scholarly journals Experimental Validation of Non-Marker Simple Image Displacement Measurements for Railway Bridges

2021 ◽  
Vol 11 (15) ◽  
pp. 7032
Author(s):  
Kodai Matsuoka ◽  
Fumiaki Uehan ◽  
Hiroya Kusaka ◽  
Hikaru Tomonaga
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Video Camera ◽  
Concrete Bridges ◽  
Displacement Measurement ◽  
Image Measurement ◽  
Railway Bridges ◽  
Image Displacement ◽  
Efficient Management ◽  
Applicable Range

Simple bridge displacement measurement using a video camera is effective in realizing the efficient management of numerous railway structures via condition-based maintenance. Although non-marker image measurement is significantly influenced by the measuring environment, its practical applicability considering the displacement measurement accuracy of non-marker images and the influence of various environments is not completely understood. In this study, the accuracy of non-marker image displacement measurement and the influence of illuminance are confirmed using a model bridge, and the accuracy and applicable range are discussed. Moreover, field tests on two bridges—a steel and a concrete bridge—on low-speed and high-speed railways confirm the accuracy and practical application of non-marker image measurement in a real environment. The displacement was observed to be measured with an accuracy of ~1/30 pixel (error of ~0.4 mm at 20 m position) in the daytime with sufficient brightness. Moreover, the settings for subset positions and post-processing methods to ensure accuracy in non-marker image measurement on concrete bridges with low surface contrast are discussed.

scholarly journals High-Speed Optical Disdrometer for Rainfall Microphysical Observations

2016 ◽  
Vol 33 (2) ◽  
pp. 231-243 ◽  
Author(s):  
F. Y. Testik ◽  
M. K. Rahman
Keyword(s):  
High Speed ◽  
Focal Depth ◽  
Field Tests ◽  
Video Camera ◽  
Rain Gauge ◽  
Accurate Information ◽  
Fall Velocity ◽  
Led Light ◽  
High Speed Video ◽  
High Speed Video Camera

AbstractA high-speed optical disdrometer (HOD) that was developed for measuring rainfall microphysical quantities, including raindrop shape, size distribution, and fall velocity/acceleration, is the subject of this paper. The main components of the HOD are a high-speed video camera, a light-emitting diode (LED) light, and a sensing unit to detect raindrops passing through the camera view frame. The high-speed video camera is directed at the LED light to capture the silhouettes of the backlit drops when triggered by a raindrop that is detected within a specified focal depth by the sensing unit. The use of a sensing unit enables the confinement of a measurement volume around the camera focal plane. This innovative operation principle ensures the capture of sharp images of raindrop silhouettes, which are then digitally processed to provide accurate information on various raindrop characteristics. The measurement capabilities of the HOD were evaluated through both laboratory and field tests. In the laboratory tests, high-precision spherical lenses with known diameters and water drops of different sizes generated for a known volume of water were used. In the field tests, the HOD was evaluated against a reference rain gauge in a number of rain events. These tests demonstrated the precise accuracy of HOD measurements and the HOD’s technological readiness for field deployment for various applications. It is expected that the HOD will play an important role in generating new insights on raindrop dynamics and related research through its unique measurement capability of providing sequential high-speed images of raindrops.

scholarly journals Displacement measurement of a concrete bridge under traffic loads with fibre-reinforced polymer-packaged optical fibre sensors

2020 ◽  
Vol 12 (3) ◽  
pp. 168781402091053 ◽  
Author(s):  
Yongsheng Tang ◽  
Jigang Cang ◽  
Yandong Yao ◽  
Ce Chen
Keyword(s):  
Optical Fibre ◽  
Field Tests ◽  
Concrete Bridges ◽  
Displacement Measurement ◽  
Concrete Bridge ◽  
Loading Test ◽  
Optical Fibre Sensors ◽  
Reinforced Polymer ◽  
Traffic Loads ◽  
Fibre Reinforced Polymer

Current displacement measurement methods cannot cope with the demands of the long-term measurement of small- or medium-span concrete bridges because of some technology or economic challenges. In this article, a displacement measurement method is proposed for concrete bridges based on fibre-reinforced polymer-packaged optical fibre sensors. The sensing principle and manufacture process of the proposed sensor are introduced as well as the strain sensing property. Then, a relationship is established between the strain and the displacement based on the distributed strain monitoring. Finally, some field tests are implemented using a simply supported concrete bridge. The tests include static loading test, dynamic loading test with specific speeds and dynamic random traffic loading test. The field test results show that the proposed method can measure the displacement of concrete bridges under traffic loads with reasonable accuracy. Moreover, different types of sensor distributions are proposed to investigate the displacement measurement effects to optimise the sensor installation. Although the sensors cover only some key parts of the girder, the results also verify the accuracy of the proposed method. Therefore, the proposed method can be implemented in concrete bridges in future.

Theoretical Calculation and Experimental Research of Shrinkage of High Strength Concrete an High-Speed Railway Bridges

2014 ◽  
Vol 1079-1080 ◽  
pp. 312-317
Author(s):  
Ming Zhou Gao ◽  
Ji Hua Li ◽  
Ru Deng Luo ◽  
Hai Long Wang
Keyword(s):  
High Strength Concrete ◽  
High Speed ◽  
Field Tests ◽  
High Strength ◽  
Concrete Bridges ◽  
High Speed Railway ◽  
Strength Concrete ◽  
Concrete Shrinkage ◽  
Tests And Measurements ◽  
Shrinkage Effect

Concrete bridges on high-speed railway are usually constructed with high strength concrete. Because of shrinkage of concrete, large stress and deformation always appear in construction and operation process of bridges. It even leads to concrete cracking. So as to guarantee the safety of structures and smoothness of tracks, correct calculation of concrete shrinkage effect must be done. Concrete shrinkage effect is a very complex non-stress strain problem which is influenced by numerous factors and difficult to calculate. According to the factors considered from different emphasis aspects, a variety of patterns or specifications are formed based on different domestic and foreign models of concrete shrinkage calculation. Combined with the construction of Jiangshan Harbor Bridge (75+2×135+75) m prestressed concrete continuous beam bridge on Hangzhou-Changsha high-speed railway, concrete shrinkage field tests and measurements were carried in which the same mix of high strength concrete as that of the bridge was used. The results of tests and measurements were compared with results of different theoretical models. The effects of high strength concrete shrinkage on high-speed railway concrete bridges were studied and some useful conclusions were obtained.

scholarly journals Application of viscoelastic dampers for reducing dynamic response of high-speed railway bridges

2020 ◽  
Vol 11 (2) ◽  
pp. 95-106
Author(s):  
Mohamed Tahiri ◽  
Abdellatif Khamlichi ◽  
Mohammed Bezzazi
Keyword(s):  
High Speed ◽  
Contact Point ◽  
Dynamic Performance ◽  
Orientation Angle ◽  
Concrete Bridges ◽  
Bottom Surface ◽  
Vertical Acceleration ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Viscoelastic Dampers

AbstractDue to the extensive development of high-speed railway lines which are operating at increasing velocities, the dynamic performance of railway bridges has become an important issue of scientific research. The aim of this study is to investigate the possibility of reducing the vertical acceleration and displacement of pre-stressed reinforced concrete bridges beams by using passive nonlinear viscoelastic dampers to retrofit them. The proposed solution is based on connecting the dampers directly to the abutments and the bottom surface of the bridge deck with an eccentricity between the neutral axis of the bridge and the contact point of the viscoelastic dampers. First, the dampers are modeled through the concept of linearized fractional derivatives to obtain energetic equivalent linear viscoelastic dampers. Optimization of the configuration of these dampers was performed then as function of the orientation angle and the eccentricity. Considering two bridges having different length that were studied in the literature with other systems of damping, it was found that the best orientation angle of dampers is close to 60°. It was found also that, in order to satisfy Eurocode 1 requirements, the total equivalent damping coefficient for the actual damping system is less than half of that required for systems using auxiliary beam to fix dampers, which indicates higher efficiency of the proposed solution.

scholarly journals Monitoring of the Static and Dynamic Displacements of Railway Bridges with the Use of Inertial Sensors

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2767 ◽  
Author(s):  
Piotr Olaszek ◽  
Ireneusz Wyczałek ◽  
Damian Sala ◽  
Marek Kokot ◽  
Andrzej Świercz
Keyword(s):  
High Speed ◽  
Inertial Sensors ◽  
Structural Response ◽  
Field Tests ◽  
Measuring System ◽  
High Speed Railway ◽  
Dynamic Component ◽  
Railway Bridges ◽  
Railway Line ◽  
Vertical Displacements

In the case of the monitoring of bridges, the determination of vertical displacements is one of the most important issues. A new measuring system has been developed and implemented for assessment of railway bridges based on measurements of the structural response to passing trains. The system uses inertial sensors: Inclinometers and accelerometers that do not need any referential points. The system records signals related to the passage of a train over a monitored bridge. The signals from inclinometers before the train’s entry are used to determine the static movement. Integrated signals from inclinometers and accelerometers are used to determine dynamic displacements when the train goes through the bridge. Signals from inclinometers are used to determine the so-called “quasi-static” component of the displacement and signal from the accelerometer to determine the dynamic component. Field tests have been carried out on a viaduct along a high-speed railway line. Periodic comparative measurements are carried out using a Total Station to verify static measurements and using inductive sensors to verify dynamic measurements. Tests of the system carried out so far have proven its usefulness for monitoring bridges in a high-speed railway (up to 200 km/h) with high accuracy while determining dynamic displacements.

Numerical Model Updating Technique for Estimating Load Carrying Capacities of High Speed Railway Bridges

2016 ◽  
Vol 106 (8) ◽  
pp. 490-497
Author(s):  
Dong-Uk PARK ◽  
Jae-Bong KIM ◽  
Nam-Sik KIM ◽  
Sung-Il KIM
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Model Updating ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Load Carrying

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

scholarly journals An Optimum Deployment Algorithm of Camera Networks for Open-Pit Mine Slope Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1148
Author(s):  
Hua Zhang ◽  
Pengjie Tao ◽  
Xiaoliang Meng ◽  
Mengbiao Liu ◽  
Xinxia Liu
Keyword(s):  
Focal Length ◽  
Field Tests ◽  
Mineral Resources ◽  
Video Camera ◽  
Open Pit Mine ◽  
Mine Safety ◽  
Open Pit ◽  
Prototype System ◽  
Mine Slope ◽  
Slope Monitoring

With the growth in demand for mineral resources and the increase in open-pit mine safety and production accidents, the intelligent monitoring of open-pit mine safety and production is becoming more and more important. In this paper, we elaborate on the idea of combining the technologies of photogrammetry and camera sensor networks to make full use of open-pit mine video camera resources. We propose the Optimum Camera Deployment algorithm for open-pit mine slope monitoring (OCD4M) to meet the requirements of a high overlap of photogrammetry and full coverage of monitoring. The OCD4M algorithm is validated and analyzed with the simulated conditions of quantity, view angle, and focal length of cameras, at different monitoring distances. To demonstrate the availability and effectiveness of the algorithm, we conducted field tests and developed the mine safety monitoring prototype system which can alert people to slope collapse risks. The simulation’s experimental results show that the algorithm can effectively calculate the optimum quantity of cameras and corresponding coordinates with an accuracy of 30 cm at 500 m (for a given camera). Additionally, the field tests show that the algorithm can effectively guide the deployment of mine cameras and carry out 3D inspection tasks.

Effect of Slice Priority for admission control in 5G Wireless Networks: A comparison study for two Fuzzy-based systems considering Software-Defined-Networks

2020 ◽  
Vol 26 (3) ◽  
pp. 169-183
Author(s):  
Phudit Ampririt ◽  
Yi Liu ◽  
Makoto Ikeda ◽  
Keita Matsuo ◽  
Leonard Barolli ◽  
...  
Keyword(s):  
Wireless Networks ◽  
Admission Control ◽  
High Speed ◽  
Additional Parameter ◽  
Fifth Generation ◽  
Efficient Management ◽  
Grade Of Service ◽  
User Request ◽  
Control Decision ◽  
And Control

The Fifth Generation (5G) networks are expected to be flexible to satisfy demands of high-quality services such as high speed, low latencies and enhanced reliability from customers. Also, the rapidly increasing amount of user devices and high user’s requests becomes a problem. Thus, the Software-Defined Network (SDN) will be the key function for efficient management and control. To deal with these problems, we propose a Fuzzy-based SDN approach. This paper presents and compares two Fuzzy-based Systems for Admission Control (FBSAC) in 5G wireless networks: FBSAC1 and FBSAC2. The FBSAC1 considers for admission control decision three parameters: Grade of Service (GS), User Request Delay Time (URDT) and Network Slice Size (NSS). In FBSAC2, we consider as an additional parameter the Slice Priority (SP). So, FBSAC2 has four input parameters. The simulation results show that the FBSAC2 is more complex than FBSAC1, but it has a better performance for admission control.

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