Journal articles: 'Post-tensioned prestressed concrete'

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Chen, Ming Zheng, Lin Qing Huang, Xiao Ying Chen, and Li Ping Wang. "The Nonlinear Finite Element Analysis to Bonded Post-Tensioned Prestressed Concrete Frame Based on Two-Stage Loading Model." Advanced Materials Research 671-674 (March 2013): 591–95. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.591.

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According to the loading character of bonded post-tensioned prestressed concrete frame, the static nonlinear finite programme in this paper could be used to analysis the whole loading process to bonded post-tensioned prestressed concrete frame, which is divided into two different stages . From the stress-strain curve of materials and considering the concrete’ tension harding and compression softening, this programme uses the layered finite element model and arc-length method to analyse the bonded post-tensioned prestressed concrete frame, during the course it considers the material nonlinearity and geometric nonlinearity in the stiffness matrix. Through the contrast to experiment , the result of the programme fits well with the experiment. The programme can be used to compute and analyse the bonded post-tensioned prestressed concrete frame.

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Braimah, Abass, Mark F. Green, and T. Ivan Campbell. "Fatigue behaviour of concrete beams post-tensioned with unbonded carbon fibre reinforced polymer tendons." Canadian Journal of Civil Engineering 33, no. 9 (September 1, 2006): 1140–55. http://dx.doi.org/10.1139/l06-063.

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Much research has been conducted in the past decade to evaluate the suitability of fibre reinforced polymer (FRP) reinforcement in concrete structures. Most of the research has concentrated on the short-term performance of FRP prestressed and reinforced concrete beams. Only a limited amount of research has considered the fatigue behaviour of FRP prestressed beams. This paper presents an experimental research program designed to examine the fatigue behaviour of unbonded carbon fibre reinforced polymer (CFRP) post-tensioned concrete beams. The fatigue test program consisted of five large-scale (4.0 m span) concrete T-beams. Three of the beams were post-tensioned with CFRP tendons, and the remaining two beams were post-tensioned with steel prestressing strands. The fatigue load limits were chosen to produce an additional stress range of about 100 MPa in the lower prestressing reinforcement. During fatigue testing, some of the prestressing strands fractured at the anchor location. In the steel post-tensioned beams, fracture of wires in the seven-wire prestressing strands did not result in total failure of the steel post-tensioned beams, as the unbroken wires continued to carry prestress force. In the CFRP post-tensioned beams, however, fracture led to splintering of the tendon between the anchors and total loss of prestress force. In general, the CFRP post-tensioned beams performed satisfactorily in fatigue, in comparison with the steel post-tensioned beams, as long as premature failure of the tendons near the anchor location was prevented.Key words: fibre reinforced polymer (FRP), anchorage, tendon, fatigue, post-tension, concrete, beam, dynamic, testing.

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Pandey, M. D., and M. A. Nessim. "Reliability-based inspection of post-tensioned concrete slabs." Canadian Journal of Civil Engineering 23, no. 1 (February 1, 1996): 242–49. http://dx.doi.org/10.1139/l96-025.

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In unbonded, post-tensioned prestressed concrete slabs and beams, corrosion of prestressed tendons due to moisture ingress and their subsequent breakage has been identified as a major problem raising serious concern over the safety of aged structures. The paper presents a practical Bayesian approach to reliability assessment of such structures based on the inspection of a randomly selected sample of prestressing tendons. To minimize inspection costs, clear guidelines are presented for selecting the minimum sample size necessary to demonstrate that the annual probability of failure of an existing structure is below the target value of 10−5, implied in the Canadian Standards Association concrete design code CAN3-A23.3-M84. A systematic and cost-effective incremental strategy is developed for inspection of existing prestressed concrete structures. Key words: reliability, Bayes theorem, prestressed concrete, unbonded post-tensioned system, inspection, corrosion, probability distribution, CSA Standard CAN3-A23.3-M84, slab.

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Yang, Xiao Hua, Chao Yang Zhou, Xue Jun He, and Teng Chen. "Research on Post-Tensioned Unbonded Prestressed Concrete Hollowed Floor." Applied Mechanics and Materials 94-96 (September 2011): 1456–62. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1456.

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In order to study the mechanical behaviors of post-tensioned unbonded prestressed concrete hollowed floors, a 1/4 scale post-tensioned unbonded prestressed reinforced concrete hollow slab-column structure model is used to act uniform distributed load on the floor. The test results showed that the load carrying capacity is enough. The points of maximum displacement are at the centers of slabs. By means of the experimental studies and elastic finite element analysis methods, the results showed that post-tensioned unbonded prestressed concrete hollowed floor presents anisotropy with layout of circular-tubes in one way. In direction parallel to layout of hollowed tubes, the continuity of floor is destruction and bending stiffness of slab is weakened. For studying the deformations of slab, it can still be considered continuous cross-slab in two directions.

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Bonopera, Marco, Kuo-Chun Chang, Chun-Chung Chen, Yu-Chi Sung, and Nerio Tullini. "Feasibility Study of Prestress Force Prediction for Concrete Beams Using Second-Order Deflections." International Journal of Structural Stability and Dynamics 18, no. 10 (October 2018): 1850124. http://dx.doi.org/10.1142/s0219455418501249.

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The safety and sustainability of prestressed concrete bridges can be improved with accurate prestress loss prediction. Considerable loss of the prestress force may imply damages hidden in the bridge. In this study, a prestress force identification method was implemented for concrete beams. Based on the Euler–Bernoulli beam theory, the procedure estimates the prestress force by using one or a set of static displacements measured along the member axis. The implementation of this procedure requires information regarding the flexural rigidity of the beam. The deflected shape of a post-tensioned concrete beam, subjected to an additional vertical load, was measured in a short term in several laboratory experiments. The accuracy of the deflection measurements provided favorable prestress force estimates. In particular, the “compression-softening” theory was validated for uncracked post-tensioned concrete beams.

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Liu, Shu Yue, and Wei Ling Wang. "Research on Post-Tensioned Prestressed Concrete Construction Technology in Construction Engineering." Advanced Materials Research 700 (May 2013): 221–24. http://dx.doi.org/10.4028/www.scientific.net/amr.700.221.

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Study of bonded post-tensioned prestressed concrete construction technology, from materials, equipment, channel reservation, prestressed reinforcement material installation, concrete pouring, the prestressed tendons tension and grouting of anchor seal is described from the aspects of the construction of the link, the specific operation steps, summarizes the method of construction, improve the following prestressed concrete construction understanding.

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You, Ruilin, Jijun Wang, Sakdirat Kaewunruen, Meng Wang, and Na Ning. "Comparative Investigations into Environment-Friendly Production Methods for Railway Prestressed Concrete Sleepers and Bearers." Sustainability 14, no. 3 (January 18, 2022): 1059. http://dx.doi.org/10.3390/su14031059.

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Prestressed concrete sleeper is a safety-critical track component widely used in ballasted railway tracks. The performance, endurance and quality of prestressed concrete sleepers can detrimentally affect the serviceability and durability of a railway track. An optimal production method is an important criterion underpinning quality and durability over the entire service life of prestressed concrete sleepers. At present, the research work of the sleeper mainly focuses on the dynamic load, bearing capacity and structural design method, etc. However, there exists a lack of research on the specific advantages and disadvantages of the sleeper production process and the improvement of the sleeper process research. This study is the world’s first to collect and analyse the technical data and characteristics of modern production methods of prestressed concrete sleepers, including the long-line system method, pre-tensioned long-mould flow method, pre-tensioned short-mould flow method, post-tensioned short-mould flow method and instant-demoulded short-mould flow method. The precautions for these prestressed concrete sleepers are highlighted in the paper as well. The research results show that the long-line system method, pre-tensioned short-mould flow method, post-tensioned short-mould flow method and instant-demoulded short-mould flow method have a higher automation level and lower efficiency than the pre-tensioned long-mould flow method. The production method of the pre-tensioned long-mould flow method has high efficiency and low cost of equipment, but more workers are needed. Through a comparative analysis, this paper also determines the environmental impacts and provide new references and suggestions for the development and progress of sleeper production technologies.

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Szydłowski, Rafał. "Concrete Properties for Long-Span Post-Tensioned Slabs." Materials Science Forum 926 (July 2018): 122–27. http://dx.doi.org/10.4028/www.scientific.net/msf.926.122.

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In contrast to foreign practice, in Poland, for many years, there has been a belief, that in prestressed constructions, more expensive concretes on basalt aggregates should be applied. This habit is due to the low quality of national river and fossil aggregates. They allow to obtain low concrete strength and modulus of elasticity. In the paper, basing on two examples of post-tensioned slabs, it has been shown, that it is possible to use concretes with a low value of modulus of elasticity for large-span slabs. These results may be significant in popularizing the use of post-tensioned slabs in buildings in poorer countries, making them cheaper in execution.

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Le, Thanh-Cao, Thi Tuong Vy Phan, Trung-Hau Nguyen, Duc-Duy Ho, and Thanh-Canh Huynh. "A Low-Cost Prestress Monitoring Method for Post-Tensioned RC Beam Using Piezoelectric-Based Smart Strand." Buildings 11, no. 10 (September 25, 2021): 431. http://dx.doi.org/10.3390/buildings11100431.

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This study proposes a cost-effective prestress monitoring method for post-tensioned reinforced concrete (RC) beams using a smart strand. Firstly, the concept of a piezoelectric-based smart strand and its implementation for prestress force monitoring are developed. The smart strand is prepared by embedding inexpensive and high-sensitivity electromechanical impedance (EMI) sensors in a steel strand. Next, the feasibility of the proposed method is experimentally verified for prestress force monitoring of a simple supported post-tensioned RC beam. A smart strand prototype is fabricated and embedded into a 6.4 m RC beam which is then prestressed with different levels. For each prestress level, the EMI responses of the smart tendon are measured and the EMI features are extracted for prestress force monitoring. The results showed that the EMI signals of the smart strand showed strong resonant peaks that varied sensitively to the prestress level of the beam. The prestress change in the prestressed RC beam was successfully estimated by using linear regression models of the EMI features.

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Jeon, Chi-Ho, and Chang-Su Shim. "Flexural Behavior of Post-Tensioned Concrete Beams with Multiple Internal Corroded Strands." Applied Sciences 10, no. 22 (November 11, 2020): 7994. http://dx.doi.org/10.3390/app10227994.

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The corrosion of prestressing steel in prestressed concrete bridges is a critical safety issue. To evaluate the strength of a prestressed concrete beam with corroded strands, it is necessary to know the mechanical properties of the corroded strands in terms of their tensile strength and ductility. In this study, material models were suggested using tensile tests of corroded strands which had been taken from existing bridges. Five prestressed concrete beams with multiple internal corroded strands of different corrosion levels and locations were fabricated and tested using the three-point bending test. The beams with corroded strands near the support did not show meaningful flexural behavior changes, while the beams with corrosion in the mid-span showed significant strength reduction. In order to suggest the appropriate evaluation of the flexural strength of a prestressed concrete beam with corroded strands, material models of the corroded strands were divided into two model categories: a bi-linear material model and a brittle material model. Strength evaluations of the corroded prestressed concrete beams according to fps approximation and strain-compatibility using OpenSEES were conducted. Results suggested the use of the strain compatibility method only when the section loss was greater than 5%.

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Borzovič, Viktor, Ján Laco, Miroslav Pecník, and Peter Pažma. "The Crack Development Mechanism of Prestressed Girder Influenced by Different Bond between Prestressed Tendons and Concrete." Key Engineering Materials 691 (May 2016): 309–20. http://dx.doi.org/10.4028/www.scientific.net/kem.691.309.

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The paper deals with formation and development of cracks up to the failure of two span post-tensioned concrete girder. It is focused on influence of different bond between prestressing units and surrounding grout. Monitored and analysed phenomena affected by different bond are as follows: crack initiation, crack spacing and crack width of the prestressed girder. Sources of analysis are results from experimental program focused on influence of oil based corrosion protection agents on bond of prestressing units. Two span post-tensioned girders were subjected to the loading in laboratory till the bending failure has occurred. Girders were in two cases prestressed with bonded tendons. Other two girders were post-tensioned with unbonded tendons and two girders with tendons with decreased bond, due to corrosion protection coatings. Girders have demonstrated different behaviour by loading regarding to the bond level of prestressing units. Experimental results are faced with the results of the theoretical calculation of crack width according to European standards.

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Xiang, Qingming, Youliang Yang, Jiaxuan Su, Tianshu Yang, and Xuansheng Cheng. "Bending Characteristics of a Post-Tensioned, Prestressed Concrete, Simply Supported Beam." Open Civil Engineering Journal 11, no. 1 (August 22, 2017): 676–84. http://dx.doi.org/10.2174/1874149501711010676.

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Introduction:To analyze the basic, mechanical properties of post-tensioned, prestressed concrete, simply supported beams with grouting material of varied porosity under load, a finite element model is established by using ANSYS finite element software.Methods:The mid-span, cracking deflection and the equivalent stress of the prestressed, concrete beams with grouting material of varied porosity are calculated under different load forms.Results and Conclusion:The analysis results show that the cracking deflection of the prestressed, concrete beams increases with the increase in the porosity of the grouting material of the beams under different load forms. By contrast, under the same porosity grouting material, the cracking deflection of the symmetrical loads is larger than that of the uniform and concentrated loads. As the porosity of the grouting material increases, the peak value of equivalent stress decreases. The equivalent, stress-peak value of the concentrated load is always larger than the equivalent, stress-peak value under the uniform and symmetrical loads.

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Lachowicz, Małgorzata, and Krystyna Nagrodzka-Godycka. "Experimental study of the post tensioned prestressed concrete corbels." Engineering Structures 108 (February 2016): 1–11. http://dx.doi.org/10.1016/j.engstruct.2015.11.007.

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Jiang, Yin Jun, and Yong Hua Zhu. "Simulation of Electric Heating Prestressed Concrete Component." Advanced Materials Research 243-249 (May 2011): 1018–22. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.1018.

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Because channel quality defects of post-tensioned prestressed concrete construction cannot be discovered on time, an electric heating method is put forward to produce effective detection. The results of the numeric simulation on the temperature field of a prestressed concrete component show that the electric heating infrared detection method, for its energy consumption, efficiency and safety, is feasible for detecting the channel quality of prestressed concrete component, but the electric current needs to be controlled to avoid high temperature which affects the physical and mechanical properties of the strand and the concrete.

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Wight, Gavin D., Jason M. Ingham, and Andrew R. Wilton. "Innovative seismic design of a post-tensioned concrete masonry houseThis article is one of a selection of papers published in this Special Issue on Masonry." Canadian Journal of Civil Engineering 34, no. 11 (November 2007): 1393–402. http://dx.doi.org/10.1139/l07-104.

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Post-tensioned concrete masonry walls provide improved seismic performance, but have had limited application in seismic regions because of a lack of research pertaining to their in-plane response. Following focused research over recent years, a consortium of product suppliers has collaborated with the University of Auckland to construct New Zealand’s first post-tensioned concrete masonry house. A feature of this innovative design was that all incorporated products were commercially available, with no proprietary products being specifically developed for the prestressed masonry system used. Consequently, it is hoped that this house will be a showcase, and provide exposure for the technology in New Zealand and elsewhere. This paper provides a brief review of previous post-tensioned concrete masonry research applications, then discusses post-tensioning details and their application to house design and construction.

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Gąćkowski, Roman, and Jacek Selejdak. "Assessment of the Effect of the Pre-cast Beams IG Axial Spacing on the Effort Bridge Span." Quality Production Improvement - QPI 1, no. 1 (July 1, 2019): 281–88. http://dx.doi.org/10.2478/cqpi-2019-0038.

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Abstract In designing of reinforced concrete bridges are often used pre-cast of pre-tensioned or post-tensioned prestressed members. In professional practice, when designing bridge span pre-cast of pre-tensioned prestressed beams IG type, different axial beams spacing’s are used and they are joined by a reinforced concrete slab. The paper presents a comparative analysis of an influence of the axial spacing of IG type beams in the cross-section of the bridge, on the bridge span effort, using standards PN-85/S-10042 and PN-EN 1992-2:2010. The optimal axial spacing of pre-cast IG type beams is presented, while maintaining the standard conditions of ULS (Ultimate Limit State). Such a solution has a positive impact on the costs of the entire project, significantly lowering the global investment cost.

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Kraľovanec, Jakub, Martin Moravčík, Petra Bujňáková, and Jozef Jošt. "Indirect Determination of Residual Prestressing Force in Post-Tensioned Concrete Beam." Materials 14, no. 6 (March 10, 2021): 1338. http://dx.doi.org/10.3390/ma14061338.

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A diagnostic survey on the precast prestressed bridge Nižná confirmed significant deterioration due to environmental distress. Evidently, decisive failures of the structure have a similar character as in the previous precast prestressed bridge in Podbiel in the northern part of Slovakia. These failures result from the unsuitable concept of the first generation of precast prestressed concrete beams, which was used in the former Czechoslovakia in the second half of the 20th century. Subsequently, experimental verification using the proof-load test was also executed. This bridge was built in 1956, so at the time of testing, it was 60 years old. The paper presents the indirect determination of prestressing level in one precast post-tensioned concrete beam using the saw-cut method. Experimental measurement was executed during the bridge demolition. Subsequently, a 2D numerical model in ATENA 2D Software, with the assumption of nonlinear material behavior for verification of experimental results, was performed. Finally, the residual prestressing force was evaluated and compared with the expected state of prestressing according to Eurocodes after 60 years of service.

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Hekmet, H. M., and A. F. Izzet. "Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature." Engineering, Technology & Applied Science Research 9, no. 5 (October 9, 2019): 4759–68. http://dx.doi.org/10.48084/etasr.3059.

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The main objective of this study is to characterize the main factors which may affect the behavior of segmental prestressed concrete beams comprised of multi segments. The 3-D finite element program ABAQUS was utilized. The experimental work was conducted on twelve simply supported segmental prestressed concrete beams divided into three groups depending on the precast segments number. They all had an identical total length of 3150mm, but each had different segment numbers (9, 7, and 5 segments), in other words, different segment lengths. To simulate the genuine fire disasters, nine beams were exposed to high-temperature flame for one hour, the selected temperatures were 300°C (572°F), 500°C (932°F) and 700°C (1292°F) as recommended by ASTM–E119. Four numerical models have been utilized to represent the unburned and the burned specimens at the three elevated temperatures. Calibration and simulation of the experimental work were conducted, while comparisons were made with the experimental results. These included the prestress effect, load-deflection relation under applied load, and load at failure of the reference beam and the beams after the exposure to fire.

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Ma, Xin Wei, Sen Zeng, Chong Hai Dong, Zhi Yu, and Guan Qi Huang. "Design of Assembled Post-Tensioned Prestressed Reactive Powder Concrete Wind Turbine Tower." Advanced Materials Research 1055 (November 2014): 38–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1055.38.

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This paper proposes a new type of assembled post-tensioned prestressed reactive powder concrete (RPC) turbine tower structure. It includes the structure design of 200kW wind turbine tower according to the specifications, calculation of loading combinations and internal force, checking calculation of bearing capacity, prestressed concrete design and calculation of reinforcement. Local stress applied on the structure is analyzed by the finite element software of ANSYS, and the calculation results show that the bearing capacity calculation of RPC tower satisfies the requirements, and it is economical comparing with the traditional steel structures.

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Yu, Fang, Jin Qing Jia, Da Li Yao, and Wei Qing Zhu. "Fatigue Behavior of Prestressed Concrete Beams under Corrosion." Advanced Materials Research 255-260 (May 2011): 360–64. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.360.

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Fatigue behaviors of prestressed concrete beams with different corrosion level are investigated in a series of bonded post-tensioned T-beams. The beams have the same designs and submitted to the same maximum and minimum load during the test. Accelerated corrosion method is used to make various corrosion rates of prestressed steel strands. With the corrosion level as main parameter, such as failure mode, fatigue life, mid-span deflection development, stiffness loss, stress expansion, are studied. The test results show that failure mode is changed fracture of non-prestressed steel bar into prestressed steel strand breaking with the increase of corrosion level. Corrosion reduces fatigue life and stiffness of beams, increase deflection and stress range of non-prestressed steel bar.

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Liu, Sixin, Changnian Weng, Pengfei Jiao, Fei Wang, Lei Fu, Xu Meng, and Linlin Lei. "GPR signal analysis of post-tensioned prestressed concrete girder defects." Journal of Geophysics and Engineering 10, no. 3 (June 1, 2013): 034005. http://dx.doi.org/10.1088/1742-2132/10/3/034005.

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El-Hacha, Raafat, Mark F. Green, and R. Gordon Wight. "Flexural behaviour of concrete beams strengthened with prestressed carbon fibre reinforced polymer sheets subjected to sustained loading and low temperature." Canadian Journal of Civil Engineering 31, no. 2 (February 1, 2004): 239–52. http://dx.doi.org/10.1139/l03-091.

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This paper presents results of an experimental investigation that examined concrete beams post-tensioned with bonded carbon fibre reinforced polymer (CFRP) sheets and then exposed to either room (+22 °C) or low (-28 °C) temperatures. The primary objective of this investigation was to assess the flexural behaviour of the strengthened beams after sustained loadings at both room and low temperatures. The strengthened beams showed significant increases in flexural stiffness and ultimate capacity as compared with the control-unstrengthened beams. Failure of the strengthened beams was by tensile rupture of the prestressed CFRP sheets. Test results showed that the long-term and low temperature effects did not adversely affect the strength of the beams. Long-term loading and low temperature exposure caused prestress losses in the CFRP sheets. The loaddeflection behaviour of the long-term beams was predicted accurately by an analytical model. These results suggest that bonded prestressed CFRP sheets could be used to increase the strength of damaged prestressed concrete girders under extreme environmental conditions.Key words: strengthening, anchorage, low temperature, long-term, prestress losses, sustained load, carbon fibre reinforced polymer sheet.

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Mao, Weizhong, Hongye Gou, Yannian He, and Qianhui Pu. "Local Stress Behavior of Post-Tensioned Prestressed Anchorage Zones in Continuous Rigid Frame Arch Railway Bridge." Applied Sciences 8, no. 10 (October 6, 2018): 1833. http://dx.doi.org/10.3390/app8101833.

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The concrete stress behavior and cause of cracking at the anchorage zones of top and bottom slabs of a post-tensioned prestressed concrete box beam were studied. Based on the complex stress distribution under local anchor problem for the Yichang Yangtze River Bridge, which is the longest continuous rigid frame arch railway bridge in the world, model tests were conducted. Two full-scale specimens of top and bottom slabs were fabricated and gradually loaded based on principle of equivalent stress. The goal was to analyze the longitudinal and transverse stress distributions of cross sections of specimens at various loading cases during the experiment. From the experimental results, it can be concluded that the mechanical behavior of the concrete and steel bars were in good agreement when prestressed tendons were loaded. Tensile stress of concrete in prestressed anchorage zone gradually increased and surpassed the ultimate tensile strength of concrete with the increasing load. Consequently, local longitudinal cracking was formed at the anchorage block. Some recommendations to avoid the concrete at the anchorage zone continuing to crack are summarized in this paper.

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Zhou, Xian Yan, Jian Luan, and Da Hai Zhang. "Inspection of Grouting Quality for Grouted Tendon Ducts Using Ground Penetrating Radar Technique." Advanced Materials Research 639-640 (January 2013): 1051–55. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.1051.

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With the wide applications of post-tensioned concrete structures, the grouting conditions of tendon ducts are paid more attentions. In order to accurately assess the internal grouting quality of the grouted tendon ducts and certainly guarantee the lifetime of prestressed concrete structures Ground Penetrating Radar (GPR), which is a kind of nondestructive testing (NDT) method, has been applied to inspect and evaluate qualitatively and quantitatively on the grouting defects, respectively. A series of in-house tests were carried out for simulating the defects of tendon ducts by foams with different sizes. The results show that the GPR technic was one of the optimal methods for inspecting the internal grouting quality of grouted tendon ducts for post-tensioned concrete structures.

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Abdel-Jaber, Hiba, and Branko Glisic. "Monitoring of long-term prestress losses in prestressed concrete structures using fiber optic sensors." Structural Health Monitoring 18, no. 1 (January 29, 2018): 254–69. http://dx.doi.org/10.1177/1475921717751870.

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This study presents a method for on-site assessment of prestress losses in prestressed concrete structures. The study is motivated by the increased use of prestressed concrete, the importance of prestressing force levels as a parameter, and the lack of formalized methods for its on-site assessment. The proposed method uses strain measurements from long-gauge fiber optic sensors to study strain changes at the centroid of stiffness (i.e. centroid of composite section) of the cross-sections. Its advantages include (1) robustness to operational load on the structure caused by seasonal and daily temperature variations, in addition to loading; (2) rigorous quantification of uncertainties associated with measurements and parameters; and (3) applicability to a wide range of beam-like structures. The application of the method is illustrated through application to measurements collected over a 7-year period from strain sensors embedded in Streicker Bridge, a post-tensioned concrete pedestrian bridge on the Princeton University campus. Application of the method indicates that prestress losses measured by sensors are of comparable magnitude to design estimates, which implies that estimates are not necessarily overly conservative.

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Funahashi, Miki, and Walter T. Young. "Cathodic Protection of Prestressed Bridge Members—Full-Scale Testing." Transportation Research Record: Journal of the Transportation Research Board 1561, no. 1 (January 1996): 13–25. http://dx.doi.org/10.1177/0361198196156100103.

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The results of a study on the use of cathodic protection on prestressed and post-tensioned concrete bridge members are summarized. Previous laboratory tests to evaluate hydrogen embrittlement of high strength steel embedded in concrete have proven that cathodic protection will generate hydrogen on high-strength steel in concrete if the potential is more negative than the thermodynamic hydrogen evolution potential. The hydrogen generated will enter the steel and cause a loss in ductility that will adversely affect the steel's performance if a notch is present. Full-scale beams were constructed to further study those phenomena. Four pretensioned beams were constructed. In addition, two post-tensioned slabs were constructed to evaluate cathodic protection of anchorages and tendons encased in metal or plastic conduits. Cathodic protection currents were supplied by IR drop-free potential controlled rectifiers. Good potential control at control points was achieved by using externally mounted silver-silver chloride reference electrodes and a conductive gel bridge. However, inconsistent potential control occurred at locations other than at the control points. Later in the study, constant current power supplies were used on two of the beams. Hydrogen entering the steel as the result of corrosion appears to have masked the presence of hydrogen that might have been produced by cathodic protection. The analysis also revealed that there was corrosion of some pretensioned wires at crossings with interior steel reinforcing bars due to interference (stray current) caused by cathodic protection application. Analysis of the post-tensioned slabs indicated little effect of cathodic protection on tendons inside plastic or metal ducts from the application of cathodic protection. Beneficial effects were noted on anchor points where mortar was in contact with the metal.

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Jin, Ling Zhi, Qiang Fu, Xia Cao, Ning Deng, Yi Hu Chen, Min Chen, and Xiao Ming Wan. "Ansys Analysis of Post-Tensioned Unbonded Prestressed Concrete Board with Open-Hole." Advanced Materials Research 163-167 (December 2010): 1349–53. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1349.

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Owing to the outstanding advantages of unbonded prestressed technology, it has been widely used in high-rise building floor. However, with the continuous improvement of the function requirements of the building, the boards with openings become more and more common, not only in new constructions but also in renovation projects. These holes will change the mechanical properties of the original floor, and cause stress concentration around the holes easily. This article carries on the simulation analysis by modeling the experimental model using ANSYS software, focuses on the deflection, crack and ultimate load of unbonded post-tensioned prestressed concrete board with open-hole (under uniform load in tensioning and loading stage). After making the comparative analyses to the mechanical behavior and failure mechanism under the different locations of the holes, the simulation results are compared with experimental results, shows that ANSYS can simulate the whole process of loading better, provides theoretical basis for its application and promotion in practical engineering.

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Kim, Jee Sang, and Tae Hong Kim. "A Stress Analysis of the Post-Tensioned Anchorage Zones Using UHPC." Key Engineering Materials 737 (June 2017): 500–504. http://dx.doi.org/10.4028/www.scientific.net/kem.737.500.

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Researches on Ultra High Performance Concrete (UHPC) have been conducted worldwide owing to its outstanding durability and strength performances compared to those of normal concrete. The application of UHPC to prestressed concrete structures, which may seem to be the most appropriate and beneficial, may result significant improvement in the design of anchorage zones due to its high compressive and tensile strength. The size of anchorage blocks and amounts of reinforcements may be reduced drastically. This paper examines the stress magnitudes and distributions of post-tensioned anchorage zones using UHPC which have nominal compressive strength levels of 120, 150 and 180 MPa respectively, by FE analysis. The analytic results are verified with the existing experimental work of 180MPa UHPC. It can be concluded that the use of UHPC to post-tensioned members gives significant reduction of anchorage zone size and no reinforcements are required.

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Wang, Zhi Feng, and Xian Yan Zhou. "Impact-Echo Based Nondestructive Evaluation of Grout Condition in Post-Tensioned Bridge Ducts." Advanced Materials Research 168-170 (December 2010): 1122–25. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1122.

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The field of Nondestructive Evaluation (NDE) is a very broad, interdisciplinary field that plays a critical role in civil engineering for controlling new structures (quality control) as well as for assessing the internal grout condition of prestressed pipes in post-tensioned concrete structures. Because it allows voids in grouted tendon ducts to be inspected and measured without damaging them, impact-echo based NDE provides an excellent balance between quality control and cost-effectiveness. This paper focuses on the nondestructive evaluation of internal injection quality in post-tensioned bridge ducts, and the developments in civil engineering NDE in China are also introduced.

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Jain, M. R., and R. N. Khapre. "Investigation of Bursting Force In I-Section Post-Tensioned Anchorage Zone." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 1363–67. http://dx.doi.org/10.38208/acp.v1.663.

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In post tensioned concrete beam the high transverse tensile stress is generated and if proper reinforcement is not given, bursting may occur. To study the effect of these stresses and to find bursting stress in end region the analytical study was carried out. In present work the end block of post-tensioned prestressed concrete beam is modelled in finite element based software with eccentric tendons. The bursting zone of beam is evaluated and parametric study was carried out by varying eccentricity, anchorage ratio and web thickness of girder. The 3D modelling was done and results are compared in terms of bursting force. The results are compared with Indian Standard 1343:2012 and inferences are drawn towards the usability of IS code equation of bursting force for I-section.

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Kamaitis, Zenonas. "DAMAGE TO CONCRETE BRIDGES DUE TO REINFORCEMENT CORROSION." TRANSPORT 17, no. 4 (August 31, 2002): 137–42. http://dx.doi.org/10.3846/16483840.2002.10414030.

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Corrosion of reinforcement initiated by concrete carbonation and chloride contamination is the most common type of deterioration of concrete bridges. Based on the author's experience a number of cases is reported in which the corrosion of ordinary and prestressed reinforcement as well as the causes and consequences of deterioration observed are presented. Investigations have shown that the main reasons are: insufficient concrete cover, poor quality of concrete, and ingress of aggressive salts. The carbonation depth must be related to the histogram ofrebar cover depths and the probability of their coincidence can be predicted. The monitoring of tendon conditions in prestressed concrete precast post-tensioned segmental bridge decks shows that the voids and the water are often present in the ducts leading to the local rusting of tendons. The wires used in tendons are liable to fail in tension that was observed in some prestressed concrete bridges. Unfortunately, no reliable procedures of determining the condition of prestressing steel in existing structures are available.

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Al-Sherrawi, Mohannad Husain, Abbas A. Allawi, Basim H. AL-Bayati, Mohanned Al Gharawi, and Ayman El-Zohairy. "Behavior of Precast Prestressed Concrete Segmental Beams." Civil Engineering Journal 4, no. 3 (April 7, 2018): 488. http://dx.doi.org/10.28991/cej-0309109.

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The structural behavior of Segmental Precast Post-tensioned Reinforced Concrete (SPPRC) beams largely depends on the behavior of the joints that connect between the segments. In this research, series of static tests were carried out to investigate the behavior of full-scale SPPRC beams with different types of epoxy-glued joint configurations; multi-key joint, single key, and plain key joint. The reference specimen was monolithically casted beam and the other specimens were segmental beams with five segments for each one. The general theme from the experimental results reflects an approximate similarity in the behavior of the four beams with slight differences. Due to the high tensile strength of the used epoxy in comparison to concrete, cracks at joints occurred in the concrete cover which was attached to the epoxy mortar.

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Dilger, Walter H., and Marwan Shatila. "Shear strength of prestressed concrete edge slab–column connections with and without shear stud reinforcement." Canadian Journal of Civil Engineering 16, no. 6 (December 1, 1989): 807–19. http://dx.doi.org/10.1139/l89-124.

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Results are reported of tests to failure on six full-scale unbonded post-tensioned prestressed concrete slab–edge column specimens. The objective is to study experimentally the strength and behaviour of this type of connections. The variables are quantity and distribution of stud shear reinforcement and length of overhang. The relevant design equations suggested by Dilger and Ghali as well as several models by others for predicting the strength of prestressed concrete slab–edge column connections are compared with test results. It is concluded that the ACI and CSA provisions for predicting the strength of such connections are conservative, and that the presence of stud shear reinforcement is a good means of increasing the strength and ductility of this type of connections. Key words: shear strength, flat slabs, prestressed concrete, unbonded tendons, shear reinforcement, design, ductility.

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Wang, Li, Donghui Cheng, Enxiang Qu, Daoming Zhang, and Chun Lv. "Calculation of Additional Internal Forces in Post-Tensioned Prestressed Concrete Frame Columns Based on Equivalent Lateral Stiffness." Buildings 12, no. 5 (May 12, 2022): 644. http://dx.doi.org/10.3390/buildings12050644.

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The additional internal forces in vertical members caused by prestressed tendons are typically overlooked in the design of post-tensioned prestressed concrete. A calculation method for additional internal forces in single-story multi-span prestressed concrete frame columns based on equivalent lateral stiffness is proposed in this paper. The slope-deflection equation for the bar element was presented using Timoshenko beam assumptions, taking into account the influence of shear and bending deformations. Subsequently, the concept of equivalent lateral stiffness and calculation equations were proposed. On this basis, the equations of the third shear and third bending moment for single-story multi-span prestressed frame columns were established. Furthermore, applying engineering examples, the method in this study was verified by ABAQUS software and previous methods. The results show that theoretical values and FEA results are in good agreement. Compared to previous methods, the method in this paper is more accurate and widely applicable. In addition, the stretching plan has a significant path effect and time-varying effect on the interlayer distribution of the third moment. It should be considered at the building stage to check the calculation of the frame column.

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Al-Zaid, Rajeh Z. "Analysis of Bonded Post-tensioned Partially Prestressed Concrete Beams under Sustained Loads." Journal of King Saud University - Engineering Sciences 13, no. 1 (2001): 1–23. http://dx.doi.org/10.1016/s1018-3639(18)30722-0.

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Park, Ho, Seungmin Jeong, Seong-Cheol Lee, and Jae-Yeol Cho. "Flexural behavior of post-tensioned prestressed concrete girders with high-strength strands." Engineering Structures 112 (April 2016): 90–99. http://dx.doi.org/10.1016/j.engstruct.2016.01.004.

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SOUZA JUNIOR, O. A., and D. R. C. OLIVEIRA. "Influence of the cable´s layout on the shearing resistance of prestressed concrete beams." Revista IBRACON de Estruturas e Materiais 9, no. 5 (October 2016): 765–95. http://dx.doi.org/10.1590/s1983-41952016000500008.

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Abstract Little information on experimental investigations regarding the influence of the prestressing forces in the shear resistance of prestressed beams is found in the technical literature. Thus, it was experimentally evaluated the shear resistance of six post-tensioned prestressed concrete beams with cross section of (150 x 450) mm2, total length of 2400 mm and concrete's compressive resistance of 30 MPa, with the variables of this work being the layout of the prestressing cable, straight or parabolic, and the stirrups geometric rate. Verticals displacement, steel and concrete's strains and a comparison of the experimental loads with the estimates of ACI 318, EUROCODE 2 and NBR 6118: 2014 codes are presented and discussed. The results showed that the cable's parabolic layout increased the beams' shear resistance in up to 16% when compared to beams with straight cables.

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Meng, Gang, Li Hua Zhang, and Jin Qing Jia. "Numerical Analysis on Flexural Capacity of Prestressed Steel Reinforced Ultra-High Strength Concrete Beams." Key Engineering Materials 531-532 (December 2012): 429–34. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.429.

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As a new type of composite structural system, the prestressed steel reinforced ultra-high strength concrete (PSRUHC) beam was applicable to large-span structures and those structures which must bearing heavy loading. But by now there is no mature calculation method for the beam with a good accuracy. So the experiment on eight post-tensioned bonded prestressed steel reinforced ultra-high strength concrete beams had been carried out to investigate the flexural performance of PSRUHC beams. Based on the test results, the flexural capacity of PSRUHC beams were analysed by the large general-purpose finite element program ANSYS. Compared the simulation results of cracking load, ultimate load, yielding load and load-displacement curve with the test results, it is proved that the numerical method is effective for analyzing flexural capacity of prestressed steel reinforced ultra-high strength concrete beams, which provides theoretical foundation for practical application of PSRUHC beam.

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Breen, John E., Michael E. Kreger, Christopher D. White, and Gordon C. Clark. "Field evaluation and model test of a composite wing-girder bridge." Canadian Journal of Civil Engineering 14, no. 6 (December 1, 1987): 753–62. http://dx.doi.org/10.1139/l87-113.

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This paper presents the key observations and conclusions from the evaluation of an innovative "loose-fit" composite, post-tensioned concrete wing-girder bridge proposed for an elevated interstate highway expansion in an urban environment. The evaluation program included both testing to destruction of a 1/2-scale model of a partial span as well as construction monitoring and field testing at service load levels of a full-scale prototype two-span bridge. Results of both construction measurements and loading tests were compared with analytical predictions. Laboratory tests showed the composite behavior of the wing-girder joint to be fully effective and a high level of load transfer between wings to be present. Recommendations for modification of the prototype design are made to improve constructibility, durability, structural performance, and economy. Key words: box girder, bridge, post-tensioned, prestressed concrete, reinforcement, stresses, temperature, tendons.

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Kennedy, John B., Saddallah Chami, and Nabil F. Grace. "Dynamic and fatigue responses of prestressed concrete girders with openings." Canadian Journal of Civil Engineering 17, no. 3 (June 1, 1990): 460–70. http://dx.doi.org/10.1139/l90-050.

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The influences of opening size, eccentricity, and location on the natural frequencies, mode shapes, damping, and deformation response of prestressed beams and girders with openings under both dynamic and cyclic loadings are presented. A theoretical study was conducted by the finite element method to determine the above structural responses for prestressed rectangular, T- and I-beams. The results were verified and substantiated by tests on six post-tensioned concrete beams. Good agreement was shown between the theoretical and experimental results. Furthermore, it was shown that cyclic loading can have a significant influence on the amplitudes of vibration and the structural response of the top and bottom chords of the opening, and a very significant effect on the tensile strains on the side of the opening resulting from the initial prestressing. Design suggestions are made. Key words: design, dynamic, fatigue, frequencies, girders, openings, prestressed concrete, stresses, structures, tests.

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41

Kim, Sang-Hyun, Sung Yong Park, and Se-Jin Jeon. "Long-Term Characteristics of Prestressing Force in Post-Tensioned Structures Measured Using Smart Strands." Applied Sciences 10, no. 12 (June 13, 2020): 4084. http://dx.doi.org/10.3390/app10124084.

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The proper distribution of prestressing force (PF) is the basis for the design of prestressed concrete (PSC) structures. However, the PF distribution obtained by predictive equations of prestress losses has not been sufficiently validated by comparison with measured data due to the poor reliability and durability of conventional sensing technologies. Therefore, the Smart Strand with embedded fiber optic sensors was developed and applied to PSC structures to investigate the long-term characteristics of PF distribution as affected by concrete creep and shrinkage. The data measured in a 20 m-long full-scale specimen and a 60 m-long PSC girder bridge were analyzed by comparing them with the theoretical estimation obtained from several design equations. Although the long-term decreasing trend of the PF distribution was similar in the measurement and theory, the equation of Eurocode 2 for estimating the long-term prestress losses showed better agreement with the measurement than ACI 209R and ACI 423.10R did. This can be attributed to the more refined form of the predictive equation of Eurocode 2 in dealing with the time-dependency of the PF. The study results also confirmed the need to compensate for the temperature variation in the long-term monitoring to derive the actual mechanical strain related to the PF. We expect our developed Smart Strand to be applied practically in PF measurement for the reasonable safety assessment and maintenance of PSC structures by improving several of the existing drawbacks of conventional sensors.

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42

Yang, Xiao Hua, Chao Yang Zhou, Xue Jun He, and Zhi Qing Yang. "Experimental Studies on Bearing Capacity of Post-Tensioned Unbonded Prestressed Concrete Hollowed Floors." Advanced Materials Research 368-373 (October 2011): 159–63. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.159.

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A 1/4 scales four-storey model of post-tensioned unbonded prestressed concrete hollow slab-column structure has been made to do the ultimate load test on the second-storey floor. By measuring the floor deflection, stresses of steel bars and cracks of floors, the bearing capacity of floor is explored. The bearing capacity tests of floor are divided into three stages: elastic stage, crack growth stage and destruction stage. Based on the test results and crack developments in floor, a improved plastic hinge model is carried out to predict the ultimate loads. The calculated results of the ultimate loads with improved plastic hinge model are in good agreement with the experiment data.

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Kim, Ki-Hyun, and Seok-Goo Youn. "Experimental Study of Vacuum Grout Injection Method for Post-Tensioned Prestressed Concrete Structures." Journal of the Korea Concrete Institute 32, no. 4 (August 31, 2020): 317–24. http://dx.doi.org/10.4334/jkci.2020.32.4.317.

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Wang, Lei, Zhuo Hu, Ju Yi, Lizhao Dai, Yafei Ma, and Xuhui Zhang. "Shear Behavior of Corroded Post-Tensioned Prestressed Concrete Beams with Full/Insufficient Grouting." KSCE Journal of Civil Engineering 24, no. 6 (April 28, 2020): 1881–92. http://dx.doi.org/10.1007/s12205-020-1777-4.

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Song, Man Rong, Bing Kang Liu, Shen Jiang Huang, and An Zhou. "Experimental Study of Seismic Performance on Three-Story Prestressed Fabricated Concrete Frame." Advanced Materials Research 250-253 (May 2011): 1287–92. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.1287.

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Based on the low reversed cyclic loading experiment of a specimen of three-story prestressed fabricated concrete frame, this paper investigates the carrying capacity, the failure mode, the load-displacement hysteresis curve of frame. The research includes the seismic performances such as failure mechanism, rigidity degradation, hysteretic behavior and etc. The results indicate that the plastic hinge first appears at the ends of beam at lower story. The connections of frame are in a state of bi-direction compression and have more joint stiffness, which therefore enhances the frame lateral stiffness and improves the deformation recovery capability. The carrying capacity of the frame hasn’t serious degradation at story drifts between 1/39 and 1/64. The post-tensioned prestressed fabricated concrete frame is a “strong column weak beam” structure.

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Baran, Jaroslav, Viktor Borzovič, and Žaneta Šenšelová. "Shear Assessment of Existing Prestressed Box Girder Bridge." IOP Conference Series: Materials Science and Engineering 1203, no. 2 (November 1, 2021): 022131. http://dx.doi.org/10.1088/1757-899x/1203/2/022131.

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Abstract The paper deals with the shear assessment of existing prestressed concrete box-girder bridges. Mainly focuses on the historical development of technical standards used in the design of prestressed concrete road bridges in the Slovak Republic. The standards for bridge design have been amended several times. A parametric study was performed on a model post-tensioned concrete bridge with a box-girder cross-section, which compares the internal forces along the length of the bridge using various standards and technical regulations., The differences in design principles and shear capacity were investigated while the amount and geometry of the longitudinal prestressing of the bridge were the same for all cases. Case of study is a road three-span post-tensioned concrete bridge with a main span of 50 m and end spans of 40 m. The single box-girder cross section height is constant of 2.5 m. The bridge is straight without any curvature in the horizontal plane. The thickness of the bottom slab is variable near the inner supports. The prestressing is formed by 19-strands tendons with a strand diameter of 15.7 mm with a polygonal cable geometry. The numerical model is considered as a beam element with neglecting of the torsional effects of the load. The parametric study points out the differences in the internal forces with use of different design regulations and standards. It also focuses on the shear resistance of the walls of the box-girder cross-section of the bridge. Differences in design methods are presented by the required area of shear reinforcement in the wall of box cross-section. The aim of the study is to point out the historical development of design from the point of view of shear resistance of prestressed bridges. When assessing existing older bridges and trying to achieve reliability according to the current Eurocodes, there is subsequently a requirement for additional shear reinforcement.

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Cao, Zhiliang, Hao Wang, and Tong Guo. "Fragility analysis of self-centering prestressed concrete bridge pier with external aluminum dissipators." Advances in Structural Engineering 20, no. 8 (October 20, 2016): 1210–22. http://dx.doi.org/10.1177/1369433216673376.

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A novel self-centering prestressed concrete pier with external energy dissipators has been developed to realize seismic resilient performance and enhanced corrosion-resisting property. Self-centering capacity of the pier is provided by the unbonded post-tensioned tendons and damage is mostly concentrated on the replaceable dissipators. To investigate the seismic behavior of the proposed pier, a detailed analytical model considering interface opening and dissipator deformation was developed and verified through existing cyclic load tests. Based on the proposed model, a prototype reinforced concrete pier and a self-centering prestressed concrete pier with similar backbone curves are designed, and fragility analyses are conducted on the two piers through incremental dynamic analysis. One maximum drift-based performance limit state (i.e. collapse prevention) and two residual drift-based performance limit states (i.e. emergent usage and reconstruction) are defined for seismic capacity evaluation. Fragility curves indicate that the self-centering prestressed concrete pier has a slightly higher peak drift demand owing to its inferior dissipating capacity as compared with the reinforced concrete pier, while sustains a much lower residual drift demand due to its inherent self-centering characteristic.

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Pisani, Marco Andrea, and Emilio Nicoli. "Beams prestressed with unbonded tendons at ultimate." Canadian Journal of Civil Engineering 23, no. 6 (December 1, 1996): 1220–30. http://dx.doi.org/10.1139/l96-931.

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This paper presents a numerical investigation on beams and slabs prestressed with either unbonded internal or external tendons. Twenty-three experimental tests (beams and slabs prestressed with unbonded internal tendons) were numerically simulated to verify the reliability of the numerical algorithm adopted. The good agreement established enables us to study the behaviour of these beams in depth and to compare it with the behaviour of similar beams prestressed with external tendons. The numerical analyses were then repeated after including the safety factors related to the materials. The outputs were then compared with the results adopted by making use of the simplified method suggested by Eurocode E.C.2 Part 1-5, to check the size of the error involved in the adoption of the latter. Key words: numerical analysis, unbonded internal tendons, external tendons, European Prestandard, prestressed concrete, beams, post-tensioned.

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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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Mordak, Arkadiusz, and Zbigniew Mańko. "Research of post-tensioned concrete composite spans with Π-beams of road viaduct." MATEC Web of Conferences 174 (2018): 03015. http://dx.doi.org/10.1051/matecconf/201817403015.

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The paper is presented the results of research conducted on the posttensioned prestressed concrete spans made with precast Π-beams of part of seventh spans Eugeniusz Kwiatkowski road viaduct located in Gdynia (between supports no. 97-104) under static field load test. Heavy trucks were used as static loads. Superstructure (main beams), deck slab, and fixed and moving bearings, and also supports (abutment and piers) in both roadways of trestle were tested. Specification and range of conducted research are presented with analysis of results from the tests and calculation, which allowed to the estimate span structures behavior and their actual load-capacity before allow them to normal service on B-class of loads.

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Journal articles on the topic 'Post-tensioned prestressed concrete'

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