the rotation derived from displacement transducers is presented due to a higher data quality.