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1
Shawky, Wael, e Ghaidaa Nabil. "Experimental and numerical study for the post buckling behaviour of plate girders subjected to bending and shear". MATEC Web of Conferences 162 (2018): 04027. http://dx.doi.org/10.1051/matecconf/201816204027.
Testo completoAbstract (sommario):
This research offers experimental and numerical study for the ultimate strength analysis and post buckling behaviour of plate girders subjected to shear and bending stresses. Two Plate girders of length 2.5m are designed consisting from three separate structural steel plates welded together to form I - section. The dimensions of the first girder section is 512 mm × 120 mm while the second girder section is 412mm × 120 mm. Mechanical properties for plate girders components were found by testing three samples of each plate. The ultimate shear strength was found by examining two plate girders in the laboratory under concentrated load applied at the middle span. A numerical study of the tested plate girders was carried out by using the software program (ANSYS) to study the behaviour of girders steel under the influence of loads application. The results showed that the ratio of the experimental ultimate load strength to the numerical ultimate load strength is 97% 94% for plate girders 1 and 2 , respectively. For the part of using theoretical study. The results obtained from the equations , it was observed that the ratio of the experimental ultimate load strength to the theoretical ultimate load strength is 83% for plate girders1 and 90% for the plate girder 2.Through comparison between experimental, numerical and theoretical results it was observed good andacceptable agreement. Thus confirming the accuracy of the modelling between this methods and obtain convergent results in all cases. Also it was found when an increase in the depth of the web has effect in increasing the ultimate shear strength for plate girder by about 19%.
2
Ezzeldin Yazeed Sayed-Ahmed. "Design aspects of steel I-girders with corrugated steel webs". Electronic Journal of Structural Engineering 7 (1 giugno 2007): 27–40. http://dx.doi.org/10.56748/ejse.772.
Testo completoAbstract (sommario):
Corrugated web girders represent a new structural system emerged in the past two decades. The girder’s flanges provide the flexural strength of the girder with no contribution from the corrugated web which provides the girder’s shear capacity. Failure of the web occurs by steel yielding, web buckling or interactively between them. Lateral torsion and local flange buckling of corrugated web girders represent another two possible failure criteria. Here, the work previously performed by the author on corrugated web girders was compiled and presented in a comprehensive format. The starting point is the shear behaviour of the corrugated webs which is investigated focusing on the failure modes affecting the web design. An interaction equation that considers web buckling and yielding is proposed. Numerical analyses are performed to investigate the buckling modes of the corrugated web, verify the validity of the proposed equation and explore the post-buckling strength of corrugated web girders. The numerical model is extended to determine the critical moment causing lateral instability for corrugated web girders. The applicability of the critical moment design equations, currently used for plane web girders, to corrugated web girders is examined. The numerical model is then used to scrutinize the local buckling behaviour of the compression flange. The applicability of the currently used limiting values for the flange outstand-to-thickness ratios to corrugated web girders is investigated.
3
Xu, Jun, Jian Li, Yu Ye, Yuanqing Xu e Chong Li. "Dynamic Response of a Long-Span Double-Deck Suspension Bridge and Its Vibration Reduction". Buildings 13, n. 7 (14 luglio 2023): 1791. http://dx.doi.org/10.3390/buildings13071791.
Testo completoAbstract (sommario):
This paper presents a dynamic analysis of a long-span double-deck suspension bridge subjected to random traffic loading using a Finite Element (FE) model. During this study, the influence of various traffic parameters, such as vehicle speed, traffic volume, traffic weight, and the location of the passing girder, on the longitudinal movement of the girders was investigated. The results reveal that schemes with double girders passing can lead to greater longitudinal displacement of the girder as compared to a long-span bridge with a single passing girder. However, the incorporation of fluid-viscous dampers at the ends of the girders significantly reduces the displacement range of each node. For instance, at the left end of the bridge, the original model (without dampers) exhibits a displacement range of approximately 0.01–0.056 m, whereas the constrained model (with dampers) shows a range of 0.025–0.033 m. A quantitative analysis demonstrates that higher damping coefficients (or smaller damping exponents) can further mitigate the girder’s movement.
4
Almoosi, Y., e N. Oukaili. "The Response of a Highly Skewed Steel I-Girder Bridge with Different Cross-Frame Connections". Engineering, Technology & Applied Science Research 11, n. 4 (21 agosto 2021): 7349–57. http://dx.doi.org/10.48084/etasr.4137.
Testo completoAbstract (sommario):
Braces in straight bridge systems improve the lateral-torsional buckling resistance of the girders by reducing the unbraced length, while in horizontally curved and skew bridges, the braces are primary structural elements for controlling deformations by engaging adjacent girders to act as a system to resist the potentially large forces and torques caused by the curved or skewed geometry of the bridge. The cross-frames are usually designed as torsional braces, which increase the overall strength and stiffness of the individual girders by creating a girder system that translates and rotates as a unit along the bracing lines. However, when they transmit the truck’s live load forces, they can produce fatigue cracks at their connections to the girders. This paper investigates the effect of using different details of cross-frames to girder connections and their impacts on girder stresses and twists. Field testing data of skewed steel girders bridge under various load passes of a weighed load vehicle incorporated with a validated 3D full-scale finite element model are presented in this study. Two types of connections are investigated, bent plate and pipe stiffener. The two connection responses are then compared to determine their impact on controlling the twist of girder cross-sections adjacent to cross-frames and also to mitigate the stresses induced due to live loads. The results show that the use of a pipe stiffener can reduce the twist of the girder’s cross-section adjacent to the cross-frames up to 22% in some locations. In terms of stress ranges, the pipe stiffener tends to reduce the stress range by 6% and 4% for the cross-frames located in the abutment and pier skew support regions respectively.
5
Mahmoud, Thamir K., e Qassim Ali Husain Al-Quraishy. "EXPERIMENTAL AND THEORETICAL INVESTIGATIONS FOR BEHAVIOR OF PRECAST CONCRETE GIRDERS WITH CONNECTIONS". Journal of Engineering 18, n. 05 (19 giugno 2023): 621–38. http://dx.doi.org/10.31026/j.eng.2012.05.07.
Testo completoAbstract (sommario):
This research presents experimental and theoretical investigation of 15 reinforced concrete spliced and nonspliced girder models. Splices of hooked dowels and cast in place joints, with or without strengthening steel plates were used. Post-tensioning had been used to enhance the splice strength for some spliced girders. The ANSYS computer program was used for analyzing the spliced and non-spliced girders. A nonlinear three dimensional element was used to represent all test girders. The experimental results have shown that for a single span girder using steel plate connectors in the splice zone has given a sufficient continuity to resist flexural stresses in this region. The experimental results have shown that the deflection of hooked dowels spliced girders is greater than that of non-spliced girder in the range of (17%-50%) at about 50% of the ultimate load which approximately corresponds to the serviceability limit state and the ultimate loads is less than that of non-spliced girder in the range of (12%-52%). For other spliced girders having strengthening steel plates at splices, the results have shown that the deflection of the spliced girder is less than that of non-spliced girder in the range of (2%-20%) at about 50% of the ultimate load and the ultimate loads for spliced girder is greater than that of nonspliced girder in the range of (1%-7%). The post-tensioned concrete girders have shown a reduction in deflection in the range of (26% - 43%) at a load of 50% of the ultimate load as compared with that of ordinary girders. Moreover, post-tensioning increases the ultimate loads in the range of (70% - 132%). The results obtained by using the finite element solution showed a good agreement with experimental results. The maximum difference between the experimental and theoretical ultimate loads for girders was in the range of (3-11%).
6
Mahmoud, Thamir K., e Ali H. Nasser. "EXPERIMENTAL AND ANALYTICAL ANALYSIS OF PRE-STRESSED CONCRETE SPLICED GIRDER MODELS". Journal of Engineering 15, n. 04 (1 dicembre 2009): 4087–106. http://dx.doi.org/10.31026/j.eng.2009.04.01.
Testo completoAbstract (sommario):
The present research is concerned with experimental and analytical studies of prestressed concrete spliced and non-spliced girder models. The test groups consisted of (16) girders of rectangular sections. Eight girders are spliced while the other eight are reference non - spliced girders. Each spliced girder is composed of three concrete segments connected by splices of ordinary reinforced concrete with hooked dowels different locations. The tested girders were of single span or continuous over intermediate supports. For single span girders two splices were used and post-tensioning was carried out for the full assembled girder. For the continuous girders pre-tensioned segments were connected by splices at quarter spans.Concentrated or uniformly distributed loads have been applied to the girders. The deflection was measured at mid-spans while the strain was measured at splice zones and at mid-spans.Nonlinear analysis of the girders was carried out using a modified computer program. A comparison among the experimental and the analytical results for spliced and non-spliced girders was carried out to study the effects of splicing for different girders. Results have shown that at about 50% of the ultimate load which is approximately corresponds to the serviceability limit state, the deflection of the spliced girders is greater than that of the reference non-spliced girders in the range of (10%-15%) and the ultimate loads for the nonspliced girders are greater than those of the spliced girders in the range of (12%-17%). The difference in deflection between the Finite Element and the experimental results at 50% ofthe ultimate load was in the range of (8%-12%). Moreover, the difference in the ultimate load between the Finite Element and the experimental results was in the range of (5%-11%).
7
Zhao, Hang, e Bassem Andrawes. "Experimental Testing and Strut-and-Tie Modeling of Full-Scale Precast Concrete Girders with FRP Repaired End Regions". Applied Sciences 10, n. 17 (22 agosto 2020): 5822. http://dx.doi.org/10.3390/app10175822.
Testo completoAbstract (sommario):
Bridges located in cold regions are susceptible to extreme deterioration due to harsh climate conditions. Distressing of girder’s end regions is among the most common damage types in these bridges. This work focuses on addressing this type of damage through the use of a fiber reinforced polymer (FRP) repair scheme. Three-point-bending tests are conducted on the control, damaged, mortar repair and carbon fiber reinforced polymer (CFRP) repair cases of bridge girders that are taken out of service. Test results are analyzed to investigate the effectiveness of FRP to repair precast concrete (PC) girders with damaged end regions. Furthermore, since the damage is mainly localized at girder’s end region where beam theory is invalid, the behavior of FRP repaired end region (D-region) is studied using the strut-and-tie method. Based on the test results, a strut-and-tie model (STM) is proposed to estimate the shear capacity of the girder with the FRP repaired end region. The outcome of the experimental work shows that the FRP laminate repair system is effective in recovering and improving the shear behavior of the girder including both peak force and ductility. The proposed STM can be used to predict the shear capacity of the PC girder with a similar damage pattern to the one considered in this study.
8
Nguyen, Hue Thi, Hiroshi Masuya, Tuan Minh Ha, Saiji Fukada, Daishin Hanaoka, Kazuhiro Kobayashi e 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.
Testo completoAbstract (sommario):
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.
9
Uemura, Tomoaki, Norihisa Hashimoto e Masatoshi Harada. "Heavy-weight floor impact sound in the state of coupled vibration of floor slab and girder of a pure framed structure". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, n. 7 (30 novembre 2023): 1497–508. http://dx.doi.org/10.3397/in_2023_0228.
Testo completoAbstract (sommario):
Examples of poor heavy-weight floor impact sound insulation performance of pure framed structures with reinforced concrete were observed relative to the floor slab thickness. To investigate the cause of the poor performance, the floor vibration characteristics of actual pure framed structures were measured during heavy-weight impact. As a result, the floor vibration characteristics of the displacement of girders and the coupled vibration of the girders and floor slabs not seen in conventional floor structures surrounded by girders with reinforced concrete walls were observed. The propagation of the vibration of the floor slab was observed in more than the range surrounded by girders and in the next slab beyond the girders owing to the vibration of the girder itself. It was confirmed that these physical phenomena can be evaluated using a numerical calculation method. The effect of the changes in girder depth on the coupled vibration of the girder and floor slab was also investigated analytically. As a result, the coupled vibration of the girder and floor slab specific to pure framed structures that contribute to heavy-weight floor impact sound insulation performance was clarified physically.
10
Diep, Hung Thanh, Jiho Moon e Byung H. Choi. "Structural Performance of Prefabricated Composite Girders for Railway Bridges along with Girder-to-Deck Interface Connections for Mechanical Injection". Applied Sciences 13, n. 11 (31 maggio 2023): 6686. http://dx.doi.org/10.3390/app13116686.
Testo completoAbstract (sommario):
Recently, to resolve a growing need for durable and resilient railway bridge construction/reconstruction systems, a great amount of research has been carried out in many countries. As a part of such studies, prefabricated composite girders with an innovative girder-to-deck connection have been proposed that facilitate construction by eliminating interference during on-site processes. In this study, a railway bridge prototype of prefabricated composite girders with girder-to-deck connections was designed to facilitate future application enhancement of off-site construction. Then, prefabricated composite girders were developed by deploying different girder-to-deck connections through geometric detailing of reinforcement, headed stud connectors, and precast decks. Based on the calculation theory of interface shear transfer, the detailed design of different girder-to-deck connections was carried out, in particular the reinforcement spacing. Furthermore, finite element analysis of prefabricated composite girders was conducted to determine the flexural moment strength of prefabricated composite girders. Parametric studies were carried out to consider the factors affecting the detailed design of the connection, ensuring that the connection is correctly designed, thereby ensuring the structural performance of prefabricated composite girders. From the results, conclusions were drawn. The developed cases satisfied the interface shear criteria according to both conventional and plastic approaches. There was no significant difference in flexural moment strength between the developed cases since all cases were designed with the full shear connection. In all cases, the flexural performance was ensured and can be used for railway bridges. The most optimum case of prefabricated composite girders is selected in specific design situations.
11
Chen, Yicong, Jialiang Zhou, Fangzhi Guo, Baochun Chen e Camillo Nuti. "Experimental Study on the Flexural Behaviors of Prestressed Segmental Ultra–High–Performance Concrete Channels and Reinforced Conventional Concrete Deck Composite Girders". Buildings 13, n. 7 (20 luglio 2023): 1841. http://dx.doi.org/10.3390/buildings13071841.
Testo completoAbstract (sommario):
Flexural testing on two prestressed segmental ultra–high–performance concrete channels and reinforced conventional concrete deck composite girders (PSUC–RCCD) was carried out. One was made up of four segments with dry joints, and the other was formed of one channel beam without a dry joint. Both of them poured a conventional concrete deck slab on site. The mechanical behaviors of the girders, including the whole loading process, the crack pattern, and the failure mode were investigated and compared. The effect of the number of segments and the steel fiber volume fraction of UHPC on the bending behavior of the PSUC–RCCD girder was explored using the finite element method. This study showed that the loading process of semi-segmental and integral girders is similar; the whole loading process of the girders can be divided into the elastic phase, crack development, and the failure phase. The only notable difference between the two girders was the stage of crack development; specifically, after cracking, the stiffness of the semi-segmental girder reduced rapidly, while the “bridging effect” of the steel fibers in the integrated girder caused a slow reduction in rigidity. The flexural cracks in the semi-segmental girder were significantly less than those in the integral girder in terms of the number of cracks, and were present only at the joints. The finite element analysis showed that the number of segments had little influence on the flexural capacity of the girders, but the girders with even numbers of segments cracked earlier than those with odd segments. Increasing the steel fiber volume fraction in UHPC (ultra–high–performance concrete) had a small effect on the cracking load of the semi-segmental girders but enhanced its ultimate flexural capacity. Based on this experiment, a calculated method for estimating the flexural capacity of semi-sectional girders was proposed. The calculated values were in good agreement with the experimental and finite element values. In the preliminary design, the flexural capacity of the semi-segmental section could be estimated by multiplying the flexural capacity of the integral section by a resistance factor of 0.95.
12
Alotaibi, Emran, Nadia Nassif, Mohamad Alhalabi, Humam Al Sebai e Samer Barakat. "Numerical investigation on redundancy of bridges with AASHTO I-girders". Bridge Structures 17, n. 1-2 (11 giugno 2021): 41–50. http://dx.doi.org/10.3233/brs-210187.
Testo completoAbstract (sommario):
Bridge safety is one of the most critical concerns among civil engineering fields due to its high importance. The redundancy of bridges was heavily investigated in the literature; however, they were focused on twin girder redundancy cases. Additionally, literatures were scarce in studies that focused on the improvement that should be made to achieve redundancy systems in different AASHTO I-girder types. Thus, this study focused on assessing the additional required number of tendons for different AASHTO I-girder types and spacing between them to achieve the redundancy of I-girder bridges. The additional unbonded tendons are suggested to be added externally or internally. The parameters varied in this study are compressive strength of ultrahigh-performance concrete (UHPC), spacing between girders (i.e. number of girders) and type of girders. Leap Bridge Concrete software was used to simulate the required structural modes. After performing extensive numerical analyses following AASHTO LRFD guidelines, the results have shown that in case of the removal of external I-girder, the tendons in the nearest girder need to be nearly increased by 1.85 to 2.3 times compared to the original design, depending on spacing, compressive strength, and the number of girders. On the other hand, in the case of interior girder removal, the number of tendons in the nearest two girders need to be increased by 1.24 to 1.32 times the original design. The effect of compressive strength variation of the used UHPC was negligible compared to spacing and type of girder. It is worth mentioning that all simulations in this study were verified using CSI Bridge software.
13
Hamood, Mohammed, Wael AbdulSahib e Ali Abdullah. "The effectiveness of CFRP strengthening of steel plate girders with web opening subjected to shear". MATEC Web of Conferences 162 (2018): 04012. http://dx.doi.org/10.1051/matecconf/201816204012.
Testo completoAbstract (sommario):
The present study is experimental by nature; it involves applying shear buckling test on seven steel-plated girders that are subjected to shear loading. Four of these girders represent the strengthened girders whereas the other three are reference girders. One of the latter type of girders has a square web opening; the second has a diamond web opening while the last one has no opening at all. The webs of the strengthened girders were adhesively attached to CFRP sheets of different patterns. This step was carried out to evaluate the most effective strengthening scheme by CFRP composite. The study aims at examining the effect of several parameters on the behavior of web girders. It further examines the percentage of increase in the ultimate shear capacity of the perforated girders that have a fixed location and size where the latter is equal to 40 percent of the web depth. Results have shown that, first, the ultimate shear load of the CFRP-strengthened girders with square web opening is higher than that of the reference girder with a square web opening; ranging from 8.7% to 15.7%. The obtained ranges depend on the orientation of the CFRP strips. Second, the ultimate shear load of the CFRP-strengthened girders with a diamond web opening is higher than the reference girder with a range of 9.8% to 21.5%. Again, the obtained ranges depend on the orientation of the CFRP strips. Analytically speaking, Von Mises stresses have been used to predict the ultimate shear load of girders with square and diamond web openings and without web opening.
14
Mochizuki, Hidetsugu, Katsuhiko Hanada, Tomokazu Nakagawa, Youji Hanawa, Ichiro Yamagiwa, Katsunori Yasuda, Yozo Fujino e Masatsugu Nagai. "Design and Construction of a Cable-Trussed Girder Bridge". Transportation Research Record: Journal of the Transportation Research Board 1696, n. 1 (gennaio 2000): 293–98. http://dx.doi.org/10.3141/1696-30.
Testo completoAbstract (sommario):
Takehana No. 3 Bridge is a cable-trussed girder bridge constructed on a highway route in Shikoku Island, Japan. This is the first application of a cable-trussed girder bridge to a highway bridge in Japan. The cable-trussed bridge (or reversed cable-stayed girder bridge) consists of relatively slender steel plate I-girders, a spatial frame-type post arranged beneath the girders at the middle of the span, and external cables anchored at the ends of the girders. The structural details, static and dynamic characteristics, and design and construction of the bridge are presented. In addition, the efficiency of this type of bridge is emphasized.
15
Naser, Mohannad, e Venkatesh Kodur. "Response of fire exposed composite girders under dominant flexural and shear loading". Journal of Structural Fire Engineering 9, n. 2 (11 giugno 2018): 108–25. http://dx.doi.org/10.1108/jsfe-01-2017-0022.
Testo completoAbstract (sommario):
Purpose This paper aims to present results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading. A finite element-based numerical model was developed to trace the thermal and structural response of composite girders subjected to simultaneous structural loading and fire exposure. This model accounts for various critical parameters including material and geometrical nonlinearities, property degradation at elevated temperatures, shear effects, composite interaction between concrete slab and steel girder, as well as temperature-induced local buckling. To generate test data for validation of the model, three composite girders, each comprising of hot-rolled (standard) steel girder underneath a concrete slab, were tested under simultaneous fire and gravity loading. Design/methodology/approach The validated model was then applied to investigate the effect of initial geometric imperfections, load level, thickness of slab and stiffness of shear stud on fire response of composite girders. Findings Results from experimental and numerical analysis indicate that the composite girder subjected to flexural loading experience failure through flexural yielding mode, while the girders under shear loading fail through in shear web buckling mode. Further, results from parametric studies clearly infer that shear limit state can govern the response of fire exposed composite girders under certain loading configuration and fire scenario. Originality/value This paper presents results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading.
16
Sami Malik, Hawraa, e David A. M. Jawad. "Parametric Study of the Intermediate External Bracing System of Composite Steel Box Girder Bridges". Basrah journal of engineering science 21, n. 1 (1 febbraio 2021): 56–60. http://dx.doi.org/10.33971/bjes.21.1.8.
Testo completoAbstract (sommario):
During the pouring of concrete deck, the installation of external bracing between the inner and outer girders may be necessary when the bridge has sharp curve in order to control the deflection and rotation of the girders. However, it is important to minimize the number of external bracing members, as they have expensive cost and they also have opposite effects for the fatigue features of the steel tub girders. The analysis of curved box girder bridges is carried out numerically by the use of finite element method through (ANSYS 19.2) software. The curved box girder with the intermediate external diaphragms was modeled and the analysis was carried out for many parameters like external bracing sections, girders with or without concrete deck, girders with end diaphragms or without them. The study concluded that ANSYS program has a good ability in evaluating the external bracing force comparing with code equations.
17
Mahmoud, Thamir K., e Musab Aied Qissab Al-Janabi. "Behavior of Spliced Steel Girders under Static Loading". Journal of Engineering 20, n. 10 (9 luglio 2023): 93–109. http://dx.doi.org/10.31026/j.eng.2014.10.07.
Testo completoAbstract (sommario):
In this paper, the behavior of spliced steel girders under static loading is investigated. A group of seven steel I-girders were tested experimentally. Two concentrated loads were applied to each specimen at third points and the load was increased incrementally up to the yield of the specimen. Two types of splices were considered; the bearing type and the friction-grip type splices. For comparison, an analytical study was made for the tested girders in which the finite element analysis program (Abaqus) was used for analysis. It was found that the maximum test load for spliced girders with bearing type splices was in the range of (34%) to (67%) of the maximum test load for the reference girder. For girders spliced by using friction-grip type splices, the maximum test load was in the range of (90%) to (99%) of the maximum test load for the reference girder. The analytical results show a good agreement with the experimental results with a difference in maximum deflection at midspan was not more than (15%) at maximum load for all girders.
18
Waldron, Peter. "The significance of warping torsion in the design of straight concrete box-girder bridges". Canadian Journal of Civil Engineering 15, n. 5 (1 ottobre 1988): 879–89. http://dx.doi.org/10.1139/l88-113.
Testo completoAbstract (sommario):
Out-of-plane warping, resulting from torsional loading, is an important feature of box-girder bridges of thin-walled cross section. This may be of some consequence in girders where warping is restrained, since it may alter the level of stress both around the cross section and along the entire length of the beam. It is well known that some girders with very thin walls are not susceptible to warping, whereas others, with thicker walls, warp significantly when twisted. It is shown that the degree of warping is not governed by wall thickness alone; cross-sectional geometry, girder configuration, and loading must also be considered. The significance of these various factors in estimating the effects of warping restraint is assessed. In many cases this will permit the selection of box-girder cross sections at the conceptual design stage for which torsional warping effects are negligible. A simply supported concrete box girder is used as an example to demonstrate the importance of cross-sectional geometry, girder configuration, and loading in the assessment procedure. This is extended to the more general case of multi-span girders subjected to realistic patterns of loading. Key words: torsion, warping, box-girders, bridges, concrete, design.
19
Hayatdavoodi, Aliakbar, e Nandivaram Elumalai Shanmugam. "Web Buckling and Ultimate Strength of Composite Plate Girders Subjected to Shear and Bending". International Journal of Structural Stability and Dynamics 15, n. 02 (3 febbraio 2015): 1450047. http://dx.doi.org/10.1142/s0219455414500473.
Testo completoAbstract (sommario):
The paper is concerned with ultimate load behavior of steel–concrete composite plate girders subjected to combined action of shear and bending. An analytical method is presented to predict the interactive response of the girder. The method considers the tension field action in the plate girder web panel and shear failure of concrete slab. The method is approximate and can be applied to composite plate girders at the preliminary stages of design. Strength of composite plate girders is investigated by varying the moment/shear ratio. It is shown that ultimate load capacity of composite plate girder is influenced by moment/shear ratio. The predicted results are compared with the corresponding finite-element values.
20
Jahjouh, Mahmoud, e Semih Erhan. "Design Optimization of PCI Girders: A Parametric Study". Bridge Structures 18, n. 3-4 (6 gennaio 2023): 101–11. http://dx.doi.org/10.3233/brs-220203.
Testo completoAbstract (sommario):
This study investigates the effect of superstructure configuration on the optimum design of slab on Precast I (PCI) girder bridges. For this purpose, more than 20,000 bridge cases of varying superstructure configurations are considered to investigate the effects of various superstructure parameters such as girder spacing, span length, slab thickness and girder types on the optimum design of slab on PCI girder bridges. PCI girders are designed conforming to the AASHTO LRFD for flexure using stress limits at the service limit state, then checked at ultimate for flexure and shear using factored loads at the strength limit state. A modified harmony search optimization algorithm is used to obtain optimum bridge design parameters using standard AASHTO PCI girders according to these AASHTO LRFD requirements. Those girders are designed taking into consideration geometrical constraints, stress constraints and constraints related to the conformity of the design with the AASHTO LRFD code. Various sensitivity analysis are performed to investigate the effect of different geometrical factors on the design of the girders, and easy-to-use design aids were developed. The outcomes of this study may facilitate the bridge engineers to choose optimum design parameters such as girder types and spacing as well as number strands for a certain span length before the design of slab on PCI girder bridges.
21
Borzovič, Viktor, Ján Laco, Miroslav Pecník e Peter Pažma. "The Crack Development Mechanism of Prestressed Girder Influenced by Different Bond between Prestressed Tendons and Concrete". Key Engineering Materials 691 (maggio 2016): 309–20. http://dx.doi.org/10.4028/www.scientific.net/kem.691.309.
Testo completoAbstract (sommario):
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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Rashid, Muhammad U., Liaqat A. Qureshi e Muhammad F. Tahir. "Investigating Flexural Behaviour of Prestressed Concrete Girders Cast by Fibre-Reinforced Concrete". Advances in Civil Engineering 2019 (1 aprile 2019): 1–11. http://dx.doi.org/10.1155/2019/1459314.
Testo completoAbstract (sommario):
The main objective of this research was to investigate the effect of adding polypropylene and steel fibres on flexural behaviour of prestressed concrete girders. Although the construction industry is frequently using prestressed concrete to increase the load-carrying capacity of structures, it can be further enhanced by using fibres. In this paper, experimental work was carried out to encourage the construction industry in utilizing fibres in prestressed concrete members to improve the mechanical properties of these members. As past investigations on fibre-reinforced prestressed beams were limited, the present work was done on small-scale fibre-reinforced I-shaped prestressed concrete girders. Six small-scale prestressed concrete girders were cast comprising a control girder, a hybrid girder, two girders with varying percentages of steel fibres, and two girders with varying percentages of polypropylene fibres. These girders were tested by centre point loading up to failure. It was concluded that, by the addition of small volume fraction of fibres, not only the ductility but also the tensile strength and flexural strength of FRC girders could be improved. It also altered the failure pattern positively by enhancing large strains in concrete and steel. Steel fibre-reinforced concrete showed higher energy absorption and deflection at ultimate loads in comparison to other specimens.
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Xu, Fen, Yikai Cheng, Kangjian Wang e Man Zhou. "Transverse Analysis of Box Girders with Corrugated Steel Webs". Buildings 14, n. 3 (21 febbraio 2024): 574. http://dx.doi.org/10.3390/buildings14030574.
Testo completoAbstract (sommario):
The utilisation of box girders with corrugated steel webs (CSWs) represents an innovative approach to bridge superstructure design that has garnered substantial popularity worldwide, with a notable prevalence in both Asia and Europe. Compared with traditional box girders, they avoid web cracking, improving the prestressing efficiency and bridge spanning ability. As an innovative box girder, a corrugated web can increase the cantilever length and transverse stiffness, and at the same time, it reduces the dead weight of the bridge deck. However, little research has been conducted on the mechanical properties of this novel spine-like box girder with CSWs, especially its transverse performance, although it has been used in many applications. In this paper, the effect of the web form on the behaviour of box girders is introduced. Therefore, three representative three-dimensional (3D) finite-element models (i.e., corrugated web box girder, flat web box girder, and ordinary equivalent concrete web box girder) have been established to quantitatively investigate the influence of corrugated web stiffness on transverse stress under the action of gravity and vehicle loads. Generally, significant differences in the mechanical performance of box girders with CSWs have been observed compared with conventional box girders with concrete webs. Additionally, parametric studies to investigate the influences of the corrugation dimensions (in term of the corrugation height, web thickness, panel width, web height and elastic modulus) on the transverse stiffness of such bridges are analyzed. The results show that a new stiffness formula can be put forward to consider the effect of web height, and a high-strength steel web needs to be developed urgently for box girders with CSWs in the near future. Overall, the results of this investigation can be used as a reference for transverse designing and segmental construction of similar projects.
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Liu, Jie, Xiangyu Huang, Juanjuan Chen e Qiaoyun Wu. "Effect of Shear Deformation at Segmental Joints on the Short-Term Deflection of Large-Span Cantilever Cast Prestressed Concrete Box Girders". Buildings 13, n. 1 (12 gennaio 2023): 219. http://dx.doi.org/10.3390/buildings13010219.
Testo completoAbstract (sommario):
The excessive deflection of large-span cantilever cast prestressed concrete (LCCPC) box girders has always been a complex problem to be solved in bridge engineering. To analyze the effect of shear deformation at segmental joints on the deflection of LCCPC box girders, comparison tests were carried out on three prestressed concrete (PC) I-girders with joints and a PC I-girder without joints, and a finite element simulation method of segmental joints was proposed based on the tests. Subsequently, finite element analysis was conducted on a test girder and the Assistant Shipping Channel Bridge of Humen Bridge (a PC continuous rigid frame bridge with a main span of 270 m) using this method. The experimental and theoretical analysis results showed that the effect of the shear deformation at joints compared to the deformation at midspan of the girder specimens was negligible. Deformation at midspan of the specimens would not significantly increase, even if shear rigidity at the joints was significantly reduced or there were more joints in the girder specimen. The effect of shear deformation at segmental joints on the deflection of LCCPC box girders was quite small and thus insignificant.
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Snyder, Russell D. "Prestressed Steel Girders for Single Span Bridges". Engineering Journal 32, n. 3 (30 settembre 1995): 83–86. http://dx.doi.org/10.62913/engj.v32i3.648.
Testo completoAbstract (sommario):
Long single span bridges are becoming more common on today's highway systems. The span lengths of these bridges grow as the widths of the underlying roadways increase to accommodate larger volumes of traffic and the use of intermediate supports in the underlying median are discouraged to allow for future widening of the roadway or mass transit corridors. Span lengths of 150 to 250 feet are not uncommon and typically require the use of steel plate girders. Since these simple spans have no benefit of continuity at the supports, the required plate sizes tend to be rather large. One method to reduce the size of the plates and thus the overall amount of steel needed for each girder is prestressing. Just as the load carrying ability of a concrete beam is enhanced by the application of prestressing, the required size of a steel girder may be reduced in comparison to its conventional counterpart. Prestressed steel girders are not a new idea, in fact eastern European designers have used prestressed steel girders for quite some time. The major application in the United States has been in the area of bridge rehabilitation. This paper summarizes the economic advantages of utilizing prestressed steel girders for proposed single span bridges by comparing conventionally designed girders to prestressed girders. The comparative analysis will report differences in material usage and will discuss the effects of the differential cost of construction and the intangible benefits of the prestressed girder alternative.
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Vinh Ha, Ho, Nguyen Ngoc Long e Ngo Van Minh. "Theoretical calculation of bending capacity of a steel beam - ultra high performance concrete slab composite girder". Transport and Communications Science Journal 74, n. 4 (15 maggio 2023): 497–506. http://dx.doi.org/10.47869/tcsj.74.4.9.
Testo completoAbstract (sommario):
The composite girder, which combines a steel beam with an ultra-high-performance concrete (UHPC) slab, has gained significant attention in recent years as a new type of bridge structure. However, accurately estimating the bending capacity of such girders remains a challenge, as practical methods are limited. In this article, the authors propose a theoretical approach based on the Euler-Bernoulli beam theory to determine the bending capacity of composite girders. This approach considers the assumptions of plane sections remaining plane and infinitesimal strains during bending. By applying this theoretical approach, the authors derive a formula that allows engineers to calculate the bending capacity of the composite girder. The formula takes into account the dimensions and properties of both the steel beam and the UHPC slab. The derived formula serves as a valuable tool for evaluating the structural behavior and performance of composite girders. To validate its accuracy, the authors compare the results obtained from their calculations with numerical simulations of composite girder failures caused by bending. The close agreement between the theoretical calculations and the numerical simulation results confirms the reliability and applicability of the proposed formula. This research significantly contributes to the field of composite girder design by providing a practical and reliable method for estimating the bending capacity of steel beam-UHPC slab composite girders. The proposed theoretical approach, validated through numerical simulations, offers valuable insights for the design and optimization of these composite girders in various engineering applications.
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Sali, Jefeena, e Regi P. Mohan. "Parametric Study of Single Cell Box Girder Bridge under Different Radii of Curvature". Applied Mechanics and Materials 857 (novembre 2016): 165–70. http://dx.doi.org/10.4028/www.scientific.net/amm.857.165.
Testo completoAbstract (sommario):
Box girders are now prominently used in freeway and bridge systems because of its structural efficiency, better stability, serviceability, economy of construction and pleasing aesthetics. Due to its high torsional rigidity box girders are most suited for curved bridges. In the present investigation, a comparative study of straight and curved box girder bridges with trapezoidal cross section has been carried out. The analysis is carried under the dead load, super imposed dead load, live load of IRC Class A tracked vehicle and prestressed load .This paper focus on the parametric study of box girders with different radius of curvature by keeping the span, cross sectional shape and material properties constant. The parametric investigations performed on curved box girders helps to evaluate the effects of change in radius of curvature on the behaviour of the box girders. This study would help the bridge engineers to better understand the behaviour of straight and curved box girder bridges. The results obtained from this study will be a valuable guidance to the bridge designers.
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Li, Li, Yu Lu e Miaojuan Peng. "Deterioration Model for Reinforced Concrete Bridge Girders Based on Survival Analysis". Mathematics 10, n. 23 (24 novembre 2022): 4436. http://dx.doi.org/10.3390/math10234436.
Testo completoAbstract (sommario):
The prediction of bridge service performance is essential for bridge maintenance, operation, and decision making. As a key component of the superstructure, the performance of the main girders is critical to the structural safety of the bridge. This study makes full use of the inspection records from the Bridge Management System (BMS) in Shanghai and performs pre-processing work on a large amount of data. Recent advances in survival analysis were utilized to investigate the inspection records of over 40,000 reinforced concrete bridge main girders over a 14-year period. Survival analysis methods based on the Weibull distribution were used to predict the service performance of the main girders, and, in addition, a COX proportional hazards model was used to analyze the effect of different covariates on the survival of the main girders. The results show that the deterioration rate of main girders increases with age, with an average life of 87 years for main girders in Shanghai. The grade of the road on which the bridge is located and the position of the main girder in the bridge superstructure have a significant impact on the probability of survival of the main girder. It can be concluded that more attention should be paid to the inspection and maintenance of side girders on branch roads to reduce the pressure on bridge management in the future. Furthermore, the analysis in this study found that the deterioration rate of the main girders is faster than the deterioration rate of the whole bridge and superstructure, and, therefore, more attention and necessary preventive maintenance measures should be taken in the maintenance and management of the main girders.
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Stojkovski, Valentino, Viktor Iliev e Filip Stojkovski. "Nаdоgrаdnjа sistеmа zа hlаđеnjе vоdоm sа mоgućnоstimа ispirаnjа". Energija, ekonomija, ekologija 23, n. 2 (2021): 48–56. http://dx.doi.org/10.46793/eee21-2.48s.
Testo completoAbstract (sommario):
This paper presents an analysis of the operating parameters of a water cooling system of the structural part of a furnace for rolling mills preparation. The structural solution of the cooling system is performed as flow, with a constant inflow of fresh water and drainage from the system. Four longitudinal pipes are installed, which are supported by vertical girders. Vertical girders should provide thermal stability to ensure pipe- plate horizontality. The vertical girders are regularly connected to the cooling system by placing pipes direct into the vertical girder, which engages the part of the water supply that cools the vertical girder, and the same water is returned to the cooling system and continuously transferred to the next girder. During operation, due to the quality of cooling water that is not chemically treated, calcium carbonate is formed; the presented impurities clog the flow channels of the cooling system in the vertical girders. The application of CFD analysis reveals the conditions of water flow in the cooling system of vertical girders. From the analysis of the obtained results, it is proposed to upgrade the existing system by installing a flushing system, which will ensure a directed and controlled inflow in the zones of the cooling system. The conceptual solution for the flushing system and the effects of its operation are given in this paper.
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Song, Chaojie, Gang Zhang, Wei Hou e Shuanhai He. "Performance of prestressed concrete box bridge girders under hydrocarbon fire exposure". Advances in Structural Engineering 23, n. 8 (3 gennaio 2020): 1521–33. http://dx.doi.org/10.1177/1369433219898102.
Testo completoAbstract (sommario):
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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Gan, Ya-Nan, Zi-Chen Zhang e Gen-Hui Wang. "The Multi-Functional Modelling Shear Lag Method for Accurate Calculation of Static Response and Accordion Effect of Improved Composite Box Girders". Baltic Journal of Road and Bridge Engineering 18, n. 1 (28 marzo 2023): 1–17. http://dx.doi.org/10.7250/bjrbe.2023-18.586.
Testo completoAbstract (sommario):
The composite box girder with corrugated web and steel bottom plate (CW-SBS) is a kind of improved steel-concrete structures. The design of CW-SBS box girders needs the accurate method to calculate the working response and accordion effect in consideration of the self-stress equilibrium condition of shear lag warping stress and shear deformation. This study proposes the multi-functional modelling shear lag (MFMSL) method which adopts the four longitudinal displacement difference functions to model the variation of shear lag in the CW-SBS box girders with different wing slab widths and thicknesses. Therefore, MFMSL is a method to calculate the static response and accordion effect of the CW-SBS composite box girders. Structural differential equations based on the energy-variation principle present that the MFMSL method effectively improves the calculating accuracy of the CW-SBS box girder static response, which can be verified by both experimental and simulative results. Also, the MFMSL method demonstrates that the accordion effect of the CW-SBS box girder is stronger than that of the traditional composite box girder and closely relates to the load distribution. Hence, the proposed method further lays the foundation for the analysis and design of CW-SBS box girders.
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Tepic, Jovan, Rade Doroslovacki e Mirko Djelosevic. "Unconventional Bearing Capacity Analysis and Optimization of Multicell Box Girders". Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/496398.
Testo completoAbstract (sommario):
This study deals with unconventional bearing capacity analysis and the procedure of optimizing a two-cell box girder. The generalized model which enables the local stress-strain analysis of multicell girders was developed based on the principle of cross-sectional decomposition. The applied methodology is verified using the experimental data (Djelosevic et al., 2012) for traditionally formed box girders. The qualitative and quantitative evaluation of results obtained for the two-cell box girder is realized based on comparative analysis using the finite element method (FEM) and the ANSYS v12 software. The deflection function obtained by analytical and numerical methods was found consistent provided that the maximum deviation does not exceed 4%. Multicell box girders are rationally designed support structures characterized by much lower susceptibility of their cross-sectional elements to buckling and higher specific capacity than traditionally formed box girders. The developed local stress model is applied for optimizing the cross section of a two-cell box carrier. The author points to the advantages of implementing the model of local stresses in the optimization process and concludes that the technological reserve of bearing capacity amounts to 20% at the same girder weight and constant load conditions.
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Abbas, Rafa'a Mahmood, e Zainab Saadi Qassem. "Load Distribution Factors For Horizontally Curved Composite Concrete-Steel Girder Bridges". Journal of Engineering 19, n. 2 (16 maggio 2023): 167–79. http://dx.doi.org/10.31026/j.eng.2013.02.01.
Testo completoAbstract (sommario):
This paper focuses on Load distribution factors for horizontally curved composite concrete-steel girder bridges. The finite-element analysis software“SAP2000” is used to examine the key parameters that can influence the distribution factors for horizontally curved composite steelgirders. A parametric study is conducted to study the load distribution characteristics of such bridge system due to dead loading and AASHTO truck loading using finite elements method. The key parameters considered in this study are: span-to-radius of curvature ratio, span length, number of girders, girders spacing, number of lanes, and truck loading conditions. The results have shown that the curvature is the most critical factor which plays an important role in the design of curved girders in horizontally curved composite bridges. Span length, number of girders and girder spacing generally affect the values of the moment distribution factors. Moreover, present study reveals that AASHTO Guide criterion to treat curved bridges with limited curvature as straight one is conservative. Based on the data generated from the parametric study, sets of empirical equations are developed for the moment distribution factors for straight and curved steel I-girder bridges when subjected to the AASHTO truck loading and due to dead loading.
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Qiao, Peng, Jin Di e Feng-jiang Qin. "Warping Torsional and Distortional Stress of Composited Box Girder with Corrugated Steel Webs". Mathematical Problems in Engineering 2018 (2018): 1–13. http://dx.doi.org/10.1155/2018/7613231.
Testo completoAbstract (sommario):
The torsional behaviors of composite box girders with corrugated steel webs are more obvious than traditional concrete girders due to the lower torsional rigidity. In this paper, the torsion and distortion of this kind of composite girder are studied. The formulas for warping normal stress and shear stress were put forward according to the second theory of Umanskii, considering the accordion effect of corrugated steel webs. Then, the influences of different dimensional parameters on the torsional and distortional stress are investigated. Results show that the effect of parameters on stress is different and implicit in composite box girders with corrugated steel webs. Under eccentric loads, the warping torsional and distortional stress in this kind of girder should not be neglected. Compared with girders under corresponding symmetric loads, the total warping stress may be as big as flexural normal stress, and the total shear stress usually reaches 30 to 50 percentage of flexural shear stress. So the warping stress and additional shear stress due to warping torsion and distortion are suggested to be calculated by the proposed equations in structural analysis, which are usually not taken into account in conventional concrete box girders.
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Wang, Zhiqiang, Tiantian Li, Hongya Qu, Hongyi Wei e Yang Zhang. "Seismic performance comparison of precast segmental bridge girders with different cross sections and boundary conditions under vertical quasi-static cyclic testing: An experimental investigation". Advances in Structural Engineering 21, n. 12 (28 febbraio 2018): 1936–48. http://dx.doi.org/10.1177/1369433218759780.
Testo completoAbstract (sommario):
In this study, five 1/5-scale bridge girder specimens are tested with vertical quasi-static cyclic loading, in order to understand their performance in high seismic zones. The study is focused on the superstructures at two critical regions: (1) close to mid-span where high moments and low shears are present (2) and close to the supports where high negative moments and high shears are induced. The first case includes one precast segmental bridge box-girder, one precast segmental bridge I-girder, and one reference cast-in-place I-girder, while the second case consists of one precast segmental bridge I-girder and one cast-in-place I-girder. The ratios of the internal and external tendons are 1:1 for case 1 and 3:5 for case 2, respectively. Test results show that cast-in-place girders have better energy dissipation capacity and higher ultimate strength, but the precast segmental girders retain larger displacement capacity and self-centering capability. Internal post-tensioning tendons are subjected to more significant stress concentration at the joint locations of the precast segmental girders, while stress of external tendons is distributed more evenly. In terms of vertical loading, box-girder and I-girder possess similar hysteretic behaviors, as long as the effective widths are the same.
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Ashiquzzaman, Md, Li Hui, Ahmed Ibrahim, Will Lindquist, Nader Panahshahi e Riyadh Hindi. "Exterior girder rotation of skew and non-skew bridges during construction". Advances in Structural Engineering 24, n. 1 (30 luglio 2020): 134–46. http://dx.doi.org/10.1177/1369433220945061.
Testo completoAbstract (sommario):
In bridge design, bridge decks regularly overhang past the exterior girders in arrange to extend the width of the deck whereas constraining the specified number of girders. The overhanging part of the deck comes about in uneven eccentric loads to the exterior girders which are by and large most prominent. These eccentric loads are primarily a result of bridge construction operations as well as the weight of new concrete and other construction live loads. These unbalanced loads can lead to a differential edge deflection of overhang deck and a rotation of the exterior girders. The girder rotation or differential deck deflection can also affect local and global stability of the entire bridge. The objective of this study is to enhance the knowledge and understanding of external girder behavior due to unbalanced eccentric construction loads and to identify the critical factors affecting their rotation. In this article, field data obtained during the construction of two skewed (one with a small skew (3.8°) and the second with a severe skew (24°)) and one non-skewed steel girder bridges are described, and a detailed comparison is presented. The three bridges experienced maximum outward exterior girder rotation during construction which subsequently decreased following construction operations. The field results were used to validate and calibrate the finite element models. The numerical and field-monitored data showed good agreement and can be used to assist bridge designers and construction engineers to design appropriate systems to limit girder rotation during construction.
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Anderson, Katherine E., e Ken P. Chong. "Least Cost Computer-aided Design of Steel Girders". Engineering Journal 23, n. 4 (31 dicembre 1986): 151–56. http://dx.doi.org/10.62913/engj.v23i4.476.
Testo completoAbstract (sommario):
Hybrid steel beams, used for over a quarter of a century, have evolved through many theories of design criteria. In this paper, emphasis is placed on stiffened hybrid girders, although unstiffened and homogeneous girders are also included as special cases. AISC has developed specifications to which a steel member must perform. The formulas in the specifications, however, do not define explicitly the best girder to do a particular structural task. Instead, a "region" is defined which contains a large number of acceptable girders from which the designer must choose. Even when a computer is used for the design, unless special programming is implemented, the output is an acceptable non-optimized region from which the final choice is made. By equipping the design procedure with the ability to rank the acceptable choices by cost or weight, an optimized girder can be located within the region. This ranking process should include the cost and availability factors for several steel grades so that a hybrid girder, having the lowest cost, can be found. Likewise, by including labor costs for manufacturing steel girders, the feasibility of using web stiffeners can also be determined. The innovative design method which follows incorporates the AISC Specifications5 and extends the techniques developed by Ken P. Chong for unstiffened built-up steel sections. The goal of the design process is to define the geometry of the girder by optimizing a particular function, which, in this case, is the depth of the girder.
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Yang, Yang, e Tijun Qiu. "Study on flexural load bearing performance of small radius steel plate composite girder bridge". E3S Web of Conferences 490 (2024): 02010. http://dx.doi.org/10.1051/e3sconf/202449002010.
Testo completoAbstract (sommario):
The study of flexural load capacity of small radius steel plate composite girder bridges is of great academic and engineering value. This study is based on an actual engineering project and modelled by MIDAS finite element software, aiming to explore the limit states of load carrying capacity of small radius steel plate girder bridges under various conditions. The results show that under different radii of curvature, the flexural performance of the inner and outer main girders is similar, and as the radius of curvature increases from R100 to R400, the maximum positive stress of the combined girder bridge changes less and does not exceed its resistance value, revealing the low sensitivity of flexural load carrying capacity to the radius of curvature. While the load carrying performance of inner and outer main girders is still similar when examining different calculated span diameters, the adverse effect of the positive temperature gradient on the flexural performance is more obvious, which makes the flexural load carrying capacity show a high sensitivity to the change of the calculated span diameter. Finally, when different numbers of main girders are considered, the positive stress values of each main girder are similar, and the sensitivity of the flexural capacity to the number of main girders remains low despite the relatively unfavourable effect of the positive temperature gradient. The study of flexural capacity of small-radius steel plate composite girder bridges is of great significance for the structural design and safety assessment of bridges.
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Hazairin, Hazairin, Euneke Widyaningsih e Nafisah Noor Sakinah. "Analisis Perbandingan Biaya Penggunaan Steel Box Girder Berdasarkan Variasi Jumlah dan Dimensi (Studi Kasus: Jembatan Cimanuk Maktal)". RekaRacana: Jurnal Teknil Sipil 8, n. 1 (14 aprile 2022): 13. http://dx.doi.org/10.26760/rekaracana.v8i1.13.
Testo completoAbstract (sommario):
ABSTRAKBiaya merupakan salah satu hal penting dalam perencanaan konstruksi. Faktor utama yang mempengaruhi biaya adalah dimensi dan jenis material konstruksi. Penentuan dimensi dan jenis material beracuan pada persyaratan yang berlaku. Namun persyaratan tersebut hanya memberikan rentang minimum dan maksimum. Maka perlu dilakukan perbandingan biaya terhadap rentang dimensi tersebut. Dalam kasus ini perhitungan struktur yang dilakukan adalah perhitungan girder jembatan. Dilakukan perhitungan biaya pada 4 variasi dimensi steel box girder. Dari hasil analisis didapatkan girder dengan dimensi 2 x 2 meter sebanyak 2 buah girder membutuhkan biaya sebesar Rp1.835.431.964,00. Dimensi 2,3 x 2,3 meter sebanyak 2 buah girder membutuhkan biaya sebesar Rp2.115.116.834,00. Untuk dimensi 1,5 x 1,6 meter, terdapat 3 buah girder dan membutuhkan biaya sebesar Rp2.294.289.955,00. Dimensi 1 x 1,2 meter membutuhkan sebanyak 4 buah girder dengan biaya sebesar Rp2.377.321.400,00. Maka girder dengan biaya paling rendah adalah girder dengan dimensi 2 x 2 meter.Kata kunci: steel box girder, estimasi biaya, perancangan struktur ABSTRACTCost is one of the most important things in construction planning. The main factors that affect the cost are the dimensions and the types of construction materials. Determination of dimensions and types of materials refers to the standard. However, the standard only provide the minimum and maximum range of dimension. So it is necessary to compare the costs from the range of dimensions. In this case the calculation of the structure which conducted is the calculation of the bridge girder. Cost calculations were conducted on 4 variations of the steel box girder dimensions. From the analysis, it was found that 2 girders with dimension of 2 x 2 meters require a cost of Rp1,835,431,964,00. Dimension of 2.3 x 2.3 meters as many as 2 girders require a cost of Rp2.115.116.834.00. For the dimension of 1.5 x 1.6 meters, there are 3 girders and they costs Rp2,294,289,955.00. Dimension of 1 x 1.2 meters need 4 pieces of girders and require a cost of Rp2,377,321,400.00. To conclude, the girder with the lowest cost is the girder with the dimension of 2 x 2 meters.Keywords: steel box girder, cost estimation, structure design
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Wexler, Neil. "Composite Girders with Partial Restraints: A New Approach". Engineering Journal 30, n. 2 (30 giugno 1993): 68–75. http://dx.doi.org/10.62913/engj.v30i2.611.
Testo completoAbstract (sommario):
Most designs for buildings with steel frames are based on girders with simple connections. To eliminate the problems associated with traditional construction (such as deep and heavy girders and large deflections during construction) structural engineers have been searching for a new design system for a long time. The stub girder system is one example of such efforts. However, the stub girder system proved to be uneconomical for most common buildings. A new and different approach to composite steel/concrete designs was undertaken by the writer resulting in light building frames and cost savings. This new design system is called partial Restraint Girder System ("RGS") (Figure 1). (A composite section is obtained in buildings with metal deck and concrete floors by welding steel studs to the top flange.) With RGS two types of restraint are possible: the first makes use of moment connections to columns; the second includes concrete reinforcement. In buildings utilizing composite girders, deflections were controlled by either shoring, camber, or further increase in girder size. RGS has arisen as a viable and cost effective alternative. In traditional designs, the engineer determined the buildings moment diagram from a moment distribution or stress analysis. In the RGS method, the Structural Engineer can control the maximum and minimum values of moment on the moment diagram (the governing design values) from the outset to fit his design, by establishing the amount of restraint. Although composite girders with partial restraints improve the moment resistance of composite girders significantly, such design is commonly ignored and the codes of practice give no guidance as to procedures that might take advantage of the improved properties.
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Chen, Jing Xi, Guang Zhang, Hong Fei Li e Fa Min Chen. "Experimental Study on Mechanical Behaviors of the Prestressed Concrete Girder". Key Engineering Materials 348-349 (settembre 2007): 361–64. http://dx.doi.org/10.4028/www.scientific.net/kem.348-349.361.
Testo completoAbstract (sommario):
The prestressed concrete girder is a new type of bridge structure. Compared with the traditional concrete girders, its crack resistance has been greatly improved. This type of new girders was used in a certain viaduct in China. In order to probe working characteristics of this type of new girders, some site tests, such as tension-camber test, concentrated load test, uniform load test and mixed load test, were carried out. The results of the tests are analyzed and summed up in this paper.
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Du, Jin Sheng, e Hai Bin Liu. "Effect of Pier Vertical Deformations on Deflections of Main Girders for High Pier and Long-Span Continuous Rigid-Frame Bridges". Advanced Materials Research 163-167 (dicembre 2010): 1436–39. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1436.
Testo completoAbstract (sommario):
In some long-span prestressed concrete box girder bridges, excessive deflections of main girders are often observed. These unacceptable deflections have detrimental influence on the serviceability and safety of the structures. To better understand and estimate short term and long term deflections for prestressed concrete box girder bridges, pier vertical deformation and its effect on deflections of main girders of Jinghe Bridg is investigated in this paper. Piers in Jinghe Bridge are tall and the difference in height between piers up to 22 m. Analysis indicates that although the short term deformations of piers are small, the long term deformations of piers can be 3 times as large as that of short-term ones. The maximum short-term downward deflection of Jinghe Bridge caused by pier deformation for main girders is 7.7 mm and the maximum long-term downward deflection is 33.3 mm. These values are relatively small compared with the span length of the bridge. But when the deflection of the main girder itself is also included, the final total deflection of the main girder may exceed the design code limit.
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Kazemi, M. T., e S. Erfani. "Analytical study of special girder moment frames using a mixed shear–flexural link element". Canadian Journal of Civil Engineering 34, n. 9 (1 settembre 2007): 1119–30. http://dx.doi.org/10.1139/l07-037.
Testo completoAbstract (sommario):
The present paper introduces a mixed shear–flexural (VM) link element that is capable of modelling shear yielding, flexural yielding, and their interaction under monotonic and cyclic loadings. The inelastic deformations are modelled using the multisurfaces approach with dissimilar yield surfaces and a stiffness matrix with nonzero off-diagonal components in shear–flexural space. A new kinematic hardening and new non-associated flow rules are employed. A special girder, which has an open web in the middle, is introduced and modelled using the developed VM link element. It is shown that the results of analyses using the VM link element are in good agreement with those from a finite element analysis. Nonlinear dynamic analyses are performed on a benchmark ordinary moment frame (OMF) and its improved versions with special girders. The special girder moment frame (SGMF), which consists of special girders at the lower storeys and ordinary girders at the roof level, has better seismic performance.Key words: mixed shear–flexural (VM) link element, inelastic zone, shear–flexural interaction, cyclic loading, multisurface, special girder, special girder moment frame (SGMF), ordinary moment frame (OMF).
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Lee, Jung Woo, Chang Joh, E. S. Choi, I. J. Kwak e Byung Suk Kim. "Estimation of Shear Behavior of Ultra High Performance Concrete I Girder without Shear Stirrups". Key Engineering Materials 525-526 (novembre 2012): 557–60. http://dx.doi.org/10.4028/www.scientific.net/kem.525-526.557.
Testo completoAbstract (sommario):
Thinner and lighter members can be designed by utilizing the high stiffness and toughness, and high compressive strength of Ultra High Performance Concrete (UHPC), which reaches up to 180MPa. This high strength and ductile tensile behavior of UHPC makes it possible to design the web of the UHPC I Girder without conventional shear stirrups, which makes the UHPC I girder slender, light and economical. However, establishing shear design procedure for UHPC I girders without stirrups requires additional theoretical and experimental studies. This paper investigated shear behavior of UHPC I girder without shear stirrups. The test results show, in spite of no shear stirrups, test specimens have high ductility due to the bridging action of steel fibers against crack opening. UHPC I girders without shear stirrups tested show gradual increase of strength after initial cracking instead of brittle loss of strength as expected from the ordinary reinforced concrete I girders without stirrups. The decrease of the shear span-depth ratio increase the shear strength of the UHPC I girder without stirrups.
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Fisher, James M., e Julius P. Van de Pas. "New Fatigue Provisions for the Design of Crane Runway Girders". Engineering Journal 39, n. 2 (30 giugno 2002): 65–73. http://dx.doi.org/10.62913/engj.v39i2.777.
Testo completoAbstract (sommario):
Proper functioning of bridge cranes is dependent upon proper crane runway girder design and detailing. The runway design must account for the fatigue effects caused by the repeated passing of the crane. Runway girders should be thought of as a part of a system comprised of the crane rails, rail attachments, electrification support, crane stops, crane column attachment, tie back and the girder itself. All of these items should be incorporated into the design and detailing of the crane runway girder system. Engineers have designed crane runway girders that have performed with minimal problems while being subjected to millions of cycles of loading.
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Zhou, Yongjun, Yu Zhao, Hengying Yao e Yuan Jing. "Full-Scale Experimental Investigation of the Static and Dynamic Stiffness of Prestressed Concrete Girders". Shock and Vibration 2019 (4 dicembre 2019): 1–13. http://dx.doi.org/10.1155/2019/7646094.
Testo completoAbstract (sommario):
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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Liu, Sumei, Hanshan Ding, Luc Taerwe e Wouter De Corte. "Shear Strength of Trapezoidal Corrugated Steel Webs for Horizontally Curved Girder Bridges". Applied Sciences 9, n. 9 (12 maggio 2019): 1942. http://dx.doi.org/10.3390/app9091942.
Testo completoAbstract (sommario):
Curved composite girder bridges with corrugated steel webs (CSWs) have already been constructed around the world. However, limited work has been done on their shear behavior. In this paper, the corrugated steel web (CSW) in horizontally curved girders (HCGs) is treated as an orthotropic cylindrical shallow shell, and the analytical formula for the elastic global shear buckling stress is deduced by the Galerkin method. Calculation tables for the global shear buckling coefficient for a four-edge simple support, for a four-edge fixed support, and for the two edges constrained by flanges fixed and the other two edges simply supported are given. Then, a parametric study based on a linear buckling analysis is performed to analyze the effect of the curvature radius and girder span on the shear buckling stress. Analytical and numerical results show that the difference of shear buckling stress of CSWs between curved girders and straight girders is small, so the shear design formulas for straight girders can be applied for curved girders. Finally, a series of tests were performed on three curved box girders with CSWs. Similar to CSWs in straight girders, the shear strain distributions of CSWs in HCGs are almost uniform along the direction of the web height and the principal strain direction angles are close to 45°. For the three specimens, CSWs carry about 76% of the shear force. In the destructive test, shear buckling after yielding occurred in all specimens which is in good agreement with the theoretical prediction, which means that the analytical formulas provide good predictions for the shear buckling stress of CSWs in HCGs and can be recommended for design purposes.
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Kettler, Markus, e Harald Unterweger. "Stress increases in crane runway girders due to rail joints". ce/papers 6, n. 3-4 (settembre 2023): 1748–53. http://dx.doi.org/10.1002/cepa.2306.
Testo completoAbstract (sommario):
AbstractVertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce two types of stresses in crane runway girders: i) global stresses due to bi‐axial bending and torsion and ii) local stresses which mainly affect the girder's web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically connected to the top flange with rail clips. These clips maintain the position of the rail in vertical and horizontal transverse direction, but they generally allow for longitudinal movement of the rail. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as finite element calculations. The aim of the investigations is to develop a better understanding of the mechanical behaviour in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint.
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Zhu, Lanying, Yuanzhang Yang, Zhijun Wang e Mengli Song. "Stability Analyses of the Upper Chord Tubes of Light Gauge Steel–Oriented Strand Board Composite Truss Girders". International Journal of Structural Stability and Dynamics 16, n. 01 (gennaio 2016): 1640012. http://dx.doi.org/10.1142/s0219455416400125.
Testo completoAbstract (sommario):
Light Gauge Steel (LGS) square tube truss girders with Oriented Strand Board (OSB) have larger bending stiffness and flexural capacities than the LGS square tube girders without OSB. In this paper, one LGS square tube truss girder without OSB and five composite LGS truss girders with OSB were tested under monotonic static loading to study the effects of OSB arrangements and screw distributions on the failure mode and flexural capacities of composite girders. Test results show that the failure mode of LGS–OSB composite truss girders tends to be local buckling of the upper chord tubes, and the ultimate bearing capacities of the composite girders are controlled by the stability of the upper chord tubes. LGS–OSB composite truss girders have higher bearing capacities than the truss girders without OSB. The thicker the OSB is, the larger the bearing capacity is. With the same OSB thickness, the number of layers and the orientation of OSB have little influence on the bearing capacities of LGS–OSB composite truss girders. Considering material, geometry and contact nonlinearities, the experimental tests were simulated using ABAQUS, and the simulation results agree well with the test observations. Finally, in order to obtain the ultimate bearing capacities of LGS–OSB composite truss girders, the modified methods for determining the effective areas and inertia moments (or sectional moduli) of the upper chord tube are proposed according to AISI S100-2007 and GB50018-2002.
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Li, Xue Min, Er Yu Zhu, Yong Zheng Zhou e Yue Hong Qin. "Research on the Key Technology in Steam Curing for 32m Simple-Supported Box Girder of High-Speed Railway". Applied Mechanics and Materials 90-93 (settembre 2011): 958–63. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.958.
Testo completoAbstract (sommario):
In the process of steam curing to high-speed railway’s simply-supported box girder, there are some problems must be faced such as the difficulty to determine steam curing system and to achieve automatic temperature control. With the construction site conditions of simple-supported box girder in Longwang beam field which is located on Shijiazhuang-Wuhan (Shi-Wu) section of Beijing-Guangzhou high-speed railway, the paper proposes the appropriate steam system for simply-supported box girders, determines the appropriate equipments, explores the temperature control system in the process of steam curing to the simply-supported box girder's concrete, and takes the temperature test of steam curing in the field. Results show that, the steam curing technology in this paper can increase the production efficiency of beam in production site, and effectively guarantee the prefabricated quality of simply-supported box girder.