Статті в журналах з теми "Prestressed concrete beams Data processing"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Prestressed concrete beams Data processing.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Prestressed concrete beams Data processing".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
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.
Повний текст джерелаАнотація:
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.
2
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.
Повний текст джерелаАнотація:
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.
3
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.
Повний текст джерелаАнотація:
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.
4
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.
Повний текст джерелаАнотація:
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.
5
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.
Повний текст джерелаАнотація:
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.
6
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.
Повний текст джерелаАнотація:
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.
7
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.
Повний текст джерелаАнотація:
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.
8
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.
Повний текст джерелаАнотація:
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.
9
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.
Повний текст джерелаАнотація:
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.
10
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.
Повний текст джерелаАнотація:
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.
11
Karpiuk, Vasyl, Yuliia Somina, Fedir Karpiuk, and Irina Karpiuk. "Peculiar aspects of cracking in prestressed reinforced concrete T-beams." Acta Polytechnica 61, no. 5 (October 31, 2021): 633–43. http://dx.doi.org/10.14311/ap.2021.61.0633.
Повний текст джерелаАнотація:
In order to study the cracking of prestressed reinforced concrete T-shaped beam structures, the authors planned and carried out a full-scale experiment with five variable factors. The following factors were chosen as variable factors: the relative span of the shear, the ratio of the table overhang width to the thickness of the beam rib, the ratio of the table overhang thickness to the working height of the beam section, the coefficient of transverse reinforcement, the level of prestressing in the working reinforcement. The article describes the cracking process and the destruction of test beams. It was found that the loading level of an opening of inclined cracks is 53% larger than the loading level of a normal crack opening. Mathematical models of bending moments and transverse forces of cracking were built using the “COMPEX” software. Also, the mathematical models of the crack opening width and the projection length of a dangerous inclined crack were obtained. These models are based on the experimental data. Analysing the obtained models, the complex influence of variable factors on the main parameters of crack formation and crack resistance was established. In particular, it was found that the prestress level in the working reinforcement has the greatest effect on the bending moment of cracking. In this case, the value of the shear force of cracking significantly depends on both the prestressing level in the reinforcement and the relative span of the shear. On the basis of the experimental data, the empirical expression is obtained for determining the projection of a dangerous inclined crack for prestressed reinforced concrete T-shaped beams. The resulting equation can be used to calculate a shear reinforcement.
12
Cao, Xia, Ling Zhi Jin, Qiang Fu, Hong Mei Zhou, Ya Qiong Liu, and Li Jiang Lan. "Mechanical Behavior Analysis of the Unbonded Prestressed Concrete Slabs with Openings Strengthened by Different Methods." Advanced Materials Research 163-167 (December 2010): 1354–58. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1354.
Повний текст джерелаАнотація:
Based on the contrast experiments of unbonded prestressed concrete slabs with openings subjected to uniform load strengthened by different methods, this paper investigates and analyzes the appearance and the development of cracks, deflections, bearing capacity of the unbonded prestressed concrete slabs that are with strengthening steel and with hidden beams. According to the experimental failure mode of the slabs, prestressed concrete slabs with openings by yield line theory considering the conditions to enhance the contribution of hidden beam and the strengthening steel. Compared with the experimental data, this paper puts forward some bearing capacity lift-off effect of the slabs under different strengthened methods.
13
Abdelrahman, Marwa A., Mohamed K. ElBatanouny, John R. Rose, and Paul H. Ziehl. "Signal processing techniques for filtering acoustic emission data in prestressed concrete." Research in Nondestructive Evaluation 30, no. 3 (January 30, 2018): 127–48. http://dx.doi.org/10.1080/09349847.2018.1426800.
Повний текст джерела
14
Sumangala, K., and C. Antony Jeyasehar. "A New Procedure for Damage Assessment of Prestressed Concrete Beams Using Artificial Neural Network." Advances in Artificial Neural Systems 2011 (November 1, 2011): 1–9. http://dx.doi.org/10.1155/2011/786535.
Повний текст джерелаАнотація:
A damage assessment procedure has been developed using artificial neural network (ANN) for prestressed concrete beams. The methodology had been formulated using the results obtained from an experimental study conducted in the laboratory. Prestressed concrete (PSC) rectangular beams were cast, and pitting corrosion was introduced in the prestressing wires and was allowed to be snapped using accelerated corrosion process. Both static and dynamic tests were conducted to study the behaviour of perfect and damaged beams. The measured output from both static and dynamic tests was taken as input to train the neural network. Back propagation network was chosen for this purpose, which was written using the programming package MATLAB. The trained network was tested using separate test data obtained from the tests. A damage assessment procedure was developed using the trained network, it was validated using the data available in literature, and the outcome is presented in this paper.
15
Ali, MS Mohamed. "Analytical models to predict structural behaviour of reinforced concrete beams bonded with prestressed fibre-reinforced polymer laminates." Advances in Structural Engineering 21, no. 4 (October 6, 2017): 532–44. http://dx.doi.org/10.1177/1369433217732666.
Повний текст джерелаАнотація:
The strengthening of reinforced concrete members with prestressed fibre-reinforced polymer laminates has been investigated by researchers due to major improvements in member serviceability characteristics. Currently, analytical models generally employ mostly empirical procedures in predicting member behaviour, and as a result, the analytical results exhibit poor correlation to experimental investigations. In this article, an analytical model is developed using new and existing theoretical techniques to critically analyse strengthened reinforced concrete beams for a range of loading scenarios to generate moment–rotation and load–deflection relationships. The prestress level and the intermediate crack debonding strain of the prestressed fibre-reinforced polymer laminate with the inclusion of mechanical end anchorage were highlighted as key parameters within the model. The proposed model adopts closed-form solutions to allow for a wide range of beams with varying steel and fibre-reinforced polymer reinforcement ratios and dimensions. The model incorporates calibrated crack spacing theory to predict the crack width and spacing as well as the length of the cracked region in the beam. The models have good correlation with collected experimental data and thus can be used for the analysis of reinforced concrete beams strengthened with prestressed fibre-reinforced polymer, throughout all stages of loading from serviceability to failure.
16
Zamblauskaitė, Renata, Gintaris Kaklauskas, and Darius Bačinskas. "DEFORMATIONAL ANALYSIS OF PRESTRESSED HIGH‐STRENGTH CONCRETE MEMBERS USING FLEXURAL CONSTITUTIVE MODEL." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 11, no. 2 (June 30, 2005): 145–51. http://dx.doi.org/10.3846/13923730.2005.9636344.
Повний текст джерелаАнотація:
In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short‐ and long‐term deformational analysis of flexural partially prestressed concrete members. The effect of tension stiffening and non‐linear time effects of creep and shrinkage are taken into account. Effective modulus method is used for modelling long‐term deformations. The proposed calculation technique is based on the layered approach and use of material stress‐strain relationships. Curvatures prediction results were tested against experimental data of partially prestressed concrete beams reported in literature.
17
Zamblauskaite, Renata, Gintaris Kaklauskas, and Povilas Vainiūnas. "LONG‐TERM DEFORMATION ANALYSIS OF NON‐CRACKED PC MEMBERS USING FLEXURAL CONSTITUTIVE MODEL AND DESIGN METHODS." Technological and Economic Development of Economy 12, no. 2 (June 30, 2006): 124–33. http://dx.doi.org/10.3846/13928619.2006.9637732.
Повний текст джерелаАнотація:
In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to long‐term deformation analysis of prestressed concrete members. The effect of non‐linear time effects of creep and shrinkage are taken into account. Effective modulus method is used for modeling of long‐term deformations. The proposed calculation technique is based on the layered approach and use of material stress and strain relationships. Curvatures and deflections prediction results were tested against experimental data of prestressed concrete beams reported in the literature.
18
Yu, Tian Lai, Xin Yu Li, Qiang Ma, and Zhen Jiang. "Study on the Method for Calculating Shear Strength of RC Beams Strengthened with Externally Prestressed Wire Rope." Applied Mechanics and Materials 94-96 (September 2011): 1442–46. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1442.
Повний текст джерелаАнотація:
Through shear test data analysis of 13 RC beams Strengthened with externally prestressed wire rope, shear failure mechanism was elaborated, and shear bearing capacity of reinforced beams were not only calculated respectively by truss -arch model and other simplified calculation methods, but also were compared with test data. Based on the result of comparation, shear capacity calculation method of RC beam Strengthed with externally prestressed wire rope was discussed. The analysis results show that the mechanism of the wire rope shear externally prestressed reinforced concrete beams against the shear is similar with stirrups inside beam. When the shear span ratio is less than 2.7, the static average ratio of the truss-arch model shear capacity caculation value and tested value is 1.02, and standard deviation statistics is 0.07. In another word, calculation value agree with experimental value. When the shear span ratio is larger than 2.7, the calculation value is bigger than test.
19
Saqan, Elias, and Hayder Rasheed. "Simplified nonlinear analysis to compute neutral axis depth in prestressed concrete rectangular beams." Journal of the Franklin Institute 348, no. 7 (September 2011): 1588–604. http://dx.doi.org/10.1016/j.jfranklin.2010.09.005.
Повний текст джерела
20
Atta, Ahmed. "Finite Element Analysis of External Prestressing Beams Made of Strain Hardening Material." Applied Mechanics and Materials 166-169 (May 2012): 259–68. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.259.
Повний текст джерелаАнотація:
The use of finite element analysis has been widely used as a means to analyze individual elements and the effects of concrete strength under loading. This paper is a study of prestressed concrete beams made of strain hardening material called UHP-SHCC (Ultra High Performance Strain Hardening Cementitious Composite) using finite element analysis to understand their response. A finite element model is studied and compared to experimental data. The basic parameters included second order effect of prestressed beam, and prestressing tendon depths have been considered in the analysis. The present study indicated the following conclusions: the number of deviators significantly influences the ultimate capacity and the strains values of UHP-SHCC beams, the change of external prestressing tendon depth has a significant effect on the cracking load, failure load, deflection values, and ultimate stress in the tendon in case of using UHP-SHCC beams but keep the final mode of failure without change.
21
Gao, Ruyu, Qin Xin, Xiuquan Hu, and Chunyu Liang. "RESIDUAL PERFORMANCE ANALYSIS OF BRIDGE STRUCTURE CONSIDERING HEAVY LOAD EFFECT." DYNA 97, no. 2 (March 1, 2022): 156–61. http://dx.doi.org/10.6036/10440.
Повний текст джерелаАнотація:
The structural performance of bridges eventually decreases, and risk in bridge operations increase, as well as the equivalent effect of vehicle loads, particularly heavy traffic. To further clarify the relationship between the residual performance of the bridge under heavy traffic and the fatigue damage, a batch of prestressed concrete fatigue test beams was designed. The equivalent fatigue load, considering the heavy load effect, was determined through investigation and statistics of actual traffic load data. The fatigue failure morphology and crack development of the test beam under the equivalent fatigue load were analyzed based on the fatigue damage principle. The constant amplitude fatigue test method was used to analyze the development law of concrete residual strain, non-prestressed tendon residual strain, and prestressed tendon residual strain. Based on the damage model theory, the damage equation between the damage variable D and the cumulative residual plastic strain ?p considering the effects of heavy traffic was found. In addition, through the test data, the fatigue damage evolution curve based on the development of residual strain was obtained. Research results show that the fatigue test failure is a bending failure of the non-prestressed tendon fatigue fracture. The fatigue life of the beam reduced drastically when the heavy load effect is considered. From the perspective of residual performance, the residual strain of concrete is a good indicator for calculating the fatigue damage index of beams. The research results provide an early warning of fatigue failure and performance evaluation.
22
Xia, Kai Quan, Xiang Gang Zhang, Zong Ping Chen, and Jiang Mei Wang. "Experimental Study on Mechanical Behavior of Serving Prestressed Concrete Poles." Advanced Materials Research 368-373 (October 2011): 1617–20. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.1617.
Повний текст джерелаАнотація:
In order to assess accurately safety performance of prestressed concrete poles servicing 30 years, bending loading tests are carried out on 3 samples extracted randomly, these ones are studied on the mechanical behavior and failure mechanism, failure modes are revealed, and important experimental data including cracking load, the ultimate load of normal use, the ultimate load of carrying capacity is obtained. Furthermore, based on measured test data, the curves of load-crack width and moment-deflection are made among the whole force process. The results show that failure modes of specimens are similar to one of “rare-reinforced beams”. Moreover, based on design method of serviceability limit state, the average security surplus coefficient is 1.2 before collapse damage.
23
Kodsy, Antony, and George Morcous. "Shear Strength of Ultra-High-Performance Concrete (UHPC) Beams without Transverse Reinforcement: Prediction Models and Test Data." Materials 15, no. 14 (July 8, 2022): 4794. http://dx.doi.org/10.3390/ma15144794.
Повний текст джерелаАнотація:
The use of Ultra-High-Performance Concrete (UHPC) in beams has been growing rapidly in the past two decades due to its superior mechanical and durability properties compared to conventional concrete. One of the areas of interest to designers is the elimination of transverse reinforcement as it simplifies beam fabrication/construction and could result in smaller and lighter beams. UHPC has a relatively high post-cracking tensile strength due to the presence of steel fibers, which enhance its shear strength and eliminate the need for transverse reinforcement. In this paper, UHPC shear test data were collected from the literature to study the effect of the following parameters on the shear strength of UHPC beams without transverse reinforcement: compressive strength, tensile strength, level of prestressing, longitudinal reinforcement ratio, and fiber volume fraction. Statistical analysis of test data indicated that level of prestressing and tensile strength are the most significant parameters for prestressed UHPC beams, whereas longitudinal reinforcement ratio and tensile strength are the most significant parameters for non-prestressed UHPC beams. Additionally, shear strength of the tested UHPC beams was predicted using five models: RILEM TC 162-TDF, 2003, fib Model Code, 2010, French Standard NF P 18-710, 2016, PCI-UHPC Structures Design Guide, 2021, and Draft of AASHTO Guide Specification for Structural Design with UHPC, 2021. Comparing measured against predicted shear strength indicated that the French Standard model provides the closest prediction with the least scatter, where the average measured-to-predicted strength was 1.1 with a standard deviation of 0.38. The Draft of AASHTO provided the second closest prediction where the average measured-to-predicted strength was 1.3 with a standard deviation of 0.64. The other three models underestimated the shear strength.
24
Zalapa-Damian, Arturo, Elia Mercedes Alonso-Guzmán, José María Ponce-Ortega, Wilfrido Martínez-Molina, Cipriano Bernabé-Reyes, and Hugo Luis Chavez-Garcia. "Machine Learning for Modeling the Bearing Capacity of Prestressed Concrete Elements Damaged by Corrosion." Advanced Materials Research 1166 (September 27, 2021): 65–79. http://dx.doi.org/10.4028/www.scientific.net/amr.1166.65.
Повний текст джерелаАнотація:
This work aims to study the prediction of bearing capacity of prestressed concrete beams subjected to accelerated corrosion process using Machine Learning (ML) techniques. After data collection, the results were used to model the behavior of flexural stress, and predict their final load capacity, considering position, length, and width of the cracks generated by corrosion as well as loss of bearing capacity. The study presents an analysis of 363 days old beams damaged by corrosion, connected to a galvanostat for 62, and 121 days to make faster the process. Six beams were analyzed; five of them were used to train the model, the other works as a basis to compare the results thrown by the model with the real data. After the treat, the results showed that Bagged Trees Model fits better to real data, it was seen that removing atypical data improves the correlation of predicted and real data. The actual data were compared with two different prediction analyzes; for the first one, the atypical data were not removed; in the second one, the atypical data were eliminated with a statistical analysis. Obtaining relative error percentages of 15.18%, 14.59%, presenting two predictions: final load of 1444 kg and 1126 kg. Which means a resistant moment of 650 T-m, and 506.7 T-m respectively, taking as a prediction the second value in the safe side.
25
Duan, Ning, Ji-Wen Zhang, and Jun Cheng. "Simulation Research on Continuous Concrete Beams Reinforced with External Prestressed CFRP Tendons." Materials 15, no. 16 (August 18, 2022): 5697. http://dx.doi.org/10.3390/ma15165697.
Повний текст джерелаАнотація:
This paper examines the effects of different loading patterns on the static characteristics of continuous concrete beams reinforced with external prestressed carbon fiber-reinforced polymer tendons (EPCFRPT) and qualitatively analyzes the results for two continuous concrete beams: SB-1 under symmetrical loading, and SB-2 under asymmetrical loading. Then, a finite element analysis model is introduced and calibrated by tests conducted at Southeast University and data collected from a literature review. Based on the FEA model, the initial prestress, cross-section area, and eccentricity of CFRP tendons as well as the steel reinforcement configuration were selected by a parametric study. The results indicated that the initial prestress and tendon cross-section area had the most influence on the tendon stress increment and the secondary bending moment of the middle support, while the reinforcement distribution and eccentricity of the tendons had little effect. The secondary bending moment had a linear positive correlation with the stress increment of tendons. These results allow a simplified equation for calculating the external load bending moment amplitude coefficient at ultimate to be proposed.
26
Zhang, Guanhua, Jiawei Wang, Jinliang Liu, Yanmin Jia, and Jigang Han. "Analysis of loss in flexural stiffness of in-service prestressed hollow plate beam." International Journal of Structural Integrity 10, no. 4 (August 12, 2019): 534–47. http://dx.doi.org/10.1108/ijsi-09-2018-0055.
Повний текст джерелаАнотація:
Purpose During service, cracks are caused in prestressed concrete beams owing to overload or other non-load factors. These cracks significantly affect the safety of bridge structures. The purpose of this paper is to carry out a non-linear iterative calculation for a section of a prestressed concrete beam and obtain the change in stiffness after the section cracks. Design/methodology/approach The existing stress of prestressed reinforcement was measured by performing a boring stress release test on two pieces of an in-service 16 m prestressed concrete hollow plate. Considering the non-linear effects of materials, the calculation model of the loss in the flexural stiffness of the prestressed concrete beam was established based on the existing prestress. The accuracy of the non-linear calculation method and the results obtained for the section were verified by conducting a bending destruction test on two pieces of the 16 m prestressed concrete hollow plate in the same batch and by utilising the measured strain and displacement data on the concrete at the top edge of the midspan section under all load levels. Findings The flexural stiffness of the section decreases rapidly at first and then gradually, and structural rigidity is sensitive to the initial cracking of the beam. The method for calculating the loss in the flexural stiffness of the section established with the existing stress of prestressed reinforcement as a parameter is accurate and feasible. It realizes the possibility of assessing the loss in the rigidity of a prestressed concrete structure by adopting the existing stress of prestressed reinforcement as a parameter. Originality/value A method for quickly determining the loss in the stiffness of structures using existing prestress is established. By employing this method, engineers can rapidly determine whether a bridge is dangerous or not without performing a loading test. Thus, this method not only ensures the safety of human life, but also reduces the cost of testing.
27
Liu, Jinliang, Yanmin Jia, Guanhua Zhang, and Jiawei Wang. "Numerical calculation of crack width in prestressed concrete beams with bond-slip effect." Multidiscipline Modeling in Materials and Structures 15, no. 2 (February 21, 2019): 523–36. http://dx.doi.org/10.1108/mmms-01-2018-0008.
Повний текст джерелаАнотація:
Purpose The calculation of the crack width is necessary for the design of prestressed concrete (PC) members. The purpose of this paper is to develop a numerical model based on the bond-slip theory to calculate the crack width in PC beams. Design/methodology/approach Stress calculation method for common reinforcement after beam crack has occurred depends on the difference in the bonding performance between prestressed reinforcement and common reinforcement. A numerical calculation model for determining the crack width in PC beams is developed based on the bond-slip theory, and verified using experimental data. The calculation values obtained by the proposed numerical model and code formulas are compared, and the applicability of the numerical model is evaluated. Findings The theoretical analysis and experimental results verified that the crack width of PC members calculated based on the bond-slip theory in this study is reasonable. Furthermore, the stress calculation method for the common reinforcement is verified. Compared with the model calculation results obtained in this study, the results obtained from code formulas are more conservative. Originality/value The numerical calculation model for crack width proposed in this study can be used by engineers as a reference for calculating the crack width in PC beams to ensure the durability of the PC member.
28
Feitosa, L. A., and E. C. Alves. "Study of global stability of tall buildings with prestressed slabs." Revista IBRACON de Estruturas e Materiais 8, no. 2 (April 2015): 196–224. http://dx.doi.org/10.1590/s1983-41952015000200008.
Повний текст джерелаАнотація:
The use of prestressed concrete flat slabs in buildings has been increasing in recent years in the Brazilian market. Since the implementation of tall and slender buildings a trend in civil engineering and architecture fields, arises from the use of prestressed slabs a difficulty in ensuring the overall stability of a building without beams. In order to evaluate the efficiency of the main bracing systems used in this type of building, namely pillars in formed "U" in elevator shafts and stairs, and pillars in which the lengths are significantly larger than their widths, was elaborated a computational models of fictional buildings, which were processed and analyzed using the software CAD/TQS. From the variation of parameters such as: geometry of the pillars, thick slabs, characteristic strength of the concrete, reduceofthe coefficient of inertia for consideration of non-linearities of the physical elements, stiffness of the connections between slabs and pillars, among others, to analyze the influence of these variables on the overall stability of the building from the facing of instability parameter Gama Z, under Brazilian standard NBR 6118, in addition to performing the processing of building using the P-Delta iterative calculation method for the same purpose.
29
Feng, Wei, Hongming Feng, Zhijun Zhou, and Xiongwei Shi. "Analysis of the Shear Capacity of Ultrahigh Performance Concrete Beams Based on the Modified Compression Field Theory." Advances in Materials Science and Engineering 2021 (June 16, 2021): 1–15. http://dx.doi.org/10.1155/2021/5569733.
Повний текст джерелаАнотація:
An analysis model of the shear capacity of prestressed ultrahigh performance concrete (UHPC) beams under the combined action of bending and shearing was established in this paper based on the modified compression field theory and by considering the unique material constitutive relation of UHPC. Shear tests were performed using three prestressed UHPC-T beams with different shear-span ratios to verify the correctness of the model. The results showed that the shear-span ratio greatly influenced the shear capacity and failure modes of UHPC-T beams. Upon increasing the shear-span ratio, the failure modes of the three beams were inclined compression failure, shear compression failure, and diagonal tension failure, successively. When the shear-span ratio changed from 1.04 to 2.12, the shear bearing capacity decreased greatly; however, when the shear-span ratio changed from 2.12 to 3.19, the decrease of the shear bearing capacity was very small. In addition, the MCFT analysis model was used to analyze the experimental data, and the predicted results were in good agreement, which proved the applicability of the model. Finally, according to the existing shear test results of UHPC beams and based on the main influencing factors, a simplified formula for predicting the shear capacity of UHPC beams was obtained by fitting. Comparing the MCFT model with the results of other pieces of literature, this formula accurately predicted the shear capacity of UHPC beams. The MCFT model and the simplified formula presented in this paper provide a powerful tool for predicting the shear performance of UHPC-T beams, which will contribute to the design and analysis of UHPC-T beams.
30
Yu, Tian Lai, and Li Yuan Zhang. "Friction Loss of Externally Prestressed Concrete Beams with Carbon Fiber-Reinforced Polymer Tendons." Advanced Materials Research 163-167 (December 2010): 3701–6. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.3701.
Повний текст джерелаАнотація:
Friction loss is an important component of the calculation of prestressing loss for external prestress strengthening technology. Unfortunately, the test data of relevant curvature friction and wobble coefficients is scarce, especially for beams strengthened by external prestressing Carbon Fiber-Reinforced Polymer (CFRP) tendons. Through the experiment of 12 concrete beams strengthened by external prestressing CFRP tendons, this study attempts to discuss the friction loss algorithm and the reasonable value of friction coefficient. The test results demonstrated that traditional friction loss algorithm for prestressed steel tendons is also suit to external prestressing CFRP tendons, but the value of curvature and wobble coefficients should be determined by different types of CFRP tendons and saddle design. What is more, aiming at the domestic production of CFRP tendons and the adopted special saddle design in this paper, the curvature friction coefficient is 0.263 and the wobble coefficient is 0.0067 at the deviator. Results of the research provide a reference for external prestress strengthening design with CFRP tendons.
31
Yuan, Jian, Feng Xu, Heng Du, Suhui Yu, and Guorui Sun. "Stressing State Analysis of Partially Prestressed Concrete Beams with High Strength Reinforcement Based on NSF Method." Materials 15, no. 9 (May 8, 2022): 3377. http://dx.doi.org/10.3390/ma15093377.
Повний текст джерелаАнотація:
This paper analyzes the flexural behavior of a partially prestressed steel high-strength reinforced concrete beams based on the structural stress state theory and the numerical shape function method. First, the generalized strain energy density is formed by the measured strain data of the test beam to reflect the structural stress state of the beams, and then the Mann–Kendall criterion is used to judge characteristic points of the generalized strain energy density curve. Two characteristic points, namely, post-elastic boundary load and failure load, are detected, so that the whole loading process is divided into three structural stressing state stages. Unlike the ultimate load, failure load is defined according to the general law from quantitative to qualitative change, which represents the starting point of the failure stage of the beam. Then, experimental strains and deflections, strain/stress fields interpolated by the numerical shape function method, and internal forces calculated by integration are respectively analyzed to obtain their changing characteristics and working behavior around the characteristic points, which can also verify the correction and effectiveness of the Mann–Kendall criterion. In addition, through the analysis above, it can be known that the failure loads of the test beams can be effectively improved by increasing the prestressed reinforcement ratio or concrete strength.
32
Vidal, Thierry, Hugo Cagnon, Nam Nguyen, Jean-Michel Torrenti, and Alain Sellier. "Risk due to creep of prestressed concrete at moderate temperature." MATEC Web of Conferences 281 (2019): 01007. http://dx.doi.org/10.1051/matecconf/201928101007.
Повний текст джерелаАнотація:
This study is a part of a French national project dealing with the mechanical behaviour of the containment vessel of French Nuclear Power Plants in case of a severe accident. The accident conditions are characterized by the increases of internal pressure, +0.5 MPa, and of temperature, up to 180°C, during two weeks. Heating can induce a strong increase of creep deformations kinetics leading to prestressing losses of concrete. Associated to internal pressure, tensile stress could occur in some areas of the structure and the potential cracking could affect the containment capacity of the vessel. One of the objectives of the project was thus to provide original creep data to develop accurate models, taking into account the coupled effects of temperature, desiccation and damage, and able to predict the behaviour of prestressed concrete structures in such insitu conditions. A wide experimental program consisted of numerous creep tests under various thermo-hydro-mechanical conditions in the values range of the accident. The presented results concern uniaxial compressive and flexural creep tests respectively performed on concrete cylinders and prestressed concrete beams, at 20°C and 40°C without desiccation.
33
Karpiuk, Irina, Denis Danilenko, Vasyl Karpiuk, Anna Danilenko, and Tatiana Lyashenko. "Bearing capacity of damaged reinforced concrete beams strengthened with metal casing." Acta Polytechnica 61, no. 6 (December 31, 2021): 703–21. http://dx.doi.org/10.14311/ap.2021.61.0703.
Повний текст джерелаАнотація:
Experimental data on the bearing capacity of damaged reinforced concrete beams with the dimensions of 2000×200×100 mm, reinforced with prestressed metal casings, are presented. Damaging in the form of through normal and crossing inclined cracks, as well as excessive vertical moving of the beam were obtained during previous tests for the effect of high-level transverse alternating loads.The authors of the article have developed a method and equipment for restoring and strengthening damaged reinforced concrete beams using a casing. Beams are manufactured and tested in accordance with the three-level design of an experiment.Previously damaged and reduced to the ultimate (pre-emergency) state, the beams were strengthened with the declared method and equipment, and then retested. New data on the bearing capacity of ordinary and damaged beams, as well as reinforced concrete elements strengthened with casings and tested for the action of transverse forces and bending moments were obtained. The research results are presented in the form of experimental-statistical dependences of the bearing capacity of the support areas, deformability and crack resistance of the investigated elements on the ratio of the most significant design factors and external factors. A comparative analysis of the influence of these factors on the main parameters of the bearing capacity of ordinary as well as previously damaged and then strengthened test beams is carried out.The possibility and appropriateness of using the proposed method of strengthening reinforced concrete beams damaged by through normal and cross-inclined force cracks in the conditions of an existing production has been experimentally proved.
34
Poudel, Prakash, Abdeldjelil Belarbi, Mina Dawood, Bora Gencturk, and Bora Acun. "Prestressing bridge girders with carbon fiber–reinforced polymer: State of knowledge and research needs." Advances in Structural Engineering 21, no. 4 (December 19, 2017): 598–612. http://dx.doi.org/10.1177/1369433217732682.
Повний текст джерелаАнотація:
Prestressing concrete bridge beams with composite materials has been investigated extensively within the last two decades. The outcomes of these research efforts, however, emerged only in a limited number of representative applications in the United States. This is partly due to a lack of comprehensive design guidelines for use by bridge engineers, especially in the American Association of State Highway and Transportation Officials Load and Resistance Factor Design format. An extensive review of literature related to the prestressing of concrete bridge beams with carbon fiber–reinforced polymer strands was conducted. A database of the beams prestressed with carbon fiber–reinforced polymer was established, and the existing design methods along with the required parameters were reviewed. Based on the collected data, the flexural and shear capacity of beams was calculated and compared with the experimentally obtained capacity and that obtained from selected design guidelines. Variables related to the design of carbon fiber–reinforced polymer prestressing that need calibration with dedicated material properties were examined, and the effects of carbon fiber–reinforced polymer on long- and short-term losses were identified.
35
Ebrahimpour Komleh, Houman, and Ali Akbar Maghsoudi. "Analytical Assessment of Bending Ductility in FRP Strengthened RHSC Beams." Civil Engineering Journal 4, no. 11 (November 30, 2018): 2719. http://dx.doi.org/10.28991/cej-03091194.
Повний текст джерелаАнотація:
Over the past few years, a wide use of externally-bonded fiber-reinforced polymer composites (EB-FRP), for rehabilitation, strengthening and repair of existing/deteriorated reinforced/prestressed-concrete (RC/PC) structures has been observed. This paper presents a nonlinear iterative analytical approach conducted to investigate the effects of concrete strength, steel-reinforcement ratio and externally-reinforcement (FRP) stiffness on the flexural behavior and the curvature ductility index of the FRP-strengthened reinforced high-strength concrete (RHSC) beams. Analysis results using the proposed technique have shown very good agreement with the experimental data of FRP-strengthened/non-strengthened RHSC beams, regarding moment–curvature response, ultimate moment and failure mode. Also, a newly prediction equation for the curvature ductility index of FRP strengthened RHSC beams has been developed and verified. Then, converting equation of the curvature ductility index to energy one is proposed. Results indicate that the proposed predictions for the curvature and energy ductility indices are accurate to within 1.87% and 3.03% error for practical applications, respectively. Finally, limit values for these bending ductility indices, based on different design codes’ criterion, are assessed and discussed.
36
Barbieri, Diego Maria, Yuechi Chen, Enrico Mazzarolo, Bruno Briseghella, and Angelo Marcello Tarantino. "Longitudinal Joint Performance of a Concrete Hollow Core Slab Bridge." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 41 (June 17, 2018): 196–206. http://dx.doi.org/10.1177/0361198118781653.
Повний текст джерелаАнотація:
Hollow core slab bridges are constructed by placing prefabricated or prestressed box beams adjacent to each other, grouting the small longitudinal space (hinge-joint) between the slabs and casting a reinforced concrete deck. The longitudinal cracking appearing at hinge-joint locations leads to a premature deterioration of the deck. This paper presents a theoretical and experimental study of a hollow core slab bridge composed of three beams and a cast-in-place deck. A real-size specimen was built according to Chinese code specifications. The behavior of the longitudinal joints was investigated by applying the standard vehicle load. The tests do not highlight any longitudinal cracks. A finite element model was created from the experimental data. A finite element parametric analysis revealed some practical design indications regarding the following inputs: deck thickness, concrete strength, and hinge-joint steel bars. Furthermore, these analyses testify that C-shape and X-shape stirrups do not play an active role in preventing the joint longitudinal cracks. This research confirms the reliability of the design method, at least for static loads, while further studies are needed to investigate the effect of both periodical loadings and different temperatures on upper and lower surfaces of the beams.
37
Liu, Zhengyu, Ali A. Semendary, and Brent M. Phares. "Numerical investigation on early age performance of ultra-high-performance concrete shear keys between an adjacent prestressed concrete box beams." Advances in Structural Engineering 25, no. 3 (December 7, 2021): 511–21. http://dx.doi.org/10.1177/13694332211056111.
Повний текст джерелаАнотація:
Adjacent precast prestressed concrete box beam bridges have been widely utilized for decades and have shown satisfactory performance. However, significant issues regarding to the longitudinal shear key cracking have been noted by bridge maintenance personnel. The cracks are typically initiated at beam-shear key interfaces due to shrinkage and temperature and propagate due to applied load. Recently, ultra-high-performance concrete (UHPC) was employed in the shear keys with the anticipation to prevent joint cracking. Although the field-collected data at early age from bridge utilizing UHPC shear keys indicated promising performance, the results only reflected the early age joint behavior at locations which were instrumented during the field test. In the current study, a 3D finite element (FE) model was developed to calculate the early age stresses due to shrinkage and temperature. The results indicated that the UHPC material associated with a specific shear key configuration created a “self-locked” phenomenon that generated compression on the upper level shear key. The early age tensile stress during the first couple of days near the end of the joint was relatively small compared to the tensile strength of UHPC material. Although the interface had sufficient capacity to resist the early age stresses, it is still a critical component and needs to be designed with sufficient capacity.
38
Gao, Hongshuai, and Quansheng Sun. "Static field test on flexural behavior of reinforced concrete T-beam bridge strengthened with MPC-PSWR." International Journal of Structural Integrity 11, no. 3 (March 13, 2020): 515–31. http://dx.doi.org/10.1108/ijsi-09-2019-0089.
Повний текст джерелаАнотація:
PurposeWith the rapid development of transportation and the continuous increase of traffic volume and load level, some bridges cannot meet the use requirements, and the demand for bridge strengthening is growing. Furthermore, bridges are affected by factors such as structure and external environment. With the increase of service time, the deterioration of bridges is also increasing. In order to avoid the waste caused by demolition and reconstruction, it is necessary to strengthen the bridge accurately and effectively to improve the bearing capacity and durability, eliminate the hidden dangers, and ensure the normal operation of the bridge. It is of great significance to study the strengthening methods. Compared with traditional strengthening methods, the advantages of using new materials and new technology to strengthen bridges are more obvious. This paper introduces a new method for bridge active strengthening, called modified polyurethane cement with prestressed steel wire rope (MPC-PSWR).Design/methodology/approachRelying on the actual bridge strengthening project, five T-beams of the superstructure of the bridge are taken as the research object, and the T-beams before and after strengthening are evaluated, calculated, and analyzed by finite element simulation and field load test. By comparing the numerical simulation and load test data, the strengthening effect of modified polyurethane cement with prestressed steel wire rope on stiffness, strength, and bearing capacity is verified, which proves that the strengthening effect of MPC-PSWR is effective for strengthening.FindingsMPC-PSWR can effectively reduce deflection, cracks, and strain, thereby significantly improving the flexural capacity of existing bridges. Under the design load, the deflection, crack width, and stress of the strengthened beams decrease in varying degrees. The overall performance of the beams strengthened by MPC-PSWR has been improved, and the flexural performance meets the requirements of the code.Originality/valueMPC-PSWR is an innovative bridge-strengthening method. Through the analysis of its MPC-PSWR effect, the MPC-PSWR method with reference to significance for the design and construction of similar bridges is put forward.
39
Niederleithinger, Ernst, Xin Wang, Martin Herbrand, and Matthias Müller. "Processing Ultrasonic Data by Coda Wave Interferometry to Monitor Load Tests of Concrete Beams." Sensors 18, no. 6 (June 19, 2018): 1971. http://dx.doi.org/10.3390/s18061971.
Повний текст джерела
40
Savino, Pierclaudio, Francesco Tondolo, Donato Sabia, Antonino Quattrone, Fabio Biondini, Gianpaolo Rosati, Mattia Anghileri, and Bernardino Chiaia. "Large-Scale Experimental Static Testing on 50-Year-Old Prestressed Concrete Bridge Girders." Applied Sciences 13, no. 2 (January 7, 2023): 834. http://dx.doi.org/10.3390/app13020834.
Повний текст джерелаАнотація:
The heritage of existing road infrastructures and in particular of bridges consists of structures that are approaching or exceeding their designed service life. Detrimental causes such as aging, fatigue and deterioration processes other than variation in loading conditions introduce uncertainties that make structural assessment a challenging task. Experimental data on their performances are crucial for a proper calibration of numerical models able to predict their behavior and life-cycle structural performance. In this scenario, an experimental research program was established with the aim of investigating a set of 50-year-old prestressed concrete bridge girders that were recovered from a decommissioned bridge. The activities included initial non-destructive tests, and then full-scale load tests followed by a destructive test on the material samples. This paper reports the experimental results of the full-scale tests conducted on the first group of four I-beams assumed to be in good condition from visual inspection at the time of testing. Loading tests were performed using a specifically designed steel reaction frame and a test setup equipment, as detailed in the present work. Due to the structural response of this first group of girders, a uniform behavior was found at both service and ultimate conditions. The failure mechanism was characterized by the crushing of the cast-in-situ top slab corresponding to a limited deflection, highlighting a non-ductile behavior. The outcomes of the experimental research are expected to provide new data for the life-cycle safety assessment of existing bridges through an extended database of validated experimental tests and models.
41
Chen, Zheheng, and Shanwen Zhang. "EM-Based Monitoring and Probabilistic Analysis of Prestress Loss of Bonded Tendons in PSC Beams." Advances in Civil Engineering 2018 (September 23, 2018): 1–9. http://dx.doi.org/10.1155/2018/4064362.
Повний текст джерелаАнотація:
The prestress level is a key factor of prestressed concrete (PSC) beams, affecting their long-term serviceability and safety. Existing monitoring methods, however, are not effective in obtaining the force or stress of embedded tendons. This paper investigates the feasibility of elastomagnetic (EM) sensors, which have been used for external tendons, in monitoring the long-term prestress loss of bonded tendons. The influence of ambient temperature, water, eccentricity ratio, plastic duct, and cement grouts on the test results of EM sensors is experimentally examined. Based on the calibrated EM sensors, prestress loss of a group of PSC beams was monitored for one year. In order to further consider the high randomness in material, environment, and construction, probabilistic analysis of prestress loss is conducted. Finally, the variation range of prestress loss with a certain confidence level is obtained and is compared with the monitored data, which provides a basis for the determination of prestress level in the design of PSC beams.
42
Yan, Baoqi, Nuoya Zhang, Ganggang Lu, and Yue Hui. "Research on Engineering Geomechanics Characteristics and CFRP Reinforcement Technology Based on Machine Learning Algorithms." Scientific Programming 2022 (January 7, 2022): 1–12. http://dx.doi.org/10.1155/2022/2765327.
Повний текст джерелаАнотація:
We have completed the design of an early warning and evaluation analysis module based on machine learning algorithms. Aiming at the prestressed CFRP-strengthened reinforced concrete bridges under natural exposure, we developed a theoretical model to analyze the long-term prestress loss of reinforced parts and the adhesion behavior of the CFRP-concrete interface under natural exposure conditions. The analysis deeply reveals the technical and engineering geomechanics characteristics of the D bridge. At the same time, through a series of experimental studies on the D bridge condition monitoring system, the data acquisition and transmission, processing and control of the D bridge condition monitoring system, and the bridge condition monitoring and evaluation software are provided. Regarding how to repair the engineering geomechanical characteristics of D bridge, we mentioned the prestressed CFRP reinforcement technology. The prestressed carbon fiber reinforced composite (CFRP) structure made of reinforced concrete (RC) makes better use of the high-strength characteristics of CFRP and changes. It strengthens the stress distribution of the components and improves the overall strength of the components. It is more supported by engineers in the civil engineering and transportation departments. However, most prestressed CFRP-reinforced RC structures are located in natural exposure environments, and the effect of natural exposure environments on the long-term mechanical properties of prestressed C FRP-reinforced RC components is still unclear. This article mainly uses the research on the engineering geomechanics characteristics and reinforcement technology of the bridge body, so that people have a deep understanding of its concept, and provides reasonable use methods and measures for the maintenance and protection of the bridge body in the future. This paper studies the characteristics of engineering geomechanics based on machine learning algorithms and applies them to the research of CFRP reinforcement technology, aiming to promote its better development.
43
Lin, Liu, and Chang. "An Investigation of the Temperature-Drift Effect on Strain Measurement of Concrete Beams." Applied Sciences 9, no. 8 (April 22, 2019): 1662. http://dx.doi.org/10.3390/app9081662.
Повний текст джерелаАнотація:
This study investigates the temperature-drift effect on strain measurement of concrete beams and proposes a method for determination of the mechanical strain of stressed concrete beams. In the study, wireless electrical resistance strain gauges were used to measure the strain of concrete beams. This study first examined how temperature changes affected the strain gauge attached to concrete beams. Subsequently, a concrete beam experiencing changes in temperature and load was monitored for six consecutive days. The test results showed that the apparent strain response of the concrete beam was significantly affected by temperature changes. After adjusting for the temperature effect, the mechanical strain generated by a load could be obtained. However, temperature-induced drift was still observed in the mechanical strain response. Based on the assumption that temperature changes are slow and gradual, and mechanical strain changes are momentary, an adjacent data subtraction method can be used to eliminate the temperature-induced drift present in the mechanical strain data. The subtraction results show that the mechanical strain generated by a load was accurately obtained. The proposed data-processing method could also be used to find the residual strain of the nonelastic response of a beam subjected to substantial short-term forces.
44
Guo, Xinyan, Dong Liu, Peiyan Huang, and Xiaohong Zheng. "Prestress Loss of CFL in a Prestressing Process for Strengthening RC Beams." International Journal of Polymer Science 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/3832468.
Повний текст джерелаАнотація:
A prestressing system was designed to strengthen reinforced concrete (RC) beams with prestressed carbon fiber laminate (CFL). During different prestressing processes, prestress loss was measured using strain gauges attached on the surface of CFL along the length direction. The prestress loss was 50–68% of the whole prestress loss, which is typically associated with CFL slipping between the grip anchors. Approximately 20–27% of the prestress loss was caused by the elastic shortening of the RC beam. An analytical model using linear-elastic theory was constructed to calculate the prestress loss caused by CFL slipping between the anchors and the elastic shortening of the strengthened beams. The compared results showed that the analytical model of prestress loss can describe the experimental data well. Methods of reducing the prestress loss were also suggested. Compared to other experiments, the prestressing system proposed by this research group was effective because the maximum percentage of prestress loss was 14.9% and the average prestress loss was 12.5%.
45
Wang, Li, Wei Ming Yan, Hao Xiang He, and Wei Wang. "Integration, Application and Analysis of the SHM System for Continuous Rigid Frame Bridge." Applied Mechanics and Materials 578-579 (July 2014): 1161–69. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.1161.
Повний текст джерелаАнотація:
This paper is aiming to present the whole situation of a three spans prestressed continuous concrete rigid frame bridge’s SHM (structural health monitoring) system. Hardware structure and software exploitation of the system were respectively elaborated combining with the practical application situation, including details of sensors layout, data acquisition, storage and transform, the developing of monitoring and management system, etc. Emphasis is placed on data processing and analyzing which is collected from the bridge in the online continuously, such as modal identification of the measured acceleration responses, calculation of deflection curves in real time, observation of changing strains and stresses on the measuring points.
46
Menh, Nguyen Cao, and Pham Xuan Khang. "DETERMINATION OF THE VIBRATION CHARACTERISTICS OF BRIDGE IN DYNAMIC DIAGNOSIS." Vietnam Journal of Mechanics 20, no. 2 (June 30, 1998): 18–26. http://dx.doi.org/10.15625/0866-7136/10017.
Повний текст джерелаАнотація:
On the basis of dynamic diagnosis equipment VDIK-1-10 of Russia and finite element method (FEM), the procedures for finding the exciting places and measurement points of vibration are presented. They give us clear information of diagnostic parameters. After data processing we can determine the dynamic characteristics parameters of the bridge. The parameters obtained are used to updating modeling parameters of FEM and therefore the technical state of the bridge could be estimated. An example for investigation of prestressed concrete bridge with 33 m span and 10m width is illustrated.
47
Dubuc, B., A. Ebrahimkhanlou, and S. Salamone. "Corrosion monitoring of prestressed concrete structures by using topological analysis of acoustic emission data." Smart Materials and Structures 28, no. 5 (March 29, 2019): 055001. http://dx.doi.org/10.1088/1361-665x/ab0e96.
Повний текст джерела
48
Bertagnoli, Gabriele, Costanza Anerdi, and Mario Ferrara. "Structural Health Monitoring Issues Using Inclinometers on Prestressed Concrete Girder Bridge Decks." IOP Conference Series: Materials Science and Engineering 1203, no. 3 (November 1, 2021): 032101. http://dx.doi.org/10.1088/1757-899x/1203/3/032101.
Повний текст джерелаАнотація:
Abstract In the last decades, assessment and rehabilitation of the existing built environment constitute one of the major challenges for engineers, practitioners and code-makers all over the world. Aging, deterioration processes, lack of or improper maintenance, and increasing occurrence of extreme events have led to the need of more efficient methods for the safety assessment and retrofitting/rehabilitation of existing concrete structures like bridges. New approaches deriving from research should be able to provide solutions devoted to reduce and/or avoid the necessity of interventions, verifying the safety conditions for human life and performances for serviceability on aged infrastructures. Structural Health Monitoring (SHM) of existing bridges has become a key issue in all western world as most of the infrastructures of each Country are reaching the end of their design life. SHM can be divided classically in two approaches: static and dynamic. Static SHM is based on the measure of displacements and their derivatives like rotations or strains regardless of the dynamic behaviour of the structure. Clinometers are among the most used devices to measure angles on structures; they can provide high accuracy when used in static mode as advanced techniques of signal processing can be used to reduce the noise of the signal working on acquisitions that can last several seconds to provide one single accurate measure of angle. Nevertheless, many issues one the affidability and the correct use of measures done with clinometers have to be addressed to achieve a trustworthy SHM using such devices. In this paper the most relevant issues related to the f.e.m. modelling of a bridge deck in view of the use of clinometers for SHM are presented providing explanation using a test case bridge that has been under continuous investigation for many months. A brief explanation of the process for data cleaning and interpretation is also given, stressing out the limits of the technology and the possible outcomes.
49
Bakht, Baidar, and Tharmalingham Tharmabala. "Steel–wood composite bridges and their static load response." Canadian Journal of Civil Engineering 14, no. 2 (April 1, 1987): 163–70. http://dx.doi.org/10.1139/l87-028.
Повний текст джерелаАнотація:
The proposed steel–wood composite bridges incorporate longitudinal steel girders which are composite with wood deckings consisting of longitudinal laminates. The laminated decking is usually transversely prestressed. By orienting the laminates longitudinally, advantage can be taken in longitudinal bending of the dominant modulus of elasticity of wood. The paper shows that the load-carrying capacity of an existing slab-on-girder bridge with steel girders and deteriorated noncomposite concrete deck slab can be considerably enhanced by using the proposed system. The paper presents results of static load tests on two types of shear connector, some composite beams, and half-scale model of a bridge. Test data confirm the effectiveness of the composite system. Key words: bridges, composite bridges, steel–wood composite bridges, laminated wood decks, shear connectors, composites.
50
Liu, Zhengyu, Brent M. Phares, Weizhuo Shi, and Behrouz Shafei. "Full-Scale Evaluation of an Innovative Joint Design between Adjacent Box Beams." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 2 (January 30, 2020): 33–44. http://dx.doi.org/10.1177/0361198120902695.
Повний текст джерелаАнотація:
The longitudinal joints on adjacent precast, prestressed box beams used in bridge construction are vulnerable to cracking. These cracks provide a direct path for water and deleterious agents to enter the structural system, causing corrosion of the embedded steel bars and tendons. To avoid significant maintenance costs, safety concerns, or both, an innovative longitudinal joint between two adjacent box beams was designed in the current study. This joint is 6½ in. wide with roughened surfaces, filled with shrinkage compensating concrete and reinforced by steel bars. The joint was evaluated on a small-scale basis and satisfactory performance was obtained in resisting early-age cracks. In the current paper, the joint design is further evaluated through experiments on a 31 ft long specimen during the joint’s early age, and when it is subjected to multiple levels of cyclic loads. A finite element (FE) model that is capable of simulating the early-age concrete hardening was also developed and validated against the experimental data. The early-age, time-dependent stress development in the joint and at the interface of the joint and box beam was investigated using the FE model. Based on the results of laboratory tests and FE simulations, the innovative joint was found to remain crack free without the utilization of a shear key or transverse post-tensioning. The “compression-dominate” joint created by the expansive joint material and transverse reinforcing bars across the interface is expected to address the issues associated with early age, while ensuring the long-term durability and performance of box-beam bridges.