Готові списки джерел за темами / Prestressed concrete beams Data processing

Добірка наукової літератури з теми "Prestressed concrete beams Data processing"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 29 січня 2023

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Статті в журналах з теми "Prestressed concrete beams Data processing"

Chen, Xiaowen, and Guanci Yang. "Data Sensing and Processing Tensioning System Based on the Internet of Things." Applied Sciences 9, no. 2 (January 16, 2019): 310. http://dx.doi.org/10.3390/app9020310.

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Tensioning is an important process for producing prestressed concrete beams and directly affects bridge performance and driving safety. Active sensing and management of tensioning process data can improve the efficiency of quality monitoring and level of prestressed concrete beams. To realize remote collection and quality monitoring of tensioning process data, a framework for data sensing and processing of tensioning system based on the Internet of Things (IoT) is proposed in this study. Firstly, we investigate the technical framework and techniques of the system and designs a work flow of sensing, transport, and application service layers. The architecture of the tensioning system is presented. Then we propose a data acquisition and preprocessing method for the sensing layer, put forwards the data-pushing mechanism of the transport layer, and designs the function and work flow of the application service layer. After that, .NET platform and Android Studio are used to implement the tensioning system based on Browser/Server (B/S) architecture and mobile terminals. Finally, the case results of the system in seven precast beam fields in the Hubei section of Zhengzhou–Wanzhou high-speed Railway are given, which show that the developed system realizes collection, active pushing, and remote monitoring of tensioning process data.

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Chen, Li, Heng Bo Xiang, and Yong Zhang. "Dynamic Analysis of Prestressed Concrete Material Beams." Applied Mechanics and Materials 48-49 (February 2011): 443–47. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.443.

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Prestressed concrete material structures have the properties of higher crack resistance, higher degree of solidity and lighter weight. A new analytical method is proposed to investigate the dynamic deflection responses of the partially prestressed concrete beams subjected to blast loads. The new method uses an equivalent single degree of freedom system, which combines an elasto/viscoplastic rate-sensitive material model with the proposed static layered section approach. The analytical results agree well with the test data.

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Cheng, Dong Hui, and Peng Zhang. "Test Research on Stiffness of Loaded Concrete Beams Strengthened with Prestressed CFRP Sheets." Advanced Materials Research 690-693 (May 2013): 752–55. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.752.

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In order to investigate the mechanical properties of concrete beams strengthened with CFRP sheets under load conditions, according to the reinforcement ratio, three groups of twelve concrete beams were made, each group included an common concrete beam and three prestressed CFRP sheets reinforced beams. Then the test with two-point loading was completed and the test date were obtained. On the basis of the test data, load state of concrete beams strengthened with prestressed CFRP sheets can effectively improve the ultimate bearing capacity, limit crack development and ameliorate the section stiffness.

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Zhang, Yao Ting, Yi Zheng, and Hong Jian Li. "A Dynamic Test of Fully Prestressed Concrete Beams." Advanced Materials Research 368-373 (October 2011): 2483–90. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2483.

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A dynamic test of two unbonded fully prestressed concrete beams has been conducted. The results indicate that the natural frequency of beams increases with the prestress force, which is opposite to the analytical arguments for homogeneous and isotropic beams subject to axial force. This paper explains the change in frequencies by discussing the change in the elastic modulus. A modified formula is also proposed, and the experimental data agree well with the theoretical analysis.

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Guo, Xin-Yan, Yi-Lin Wang, Pei-Yan Huang, Xiao-Hong Zheng, and Yi Yang. "Fatigue Life Prediction of Reinforced Concrete Beams Strengthened with CFRP: Study Based on an Accumulative Damage Model." Polymers 11, no. 1 (January 13, 2019): 130. http://dx.doi.org/10.3390/polym11010130.

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With the prestressed carbon fiber reinforced polymer (CFRP) strengthening technique widely used in reinforced concrete (RC) structures, it is more and more important to study the fatigue performance of RC structures. Since the fracture of a tensile steel bar at the main cracked section is the leading reason for the failure of RC beams reinforced by prestressed CFRP, a fatigue life prediction model of RC beams reinforced by prestressed CFRP was developed based on an accumulative damage model. Moreover, gradual degradation of the performance of the concrete was considered in the fatigue life prediction model. An experimental study was also conducted to research the fatigue behavior of RC beams reinforced by prestressed or non-prestressed carbon fiber laminate (CFL). During the tests, fatigue crack patterns were captured using a digital image correlation (DIC) technique, and the fatigue lives of a total of 30 beams were recorded. The results showed that the predicted main crack propagation curves and the fatigue lives were close to the experimental data. This study also exhibited that the prestressed CFRP could reduce the stress of main steel bars in RC beams and effectively improve the fatigue performance of the RC beams.

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Li, Rui Ge, and Guo Li Yang. "Nature Frequency Identification of Prestressed Concrete Beam with RBF Network." Advanced Materials Research 446-449 (January 2012): 362–65. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.362.

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Abstract. The relationship of pre-stressed concrete (PSC) beam natural frequency and pre-stressed force is difficult to described accurately with mechanical model. The past experimental data are collected. Then five unbonded post-tensioned PSC beams are designed. Frequencies and damps are collected in the dynamic experiment of five PSC beams. Radial basis function neural network is constructed to identify the natural frequencies of prestressed beam with different levels prestressing force based on previous test data and new dynamic test beam data. Then the input and output node numbers of neural network are selected and the appropriate training algorithm and expansion coefficient is determined. In order to verify that the network performance, one prestressed concrete beam test data are left to simulation test. Simulation results show that the radial basis function neural network is feasibility to recognize the frequency of PSC beams.

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Shen, Jie, Ismail Yurtdas, Cheikhna Diagana, and Alex Li. "Influence of Compressive Strength of Self-Compacting Concrete on Shear Behavior of Prestressed RC Beams." Applied Mechanics and Materials 147 (December 2011): 14–18. http://dx.doi.org/10.4028/www.scientific.net/amm.147.14.

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The shear behavior of prestressed self-compacting concrete (SCC) beams has been investigated in this study. The effect of compressive strength of SCC on the shear strength has been taken into account in test program. Based on the experimental data, the failure mechanism of the prestressed SCC beams was discussed and the shear transfer mechanism of the RC beam after the flexure-shear cracking was also analyzed.

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Mariak, A., and K. Wilde. "Multipoint Ultrasonic Diagnostics System Of Prestressed T-Beams." Archives of Civil Engineering 60, no. 4 (December 1, 2014): 475–92. http://dx.doi.org/10.2478/ace-2014-0032.

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AbstractThis paper is devoted to the application of ultrasonic wave propagation phenomena for the diagnostics of prestressed, concrete, bridge T-beams. A multi-point damage detection system is studied with use of numerically obtained data. The system is designed to detect the presence of the material discontinuities as well as their location.

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Yang, Chang Jing, Li Bing Jin, De Cai Chen, and Ji Peng Qi. "Practical Measurement for Steel Fiber Distribution of the SFRC Beams." Applied Mechanics and Materials 256-259 (December 2012): 840–43. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.840.

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This paper introduces practical measurement of steel fiber distribution in steel fiber reinforced concrete (SFRC) which serves as the matrix of prestressed SFRC beams. Using digital image processing in mesos-copical mechanism of SFRC, “the Dynamic System of Measuring Steel Fiber Distribution” is developed. Compared with theoretical analysis, the system is practical and valid, and a new method is provided for guiding production technology of SFRC and controlling constructional quality.

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Chowdhury, S. H., and Y. C. Loo. "A New Formula for Prediction of Crack Widths in Reinforced and Partially Prestressed Concrete Beams." Advances in Structural Engineering 4, no. 2 (April 2001): 101–10. http://dx.doi.org/10.1260/1369433011502390.

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A new formula for predicting the average crack widths in reinforced and partially prestressed concrete beams has been developed incorporating four governing parameters. The performance of the proposed formula is checked using the authors' test results which includes crack spacing and crack width measurements from 18 reinforced and 12 partially prestressed concrete beams. Also included in the comparison are published data on 76 beams from other laboratory investigations. The comparative study indicates that the predictions are accurate. The performance of the proposed formula is also compared with three major code formulas, viz those recommended in the ACI Building Code, the British Standard and the Eurocode. It is concluded that better correlation with test data is achieved by the proposed formula.

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Більше джерел

Дисертації з теми "Prestressed concrete beams Data processing"

Du, Toit André Johan. "Preslab - micro-computer analysis and design of prestressed concrete slabs." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/17057.

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Bibliography: pages 128-132.
A micro-computer based package for the analysis and design of prestressed flat slabs is presented. The constant strain triangle and the discreet Kirchhoff plate bending triangle are combined to provide an efficient "shell" element. These triangles are used for the finite element analysis of prestressed flat slabs. An efficient out-of-core solver for sets of linear simultaneous equations is presented. This solver was developed especially for micro-computers. Subroutines for the design of prestressed flat slabs include the principal stresses in the top and bottom fibres of the plate, Wood/Armer moments and untensioned steel areas calculated according to Clark's recommendations. Extensive pre- and post-processing facilities are presented. Several plotting routines were developed to aid the user in his understanding of the behaviour of the structure under load and prestressing.

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Navarro, Cota Juan Pedro Martin 1963. "DESIGN AND BEHAVIOR OF COMPOSITE SPACE TRUSSES." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276505.

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A fully automated computer program is developed for the optimum design of steel space trusses acting compositely with a concrete slab placed on top. The program sizes the truss members to meet the requirements of the load and resistance factor design specification of the American Institute of Steel Construction using the load combinations of ANSI. Earthquake loading is not considered. The optimum size is based on minimum cost, regarding the amount of welding required at the joints and of the member itself. The total cost is based on all steel work in the truss. Once the truss configuration has been defined, and it has been ensured that linear elastic behavior exists, the structure is analyzed for the construction process, to make sure that no overstressing will take place in any structural element at any time during construction and service. The analysis and design principles are presented and an actual design case is solved. (Abstract shortened with permission of author.)

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Hon, Alan 1976. "Compressive membrane action in reinforced concrete beam-and-slab bridge decks." Monash University, Dept. of Civil Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5629.

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Книги з теми "Prestressed concrete beams Data processing"

Hulse, R. Prestressed concrete design by computer. Basingstoke: Macmillan Education, 1987.

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Lazić, Vera B. Mathematical theory of composite and prestressed structures. Beograd: Matematički institut SANU, 2003.

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Mosley, W. H., and R. Hulse. Prestressed Concrete Design by Computer. Scholium International, Inc., 1987.

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Mosley, W. H., and R. Hulse. Prestressed Concrete Design by Computer. Scholium International, Inc., 1987.

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Частини книг з теми "Prestressed concrete beams Data processing"

Jávor, T., and J. Trenčina. "Experimental Stress Analysis with Automation of MeasureMents and Data Processing Using Vibro-Wire Gauges During the Construction of One Segmental Box-Girder Prestressed Concrete Bridge." In Experimental Stress Analysis, 65–73. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4416-9_8.

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Al-Ghalib, Ali, Fouad Mohammad, Mujib Rahman, and John Chilton. "Damage and repair quantification in reinforced concrete beams using vibration data." In Computational Vision and Medical Image Processing, 575–84. CRC Press, 2011. http://dx.doi.org/10.1201/b11570-86.

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Тези доповідей конференцій з теми "Prestressed concrete beams Data processing"

GARCEZ, M. R., L. C. MENEGHETTI, and R. M. TEIXEIRA. "S-N curves for RC beams post-strengthened with prestressed CFRP based on experimental data." In 9th International Conference On Concrete Under Severe Conditions - Environment and Loading. MENVIA, 2019. http://dx.doi.org/10.31808/5ca6e03d5ca4f0d406ac88a1.

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Wang, Yingxiang, Xusheng Feng, Pengfei He, Luguang Wang, and Zhichao Chen. "Experimental Study and Finite Element Analysis on Stress Transfer Mechanism of Retard-Bonded Prestressed Concrete Beams." In 2020 International Conference on Intelligent Transportation, Big Data & Smart City (ICITBS). IEEE, 2020. http://dx.doi.org/10.1109/icitbs49701.2020.00066.

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KOWALSKI, D. "Nonlinear Analysis of Beams made of High Strength Concrete Prestressed with Unbonded Tendons." In Terotechnology XII. Materials Research Forum LLC, 2022. http://dx.doi.org/10.21741/9781644902059-12.

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Abstract. The paper presents numerical analysis methods of High-Strength Concrete (HSC) beams prestressed with unbonded tendons. Furthermore, it compares obtained results with experimental data from the literature. Prestressing tendons have been modelled in a discrete form, using one-dimensional finite elements. A temperature drop inflicted prestress force. Contact issues have been considered, i.e. friction and pressure at the interface between the cable and the duct wall. In the work, it was found that it is possible to obtain satisfactory accuracy of results with the model in use. Accurate P-Δ (load-deflection) curves were achieved matching experimental data.

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Zhuo, Yi. "Research on the automatic tension control and management integrated system of railway prestressed concrete beam." In IABSE Conference, Kuala Lumpur 2018: Engineering the Developing World. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2018. http://dx.doi.org/10.2749/kualalumpur.2018.0143.

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<p>Pre-stressed tension construction is the key link of the production process of pre-stressed concrete precast beams. The traditional manual operation has many disadvantages, such as low precision, low efficiency, complex operation, and poor synchronization, high frequency of calibration and uncontrollable authenticity of results. In view of the problems existing in the traditional pre-stressed tensioning of railway bridges at present. In this paper, based on big data, cloud technology and radio frequency identification technology, the Railway Pre-Stressed Concrete Beam Intelligent Tensioning Control and Management Integration System (BPS) was developed. The current BPS system includes intelligent tensioning pump station, intelligent tensioning jack equipment, intelligent software platform and intelligent handheld device. Furtherly, the BPS system has been tested and applied in Shijiazhuang-Jinan passenger dedicated line girder yard. The test verification results show that the tension control accuracy, construction quality and work efficiency has been improved due to the realization of automation, informatization, remote and real-time operation of the tensioning process. The BPS system has been developed according to the specifications and processes of the pre-stressed tensioning of railway bridges, the applicability of the railway beam field is strong. And the validity of the system is verified through automatic and manual tension test. Moreover, the system has been successfully applied to large beam fields of Shijiazhuang-Jinan, Jinan-Qingdao and other passenger dedicated line, the effect is good. Therefore, a solid foundation for the popularization of the Internet of things technology in the railway field in China has been laid through research and development of BPS system.</p>

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Scott, James D., Robert J. Peterman, B. Terry Beck, Aaron A. Robertson, Kyle A. Riding, and Chih-Hang John Wu. "Determining the Remaining Prestress Force in a Prestressed Concrete Railroad Tie Through Loading in Direct Tension." In 2018 Joint Rail Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/jrc2018-6168.

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Extensive research has been conducted by the research team in recent years to determine the prestressing steel and concrete properties that must be provided to ensure that the transfer length of a prestressed concrete railroad tie is shorter than the distance from the edge of the tie to the rail seat. In addition, a significant of amount of data has been collected that indicates high bonding stresses can produce longitudinal splitting cracks along the reinforcement. In a study of how prestressing steel and concrete properties relate to a ties propensity for longitudinal cracking, existing ties that have performed well in track for over 25 years without issues are being evaluated. One parameter of interest that affects the bonding stress is the amount of prestress force in a railroad tie, which is unknown for the existing ties being evaluated. The current paper focuses on a new method that was developed for determining the remaining prestress force in a tie. In a previous method for determining the prestress force, ties were first loaded in four-point bending to initiate flexural cracking. The crack opening displacement was measured in order to determine the applied load required to reopen the crack. Using this load and the cross-sectional parameters at the location of the crack, the prestress force in the tie can be calculated using static equilibrium. The issue with this method is that as a tie is being loaded and the crack propagates, there is a continuous change in the stiffness of the cross-section. This results in the load versus crack opening displacment curve being overly rounded. This increases the error when determining the load required to reopen the crack, and increases the uncertainty of the calculated prestress force. The new test method eliminates the problems associated with flexural testing by loading the ties longitudinally in tension. In the new proposed experimental method, ties that have been pre-cracked in the center are pulled in tension. Similar to the previous method, the crack opening displacement is measured while the tie is loaded. For the crack to fully open, the applied load must exceed the prestress force holding the crack closed. Prior to the crack opening, the applied load is resisted by the composite section of concrete and prestressing tendons. Once the crack as fully opened, the applied load is resisted by the prestessing tendons only. This creates two distinctly linear portions of the load versus crack opening displacement curve, one prior to the crack opening, and one after. The beginning of the linear portion post-crack opening marks a very clear upper bound for the amount of prestressing force in a tie. This method can estimate the remaining prestress force in a tie with much greater accuracy than the previous method, and eliminates the need of the cross-sectional parameters at the crack location. To verify this method, tests were first conducted on a smaller scale with prismatic beams with a known initial prestressing force. Then the method was applied to a full scale existing tie to determine the remaining prestress force. Results are presented for testing of both the prismatic beams, and the full scale tie.

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Yoneda, Taiju, Jie Fang, Hideyuki Otani, Satoshi Tsuchiya, Satoru Oishi, and Tetsuya Ishida. "Development of a 3D Finite-Element Modelling Generation System Based on Data Processing Platform and Fatigue Analysis of Full-Scale Reinforced-Concrete Bridge." In IABSE Symposium, Prague 2022: Challenges for Existing and Oncoming Structures. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2022. http://dx.doi.org/10.2749/prague.2022.0415.

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<p>This study presents a technology development for creating 3D finite-element full-scale bridge models based on a data processing platform (DPP) and explores the trial fatigue analysis to serve as an important reference for future practical applications. Until now, the model generation, validation and calculation for a large-scale model of conventional method consume huge time and money. Currently, developments in High- Performance Computing (HPC) and preparation for large parallel computers make numerical simulation operation more efficient. Moreover, through the grouping structure technique, different types of data can be linked together. In this research, a 3D finite-element full-scale bridge superstructure model was created using the DPP. A trial fatigue analysis was performed using a high-performance computer. By considering the details such as the position of each reinforcing bar, prestressed tendon, the slope, etc., the DPP model more closely captures the real structure. Therefore, it could be said that the model made by the DPP has higher analytical accuracy. This research paved the way for the implementation of large-scale fatigue analysis, which has significant engineering applications prospects.</p>

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Jing, Yuan, Z. John Ma, Richard M. Bennett, and David B. Clarke. "Lateral Impact of Railroad Bridges With Hybrid Composite Beams: Finite Element Modeling and Preliminary Dynamic Behavior Study of HCB." In 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3739.

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Grade separations have been used along High-Speed Rail (HSR) to decrease traffic congestion and the danger that occurs at grade crossings. However, the concern with grade separations is the potential damage due to lateral impact of bridge superstructures by over-height vehicles. This is a concern with existing bridges, and lateral impact is not included in standard bridge code provisions. A new bridge technology, Hybrid Composite Beam (HCB), was proposed to meet the requirements of another HSR objective, that of a sustainable solution for the construction of new and replacement bridges in rail infrastructure. The hybrid composite beam combines advanced composite materials with conventional concrete and steel to create a bridge that is stronger and more resistance to corrosion than conventional materials. The HCB is composed of three main parts; the first is a FRP (fiber reinforced polymer) shell, which encapsulates the other two parts. The second part is the compression reinforcement which consists of concrete or cement grout that is pumped into a continuous conduit fabricated into the FRP shell. The third part of the HCB is the tension reinforcement that could consist of carbon or glass fibers, prestressed strands, or other materials that are strong in tension, which is used to equilibrate the internal forces in the compression reinforcement. The combination of conventional materials with FRP exploits the inherent benefits of each material and optimizes the overall performance of the structure. The behavior of this novel system has been studied during the last few years and some vertical static tests have been performed, but no dynamic or lateral impact tests have been conducted yet. Therefore, the main objective of this study is to evaluate the performance of HCB when subjected to lateral impact loading caused by over-height vehicles. This paper explains the advantages of HCB when used in bridge infrastructures. The commercial software ABAQUS was used to perform the finite element (FE) modeling of a 30ft long HCB. Test data was used to validate the results generated by FE analysis. A constant impact loading with a time duration of 0.1 second was applied to an area at the mid-span of the HCB. Lateral deflection and stress distribution were obtained from FE analysis, and local stress concentration can be observed from the stress contour. Full-scale beam dynamic testing will be conducted in the future research to better study the behavior of HCB when subjected to over-height vehicles.

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Beck, B. Terry, Robert J. Peterman, Chih-Hang John Wu, and Naga Narendra B. Bodapati. "In-Plant Testing of a New Multi-Camera Transfer Length Measurement System for Monitoring Quality Control of Railroad Crosstie Production." In 2015 Joint Rail Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/jrc2015-5749.

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Knowledge of transfer length is critical for maintaining continuous production quality in the modern manufacture of prestressed concrete railroad ties. Traditional manual laboratory methods for measuring transfer length are simply not suitable for production operation. They are much too time-consuming to implement, and typically require extensive surface preparation in order to obtain the required surface strain measurements needed for determining the transfer length. In addition, the traditional 95% Average Maximum Strain (95% AMS) method of assessing transfer length from the measured surface strain profile has been shown to possess bias. The accuracy of transfer length assessment using this method is generally influenced by individual operator judgment; therefore, making it unsuitable for use as a reliable production quality-control parameter. This paper presents recent in-plant testing of a newly developed prototype multi-camera non-contact transfer length measurement system, representing a major improvement over the traditional manual methods. The testing was conducted on concrete railroad ties at a manufacturing facility in North America. Concrete ties tested included those which were manufactured using indented prestressing wire as well as with 7-wire strand. The new device represents a next generation version of the previously successful Laser-Speckle Imaging (LSI) system developed by the authors. The multi-camera system is shown to provide nearly real-time surface strain profile measurements (subsequent to de-tensioning), with surface strain accuracy comparable to the mechanical Whittemore gage device, yet with little or no required surface preparation. Furthermore, with the previously demonstrated Zhao-Lee (ZL) transfer length processing algorithm built into a LabVIEW data acquisition and control interface, the multi-camera system is shown to provide assessments of transfer length within a nominal tolerance of +/− 1.5 inches using as few as six uniformly spaced surface strain measurements. This brings within reach the ultimate goal of providing the railroad tie manufacturer with the ability to measure the transfer length of every tie produced prior to leaving the plant, thereby ensuring that they are within an acceptable tolerance, and providing the means to quickly identify the need to modify production (e.g., concrete mix) if transfer length specifications fall out of desired range.

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Zhao, Weixin, B. Terry Beck, Robert J. Peterman, and Chih-Hang John Wu. "Development of a 5-Camera Transfer Length Measurement System for Real-Time Monitoring of Railroad Crosstie Production." In 2013 Joint Rail Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/jrc2013-2468.

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Knowledge of transfer length during production is critical for maintaining continuous production quality in the modern manufacture of prestressed concrete railroad crossties. Traditional laboratory methods for measuring transfer length, using manual instruments such as a Whittemore mechanical gauge or surface mounted resistance-type strain gauge, are simply not suitable for production operation. They are too time-consuming to implement, require extensive surface preparation, and can also require special operator training to provide accurate and reliable surface strain profiles from which the transfer length can be determined in a post-processing manner. In contrast with earlier manual methods, the newly developed non-contact Laser Speckle Imaging (LSI) technique has been shown to be capable of providing rapid and accurate surface strain measurement and consequently also rapid transfer length assessment. This system has recently been automated and combined with the new Zhao-Lee (ZL) least-squares strain profile fitting technique for quickly and reliably processing surface strain data. The automated system and processing procedure have been shown to provide an improved assessment of transfer length, unhampered by human intervention and subsequent potential human judgment bias. This paper presents recent progress toward the development of a 5-camera non-contact transfer length measurement system that is capable of continuous monitoring of railroad crossties in a production plant. This is made possible using an optimized version of the previously successful LSI system, which minimizes the number of surface strain measurements required to achieve reliable transfer length assessment. Experimental results and analysis will be presented for the latest multi-camera prototype concept for this new system design, demonstrating that only a few discrete surface strain measurements are required to achieve accurate and reliable transfer length assessment. Thus, for the first time it is now possible to envision practical real-time quality control monitoring of railroad crossties during an in-plant production operation.

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Beck, B. Terry, Aaron A. Robertson, Robert J. Peterman, Kyle A. Riding, and John Wu. "Accuracy of High Resolution 3D Optical Scanning of Crosstie Geometry for Assessment of Cross-Sectional Parameters and Long-Term Abrasion and Wear." In 2017 Joint Rail Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/jrc2017-2296.

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Анотація:

Current research is attempting to develop a comprehensive understanding of the material and manufacturing characteristics that have caused splitting failures in prestressed concrete railroad ties, in contrast with those characteristics that have resulted in ties that have performed well after many years in track. As part of this effort, a three-dimensional (3D) Optical Scanning System is being used to accurately scan and quantify the surface geometry and volume (abrasion and wear) of a large sample of previously manufactured ties. A commercially-available 3D Laser-Based Optical Scanning System, having a maximum spatial resolution of approximately 0.1mm, is being used to perform the surface scanning operation. The scanning procedure ideally produces an accurate 3D CAD model of the tie geometry, which can then be analyzed to determine the desired geometrical features at any given cross-section. It can likewise yield a measure of the tie volume, the variation of which gives some direct indication of the extent of abrasion and wear. The feasibility of the scanning system has previously been demonstrated by extracting the detailed longitudinal variation of geometrical cross-section crosstie parameters of a typical CXT tie, including cross-sectional area, centroid, moment of inertia, and the eccentricity of the prestressing wires. These parameters are also known to be of importance to the accurate determination of transfer length from measured surface strain. The CXT tie geometry provides an excellent test case, and a challenge to the optical scanning system, since it has a complex scalloping along its length. While the basic feasibility of the system operation has been demonstrated, the repeatability of the geometrical information obtained from the overall scanning and subsequent post-processing of surface geometrical data has yet to be assessed. The main objective of this paper is to first demonstrate the volumetric measurement resolution experimentally by conducting repeated scans of the same tie by the same operator. The experimental scatter in scan results is presented for both cross-section parameter detail and tie volume assessment. The statistical variation in the measured tie volume ideally provides a reasonable measure of the expected volume resolution. In addition to assessing the statistics of these repeated scans, a CXT tie was subjected to induced abrasions of known (measurable) volume for direct comparison with the volume measurements obtained using the optical scanning procedure. This work represents an important next step toward identifying the accuracy of the assessment of abrasion and wear for the large number of ties currently being scanned after having been in long-term service.

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