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1
Abdul Salam, Ayisha Sana, e Anila S. "Response of T Beam Bridge by Varying Skew Angle". Journal of Recent Activities in Infrastructure Science 9, n. 2 (10 luglio 2024): 22–26. http://dx.doi.org/10.46610/jorais.2024.v09i02.003.
Testo completoAbstract (sommario):
Bridges are ensuring the smooth flow of goods and people. The seismic performance of bridges, especially those with unique geometries, such as T-beam bridges with zero skew angles, is paramount in earthquake-prone regions. This project comprehensively analyses a T-beam bridge with a 10⁰ to 50⁰ skew angle. The response of T-beam bridges to varying skew angles is a critical area of study in structural engineering, as skewed bridges are standard in modern infrastructure due to geometric and site constraints. This research investigates the impact of different skew angles on the structural performance of T-beam bridges, focusing on parameters such as bending moments, shear forces, deflections, and stress distribution. The study uses finite element analysis and empirical data to reveal how increasing skew angles affect T-beam bridges' load-carrying capacity and deformation behaviour. The study encompasses several key aspects: Detailed documentation of the bridge's geometry, materials used, and construction techniques employed in the T-beam Bridge under consideration and the development of a finite element model to represent the T-beam Bridge accurately, comparison by varying the skew angles and applying various seismic ground motion records to simulate the bridge's response under earthquake-induced loading and assess the bridge's performance using performance metrics such as moment, shear and torsion levels.
2
Radnić, Jure, Domagoj Matešan e Ivan Banović. "Bridges with multiple structural systems: The example of Trilj Bridge reconstruction in Croatia". Bridge Structures 17, n. 1-2 (11 giugno 2021): 65–75. http://dx.doi.org/10.3233/brs-210185.
Testo completoAbstract (sommario):
Development of multiple structural systems for bridges is useful in the design of new bridges and rehabilitation of existing bridges. This paper briefly presents some existing bridges with multiple structural systems and succinctly discusses design ideas for bridges with such systems. As an example of a bridge with multiple structural systems, the paper presents the reconstruction of a pedestrian suspension bridge in the City of Trilj, Croatia. The new bridge’s load-bearing structure is composed of several structural systems. Namely, the reconstructed bridge is a combination of suspension, cable-stayed and stress-ribbon bridge, which is laterally restrained with horizontal tensioned ropes. Numerical analysis was conducted on the renovated bridge. The results have shown an acceptable levels of stresses and deflections verifying the structural safety of the restored bridge. It is believed that this example of the bridge renovation may be useful in the design of new and strengthening of existing similar bridges.
3
Mohandas G.V e Sitansu k.Panda. "Hair pin bends of epicardial coronary arteries - a unique feature in multiple myocardial bridges". International Journal of Research in Pharmaceutical Sciences 10, n. 3 (26 luglio 2019): 2250–54. http://dx.doi.org/10.26452/ijrps.v10i3.1460.
Testo completoAbstract (sommario):
Myocardial bridge(MB) is an anatomical variant. Sometimes MB can cause compression over the coronary arteries and causes ischemic heart diseases.MB associated with bends of coronary arteries double the risk of coronary artery disease. So the present study aimed to find out the incidence of bends of the coronary artery along with the myocardial bridging. 100 heart specimens were obtained from routine dissection conducted for undergraduate students in the department of Anatomy IMS & SUM Hospital Bhubaneswar. After the simple dissecting procedure, epicardial coronary arteries, their branches and myocardial bridges and hairpin bends of coronary arteries were observed. Myocardial bridges present 41 (41%) over Left anterior descending artery(LAD) only.Among 41 hearts single myocardial bridge present in 37((90.25%) hearts, double myocardial bridge were present in 3((7.31%) hearts and triple myocardial bridges present in only one heart(2.44%). Hairpin bends of the coronary artery were present in double and triple myocardial bridged hearts only. No hairpin bends of the coronary artery was observed in the single myocardial bridge. Hair pin bends of the coronary arteries are the unique features of the myocardial bridges in multiple myocardial bridges, i.e. double and triple myocardial bridges. However, hairpin bends of coronary arteries were absent in single myocardial bridged hearts.
4
SOUSA, Helder, Bruno J. A. COSTA, António Abel HENRIQUES, João BENTO e Joaquim A. FIGUEIRAS. "ASSESSMENT OF TRAFFIC LOAD EVENTS AND STRUCTURAL EFFECTS ON ROAD BRIDGES BASED ON STRAIN MEASUREMENTS". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 22, n. 4 (13 dicembre 2015): 457–69. http://dx.doi.org/10.3846/13923730.2014.897991.
Testo completoAbstract (sommario):
Several technical and scientific publications have been made available focussing on Bridge Weight-in-Motion (BWIM) concerning railway bridges. On the contrary, BWIM analysis on road bridges are more scarce and therefore, this work intends to provide a contribution by presenting the BWIM analysis performed on two major road bridges in Portugal – Lezíria Bridge and Pinhão Bridge. These bridges are equipped with electric and optical strain gauges, acquisition systems with features that allow high sampling rates. Based on the collected data and focussing on the bridges’ lifetime, a probabilistic approach to quantify extreme traffic loads was implemented using extreme distribution functions. The bridges’ behaviour to these extreme traffic loads is numerically evaluated and a comparison with the alarm levels established by the bridge designers is performed. Although the bridge’s safety is not compromised, it was concluded that the representativeness of the observation period is a critical issue and the analysis of this kind of results must be carefully considered. A comprehensive discussion about this matter is carried out at the end of this work.
5
Wibowo, Heriyanto, e Sinung Tri Nugroho. "Penerapan Metode Analythic Hierarchy Process untuk Pengambilan Keputusan Pemilihan Desain Jembatan Kereta Api". Jurnal Teknik Transportasi 1, n. 1 (20 aprile 2020): 40. http://dx.doi.org/10.54324/jtt.v1i1.429.
Testo completoAbstract (sommario):
Padalarang - Purwakarta line track is a very crowded but potential track since it connects Jakarta - Bandung. Argo Parahyangan train and freight train are passing through this track. Therefore, it is crucial to build double track lane. However, it is difficult to execute due to a wide and deep river which requires a new bridge with a complex high cost construction. That is the reason why, an in-depth evaluation of the bridge design is needed. In selecting the bridge design, the Analytical Hierarchy Process was used as the selection method. The method would applied a four-level developed structure: the first level was the goal of choosing the Optimum Bridge Design, the second level was the people involved, the third level was the evaluation criteria, the last level was the alternative bridge to be built. The data was taken from the questionnaires filled by six respondents of the railway bridge's construction experts. The results show that the order of the bridge's design selection is as follows: 0.395 for concrete bridges; 0.213 for steel arch bridges; 0.199 for steel frame bridges; and 0.194 for cable bridges.
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Tasnic, Mihail, e Ilia Catereniuc. "Some morphological aspects of myocardial bridges". Moldovan Medical Journal 64, n. 2 (maggio 2021): 58–64. http://dx.doi.org/10.52418/moldovan-med-j.64-2.21.11.
Testo completoAbstract (sommario):
Background: Myocardial bridges are variants of the intramyocardial position of the coronary arteries. In the specialty literature, hot topics in cardiovascular field are myocardial infarction and non-obstructive coronary artery disease with frequent connection with myocardial bridges. Material and methods: The morphological study was based on the analysis of 200 human hearts and fragments of coronary arteries. The retrospective study was focused on the analysis of 6168 coronary angiography reports, to identify patients with myocardial bridges, their preferred location, the degree of systolic stenosis, the association between myocardial bridges and proximal to bridge and under the bridge coronary atherosclerosis. Results: The complete myocardial bridges were described in 62% of the analyzed hearts and only in 5.3% of the total number of studied coronarographies. In the majority of cases, the complete myocardial bridges covered the anterior interventricular branch. The degree of subpontine arterial systolic stenosis varied within 10-95%. The comparative study did not determine any correlations between the degree of subpontine vascular compression and the degree of the left ventricular myocardial hypertrophy. In 32% of cases were described proximal to bridge atherosclerotic plaques and only in one case (0.5%) – distal to bridge atherosclerotic plaques, located immediately under the bridge. Conclusions: The research findings underline the differences in anatomical and angiographic incidence of myocardial bridges, and the inability of all bridges to reduce the lumen of under bridged artery. Current study emphasizes attention to the topography of bridges, the correlation with ventricular hypertrophy and coronary atherosclerosis.
7
Li, Zi Qi, e Yan Yan Fan. "Study on Seismic Response Reduction of a Long-Span Cable-Stayed Bridge by Adding Viscous Dampers at the Different Positions". Advanced Materials Research 295-297 (luglio 2011): 2304–8. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.2304.
Testo completoAbstract (sommario):
Bridge is an important part of transport system, especially for the long-span bridges of important route. And it belongs to the lifeline project. It is an important measure for reducing the secondary disaster to ensure bridge’s normality in traffic after the earthquake. Currently, the isolation seismic design of long-span bridges with the special structure is used to reduce damage of bridges by the reason of the earthquake. Based on damping principle of the viscous dampers, the calculation and analysis of what the effect of shock absorption done by damper in decorate position of long-span cable-stayed bridge to structure of bridges are formulated in this paper.
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Campbell, Kristopher, Myra Lydon, Nicola-Ann Stevens e Su Taylor. "Analysis of Arch Bridge Condition Data to Identify Network-Wide Controls and Trends". Infrastructures 9, n. 4 (4 aprile 2024): 70. http://dx.doi.org/10.3390/infrastructures9040070.
Testo completoAbstract (sommario):
This paper outlines an initial analysis of 20 years of data held on an electronic bridge management database for approximately 3500 arch bridges across Northern Ireland (NI) by the Department for Infrastructure. Arch bridges represent the largest group of bridge types, making up nearly 56% of the total bridge stock in NI. This initial analysis aims to identify trends that might help inform maintenance decisions in the future. Consideration of the Bridge Condition Indicator (BCI) average value for the overall arch bridge stock indicates the potential for regional variations in the overall condition and the potential for human bias in inspections. The paper presents the most prevalent structural elements and associated defects recorded in the inspections of arch bridges. This indicated a link to scour and undermining for the worst-conditioned arch bridges. An Analysis of Variance (ANOVA) analysis identified function, number of spans, and deck width as significant factors during the various deterioration stages in a bridge’s lifecycle.
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Mudahemuka, Eugene, Masatatsu Miyagi, Ryota Shin, Naoki Kaneko, Yukihiko Okada e Kyosuke Yamamoto. "Estimating Bridge Natural Frequencies Based on Modal Analysis of Vehicle–Bridge Synchronized Vibration Data". Sensors 24, n. 4 (6 febbraio 2024): 1060. http://dx.doi.org/10.3390/s24041060.
Testo completoAbstract (sommario):
This paper presents a method for accurately estimating the natural frequencies of bridges by simultaneously measuring the acceleration vibration data of vehicles and bridges and applying modal analysis theory. Vibration sensors synchronized with GPS timing were installed on both vehicles and bridges, achieving stable and high-precision time synchronization. This enabled the computation of the bridge’s Frequency Response Functions (FRFs) for each mode, leading to a refined estimation of natural frequencies. The validity of the theory was confirmed through numerical simulations and experimental tests. The simulations confirmed its effectiveness, and similar trends were observed in actual bridge measurements. Consequently, this method significantly enhances the feasibility of bridge health monitoring systems. The proposed method is suitable for road bridges with spans ranging from short- to medium-span length, where the vehicle is capable of exciting the bridge.
10
Zhang, Tian, Haonan Chen, Xinjia Cui, Pengfei Li e Yunfeng Zou. "Condition Rating Prediction for Highway Bridge Based on Elman Neural Networks and Markov Chains". Applied Sciences 14, n. 4 (9 febbraio 2024): 1444. http://dx.doi.org/10.3390/app14041444.
Testo completoAbstract (sommario):
Bridges are a critical component of transportation infrastructure, playing a vital role in connectivity. The safe operation of bridges demands significant resource and capital investment, particularly as the operation phase is the most extended period in a bridge’s life cycle. Therefore, the efficient allocation of resources and funds is crucial for the maintenance and repair of bridges. This study addresses the need to predict changes in bridge condition over time. The commonly used state-based Markov chain method for bridge condition rating prediction is straightforward but limited by its assumptions of homogeneity and memorylessness. To improve upon this, we propose a novel method that integrates an Elman neural network with a Markov chain to predict the bridge condition rating. Initially, the ReliefF algorithm conducts a sensitivity analysis on bridge features to obtain the importance ranking of these features that affect the bridge condition. Next, six significant features are selected for data classification: bridge age, average daily truck traffic volume, material type, skew angle between bridges and roads, bridge deck structure type, and bridge type. The Elman neural network is then trained to train a prediction model for bridge condition ratings using the classified data, which can predict the condition levels of bridges. The Markov chain’s transition probability matrix is derived using a genetic algorithm to match the deterioration curve predicted by the Elman neural network. This proposed method, when applied to actual bridge data, demonstrates its effectiveness as evidenced by the condition rating of an actual bridge.
11
Helowicz, Andrzej. "Integral bridge and culvert design, Designer’s experience". Open Engineering 10, n. 1 (5 giugno 2020): 499–505. http://dx.doi.org/10.1515/eng-2020-0059.
Testo completoAbstract (sommario):
AbstractThis paper describes a small single-span integral bridge made of in-situ concrete. The bridge was designed by the author and built on the M9 motorway between the towns of Waterford and Kilcullen in Ireland. Selected parts of the bridge design are presented. First the principles of modelling and designing integral bridges and culverts are explained. Then the considered bridge’s design is described. The advantages and disadvantages of such structures are discussed. The focus is on the design, construction, cost and in-service behaviour of small integral bridges and culverts. In Conclusions the author shares his knowledge and experience relating to the design of small integral bridges and culverts and puts forward recommendations as to further research on this type of structures in Poland.
12
Yao, Juncheng, Hekuan Zhou, Jiahua Zhu, Liang Huang, Jianguo Xu e Weiguo Li. "Reduction of Vibrations in Long-Span Continuous Girder Bridges with Pounding Tuned Mass Dampers". Advances in Civil Engineering 2022 (3 ottobre 2022): 1–18. http://dx.doi.org/10.1155/2022/7796204.
Testo completoAbstract (sommario):
Earthquakes often cause bridges to vibrate to different degrees; moreover, in the case of poor road conditions, the vibration amplitude of bridges caused by vehicles often exceeds a reasonable range, thus causing different degrees of damage to bridges. Therefore, this article studies the vibration reduction effect of the pounding tuned mass dampers (PTMD) on long-span continuous bridges under earthquake and vehicle loads. The PTMD used in this study can reduce the vibration in both lateral and vertical directions. The PTMD provides a stronger vibration dampening effect compared to the TMD since it increases collision to use energy. The LS-DYNA software is used for numerical modeling to optimize the parameters of the PTMD and to determine the size and installation position of the PTMD. Then, the bridge is subjected to two recorded ground motions, and the bridge response with and without the PTMD is compared and analyzed, which shows how PTMD might lessen bridge vibration in its transverse direction. To assess how efficiently the PTMD dampens vibrations induced by vehicle loads on bridges, a vehicle/bridge/PTMD system is simulated using a refined vehicle model. The findings demonstrate that the PTMD may significantly lessen the bridge’s lateral and vertical vibration while enhancing driving comfort. Thus, this research study is of great significance for vertical and lateral vibration control of long-span continuous girder bridges.
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Shin, Ryota, Yukihiko Okada e Kyosuke Yamamoto. "Application of C-LSTM Networks to Automatic Labeling of Vehicle Dynamic Response Data for Bridges". Sensors 22, n. 9 (3 maggio 2022): 3486. http://dx.doi.org/10.3390/s22093486.
Testo completoAbstract (sommario):
Maintaining bridges that support road infrastructure is critical to the economy and human life. Structural health monitoring of bridges using vibration includes direct monitoring and drive-by monitoring. Drive-by monitoring uses a vehicle equipped with accelerometers to drive over bridges and estimates the bridge’s health from the vehicle vibration obtained. In this study, we attempt to identify the driving segments on bridges in the vehicle vibration data for the practical application of drive-by monitoring. We developed an in-vehicle sensor system that can measure three-dimensional behavior, and we propose a new problem of identifying the driving segment of vehicle vibration on a bridge from data measured in a field experiment. The “on a bridge” label was assigned based on the peaks in the vehicle vibration when running at joints. A supervised binary classification model using C-LSTM (Convolution—Long-Term Short Memory) networks was constructed and applied to data measured, and the model was successfully constructed with high accuracy. The challenge is to build a model that can be applied to bridges where joints do not exist. Therefore, future work is needed to propose a running label on bridges based on bridge vibration and extend the model to a multi-class model.
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Siwowski, Tomasz, e Piotr Żółtowski. "Strengthening Bridges with Prestressed CFRP Strips". Selected Scientific Papers - Journal of Civil Engineering 7, n. 1 (1 giugno 2012): 79–86. http://dx.doi.org/10.2478/v10299-012-0021-2.
Testo completoAbstract (sommario):
Abstract Limitation of bridge’s carrying bearing capacity due to aging and deterioration is a common problem faced by road administration and drivers. Rehabilitation of bridges including strengthening may be applied in order to maintain or upgrade existing bridge parameters. The case studies of strengthening of two small bridges with high modulus prestressed CFRP strips have been presented in the paper. The first one - reinforced concrete slab bridge - and the other - composite steel-concrete girder bridge - have been successfully upgraded with quite new technology. In both cases the additional CFRP reinforcement let increasing of bridge carrying capacity from 15 till 40 metric tons. The CFRP strip prestressing system named Neoxe Prestressing System (NPS), developed by multi-disciplinary team and tested at full scale in Rzeszow University of Technology, has been also described in the paper.
15
Zdravkov, Lyubomir A. "Wind loads on girder bridges". Challenge Journal of Structural Mechanics 8, n. 1 (24 marzo 2022): 9. http://dx.doi.org/10.20528/cjsmec.2022.01.002.
Testo completoAbstract (sommario):
Bridges are facilities that are in exploitation outdoor. Often the wind is the leading horizontal force in the transverse direction. Therefore the bridges have received the due attention in the standards for wind loading. Unfortunately, in all available standards for wind load on the bridges, one, summarized value of the aerodynamic coefficient is indicated. It is related to the entire cross-section of the facility. There is no differentiation for the individual longitudinal girders and/or roadway. Information about the specific wind pressure on each of the bridge’s element is required for the correct design of their supporting systems, whether they are framed or braced type. To fill this gap, the author has built several models of bridges with longitudinal girders, using a Computational Fluid Dynamics (CFD) analysis. Through them he determined the values of the aerodynamic coefficients for each of the bridge girders under the roadway and the cross-section of the bridge as a whole. Conclusions are summarized and the results clearly show the values of the aerodynamic coefficients for the whole section of the bridge are with 50-60% lower than the ones reported for the windward girder.
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Yin, Xinfeng, Yang Liu, Shihui Guo, W. Zhang e C. S. Cai. "Three-Dimensional Vibrations of a Suspension Bridge Under Stochastic Traffic Flows and Road Roughness". International Journal of Structural Stability and Dynamics 16, n. 07 (3 agosto 2016): 1550038. http://dx.doi.org/10.1142/s0219455415500388.
Testo completoAbstract (sommario):
When studying the vibration of a bridge–vehicle coupled system, most researchers mainly focus on the vertical vibration of bridges under moving vehicular loads, while the lateral and longitudinal vibrations of the bridges and the stochastic characteristics of the traffic flows are neglected. However, for long-span suspension bridges, neglecting the bridge’s three-dimensional (3D) vibrations under stochastic traffic flows can cause considerable inaccuracy in predicting the dynamic performance. This study is mainly focused on establishing a new methodology fully considering a suspension bridge’s vertical, lateral, and longitudinal vibrations induced by stochastic traffic flows under varied road roughness conditions. A new full-scale vehicle model with 18 degrees of freedom (DOFs) was developed to predict the longitudinal and lateral vibrations of the vehicle. An improved Cellular Automaton (CA) model considering the influence of the next-nearest vehicle was introduced. The bridge and vehicles in traffic flow coupled equations are established by combining the equations of motion of both the bridge and vehicles using the displacement relationship and interaction force relationship at the patch contacts. The numerical simulations show that the proposed method can rationally simulate the 3D vibrations of the suspension bridge under stochastic traffic flows.
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Rai, Gunjan, Soumya Khanna e Royana Singh. "Myocardial bridging in the course of coronary arteries and its clinical significance". Asian Journal of Medical Sciences 11, n. 6 (1 novembre 2020): 58–62. http://dx.doi.org/10.3126/ajms.v11i6.29989.
Testo completoAbstract (sommario):
Background: Sudden death in young adults in absence of any risk factor related to coronary arterial disease has been reported. It could be because of some unrecognized congenital coronary artery anomalies like myocardial bridging. The clinician should keep myocardial bridging as a differential diagnosis in cases of sudden death in young individuals having no risk factors of coronary artery diseases.
Aims and Objective: The present study was conducted to know the prevalence of myocardial bridge and percentage of distribution of myocardial bridges in the course of different coronary arteries of cadaveric hearts.
Material and Methods: The study was conducted in the department of Anatomy, IMS, BHU Varanasi. Total numbers of 49 formalin preserved hearts were taken for the study. The hearts were meticulously dissected to see the distribution and location of myocardial bridge. Coronary arteries with myocardial bridge were photographed and data was statistically analyzed.Out of 49 hearts, 26(53.06%) showed myocardial bridging. Total numbers of bridges were found to be 34 in number. Among the 26 myocardial bridged hearts 8 hearts (30.76%) showed double myocardial bridges and 18 hearts (69.23%) showed single myocardial bridges. In hearts with double myocardial bridging, 5 of them showed myocardial bridging in the territory of both anterior interventricular artery (AIVA) and posterior interventricular artery (PIVA) and 3 showed bridging in the territory of anterior interventricular artery and its diagonal branch. Among the18 single myocardial bridging 16 were in the course of anterior interventricular artery and two showed myocardial bridging in one of the diagonal branch of AIVA. There were 24 myocardial bridges in the course of AIVA, 16 as a part of single myocardial bridged hearts and 8 as a part of double myocardial bridged heart with the percentage of distribution were 2 (8.33%)in the proximal 1/3rd,18(75%)were in middle 1/3rd and 4(16.66%) were in distal 1/3rd.
Conclusion: Due to the presence of high percentage of reported myocardial bridges in cadaveric hearts, the clinicians should always screen the young individuals and athletes having myocardial ischemia for the myocardial bridges along with other etiological factors.
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Istiono, Heri, e Jaka Propika. "Analisa Non-Linier Pada Mekanisme Keruntuhan Jembatan Rangka Baja Tipe Pratt". Borneo Engineering : Jurnal Teknik Sipil 1, n. 2 (25 dicembre 2017): 68. http://dx.doi.org/10.35334/be.v1i2.604.
Testo completoAbstract (sommario):
Steel truss bridge collapse often occurs, both in Indonesia and in other countries. As a result of the collapse of the bridge is in addition to the casualties also losses from the financial aspects. This collapse caused due to various factors, one of them because of a decrease in the strength of the bridge structure. To minimize required maintenance of the bridge's collapse and to facilitate the maintenance of one of them must be known failure mechanisms existing bridges. In the analysis of this collapse, will be modeled steel truss bridge pratt’s type with long spans is 60 meters. Analysis of the collapse of the steel truss bridge's, utilizing a pushover analysis to analyze the behavior of the bridge structure. Pushover analysis done with give vertical static load pattern at the structure, next gradually increase by a factor until one vertical displacement target of the reference point is reached. The study shows that at model singe span failure occurred on the chord on mid span. The performance level of structure shows all models of bridges in the state are IO, this case based on the target displacement FEMA 356 and the actual ductility occurs in all models of bridges is compliant with SNI 2833-2008.
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Sanli, Ahmet K., Erdogan A. Uzgider, Ozden B. Caglayan, Kadir Ozakgul e Jan Bien. "Testing Bridges by Using Tiltmeter Measurements". Transportation Research Record: Journal of the Transportation Research Board 1696, n. 1 (gennaio 2000): 111–17. http://dx.doi.org/10.3141/1696-51.
Testo completoAbstract (sommario):
An efficient numerical procedure based on the cubic spline technique is developed to obtain the vertical displacements of the bridge deck using the slope values measured at selected points under the test loading. Most static load tests of bridges are performed to evaluate the stiffness characteristics of bridge structures or to check the accuracy of their computer models. From this standpoint, vertical displacements of the bridge under certain loads have a crucial importance. However, if the bridge is over a river, a lake, muddy ground, or a major highway, conventional displacement transducers cannot be used appropriately for this purpose. Furthermore, strong wind and the bridge’s height badly affect the accuracy of the transducers. Another way to obtain bridge deflection is to use an indirect method. Tiltmeters, which have been increasingly used for construction monitoring and structural testing of bridges, are suitable devices in terms of indirect deflection measurements because of their characteristics such as high sensitivity, easy installation, and small electrical drift. The testing and evaluation procedure developed was applied on a real bridge, and the results indicated that this method could be applied to obtain vertical displacements of bridges as an alternative to the use of conventional displacement transducers.
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Xu, Rongjing. "Influence of Extreme Weather and Its Secondary Disasters on Bridges". Highlights in Science, Engineering and Technology 18 (13 novembre 2022): 148–54. http://dx.doi.org/10.54097/hset.v18i.2650.
Testo completoAbstract (sommario):
Global climate change causes more and more extreme weather happened frequently. It poses a new challenge to the structural safety of civil engineering. Nowadays, bridge engineering designs must consider the possibility of extreme climates and the social, economic, and environmental damage they cause. In this paper, the influence of three kinds of extreme weather on bridges is summarized by the method of comprehensive narration, and the influence of secondary disasters is described. Results show that both extreme weather and secondary disasters can significantly impact bridges. Extreme weather includes rainstorms, typhoons and earthquakes and affects the structure and materials of the bridge. Heavy rain erodes the bridge's structure and material and causes flood and debris flow to harm the bridge. Flood water would continue to impact the pier and cause damage to the understructure of the bridge. Meanwhile, they could also induce secondary disasters such as aftershocks and debris flow, impacting the bridges and disrupting the function of the city.
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Yadav, Anand Gaurav. "Exploring the Cable-Stayed Bridge with Shifting the Cable Arrangement at Deck Level". INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 07, n. 10 (1 ottobre 2023): 1–11. http://dx.doi.org/10.55041/ijsrem26565.
Testo completoAbstract (sommario):
Cable stayed bridges are becoming a more and more viable option for lengthy spans with the development of computer-based optimisation techniques. Additionally, because they are suspended structures, they can be constructed with ease in locations where it would be challenging to provide several foundations or piers. The pre-tensioning forces of the cables on Sikkim's Akkar Bridge have been determined through this investigation. CSiBridge software is the programme utilised for the investigation. A analysis of the bridge's several parameters concludes this work. The parametric analysis looks at the deck moment, the bridge's span-wise reaction, the height of the pylon, and the length of the span in relation to the girder thickness. Also investigated is the impact of superstructure modifications on substructure. Due to a lack of resources, particularly steel, cable stayed bridges were initially created in Germany in the years following World War II. The effective introduction of cable stayed bridges is made feasible by the development of welding processes, advancements in structural analysis, the use of high strength steel, orthotropic type decking, and the previously noted shortage of steel in the years following World War II. Cable stayed bridges were extremely statically indeterminate structures. Electronic computers were essential in determining the precise solution to these extremely indeterminate systems and in analysing the cable stayed bridge. The software CSi Bridge is used to perform the analysis. Three distinct models of cable-stayed bridges have been constructed, each taking into account identical cable configurations under varying situations. Since the cables are arranged on the deck at various angles and attachment locations, their effects may be thoroughly investigated. IRC Class 70R Vehicle load was taken into consideration when taking live loads in accordance with IRC: 6-2017. Key Words: Cable-stayed Bridge, CSiBridge Software, IRC - 6, Analysis.
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Wei, Biao, Qing Yuan Zeng e Wei An Liu. "Applicability of Modal Pushover Analysis on Bridges". Advanced Materials Research 255-260 (maggio 2011): 806–10. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.806.
Testo completoAbstract (sommario):
Taking one irregular continuous bridge as an example, modal pushover analysis (MPA) has been conducted to judge whether it would be applicable for seismic analysis of irregular bridge structures. The bridge’s seismic demand in the transverse direction has been determined through two different methods, inelastic time history analysis (ITHA) and MPA respectively. The comparison between those two results indicates that MPA would be suitable only for bridges under elastic or slightly damaged state. Finally, some modifications are used to improve the MPA’s scope of application, and the results illustrate that the adapted MPA will be able to estimate bridges’ seismic demands to some extent.
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Hamunzala, Bennie, Koji Matsumoto e Kohei Nagai. "Improved Method for Estimating Construction Year of Road Bridges by Analyzing Landsat Normalized Difference Water Index 2". Remote Sensing 15, n. 14 (11 luglio 2023): 3488. http://dx.doi.org/10.3390/rs15143488.
Testo completoAbstract (sommario):
The construction year of road bridges plays an important role in bridge management systems. Based on the age of road bridges and other factors, deterministic and probabilistic deterioration models can be used to calculate deterioration rates and predict the future physical condition of road bridges. Two new techniques are proposed in this manuscript for estimating the construction year of road bridges by analyzing the normalized difference water index 2 (NDWI_2). Technique 1 uses both the target bridge point (TBP) and a selected optimal reference control point, while Technique 2 uses only the TBP. Landsat 5 Thematic Mapper NDWI_2 data were analyzed at all 44 road bridges in Nago City, Japan of the bridges’ overall length ≤ 100 m and construction year between 1990 and 2006. The sequential t-test analysis of the regime shift method, at a significance level α = 0.05 and cutoff length l = 2 to l = 27, was used to interpret the estimated construction year from the NDWI_2 for both techniques. Both techniques successfully determined the estimated construction year, which was statistically significant with p-values < 0.05, except for seven road bridges in Technique 1 and one road bridge in Technique 2. The correlation and comparative analysis of the actual and estimated construction years yielded R2 = 0.24 and R2 = 0.33, as well as an average deviation of S = 5.81 years and S = 4.08 years for Technique 1 and Technique 2, respectively. The findings suggest that Technique 2 is more accurate and provides a better estimate than Technique 1. It was observed that, as the cutoff length l increased, the absolute error between the actual and estimated construction year increased. Therefore, as a measure of accuracy, the upper limit of cutoff length l was set to l≤ 12. It was also observed that the increase in the bridge’s overall length and forested area contributed to the accuracy of the results. By using the construction year as one of the inputs into bridge management systems, bridge managers can make more informed decisions about how best to maintain and improve road bridges to ensure user safety and road bridge preservation for the future.
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Che, Xiao Jun, Xie Dong Zhang e Chao Yang. "Remaining Pre-Stress Identification of Diseased Pre-Stressed Concrete Bridges Based on Neural Network". Advanced Materials Research 639-640 (gennaio 2013): 1056–59. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.1056.
Testo completoAbstract (sommario):
According to experimental record of bridges in use, more and more damage bridges have appeared, and the most common and severe defect is the bridge damage and cracking problem, which has seriously affected the normal usage of bridges. Analyzing the disease cause of defective bridges more effectively and deeply, in order to optimize the design and construction of bridges becomes the urgent problem in the engineering field. The study is based on the design, construction data and experimental record of the bridge.A non-linear mapping function from multiple input data (the deck elevation of each element in destructing) to multiple output data(the change of pre-stress) is constructed within BP neural networks. Based on the theory of continuous function, the convergence is disadvantageous between 0 and 1. The study shows the expected output data between 0.05 and 0.95 are better for convergence. According to the real data of bridge floor line change in process of destruction, the released pre-stresses are recognized, and the real pre-stresses in existence are calculated by scheme of cable design. The study not only offers reliable scientific basis for analyzing the disease cause in the bridges, but also is helpful to design of the bridges having same structural style.
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Chacón, Rolando, Carlos Ramonell, Hector Posada, Rahul Tomar, Christian Martínez de la Rosa e Irina Stipanovic. "Measurements, Simulation, Analysis and Geolocation in a Digital Twin tool for bridge management". ce/papers 6, n. 5 (settembre 2023): 474–82. http://dx.doi.org/10.1002/cepa.2017.
Testo completoAbstract (sommario):
AbstractThis paper presents a digital‐twin based tool that can be used for bridge management. The tool offers various capabilities that include embedding BIM geometries, simulations, measurements, GIS location, and performance analysis. These features enable efficient and effective management of bridges by providing detailed information and analysis of the bridge's performance, which can help in identifying potential issues and implementing appropriate solutions. The methodology represents one of the outcomes of Ashvin, an H2020 project aimed to providing assistant solution for design, construction and management of infrastructure systems. The hitherto obtained findings include this digital tool which can be of practical and beneficial use for bridge owners and operators, as it can help them to organize and centralize the bridge data in a way it helps making informed decisions regarding the maintenance, repair, and replacement of bridges. Overall, this paper highlights the importance of embracing technology in the management of critical infrastructure such as bridges, which can significantly improve their performance and extend their lifespan.
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O’Higgins, Connor, David Hester, Patrick McGetrick, Wai Kei Ao e Elizabeth J. Cross. "Refinement and Validation of the Minimal Information Data-Modelling (MID) Method for Bridge Management". Sensors 24, n. 12 (15 giugno 2024): 3879. http://dx.doi.org/10.3390/s24123879.
Testo completoAbstract (sommario):
Various approaches have been proposed for bridge structural health monitoring. One of the earliest approaches proposed was tracking a bridge’s natural frequency over time to look for abnormal shifts in frequency that might indicate a change in stiffness. However, bridge frequencies change naturally as the structure’s temperature changes. Data models can be used to overcome this problem by predicting normal changes to a structure’s natural frequency and comparing it to the historical normal behaviour of the bridge and, therefore, identifying abnormal behaviour. Most of the proposed data modelling work has been from long-span bridges where you generally have large datasets to work with. A more limited body of research has been conducted where there is a sparse amount of data, but even this has only been demonstrated on single bridges. Therefore, the novelty of this work is that it expands on previous work using sparse instrumentation across a network of bridges. The data collected from four in-operation bridges were used to validate data models and test the capabilities of the data models across a range of bridge types/sizes. The MID approach was found to be able to detect an average frequency shift of 0.021 Hz across all of the data models. The significance of this demonstration across different bridge types is the practical utility of these data models to be used across entire bridge networks, enabling accurate and informed decision making in bridge maintenance and management.
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Liu, Bo, Xu Meng, Ji Li e Zhi Tu. "Defect Inspection Technology for Steel Truss Suspension Bridges". Journal of World Architecture 8, n. 2 (21 maggio 2024): 12–16. http://dx.doi.org/10.26689/jwa.v8i2.6947.
Testo completoAbstract (sommario):
Steel truss suspension bridges are prone to developing defects after prolonged use. These defects may include corrosion of the main cable or the steel truss. To ensure the normal and safe functioning of the suspension bridge, it is necessary to inspect for defects promptly, understand the cause of the defect, and locate it through the use of inspection technology. By promptly addressing defects, the suspension bridge's safety can be ensured. The author has analyzed the common defects and causes of steel truss suspension bridges and proposed specific inspection technologies. This research is intended to aid in the timely discovery of steel truss suspension bridge defects.
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Yuan, JC, XL Liu, Y. Ding, XJ Wang, ZB Cao e JH Zhou. "Rapid Intelligent Risk Assessment of Bridges under Typhoon Disasters". Journal of Physics: Conference Series 2476, n. 1 (1 aprile 2023): 012030. http://dx.doi.org/10.1088/1742-6596/2476/1/012030.
Testo completoAbstract (sommario):
Abstract In order to improve the risk early-warning performance of highway bridges caused by typhoon disasters, a fast and intelligent risk assessment model for highway bridges is proposed in this paper. A three-level accident possibility index system is established in which the top-level index is the possibility of bridge accident, the second-level indices comprise the accident causing factor, the surrounding environment factor, and the accident bearing body, and the third-level indices are selected from the disaster conditions and the bridge’s own technical conditions. With the rapid risk assessment model of highway bridges under typhoon disasters, the intelligent risk assessment software platform is developed. In the case analysis, the automatic and intelligent risk assessment of highway bridges in Ningbo under Typhoon “Lekima” on August 10, 2019, was realized.
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Hajali, Mohammad, Abdolrahim Jalali e Ahmad Maleki. "Effects of Near Fault and Far Fault Ground Motions on Nonlinear Dynamic Response and Seismic Improvement of Bridges". Civil Engineering Journal 4, n. 6 (4 luglio 2018): 1456. http://dx.doi.org/10.28991/cej-0309186.
Testo completoAbstract (sommario):
In this study, the dynamic response of bridges to earthquakes near and far from the fault has been investigated. With respect to available data and showing the effects of key factors and variables, we have examined the bridge’s performance. Modeling a two-span concrete bridge in CSI Bridge software and ability of this bridge under strong ground motion to near and far from fault has been investigated. Nonlinear dynamic analysis of time history includes seven records of past earthquakes on models and it was observed that the amount of displacement in the near faults is much greater than the distances far from faults. Bridges designed by seismic separators provide an acceptable response to a far from fault. This means that in bridges using seismic separators, compared to bridges without seismic separators, Acceleration rate on deck, base shearing and the relative displacement of the deck are decrease. This issue is not seen in the response of the bridges to the near faults. By investigating earthquakes near faults, it was observed that near-fault earthquakes exhibit more displacements than faults that are far from faults. These conditions can make seismic separators critical, so to prevent this conditions FDGM should be used to correct the response of these bridges. Based on these results, it can be said that the displacement near faults with forward directivity ground motion is greater than far from faults. So that by reducing the distance from the faults, the maximum value of the shearing and displacement of the deck will be greater.
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Ranf, R. T., M. O. Eberhard e S. Malone. "Post-earthquake Prioritization of Bridge Inspections". Earthquake Spectra 23, n. 1 (febbraio 2007): 131–46. http://dx.doi.org/10.1193/1.2428313.
Testo completoAbstract (sommario):
Bridge damage reports from the 2001 Nisqually earthquake were correlated with estimates of ground-motion intensity at each bridge site (obtained from ShakeMaps) and with bridge properties listed in the Washington State Bridge Inventory. Of the ground-motion parameters considered, the percentage of bridges damaged correlated best with the spectral acceleration at a period of 0.3 s. Bridges constructed before the 1940s, movable bridges, and older trusses were particularly vulnerable. These bridge types were underestimated by the HAZUS procedure, which categorizes movable bridges and older trusses as “other” bridges. An inspection prioritization strategy was developed that combines ShakeMaps, the bridge inventory and newly developed fragility curves. For the Nisqually earthquake, this prioritization strategy would have made it possible to identify 80% of the moderately damaged bridges by inspecting only 481 (14%) of the 3,407 bridges within the boundaries of the ShakeMap. To identify these bridges using a prioritization strategy based solely on epicentral distance, it would have been necessary to inspect 1,447 (42%) bridges. To help the Washington State Department of Transportation (WSDOT) rapidly identify damaged bridges, the prioritization procedure has been incorporated within the Pacific Northwest Seismic Network (PNSN) ground-motion processing and notification software.
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Abdellaoui, Mohammed, Mohamed Badaoui, Mahmoud Bensaibi e Koriga Said. "Developing a seismic bridge reliability model to enhance its resilience: a study on reinforced concrete bridges in Algeria". STUDIES IN ENGINEERING AND EXACT SCIENCES 5, n. 1 (21 maggio 2024): 2088–101. http://dx.doi.org/10.54021/seesv5n1-103.
Testo completoAbstract (sommario):
Bridges are critical points in transportation networks because they are exposed to various natural and human-caused hazards, leading to partial or complete service interruption. Bridges must maintain their societal functions, especially after events such as earthquakes, because they play a vital role in emergency response, relief operations and damage mitigation. This paper proposes an improved model for evaluating the reliability of reinforced concrete bridges before seismic events, to improve their resilience to earthquakes and enable effective preparedness for disasters. In the first phase of this study, a group of important factors that affect the reliability of the bridge were identified, based on the opinions of experts and a comprehensive reading of the current literature in this field, These factors include the current physical condition of the bridge, the seismic hazard, the seismic design, the importance of the bridge in terms of traffic, and the geometry of the bridges. In the second stage, the Analytical Hierarchy Process (AHP) was used to determine the relative impact of each factor compared to other factors.The third stage is to calculate the bridge's seismic reliability index (RSI) by combining the weights of these factors with the score for each case.Three classifications of seismic reliability were proposed for low, medium and high. The model has been applied to many reinforced concrete bridges in earthquake-prone areas in Algeria. The model provides valuable insights for evaluating bridge reliability and can help decision makers and officials make proactive decisions that will improve seismic resilience. Finally, the results obtained are summarized in this paper.
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Maryono e Eka Juliar. "METODE PLAKSANAAN PEKERJAAN SLAB PADA JEMBATAN CILUTUNG DI KEC. TOMO KAB. SUMEDANG". SEMINAR TEKNOLOGI MAJALENGKA (STIMA) 7 (27 settembre 2023): 54–64. http://dx.doi.org/10.31949/stima.v7i0.882.
Testo completoAbstract (sommario):
Cilutung Bridge is one of the bridges located on Jalan Raya Tolengas, Tolengas, Tomo District, Sumedang Regency. Bridges have various types of bridges, namely girder bridges, arch bridges, truss bridges, suspension bridges. The bridge component is divided into two, namely the superstructure and the substructure. The structure of the bridge generally includes: sidewalks, vehicle floor slabs, girders, diaphragm beams, and platforms. The structure under the bridge generally includes: the base of the bridge (abutments), bridge pillars (piers) and foundations. The bridge slab is a horizontal structural element that functions to distribute dead and live loads to the vertical support frame of a structural system. The stages of implementing the bridge slab work are 1. Preparatory work, 2. Steel bridge deck installation, 3. Steel bridge deck grouting work, 4. Cantilever slab formwork assembly, 5. Slab and parapet reinforcement assembly, 6. Cantilever slab formwork installation, 7. Check completeness and measurement, 8. Bridge slab reinforcement installation, 9. Bridge parapet reinforcement installation, 10. Bridge slab formwork installation 11. Measurement, 12. Block out deck drain installation, 13. Bridge slab floor cleaning, 14. Inspection, 15. Bridge slab casting, 16. Slump and quality check, 17. Formwork demolition work, 18. Maintenance and tidiness.
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Sukenik, Shahar, Yoav Boyarski e Daniel Harries. "Effect of salt on the formation of salt-bridges in β-hairpin peptides". Chem. Commun. 50, n. 60 (2014): 8193–96. http://dx.doi.org/10.1039/c4cc03195d.
Testo completoAbstract (sommario):
The formation of salt-bridges in β-hairpin peptides is measured in increasing salt concentrations, indicating a decrease in the salt-bridged population due to charge–charge screening, as well as non-cooperative salt-bridge triads.
34
Ahmed, Zuber, e Esar Ahmed. "Non-Linear Analysis of Cable Stayed Bridges". International Journal of Emerging Research in Management and Technology 6, n. 9 (24 giugno 2018): 36. http://dx.doi.org/10.23956/ijermt.v6i9.82.
Testo completoAbstract (sommario):
The concept of cable-stayed bridges dates back to the seventeenth century. Due to their aesthetic appearance, efficient utilization of material, and availability of new construction technologies, cable-stayed bridges have gained much popularity in the last few decades. After successful construction of the Sutong Bridge, a number of bridges of this type have been proposed and are under construction, which calls for extensive research work in this field. Nowadays, very long span cable-stayed bridges are being built and the ambition is to further increase the span length using shallower and slender girders. In order to achieve this, accurate procedures need to be developed which can lead to a thorough understanding and a realistic prediction of the bridge’s structural response under different load conditions.In the present study, an attempt has been made to analyze the seismic response of cable stayed bridges with single pylon and two equal side spans. This study has made an effort to analyze the effect of both static and dynamic loadings on cable-stayed bridges and corresponding response of the bridge with variations in span length, pylon height and pylon shape. Comparison of static analysis results have been made for different configuration of bridges - their mode shapes, time period, frequency, pylon top deflection, maximum deck deflection; and longitudinal reaction, lateral reaction and longitudinal moment at pylon bottom. Time history analysis results have been investigated for different configuration of bridges under the effects of three earthquakes response spectrum (Bhuj, El Centro and Uttarkashi) - axial forces in stay cables, deck deflections and stress diagrams at maximum peak ground acceleration of the above mentioned earthquakes.
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DePrekel, Kirsten, El Bouali e Thomas Oommen. "Monitoring the Impact of Groundwater Pumping on Infrastructure Using Geographic Information System (GIS) and Persistent Scatterer Interferometry (PSI)". Infrastructures 3, n. 4 (15 dicembre 2018): 57. http://dx.doi.org/10.3390/infrastructures3040057.
Testo completoAbstract (sommario):
Transportation infrastructure is critical for the advancement of society. Bridges are vital for an efficient transportation network. Bridges across the world undergo variable deformation/displacement due to the Earth’s dynamic processes. This displacement is caused by ground motion, which occurs from many natural and anthropogenic events. Events causing deformation include temperature fluctuation, subsidence, landslides, earthquakes, water/sea level variation, subsurface resource extraction, etc. Continual deformation may cause bridge failure, putting civilians at risk, if not managed properly. Monitoring bridge displacement, large and small, provides evidence of the state and health of the bridge. Traditionally, bridge monitoring has been executed through on-site surveys. Although this method of bridge monitoring is systematic and successful, it is not the most efficient and cost-effective. Through technological advances, satellite-based Persistent Scatterer Interferometry (PSI) and Geographic Information Systems (GIS) have provided a system for analyzing ground deformation over time. This method is applied to distinguish bridges that are more at risk than others by generating models that display the displacement at various locations along each bridge. A bridge’s health and its potential risk can be estimated upon analysis of measured displacement rates. In return, this process of monitoring bridges can be done at much faster rates; saving time, money and resources. PSI data covering Oxnard, California, revealed both bridge displacement and regional ground displacement. Although each bridge maintained different patterns of displacement, many of the bridges within the Oxnard area displayed an overall downward movement matching regional subsidence trends observed in the area. Patterns in displacement-time series plots provide evidence for two types of deformation mechanisms. Long-term downward movements correlate with the relatively large regional subsidence observed using PSI in Oxnard. Thermal dilation from seasonal temperature changes may cause short-term variabilities unique to each bridge. Overall, it may be said that linking geologic, weather, and groundwater patterns with bridge displacement has shown promise for monitoring transportation infrastructure and more importantly differentiating between regional subsidence and site-specific displacements.
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Sigdel, Lila Dhar, Ahmed Al-Qarawi, Chin Jian Leo, Samanthika Liyanapathirana e Pan Hu. "Geotechnical Design Practices and Soil–Structure Interaction Effects of an Integral Bridge System: A Review". Applied Sciences 11, n. 15 (2 agosto 2021): 7131. http://dx.doi.org/10.3390/app11157131.
Testo completoAbstract (sommario):
Integral bridges are a class of bridges with integral or semi-integral abutments, designed without expansion joints in the bridge deck of the superstructure. The significance of an integral bridge design is that it avoids durability and recurring maintenance issues with bridge joints, and maybe bearings, which are prevalent in traditional bridges. Integral bridges are less costly to construct. They require less maintenance and therefore cause less traffic disruptions that incur socio-economic costs. As a consequence, integral bridges are becoming the first choice of bridge design for short-to-medium length bridges in many countries, including the UK, USA, Europe, Australia, New Zealand and many other Asian countries. However, integral bridge designs are not without challenges: issues that concern concrete creep, shrinkage, temperature effects, bridge skew, structural constraints, as well as soil–structure interactions are amplified in integral bridges. The increased cyclic soil–structure interactions between the bridge structure and soil will lead to adverse soil ratcheting and settlement bump at the bridge approach. If movements from bridge superstructures were also transferred to pile-supported substructures, there is a risk that the pile–soil interactions may lead to pile fatigue failure. These issues complicate the geotechnical aspects of integral bridges. The aim of this paper is to present a comprehensive review of current geotechnical design practices and the amelioration of soil–structure interactions of integral bridges.
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Cao, Hengtao, Yao Lu e Daihai Chen. "Analysis of Vehicle-Bridge Coupling Vibration Characteristics of Curved Girder Bridges". Applied Sciences 14, n. 5 (29 febbraio 2024): 2021. http://dx.doi.org/10.3390/app14052021.
Testo completoAbstract (sommario):
When vehicles move on a bridge, the coupling effect between vehicles and bridges can affect driving safety and comfort, especially for curved bridges, therefore, choosing reasonable design parameters for curved bridges is crucial. In this article, a three-span curved continuous box-girder bridge was taken as the research object; the entire process of vehicle-bridge coupling vibration of highway curved girder bridges was conducted via numerical simulation and the vehicle-bridge coupling vibration analysis program Cmck 1.0 was developed. Then, the influence factors such as curvature radius, constraint mode, and vehicle characteristics on the vehicle-bridge coupling vibration of curved girder bridges were explored. The results showed that as the curvature radius increased, the dynamic response of the bridge offered a gradually decreasing trend and compared to the vertical dynamic response, the torsional response was more sensitive to the influence of the curvature radius. Different constraint methods significantly impacted the dynamic response of bridges, and the vertical and torsional dynamic responses of bridges under general constraint arrangement of straight bridges were increased compared to those under boundary conditions for curved beam bridges. As the axle load of the car decreases, the bridge mid-span vertical and torsional dynamic responses showed a decreasing trend. In contrast, the lateral dynamic response gradually increased.
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Su, Dan, Yi-Sheng Liu, Xin-Tong Li, Xiao-Yan Chen e Dong-Han Li. "Management Path of Concrete Beam Bridge in China from the Perspective of Sustainable Development". Sustainability 12, n. 17 (1 settembre 2020): 7145. http://dx.doi.org/10.3390/su12177145.
Testo completoAbstract (sommario):
More and more bridges have entered the maintenance stage, which has potential collapse hazards and threatens life and property safety. More attention has been paid to the improvement of maintenance management levels during the operation period in terms of extending the service life of the bridge, but less attention has been paid to it from the perspective of the whole life cycle. One hundred and ninety examples of concrete beam bridges in China were collected, based on which the collapse characteristics and collapse causes of concrete beam bridges were analyzed. The causes of bridge collapse come from all stages of bridge life cycle, including environmental factors and human factors. Moreover, the effects of the previous phase carry over to the next. Superficially, poor maintenance management during an operation led to bridge collapse. However, the root cause may have occurred at an earlier stage. On this basis, a fuzzy interpretation structure model (FISM) for concrete beam bridge deterioration is conducted. The model can decompose the complex and messy relationship among the factors of bridge collapse into a clear, multi–level and hierarchical structure. Compared with qualitative analysis, an ISM chart can directly reflect the relationship between collapse factors, which is convenient for further analysis. Poor maintenance management during operation is the direct cause, while improper planning, imperfect standards and weak supervision in the early stage are the fundamental causes. Finally, in order to improve the sustainability of concrete beam bridges scientifically, management suggestions are put forward for the participants involved in each stage of the bridge’s life cycle.
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Ye, Yi, Shen Shan Pan e Zhe Zhang. "A Method of Strengthening Concrete Suspension Bridges". Advanced Materials Research 163-167 (dicembre 2010): 3707–12. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.3707.
Testo completoAbstract (sommario):
The method of strengthening the existing reinforced concrete suspension bridges by changing suspension system into cable – stayed- suspension system is presented in this paper. Based on a typical bridge, the analysis of the static behavior of the bridge before and after the strengthening is preformed. The results show that the bending moment of the girder is reduced obviously and the capacity of carrying load is greatly improved. The original cable system is fully utilized and can meet force requirement. It has certain theory significance and practical engineering value to the similar bridge’s strengthening.
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Yang, Mei Liang, Fang Xu e Chuan Xi Li. "The Force Analysis of PC Rigid Frame Curved Bridges with Long Span". Applied Mechanics and Materials 204-208 (ottobre 2012): 2040–44. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2040.
Testo completoAbstract (sommario):
Depend on the Cha Ping Bridge on Yan-Ru Highway, through modeling a dimensional, the thesis researches the curved bridge’s force analysis under different radius of curvature and working conditions. Studies shows as follows: 1) as the continuous rigid frame curved bridges exist greater torque, the box girder generates lateral deformation. 2)the lateral deformation is inversely proportional to the curved bridge’s radius of curvature, the larger the radius of curvature is, the greater the lateral deformation is. 3) variation of the radius of curvature has little effects on the longitudinal stress, vertical deformation and vehicle load. The above conclusions can be borrowed for the design and construction of the similar continuous rigid frame curved bridges.
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Mahfuz, Mahfuz, Mochammad Afifuddin e Renni Anggraini. "TINJAUAN GAYA TSUNAMI PADA JEMBATAN KRUENG RABA". Jurnal Arsip Rekayasa Sipil dan Perencanaan 3, n. 2 (23 settembre 2020): 177–85. http://dx.doi.org/10.24815/jarsp.v3i2.16568.
Testo completoAbstract (sommario):
Aceh Province is located in one of the earth's fault lines in Indonesia, which is an area prone to earthquakes and the potential for a tsunami disaster. Therefore, any planning of structures located on the coast must consider the potential for a tsunami to obtain a strong structure to withstand the forces affected by the tsunami. During the 2004 tsunami, many bridges were carried away by the tsunami. Both bridges made of concrete, as well as steel frame bridges, such as the Krueng Raba steel frame bridge, Lhoknga, the Krueng No bridge, the Meunasah Kulam bridge, and several other bridges. This study aims to analyze and calculate the force and load effects of the tsunami on the structure of one of these bridges, namely the Krueng Raba steel frame bridge, Lhoknga. The force and load of the tsunami effect (Ts) will be analyzed by adopting the Guidelines for Design of Structures for Vertical Evacuation from Tsunamis, 2012, namely: (1) hydrostatic force; (2) buoyant forces; (3) hydrodynamic forces; (4) impulsive forces; (5) debris impact forces; (6) debris damming forces; (7) lift force; and (8) additional gravity load from water retained on the bridge floor. From the results of this study, it is shown that each of the tsunami forces acting on the crew-raba Lhoknga bridge at the minimum tsunami height variable, 11 meters, which is the initial height of the tsunami touching the bridge's superstructure are: 94.866 KN hydrodynamic force; 142,299 KN thrust; 133,810 KN debris impact force; 14,244 KN debris dam force, and 34,018 KN lift force. Meanwhile, the maximum tsunami height variable, 25 meters, is 24634.934 KN hydrodynamic force; 36952,400 KN thrust; 720,591 KN collision force; 3698,939 KN debris blocking force; and 986,519 KN lift styles. The results of the analysis using computational methods, by inputting the magnitude of the tsunami forces to the bridge model, it can be seen that the ability of the Krueng Raba, Lhoknga steel frame bridge to withstand the forces and loads caused by the tsunami only up to a height of 14 meters.
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Lin, Sophia, Shen-En Chen, Wenwu Tang, Vidya Chavan, Navanit Shanmugam, Craig Allan e John Diemer. "Landslide Risks to Bridges in Valleys in North Carolina". GeoHazards 5, n. 1 (21 marzo 2024): 286–309. http://dx.doi.org/10.3390/geohazards5010015.
Testo completoAbstract (sommario):
This research delves into the intricate dynamics of landslides, emphasizing their consequences on transportation infrastructure, specifically highways and roadway bridges in North Carolina. Based on a prior investigation of bridges in Puerto Rico after Hurricane Maria, we found that bridges above water and situated in valleys can be exposed to both landslide and flooding risks. These bridges faced heightened vulnerability to combined landslides and flooding events due to their low depth on the water surface and the potential for raised flood heights due to upstream landslides. Leveraging a dataset spanning more than a century and inclusive of landslide and bridge information, we employed logistic regression (LR) and random forest (RF) models to predict landslide susceptibility in North Carolina. The study considered conditioning factors such as elevation, aspect, slope, rainfall, distance to faults, and distance to rivers, yielding LR and RF models with accuracy rates of 76.3% and 82.7%, respectively. To establish that a bridge’s location is at the bottom of a valley, data including landform, slope, and elevation difference near the bridge location were combined to delineate a bridge in a valley. The difference between bridge height and the lowest river elevation is established as an assumed flooding potential (AFP), which is then used to quantify the flooding risk. Compared to traditional flood risk values, the AFP, reported in elevation differences, is more straightforward and helps bridge engineers visualize the flood risk to a bridge. Specifically, a bridge (NCDOT ID: 740002) is found susceptible to both landslide (92%) and flooding (AFT of 6.61 m) risks and has been validated by field investigation, which is currently being retrofitted by North Carolina DOT with slope reinforcements (soil nailing and grouting). This paper is the first report evaluating the multi-hazard issue of bridges in valleys. The resulting high-fidelity risk map for North Carolina can help bridge engineers in proactive maintenance planning. Future endeavors will extend the analysis to incorporate actual flooding risk susceptibility analysis, thus enhancing our understanding of multi-hazard impacts and guiding resilient mitigation strategies for transportation infrastructure.
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Atadero, Jia, Abdallah e Ozbek. "An Integrated Uncertainty-Based Bridge Inspection Decision Framework with Application to Concrete Bridge Decks". Infrastructures 4, n. 3 (8 agosto 2019): 50. http://dx.doi.org/10.3390/infrastructures4030050.
Testo completoAbstract (sommario):
The limitations of the standard two-year interval for the visual inspection of bridges required by the U.S. National Bridge Inspection Standards have been well documented, and alternative approaches to bridge inspection planning have been presented in recent literature. This paper explores a different strategy for determining the interval between inspections and the type of inspection technique to use for bridges. The foundational premise of the proposed approach is that bridge inspections are conducted to increase knowledge about the bridge’s current condition, and therefore, are only required when uncertainty about the knowledge of the bridge condition is too high. An example case of a reinforced concrete bridge deck was used to demonstrate how this approach would work. The method utilized deterioration models for predicting corrosion and crack initiation time, considering the uncertainty in the models’ parameters. Bridge inspections were used to update the current condition information and model parameters through Bayesian updating. As this paper presents a new idea for inspection planning, not all of the data or models necessary to fully develop and validate the approach currently exist. Nonetheless, the method was applied to a simulated example which demonstrates how the timing and means of bridge inspection can be tailored to provide the required data about individual bridges needed for effective bridge management decision making.
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Qu, Zhanhui, Zemin Han, Haoyu Tang, Jiangbo Xu, Heping Wang e Yifan Liu. "Study on Numerical Simulation of Arch Mechanism of Bridge Pile Foundation". Buildings 14, n. 1 (7 gennaio 2024): 146. http://dx.doi.org/10.3390/buildings14010146.
Testo completoAbstract (sommario):
Bridges are situated in a complex area with geological conditions that are challenging for engineering. It has been observed that certain pile foundations of bridges have been uplifted to varying degrees by up to 309 mm. This has a significant impact on the bridge’s operation and driving safety. The causal mechanism of the bridge pile foundation arch is analyzed through a theoretical analysis and a Plaxis 3D (v.2013) finite element software simulation. The influence of the ground stress and goaf on the bridge pile foundation under different working conditions is studied. The findings indicate that the uplift of the bridge pile foundation due to an equivalent ground stress is the largest, reaching approximately 300 mm in the bridge valley area. Additionally, the uplift of the non-bridge area in the goaf is greater than that of the bridge pile foundation. These results suggest that ground stress is the primary cause of the arching of a bridge pile foundation.
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Greenfield, Tina M., e Eugene S. Takle. "Bridge Frost Prediction by Heat and Mass Transfer Methods". Journal of Applied Meteorology and Climatology 45, n. 3 (1 marzo 2006): 517–25. http://dx.doi.org/10.1175/jam2356.1.
Testo completoAbstract (sommario):
Abstract Frost on roadways and bridges can present hazardous conditions to motorists, particularly when it occurs in patches or on bridges when adjacent roadways are clear of frost. To minimize materials costs, vehicle corrosion, and negative environmental impacts, frost-suppression chemicals should be applied only when, where, and in the appropriate amounts needed to maintain roadways in a safe condition for motorists. Accurate forecasts of frost onset times, frost intensity, and frost disappearance (e.g., melting or sublimation) are needed to help roadway maintenance personnel decide when, where, and how much frost-suppression chemical to use. A finite-difference algorithm (BridgeT) has been developed that simulates vertical heat transfer in a bridge based on evolving meteorological conditions at its top and bottom as supplied by a weather forecast model. BridgeT simulates bridge temperatures at numerous points within the bridge (including its upper and lower surface) at each time step of the weather forecast model and calculates volume per unit area (i.e., depth) of deposited, melted, or sublimed frost. This model produces forecasts of bridge surface temperature, frost depth, and bridge condition (i.e., dry, wet, icy/snowy). Bridge frost predictions and bridge surface temperature are compared with observed and measured values to assess BridgeT's skill in forecasting bridge frost and associated conditions.
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Leal Junior, José Wilson, e Leandro Gomes Domingos. "Economic evaluation of the wooden bridges replacement for steel-reinforced concrete composite bridges in the Balsas-MA rural zones". CONTRIBUCIONES A LAS CIENCIAS SOCIALES 17, n. 2 (14 febbraio 2024): e4576. http://dx.doi.org/10.55905/revconv.17n.2-089.
Testo completoAbstract (sommario):
A river is a natural obstacle in the passage between two points. One way to overcome this obstacle is building a bridge that can be made of rock, wood, steel, concrete, or a combination of these materials. In Balsas, Maranhão’s country town, it is common to use wooden bridges to connect rural communities to each other and to the city’s downtown. However, heavy vehicle traffic has led to the collapse of these bridges, causing isolation and disruption to these communities. The study purpose was to economic evaluation of the wooden bridges replacement for steel-reinforced concrete composite bridges in Balsas, as composite structures are more resistant to applied loads when compared to wooden bridges built in the region. Therefore, replacing budgets for wooden bridge were made and compared with composite bridges construction. The results indicated that composite bridges have a higher cost, but, when analyzing the proposition economically, through net present value, internal rate of return, discounted payback, and cost-benefit, it was found that the proposition is economically viable when the wooden bridge service life lasts for one year. Therefore, it can be concluded that replacing the wooden bridge with a composite bridge is necessary for bridges with a higher collapse incidence. Nevertheless, if the problems caused by isolation due to the collapse of the wooden bridge are considered, replacing the wooden bridge with composite bridges is necessary.
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Made, Suangga, e Irpanni Herry. "Aerodynamic performance of long span steel truss bridges in Indonesia". MATEC Web of Conferences 195 (2018): 02032. http://dx.doi.org/10.1051/matecconf/201819502032.
Testo completoAbstract (sommario):
Indonesia is the world’s largest archipelago with many major rivers in the big islands of Sumatera, Kalimantan, and Java. As part of its road network, major bridges are constructed to cross these rivers. Considering the span of the bridges and its aesthetic point of view, the application of Long Span Steel Truss Bridges in Indonesia is very popular among others. Its span varies from 70 to 270 meters in length. For long span bridges, aerodynamics is an important aspect for the design and construction of the bridges. In order to ensure the stability of the bridges against the aerodynamic effect of the wind, wind tunnel study and test has been conducted for most of the bridges. This paper presents the parameter and characteristic of several Long Span Steel Truss Bridges in Indonesia, i.e. Tayan Kapuas Bridge, Musi VI Bridge, New Kutai Kartanegara Bridges and Teluk Mesjid Bridge. The bridges will be assessed against BD 49/01. Parameters and assessment results are then compared with wind tunnel results.
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Li, Jie, e Lijie Ma. "Research on Quality Inspection and Reinforcement Technology of Road Bridge". Academic Journal of Science and Technology 10, n. 2 (15 aprile 2024): 51–54. http://dx.doi.org/10.54097/np120e98.
Testo completoAbstract (sommario):
With the acceleration of urbanization, road bridges play a crucial role in urban transportation, and their quality condition is directly related to traffic safety and urban development. The article analyzes the common problems of existing road bridges, mainly including cracks, settlement problems and other aspects, to provide a reliable basis for the maintenance and reinforcement of road bridges. Based on this, the article mainly researches the quality inspection technology of road bridges and the reinforcement technology of old bridges at the present stage, and analyzes the application of quality inspection technology and reinforcement technology in improving the structural quality of road bridges according to the construction cases of Jialingjiang Bridge, Qiuyun Bridge and Luoxi Bridge in Heyang, so as to improve the safety of road bridges and prolong the service life of bridges.
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Van Bogaert, Philippe, e Bart De Pauw. "Load‐carrying capacity of Vierendeel bridges in Mechelen". ce/papers 6, n. 5 (settembre 2023): 416–21. http://dx.doi.org/10.1002/cepa.2086.
Testo completoAbstract (sommario):
AbstractFrom 1930 to 1960, in Belgium, steel railway bridges were regularly designed using the vierendeel system. Three railway lines cross the Mechelen‐Leuven canal in the town of Mechelen, providing a unique example of this type of application. Two of these bridges, which were constructed in 1953 were renovated in 2021–2022, including the installation of a new rail fastening. It was discovered that the 1936‐built third and oldest bridge had multiple cracks, mostly in the vertical members of the Vierendeel structure. Furthermore, secondary components like longitudinal beams and cross beams are severely harmed by corrosion. As a result, uncertainty grew over this bridge's ability to support loads. The monuments organization promotes the preservation of these old structures. The material properties, as well as the load‐bearing capacity and the fatigue strength, were evaluated by a thorough experimental and numerical investigation. The results of the examinations suggest that the significant strength variation of the steel components may be the cause of the cracking. It is more likely that cracks developed during the bridge's construction and subsequent repairs than that fatigue is to blame. In conclusion, the arrangement of the three bridges is too special to be destroyed and replaced, and the third bridge may also be sufficiently repaired and rebuilt for long‐term further use.
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Marasabessy, Erwin. "IMPLEMENTATION OF BRIDGE MANAGEMENT SYSTEM ON INTERURBAN BRIDGE IN MALUKU PROVINCE". Journal of the Civil Engineering Forum 1, n. 2 (16 luglio 2017): 63. http://dx.doi.org/10.22146/jcef.23999.
Testo completoAbstract (sommario):
Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS). The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS) complemented with a computer-based Bridge Management Information System (BMIS). Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.