Academic literature on the topic 'Scaled prestress bridge girders'
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Journal articles on the topic "Scaled prestress bridge girders"
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Song, Chaojie, Gang Zhang, Wei Hou, and Shuanhai He. "Performance of prestressed concrete box bridge girders under hydrocarbon fire exposure." Advances in Structural Engineering 23, no. 8 (January 3, 2020): 1521–33. http://dx.doi.org/10.1177/1369433219898102.
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This article presents an approach for investigating performance of prestressed concrete box bridge girders under hydrocarbon fire exposure. A three-dimensional nonlinear finite element model, developed in computer program ANSYS, is utilized to analyze the response of prestressed concrete box bridge girders under combined effects of fire exposure duration and simultaneous structural loading. The model validation is performed using a scaled prestressed concrete box girder exposed to ISO834 fire in furnace. Subsequently, the validated model is used to investigate fire performance of prestressed concrete box bridge girders through taking into consideration some variables, namely concrete cover thickness to prestressing strands, prestress degree, load level, fire exposure length, and position. Through a case study, results from numerical analysis show that concrete cover thickness to prestressing strands and load level has significant effect on fire resistance of prestressed concrete box bridge girders. Increasing prestress degree in prestressing strands can speed up the progression of deflection (sudden collapse) in prestressed concrete box bridge girder toward the final fire exposure stage. Reducing fire exposure length or preventing fire exposure on mid-span zone can highly enhance the fire resistance of simply supported prestressed concrete box bridge girders. Failure of prestressed concrete box bridge girder, under hydrocarbon fire exposure conditions, is governed by rate of deflection failure criterion in particular cases.
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Ji, Wei, Kui Luo, and Jingwei Zhang. "Computation of Deflections for PC Box Girder Bridges with Corrugated Steel Webs considering the Effects of Shear Lag and Shear Deformation." Mathematical Problems in Engineering 2020 (July 18, 2020): 1–12. http://dx.doi.org/10.1155/2020/4282398.
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Prestressed concrete (PC) girders with corrugated steel webs (CSWs) have received considerable attention in the past two decades due to their light self-weight and high prestressing efficiency. Most previous studies were focused on the static behavior of CSWs and simple beams with CSWs. The calculation of deflection is an important part in the static analysis of structures. However, very few studies have been conducted to investigate the deflection of full PC girders or bridges with CSWs and no simple formulas are available for estimating their deflection under static loads. In addition, experimental work on full-scale bridges or scale bridge models with CSWs is very limited. In this paper, a formula for calculating the deflection of PC box girders with CSWs is derived. The longitudinal displacement function of PC box girders with CSWs, which can consider the shear lag effect and shear deformation of CSWs, is first derived. Based on the longitudinal displacement function, the formula for predicting the deflection of PC box girders with CSWs is derived using the variational principle method. The accuracy of the derived formula is verified against experimental results from a scaled bridge model and the finite element analysis results. Parametric studies are also performed, and the influences of shear lag and shear deformation on the deflection of the box girder with CSWs are investigated by considering different width-to-span ratios and different girder heights. The present study provides an effective and efficient tool for determining the deflection of PC box girders with CSWs.
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Park, Jae Hyung, Dong Soo Hong, Jeong Tae Kim, Ki Young Koo, Chung Bang Yun, and Gyuhae Park. "Wireless Sensing and Embedded Monitoring Algorithm for Damage Diagnosis in PSC Girders." Advances in Science and Technology 56 (September 2008): 420–25. http://dx.doi.org/10.4028/www.scientific.net/ast.56.420.
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In this study, a hybrid health monitoring technique that combines wireless sensing and embedded monitoring algorithms is proposed to realize the diagnosis of damage in PSC girder bridges. Firstly, a hybrid damage monitoring system that can alarm damage occurrence and classify damage-types is designed for PSC girder bridges. Secondly, smart sensor nodes that have wireless, stand-alone, sensing and monitoring capacities of acceleration and impedance are developed for hybrid health monitoring of the structures. Finally, the performance of the smart sensor nodes is evaluated using a laboratory-scale PSC girder bridge model for which acceleration and impedance signals were measured for prestress-loss and stiffness-loss cases.
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Lin, Jian Jun, Denis Beaulieu, and Mario Fafard. "Parametric study on noncomposite slab-on-girder bridges with enforced frictional contact." Canadian Journal of Civil Engineering 21, no. 2 (April 1, 1994): 237–50. http://dx.doi.org/10.1139/l94-027.
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Using post-tensioned steel rods for strengthening noncomposite slab-on-steel girder bridges has the beneficial effects of both stabilizing the steel girders laterally and developing partial composite action longitudinally. The stabilizing effect and development of partial composite action are achieved by taking advantage of friction developed at the steel–concrete interface. A bridge reinforced by this technique is expected to have a higher load-carrying capacity and better load distribution under heavy traffic loads. Prestressed rods have been successfully used to strengthen 1/3 scale noncomposite bridge models in laboratory.The concrete slab-on-steel girder bridge models reinforced by prestressed rods are analyzed numerically in this paper by the use of the finite element method. Corresponding noncomposite models are also simulated for comparison to investigate the efficiency of this strengthening technique. The effects of variables such as the number of rods, prestressing level, type of load, slab thickness, steel girder slenderness, girder spacing, and ratio of radii of gyration of steel girders on the strengthening efficiency are studied by the finite element method. A full-scale bridge is analyzed to demonstrate the effect of the proposed reinforcing technique. Key words: bridge, composite action, contact, finite element, friction, parametric study, strengthening.
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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.
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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.
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Qiao, Lan, and Shao Wen Zhang. "Analysis of the Arrangement of Prestressed Steel in Web of Continuous Concrete Box-Girder Bridges." Applied Mechanics and Materials 587-589 (July 2014): 1359–63. http://dx.doi.org/10.4028/www.scientific.net/amm.587-589.1359.
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Concrete continuous box- girder bridges have a large proportion in small span and long span bridges, and it has very broad prospects for development. Along with the large-scale construction of this kind of bridge, various problems have also emerged, especially the damage of RC beam’s diagonal section in bridge girder deflection. It always appears the inclined cracks in webs which cause by principal tensile stress, so it will be the potential damage to the whole bridge. However, the existence of the vertical prestress, will make the principal tensile stress of box girder in greatly reduced. So as to make cracking resistance performance of diagonal section is better than the ordinary reinforced concrete bridge. For an engineering example, this paper puts forward several different vertical prestressed steel arrangements. Based on different decorate a form of vertical pretressd bridge girder under stress numerical simulation, it is concluded that bridge’s web principal tensile stress distribution and its variation law, and then optimize the vertical reinforcing steel arrangement, improve the overall safety of bridge structure. It can provide the reference in the process of construction when we face the similar problems in the future.
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Nguyen, Hue Thi, Hiroshi Masuya, Tuan Minh Ha, Saiji Fukada, Daishin Hanaoka, Kazuhiro Kobayashi, and Eiji Koida. "Long-term Application of Carbon Fiber Composite Cable Tendon in the Prestressed Concrete Bridge-Shinmiya Bridge in Japan." MATEC Web of Conferences 206 (2018): 02011. http://dx.doi.org/10.1051/matecconf/201820602011.
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Carbon fiber reinforced plastic (Carbon Fiber Composite Cable, CFCC) has the outstanding features in comparison with regular steel. In October 1988, CFCC was applied as the tensioning material in main girders of new Shinmiya Bridge in Ishikawa, Japan. This was the first bridge in Japan and in the world, which CFCC tendons were used in the prestressed concrete bridge to counter salt damage. To investigate the serviceability and durability of the main girders and CFCC, three full-scale test girders were fabricated in 1988. At the same time, a bending experiment was conducted on one girder to investigate the ultimate behavior, load carrying capacity of the PC girder, as well the strain behavior of the CFCC. Besides, two PC girders were placed next to the main girders of the bridge in the same conditions. One of them was used for a destructive test after six years of the construction time (1994). In this study, another test specimen that was exposed to the actual corrosive environment after nearly 30 years was subjected to a destructive test by bending load. The load carrying capacity of the girder was clarified, and the durability of the PC girders using CFCC tendon was confirmed.
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Wang, Jianqun, Shenghua Tang, Hui Zheng, Cong Zhou, and Mingqiao Zhu. "Flexural Behavior of a 30-Meter Full-Scale Simply Supported Prestressed Concrete Box Girder." Applied Sciences 10, no. 9 (April 28, 2020): 3076. http://dx.doi.org/10.3390/app10093076.
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Compared with scaled-model testing, full-scale destructive testing is more reliable since the test has no size effect and can truly record the mechanical performance of the structure. However, due to the high cost, only very few full-scale destructive tests have been conducted on the flexural behavior of prestressed concrete (PC) box girders with girders removed from decommissioned bridges. Moreover, related destructive testing on the flexural behavior of a new precast box girder has been rarely reported. To investigate the flexural behavior and optimize the design, destructive testing of a 30-meter full-scale simply supported prestressed box girder was conducted at the construction site. It is illustrated that the failure mode of the tested girder was fracture of the prestressing tendon, and the corresponding maximum compressive strain in the top flange was only 1456 μ ε , which is far less than the ultimate compressive strain (3300 μ ε ). Therefore, the concrete in the top flange was not fully utilized. A nonlinear analysis procedure was performed using the finite strip method (FSM). The validity of the analysis was demonstrated by comparing the analytical results with those of the full-scale test in the field and a scaled model test in a laboratory. Using the developed numerical method, parametric analyses of the ratio of reinforcement were carried out. The prestressing tendon of the tested girder was increased from four strands to six strands in each duct. After the optimization of the prestressed reinforcement, the girder was ductile and the bearing capacity could be increased by 44.3%.
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Zhou, Yongjun, Yu Zhao, Hengying Yao, and Yuan Jing. "Full-Scale Experimental Investigation of the Static and Dynamic Stiffness of Prestressed Concrete Girders." Shock and Vibration 2019 (December 4, 2019): 1–13. http://dx.doi.org/10.1155/2019/7646094.
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Cracking damage influences the stiffness of the girders. Many articles in the literatures have studied the development of stiffness of the scale-down model; however, full-scale model testing cannot be completely replaced by scale-down testing because of material component characteristics and boundary effects. This paper deals with the effects of cracking damage on the structural static and dynamic stiffness based on three prestressed concrete (PC) girders which were removed from an old bridge. First, the equivalent flexural rigidity of cracked prestressed concrete girder was assessed using the measured load-deflection response under cycles of loading and unloading. Then, after unloading, the frequencies were measured on the PC girders supported by the elastomeric bearings. Next, the development of frequency under different damage was studied, and finally, the dynamic stiffness of PC girders with cracks was assessed. The results indicate that the first frequency is more sensitive to the cracking of concrete compared with the second frequency and that the mode shapes are not sensitive to girder damage. The test girders cannot be simplified as an ideal simply supported beam for the purpose of identifying frequencies. In addition, the “final” (the end of the ultimate load case) equivalent flexural rigidity of the girders is 30% of the “initial” (the beginning of the first load case) equivalent flexural rigidity, compared with 50% in the scale-down test; and the final dynamic stiffness is approximately 84% of the initial dynamic stiffness, whereas the scale-down test is 72%.
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KIM, SUNG-IL, and NAM-SIK KIM. "DYNAMIC PERFORMANCES OF A RAILWAY BRIDGE UNDER MOVING TRAIN LOAD USING EXPERIMENTAL MODAL PARAMETERS." International Journal of Structural Stability and Dynamics 10, no. 01 (March 2010): 91–109. http://dx.doi.org/10.1142/s0219455410003397.
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In the design of railway bridges, it is necessary to be able to predict their dynamic behavior under a moving train load so as to avoid a resonance state from repetitive moving axle forces with uniform intervals. According to design trends, newly developed girder bridges weigh less and have longer spans. Since the dynamic interaction between bridge superstructures and passing trains is one of the critical issues concerning such railway bridges that are designed with greater flexibility, it is very important to evaluate the modal parameters of newly designed PSC girders before carrying out dynamic analyses. In this paper, a full scale incrementally prestressed 25-meter long concrete girder was fabricated as a test specimen and modal testing was performed at every prestressing stage in order to evaluate the modal parameters, including the natural frequency and the modal damping ratio. Young's modulus was also obtained from the global stiffness of the test specimen. During the modal testing, a digitally controlled vibration exciter and an impact hammer were applied in order to obtain precise frequency response functions, and the modal parameters were evaluated at various construction stages. With the availability of reliable properties from the modal experiments, dynamic performance estimation of a PSC girder railway bridge during the passage of a moving train can be carried out.
Dissertations / Theses on the topic "Scaled prestress bridge girders"
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Osborn, Parry. "Ultimate Shear Capacity and Residual Prestress Force of Full-Scale, Forty-One-Year-Old Prestressed-Concrete Girders." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/591.
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The ultimate shear capacity of prestressed concrete beams is difficult to predict accurately, especially after being in service for an extended period of time. The Utah Department of Transportation asked researchers at Utah State University to experimentally determine the existing shear capacity of 41-year-old prestressed, decommissioned concrete bridge girders and then provide recommendations on how to increase that ultimate shear capacity. This thesis presents the research findings that relate to the existing shear capacity of the prestressed concrete girders. Eight AASHTO Type II bridge girders were tested up to failure by applying external loads near the supports to determine their ultimate shear capacities. The measured results were then compared to calculated values obtained using the AASHTO LRFD bridge design code, and the ACI 318-08 design code. Prestress losses were also measured by means of a cracking test and then compared to values calculated according to the AASHTO prestress loss equations. Both the ultimate shear capacities and the residual prestress forces were used to evaluate the girders after being in service for more than 40 years.
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Canfield, Scott Robinson. "Full Scale Testing of Prestressed, High Performance Concrete, Bridge Girders." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7131.
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The objective of this research was to evaluate the current design specifications for use on prestressed, High Performance Concrete (HPC) bridge girders. An AASHTO Type IV and modified BT-56 girders were constructed with a 10,000 psi HPC to which a composite 7000 psi HPC deck was cast on top. The composite girders were tested in flexure, with the Type IV being tested to failure. The results of the flexure tests showed that the current AASHTO Specification for cracking moment and ultimate capacity are conservative.
In addition to flexural testing, each composite girder was studied with respect to the deck contraction induced girder deflection. Each deck and girder were instrumented with strain gauges and string potentiometes. The results of the study indicated the induced deflections are significantly greater than deflections from the deck dead load, and should be considered to accurately predict bridge deflection.
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Stillings, Tyler W. "Load Distribution and Ultimate Strength of an Adjacent Precast, Prestressed Concrete Box Girder Bridge." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1335463075.
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Angomas, Franklin B. "Behavior of Prestressed Concrete Bridge Girders." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/405.
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For this research, prestress losses were monitored in six HPC bridge girders. These measured losses were compared to predicted losses according to four sources. Prestress loss predictive methods considered for this research were: 1- AASHTO LRFD 2004, 2- AASHTO LRFD 2004 Refined, 3- AASHTO LRFD 2007, and 4- AASHTO LRFD Lump Sum method. On the other hand, the camber prediction methods used in the present research were: 1- Time dependent method described in NCHRP Report 496, 2- PCI multiplier method, and 3- Improved PCI Multiplier method. For the purpose of this research, long-term prestress losses were monitored in select girders from Bridge 669 located near Farmington, Utah. Bridge 669 is a three-span prestress concrete girder bridge. The three spans have lengths of 132.2, 108.5, and 82.2 feet long, respectively. Eleven AASHTO Type VI precast prestressed girders were used to support the deck in each span. The deflection of several girders from a three-span, prestressed, precast concrete girder bridge was monitored for 3 years. Fifteen bridge girders were fabricated for the three span-bridge. Ten girders from the exterior spans had span length of 80 feet, and five girders from the middle span had span length of 137 feet. From the results of this research, in both the 82- and 132-foot-long, the AASHTO LRFD 2004 Refined Method does a better job predicting the prestress loss and it can be concluded that all the prediction methods do a better job predicting the loss for the larger girders. The Lump Sum method predicted very accurately the long term prestress loss for the 132-foot-long girders.
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Bolduc, Matthew W. "Full-Scale Testing of Pretensioned Concrete Girders with Partially Debonded Strands." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613748086228573.
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Sathiraju, Venkata Sai Surya Praneeth. "Lateral Stability Analysis of Precast Prestressed Bridge Girders During All Phases of Construction." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553252005286553.
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Cross, Benjamin Thomas. "Structural Performance of High Strength Lightweight Concrete Pretensioned Bridge Girders." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/26190.
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The use of high compressive strengths in prestressed bridge girders can lower costs by allowing for longer spans, increased girder spacing, and smaller cross-sections. If high strength lightweight concrete (HSLWC) is used, these advantages are further enhanced due to the corresponding reduction in self-weight. Additional benefits can then be realized in the form of more traffic lanes, increased load capacity, smaller substructures, reduced crane capacity requirements, and lower shipping costs.
Despite the possible economic savings, HSLWC has been used infrequently in prestressed bridge girder applications across the nation. While recent research has been performed to extend the applicability of current bridge design specifications to normal weight concretes with strengths as high as 18 ksi, little
has been done by comparison with regards to HSLWC. The purpose of the research in this report was to assess whether current bridge design specifications for transfer length, development length, prestress loss, camber, and flexural capacity are satisfactory for use with fully-bonded, pretensioned flexural members consisting of HSLWC and to make recommendations for improvements where necessary.
Twelve high strength pretensioned beams of variable unit weight (eight lightweight beams and
four normal weight beams) and strand size (eight beams with 0.5-in. strand and four beams with 0.6-in. strand) were cast at the Thomas M. Murray Structural Engineering Laboratory at Virginia Tech. These beams were allowed to sit for a period of several months after fabrication while measurements were taken regarding transfer length, prestress loss, and camber. After this period, the beams were load tested to collect development length data, flexural data, and further data related to prestress loss. In
addition to the laboratory cast beams, prestress loss and camber data from six full-size bridge beams (five lightweight beams and one normal weight beam) cast as part of a separate project at Virginia Tech was examined. Analysis of the results for all beams shows that with a few caveats, the current AASHTO LRFD Specifications and other design methods examined regarding the topics under consideration are satisfactory for use in the design of HSLWC pretensioned bridge girders with properties similar to those of the beams studied.Ph. D.
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Duran, Heriberto C. "ASSESSMENT OF LIVE LOAD DEFLECTIONS IN A SIMPLE SPAN COMPOSITE BRIGDE WITH PRESTRESSED PRECAST CONCRETE GIRDERS." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/1862.
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The purpose of this study is to investigate how accurately the distribution factor method estimates the live load deflections under the principles of the 2012 AASHTO LRFD Bridge Design Specifications (AASHTO LRFD specifications) compared to the results of the NISA finite element analysis software. The simple span bridge model analyzed is developed very similarly to the design example of the PCI Bridge Design Manual. The main difference is a shorter span length and smaller AASHTO-PCI bulb tee sections. Three main finite element models are created to estimate the live load deflections under the recommended live load conditions as per AASHTO LRFD specifications. The first model is simulated with simple support conditions. The purpose of this model is two-fold: compare the deflections to the distribution factor method and to the deflections of the second model that is simulated with elastomeric steel reinforced bearing pads. Thus, the stiffnesses of the elastomeric bearing pads of the second model are varied within the AASHTO LRFD specifications acceptable limits and under low temperature conditions the stiffness is increased accordingly for two cases. The purpose is to investigate if the stiffness have any significant affect on the deflections of the girders. Then a third model is created to investigate if the removal of the intermediate diaphragms have any affect on the deflections. The results of the first and second models, including the models with the allowed varied stiffnesses of the bearing pads, found only the interior girders deflecting up to 4% more and the exterior girders were deflecting up to 5.55% less than the estimates of the distribution factor method. In the case when the diaphragms are removed, the deflections of the inner most interior girders are deflecting up to 10.85% more compared to the same girders of the model which includes the intermediate diaphragms and the bearing pads. In the unique case of the second model where the bearing pads may stiffen significantly under low temperatures, the girders are deflecting up to 23% less than when at room temperature conditions. All these findings and other summarized results are discussed in greater detail in this study.
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Neeli, Yeshwanth Sai. "Use of Photogrammetry Aided Damage Detection for Residual Strength Estimation of Corrosion Damaged Prestressed Concrete Bridge Girders." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/99445.
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Corrosion damage reduces the load-carrying capacity of bridges which poses a threat to passenger safety. The objective of this research was to reduce the resources involved in conventional bridge inspections which are an important tool in the condition assessment of bridges and to help in determining if live load testing is necessary. This research proposes a framework to link semi-automated damage detection on prestressed concrete bridge girders with the estimation of their residual flexural capacity. The framework was implemented on four full-scale corrosion damaged girders from decommissioned bridges in Virginia. 3D point clouds of the girders reconstructed from images using Structure from Motion (SfM) approach were textured with images containing cracks detected at pixel level using a U-Net (Fully Convolutional Network). Spalls were detected by identifying the locations where normals associated with the points in the 3D point cloud deviated from being perpendicular to the reference directions chosen, by an amount greater than a threshold angle. 3D textured mesh models, overlaid with the detected cracks and spalls were used as 3D damage maps to determine reduced cross-sectional areas of prestressing strands to account for the corrosion damage as per the recommendations of Naito, Jones, and Hodgson (2011). Scaling them to real-world dimensions enabled the measurement of any required dimension, eliminating the need for physical contact.
The flexural capacities of a box beam and an I-beam estimated using strain compatibility analysis were validated with the actual capacities at failure sections determined from four destructive tests conducted by Al Rufaydah (2020). Along with the reduction in the cross-sectional areas of strands, limiting the ultimate strain that heavily corroded strands can develop was explored as a possible way to improve the results of the analysis. Strain compatibility analysis was used to estimate the ultimate rupture strain, in the heavily corroded bottommost layer prestressing strands exposed before the box beam was tested. More research is required to associate each level of strand corrosion with an average ultimate strain at which the corroded strands rupture. This framework was found to give satisfactory estimates of the residual strength. Reduction in resources involved in current visual inspection practices and eliminating the need for physical access, make this approach worthwhile to be explored further to improve the output of each step in the proposed framework.Master of Science
Corrosion damage is a major concern for bridges as it reduces their load carrying capacity. Bridge failures in the past have been attributed to corrosion damage. The risk associated with corrosion damage caused failures increases as the infrastructure ages. Many bridges across the world built forty to fifty years ago are now in a deteriorated condition and need to be repaired and retrofitted. Visual inspections to identify damage or deterioration on a bridge are very important to assess the condition of the bridge and determine the need for repairing or for posting weight restrictions for the vehicles that use the bridge. These inspections require close physical access to the hard-to-reach areas of the bridge for physically measuring the damage which involves many resources in the form of experienced engineers, skilled labor, equipment, time, and money. The safety of the personnel involved in the inspections is also a major concern. Nowadays, a lot of research is being done in using Unmanned Aerial Vehicles (UAVs) like drones for bridge inspections and in using artificial intelligence for the detection of cracks on the images of concrete and steel members. Girders or beams in a bridge are the primary longitudinal load carrying members. Concrete inherently is weak in tension. To address this problem, High Strength steel reinforcement (called prestressing steel or prestressing strands) in prestressed concrete beams is pre-loaded with a tensile force before the application of any loads so that the regions which will experience tension under the service loads would be subjected to a pre-compression to improve the performance of the beam and delay cracking. Spalls are a type of corrosion damage on concrete members where portions of concrete fall off (section loss) due to corrosion in the steel reinforcement, exposing the reinforcement to the environment which leads to accelerated corrosion causing a loss of cross-sectional area and ultimately, a rupture in the steel. If the process of detecting the damage (cracks, spalls, exposed or severed reinforcement, etc.) is automated, the next logical step that would add great value would be, to quantify the effect of the damage detected on the load carrying capacity of the bridges. Using a quantified estimate of the remaining capacity of a bridge, determined after accounting for the corrosion damage, informed decisions can be made about the measures to be taken. This research proposes a stepwise framework to forge a link between a semi-automated visual inspection and residual capacity evaluation of actual prestressed concrete bridge girders obtained from two bridges that have been removed from service in Virginia due to extensive deterioration. 3D point clouds represent an object as a set of points on its surface in three dimensional space. These point clouds can be constructed either using laser scanning or using Photogrammetry from images of the girders captured with a digital camera. In this research, 3D point clouds are reconstructed from sequences of overlapping images of the girders using an approach called Structure from Motion (SfM) which locates matched pixels present between consecutive images in the 3D space. Crack-like features were automatically detected and highlighted on the images of the girders that were used to build the 3D point clouds using artificial intelligence (Neural Network). The images with cracks highlighted were applied as texture to the surface mesh on the point cloud to transfer the detail, color, and realism present in the images to the 3D model. Spalls were detected on 3D point clouds based on the orientation of the normals associated with the points with respect to the reference directions. Point clouds and textured meshes of the girders were scaled to real-world dimensions facilitating the measurement of any required dimension on the point clouds, eliminating the need for physical contact in condition assessment. Any cracks or spalls that went unidentified in the damage detection were visible on the textured meshes of the girders improving the performance of the approach. 3D textured mesh models of the girders overlaid with the detected cracks and spalls were used as 3D damage maps in residual strength estimation. Cross-sectional slices were extracted from the dense point clouds at various sections along the length of each girder. The slices were overlaid on the cross-section drawings of the girders, and the prestressing strands affected due to the corrosion damage were identified. They were reduced in cross-sectional area to account for the corrosion damage as per the recommendations of Naito, Jones, and Hodgson (2011) and were used in the calculation of the ultimate moment capacity of the girders using an approach called strain compatibility analysis. Estimated residual capacities were compared to the actual capacities of the girders found from destructive tests conducted by Al Rufaydah (2020). Comparisons are presented for the failure sections in these tests and the results were analyzed to evaluate the effectiveness of this framework. More research is to be done to determine the factors causing rupture in prestressing strands with different degrees of corrosion. This framework was found to give satisfactory estimates of the residual strength. Reduction in resources involved in current visual inspection practices and eliminating the need for physical access, make this approach worthwhile to be explored further to improve the output of each step in the proposed framework.
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Garber, David Benjamin. "Effect of new prestress loss estimation procedure on precast, pretensioned bridge girders." Thesis, 2014. http://hdl.handle.net/2152/24899.
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The prestress loss estimation provision in the AASHTO LRFD Bridge Design Specifications was recalibrated in 2005 to be more accurate for "high-strength [conventional] concrete." Greater accuracy may imply less conservatism, the result of which may be flexural cracking of beams under service loads. Concern with a potential lack of conservatism and the degree of complexity of these recalibrated prestress loss estimation provisions prompted the investigation to be discussed in this dissertation. The primary objectives of this investigation were: (1) to assess the conservatism and accuracy of the current prestress loss provisions, (2) to identify the benefits and weaknesses of using the AASHTO LRFD 2004 and 2005 prestress loss provisions, and (3) to make recommendations to simplify the current provisions. These objectives were accomplished through (1) the fabrication, conditioning, and testing of 30 field-representative girders, (2) the assembly and analysis of a prestress loss database unmatched in size and diversity when compared with previously assembled databases, and (3) a parametric study investigating the design implications and sensitivity of the current loss provisions. Based on the database evaluation coupled with the experimental results, it was revealed that the use of the AASHTO LRFD 2005 prestress loss provisions resulted in underestimation of the prestress loss in nearly half of all cases. A loss estimation procedure was developed based on the AASHTO LRFD 2005 provisions to greatly simplify the procedure and provide a reasonable level of conservatism.text
Books on the topic "Scaled prestress bridge girders"
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(US), National Research Council. Prestress Losses in Pretensioned High-Strength Concrete Bridge Girders (NCHRP report). Transportation Research Board National Resear, 2003.
Find full textBook chapters on the topic "Scaled prestress bridge girders"
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Shi, Xuefei, Zhiquan Liu, and Zijie Zhou. "Full-Scale Model Test of Prestressed Segmental Precast Continuous Girder Bridge." In High Tech Concrete: Where Technology and Engineering Meet, 1263–71. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59471-2_146.
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Tondolo, F., D. Sabia, B. Chiaia, A. Quattrone, P. Savino, F. Biondini, G. Rosati, and M. Anghileri. "Full-scale testing and analysis of 50-year old prestressed concrete bridge girders." In Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 1775–82. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003322641-220.
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Balaji Rao, K., and M. B. Anoop. "Polya Urn Model for Assessment of Prestress Loss in Prestressed Concrete (PSC) Girders in a Bridge System using Limited Monitoring Data." In Risk Based Technologies, 257–78. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-5796-1_14.
Full textConference papers on the topic "Scaled prestress bridge girders"
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Leyong, Wei, Yan Yonglun, Huang Liji, Ma Zeng, and Song Yingtong. "Overall Design of the Nanjing Jiangxinzhou Yangtze River Bridge." In IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2022. http://dx.doi.org/10.2749/nanjing.2022.0157.
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<p>This paper systematically introduces the overall design concept of the Nanjing Jiangxinzhou Yangtze River Bridge. The main bridge is a three-tower cable-stayed bridge featuring a longitudinal diamond cable tower and dual central cable planes. The bridge span is designed to be a total of 80+218+600+600+218+80 = 1796m. A steel-shell composite cable tower design is adopted, with the main girder including a high-performance steel-coarse aggregate reactive powder concrete</p><p>（CA-RPC） composite girder structure. The cable tower uses cast-in-situ bored pile group foundations, and the stay cables are formed of steel strands. The south and north approach bridges use segmented prefabricated prestressed concrete box girders. The bridge over the river dyke uses a continuous box girder made of prestressed corrugated steel webs for the 78m span and the construction technology of segmented prefabrication has being used for the first time. Nanjing Jiangxinzhou Yangtze River Bridge has become a classic engineering structure which not only environmentally-friendly, but also meets all requirements of industrial construction attributed to the application of a high-performance composite structure for the main bridge, as well as large-scale prefabricated assembly structures for approach bridges and bridges over river dykes.</p>
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Lantsoght, Eva O. L., Cor van der Veen, Rutger Koekkoek, and Henk Sliedrecht. "Capacity of prestressed concrete bridge decks under fatigue loading." In IABSE Congress, Ghent 2021: Structural Engineering for Future Societal Needs. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/ghent.2021.0313.
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<p>In The Netherlands, existing slab-between-girder bridges with prestressed girders and thin transversely prestressed concrete decks require assessment. The punching capacity was studied in a previous series of experiments, showing a higher capacity thanks to compressive membrane action in the deck. Then, concerns were raised with regard to fatigue loading. To address this, two series of large-scale experiments were carried out, varying the number of loads (single wheel print versus double wheel print), the loading sequence (constant amplitude versus variable amplitude, and different loading sequences for variable amplitude), and the distance between the prestressing ducts. An S-N curve is developed for the assessment of slab-between-girder bridges. The experiments showed that compressive membrane actions enhances the capacity of thin transversely prestressed decks subjected to fatigue loading.</p>
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Cartiaux, François-Baptiste, Véronique Le Corvec, Jorge Semiao, Bernard Jacob, Franziska Schmidt, Alexandre Brouste, and Alain Ehrlacher. "Real condition experiment on a new bridge weigh-in-motion solution for the traffic assessment on road bridges." In IABSE Congress, Ghent 2021: Structural Engineering for Future Societal Needs. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/ghent.2021.1242.
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<p>Weigh-in-Motion is currently the only way to precisely assess and monitor traffic loads on road bridges from real measurements. This assessment helps to detect potential overweight vehicles and to optimize the maintenance operations on the bridge thanks to an accurate knowledge of its real load conditions.</p><p>An experiment, performed on a precast prestressed concrete beam girders bridge overcrossing a highway in France, is described. The Weigh-in-Motion (WIM) system uses the bridge deck as a large scale, part of the weighing device, and measures strain in critical parts of the structure.</p><p>The system is able to get significantly accurate estimations of the gross weight of the vehicles on most types of bridges, including long span box girders, large composite decks or the multiple precast prestressed concrete beams considered in the study. However, the axle load estimation is still much less accurate and not presented here.</p><p>The experiment started in February 2019 and is still going on, also proving the robustness of the solution for an operation over long durations, as a permanent part of the bridge management through its whole lifecycle. Thus, the WIM sensors used are relevant for the Structural Health Monitoring of the bridge deck as well.</p>
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Cartiaux, François-Baptiste, Véronique Le Corvec, Jorge Semiao, Bernard Jacob, Franziska Schmidt, Alexandre Brouste, and Alain Ehrlacher. "Real condition experiment on a new bridge weigh-in-motion solution for the traffic assessment on road bridges." In IABSE Congress, Ghent 2021: Structural Engineering for Future Societal Needs. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/ghent.2021.1242.
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<p>Weigh-in-Motion is currently the only way to precisely assess and monitor traffic loads on road bridges from real measurements. This assessment helps to detect potential overweight vehicles and to optimize the maintenance operations on the bridge thanks to an accurate knowledge of its real load conditions.</p><p>An experiment, performed on a precast prestressed concrete beam girders bridge overcrossing a highway in France, is described. The Weigh-in-Motion (WIM) system uses the bridge deck as a large scale, part of the weighing device, and measures strain in critical parts of the structure.</p><p>The system is able to get significantly accurate estimations of the gross weight of the vehicles on most types of bridges, including long span box girders, large composite decks or the multiple precast prestressed concrete beams considered in the study. However, the axle load estimation is still much less accurate and not presented here.</p><p>The experiment started in February 2019 and is still going on, also proving the robustness of the solution for an operation over long durations, as a permanent part of the bridge management through its whole lifecycle. Thus, the WIM sensors used are relevant for the Structural Health Monitoring of the bridge deck as well.</p>
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Amir, Sana, Cor van der Veen, Joost C. Walraven, and Ane de Boer. "Bearing capacity of transversely prestressed concrete deck slabs." In IABSE Conference, Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2018. http://dx.doi.org/10.2749/copenhagen.2018.298.
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All over the world, the safety of old structures is a question that has become increasingly important with the passage of time. In the Netherlands, there are a large number of thin, transversely prestressed concrete bridge decks, cast in-situ between the flanges of long prestressed concrete girders. These bridges date back to the 60’s and 70’s of the last century and are found to be critical in shear when analyzed using the recently implemented EN 1992-1-1:2005 (CEN 2005). With the on-going economic recession, it is an astute approach to check if such bridges can still be used for a few more decades, provided they are safe and reliable against the modern traffic loads. The results could then be applied on a wider range of structures, especially in developing countries facing economic constraints. Therefore, a prototype bridge was selected and experimental, numerical and theoretical approach was used to investigate its bearing capacity, loaded by a single and double wheelprint loadcase. Nineteen tests on a 1:2 scale model of the bridge were carried out in the laboratory. Later the bridge was modelled as a 3D solid, 1:2 scale using the finite element software TNO DIANA 9.4.4 and several nonlinear analyses were carried out. Furthermore, a theoretical analysis, using the bearing capacity obtained from the fib Model code 2010 punching shear provisions (based on the Critical Shear Crack Theory for prestressed slabs), and the experimental and numerical ultimate capacities, showed comparable results. A coefficient of variation of 11% and 9% was obtained when the experimental and the finite element analysis punching loads were compared with the theoretical results involving compressive membrane action, respectively. This led to the conclusion that the existing transversely prestressed concrete bridge decks still have sufficient residual bearing (punching shear) capacity and considerable saving in cost can be made if compressive membrane action is considered in the analysis.
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Peng, Yuan-cheng. "Structural System Conception and Overall Design of a Mega Suspension Bridge with Four Main Cables." In IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2022. http://dx.doi.org/10.2749/nanjing.2022.2081.
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<p>Hubei Yanji Yangtze River Bridge integrates the functions of expressway and urban road. It adopts the scheme of 1860 m double deck steel truss girder suspension bridge with a single span across navigable waters and fault zones. The bridge is close to the airport, and the height of the tower is limited due to the aviation height limit, so that the sag of the main cable is too small and the scale of the main cable is too large. To solve the above problems, a new suspension bridge structure system with four main cables with different sags is proposed. The main features of this system are: four main cables are symmetrically arranged on two sides, and two main cables on the same side adopt different sags. The truss girders are alternately suspended on two groups of main cables with different sags at intervals, and the main cables with different sags are staggered and anchored to ground anchors in front and back of the longitudinal direction. The new system reduces the scale of a single main cable, and has better wind stability. The midspan of lower main cable on the outside can be lowered below the bridge deck to increase the sag, which better solves the construction problem of the tower height limitation. Based on this system, the upper main cable span of the bridge is (550+1860+450) m, the midspan sag is 142.445 m, the lower main cable span is (510+1860+410) m, and the midspan sag is 153.345 m. The cable of the bridge adopts galvanized-aluminium alloy coated high-strength steel wire, the girder adopts Warren truss, the anchorage adopts replaceable prestressed anchorage system, the tower adopts gatehouse shape, and the foundation adopts bored piles.</p>
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Kaka, Venkatesh Babu, and Shih-Ho Chao. "Investigation of Eliminating Prestress in Bridge Girders with the Use of Non-Prestressed Ultra-High-Performance Fiber-Reinforced Concrete Girders." In Structures Congress 2018. Reston, VA: American Society of Civil Engineers, 2018. http://dx.doi.org/10.1061/9780784481332.006.
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Gallardo, J., D. Garber, D. Deschenes, and O. Bayrak. "Simplified Element-Based Model to Estimate Strain-Related Prestress Loss in Pretensioned Simply Supported Bridge Girders." In 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures. Reston, VA: American Society of Civil Engineers, 2015. http://dx.doi.org/10.1061/9780784479346.171.
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Meng, Jie, Xiaohu Chen, Xueshan Liu, Bowen Liang, and Haoxiang Huang. "Advantages of New Type of Steel Box Coarse Aggregate Reactive Powder Concrete Composite Continuous Beam Bridge." In IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2022. http://dx.doi.org/10.2749/nanjing.2022.0461.
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<p>Coarse aggregate activated powder concrete (CA-RPC) is a new modified material for the large- scale application of existing ultra-high-performance concrete (UHPC), which can improve the technical difficulties of existing materials such as harsh materials selection, high construction viscosity, large self-shrinkage, etc., and has the characteristics of ultra-high strength, low viscosity, low shrinkage, high toughness and high elastic modulus. Nanjing Lvdu Road bridge over New QinHuai River innovatively introduced coarse aggregate activated powder concrete and formed a new composite continuous beam bridge system with steel box. Through comparative analysis with the steel box- conventional concrete composite continuous girder bridge, prestressed concrete continuous girder bridge and other structural systems, the advantages of the new structural system such as large span lightweight, prefabricated assembly, and ecological environmental protection are expounded.</p>
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Yaqub, Muhammad Arslan, Stijn Matthys, and Christoph Czaderski. "Potential of memory steel reinforcement for shear strengthening of concrete bridge girders with I-sections." In IABSE Symposium, Prague 2022: Challenges for Existing and Oncoming Structures. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2022. http://dx.doi.org/10.2749/prague.2022.1180.
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<p>This study was carried out to access the performance of near surface mounted (NSM) memory steel reinforcement for shear strengthening of concrete girders with I-sections. Specially designed/strengthened concrete I-sections were tested in tension and the bond behaviour of memory steel was observed and reported as failure mode, load displacement and strain variation. It has been demonstrated that the memory steel reinforcement has a great potential for active shear strengthening of concrete girders with I-section. The activation of memory steel apply prestress on the I-section that delays the cracking and increases the ultimate failure load. The delayed shear cracking will consequently retain the aggregate interlock mechanism that is the main component of shear strength. Besides the additional strength of the external reinforcement, the yielding of internal stirrups is also delayed that further retains the intrinsic shear strength.</p><p>The results reported in this paper are part of a wider study to investigate various shear strengthening configurations for precast prestressed I-girders using memory steel reinforcement and fibre reinforced polymers (FRPs).</p>