Download or read book Numerical Simulations on the Effects of Edge Details on Aerodynamic Characteristics of Long Span Bridge Deck Sections written by Richard A. Obisanya and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Effects on Cable Supported Bridges written by You-Lin Xu and published by John Wiley & Sons. This book was released on 2013-03-07 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: As an in-depth guide to understanding wind effects on cable-supported bridges, this book uses analytical, numerical and experimental methods to give readers a fundamental and practical understanding of the subject matter. It is structured to systemically move from introductory areas through to advanced topics currently being developed from research work. The author concludes with the application of the theory covered to real-world examples, enabling readers to apply their knowledge. The author provides background material, covering areas such as wind climate, cable-supported bridges, wind-induced damage, and the history of bridge wind engineering. Wind characteristics in atmospheric boundary layer, mean wind load and aerostatic instability, wind-induced vibration and aerodynamic instability, and wind tunnel testing are then described as the fundamentals of the subject. State-of-the-art contributions include rain-wind-induced cable vibration, wind-vehicle-bridge interaction, wind-induced vibration control, wind and structural health monitoring, fatigue analysis, reliability analysis, typhoon wind simulation, non-stationary and nonlinear buffeting response. Lastly, the theory is applied to the actual long-span cable-supported bridges. Structured in an easy-to-follow way, covering the topic from the fundamentals right through to the state-of-the-art Describes advanced topics such as wind and structural health monitoring and non-stationary and nonlinear buffeting response Gives a comprehensive description of various methods including CFD simulations of bridge and vehicle loading Uses two projects with which the author has worked extensively, Stonecutters cable-stayed bridge and Tsing Ma suspension bridge, as worked examples, giving readers a practical understanding

Download or read book Experimental and CFD Investigations of the Megane Multi box Bridge Deck Aerodynamic Characteristics written by Zhida Wang and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Engineering International written by and published by . This book was released on 2002 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Methods for the Multi Physical Analysis of Long Span Cable Stayed Bridges written by Nazim Abdul Nariman and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The main categories of wind effects on long span bridge decks are buffeting, flutter, vortex-induced vibrations (VIV) which are often critical for the safety and serviceability of the structure. With the rapid increase of bridge spans, research on controlling wind-induced vibrations of long span bridges has been a problem of great concern.The developments of vibration control theories have led to the wide use of tuned mass dampers (TMDs) which has been proven to be effective for suppressing these vibrations both analytically and experimentally. Fire incidents are also of special interest in the stability and safety of long span bridges due to significant role of the complex phenomenon through triple interaction between the deck with the incoming wind flow and the thermal boundary of the surrounding air. This work begins with analyzing the buffeting response and flutter instability of three dimensional computational structural dynamics (CSD) models of a cable stayed bridge due to strong wind excitations using ABAQUS finite element commercial software. Optimization and global sensitivity analysis are utilized to target the vertical and torsional vibrations of the segmental deck through considering three aerodynamic parameters (wind attack angle, deck streamlined length and viscous damping of the stay cables). The numerical simulations results in conjunction with the frequency analysis results emphasized the existence of these vibrations and further theoretical studies are possible with a high level of accuracy. Model validation is performed by comparing the results of lift and moment coefficients between the created CSD models and two benchmarks from the literature (flat plate theory) and flat plate by (Xavier and co-authors) which resulted in very good agreements between them. Optimum values of the parameters have been identified. Global sensitivity analysis based on Monte Carlo sampling method was utilized to formulate the surrogate models and calculate the sensitivity indices. The rational effect and the role of each parameter on the aerodynamic stability of the structure were calculated and efficient insight has been constructed for the stability of the long span bridge. 2D computational fluid dynamics (CFD) models of the decks are created with the support of MATLAB codes to simulate and analyze the vortex shedding and VIV of the deck. Three aerodynamic parameters (wind speed, deck streamlined length and dynamic viscosity of the air) are dedicated to study their effects on the kinetic energy of the system and the vortices shapes and patterns. Two benchmarks from the literature (Von Karman) and (Dyrbye and Hansen) are used to validate the numerical simulations of the vortex shedding for the CFD models. A good consent between the results was detected. Latin hypercube experimental method is dedicated to generate the surrogate models for the kinetic energy of the system and the generated lift forces. Variance based sensitivity analysis is utilized to calculate the main sensitivity indices and the interaction orders for each parameter. The kinetic energy approach performed very well in revealing the rational effect and the role of each parameter in the generation of vortex shedding and predicting the early VIV and the critical wind speed. Both one-way fluid-structure interaction (one-way FSI) simulations and two-way fluid-structure interaction (two-way FSI) co-simulations for the 2D models of the deck are executed to calculate the shedding frequencies for the associated wind speeds in the lock-in region in addition to the lift and drag coefficients. Validation is executed with the results of (Simiu and Scanlan) and the results of flat plate theory compiled by (Munson and co-authors) respectively. High levels of agreements between all the results were detected. A decrease in the critical wind speed and the shedding frequencies considering (two-way FSI) was identified compared to those obtained in the (one-way FSI). The results from the (two-way FSI) approach predicted appreciable decrease in the lift and drag forces as well as prediction of earlier VIV for lower critical wind speeds and lock-in regions which exist at lower natural frequencies of the system. These conclusions help the designers to efficiently plan and consider for the design and safety of the long span bridge before and after construction. Multiple tuned mass dampers (MTMDs) system has been applied in the three dimensional CSD models of the cable stayed bridge to analyze their control efficiency in suppressing both wind -induced vertical and torsional vibrations of the deck by optimizing three design parameters (mass ratio, frequency ratio and damping ratio) for the (TMDs) supporting on actual field data and minimax optimization technique in addition to MATLAB codes and Fast Fourier Transform technique. The optimum values of each parameter were identified and validated with two benchmarks from the literature, first with (Wang and co-authors) and then with (Lin and co-authors). The validation procedure detected a good agreement between the results. Box-Behnken experimental method is dedicated to formulate the surrogate models to represent the control efficiency of the vertical and torsional vibrations. Sobol's sensitivity indices are calculated for the design parameters in addition to their interaction orders. The optimization results revealed better performance of the MTMDs in controlling both the vertical and the torsional vibrations for higher mode shapes. Furthermore, the calculated rational effect of each design parameter facilitates to increase the control efficiency of the MTMDs in conjunction with the support of the surrogate models which simplifies the process of analysis for vibration control to a great extent. A novel structural modification approach has been adopted to eliminate the early coupling between the bending and torsional mode shapes of the cable stayed bridge. Two lateral steel beams are added to the middle span of the structure. Frequency analysis is dedicated to obtain the natural frequencies of the first eight mode shapes of vibrations before and after the structural modification. Numerical simulations of wind excitations are conducted for the 3D model of the cable stayed bridge. Both vertical and torsional displacements are calculated at the mid span of the deck to analyze the bending and the torsional stiffness of the system before and after the structural modification. The results of the frequency analysis after applying lateral steel beams declared that the coupling between the vertical and torsional mode shapes of vibrations has been removed to larger natural frequencies magnitudes and higher rare critical wind speeds with a high factor of safety. Finally, thermal fluid-structure interaction (TFSI) and coupled thermal-stress analysis are utilized to identify the effects of transient and steady state heat-transfer on the VIV and fatigue of the deck due to fire incidents. Numerical simulations of TFSI models of the deck are dedicated to calculate the lift and drag forces in addition to determining the lock-in regions once using FSI models and another using TFSI models. Vorticity and thermal fields of three fire scenarios are simulated and analyzed. The benchmark of (Simiu and Scanlan) is used to validate the TFSI models, where a good agreement was manifested between the two results. Extended finite element method (XFEM) is adopted to create 3D models of the cable stayed bridge to simulate the fatigue of the deck considering three fire scenarios. The benchmark of (Choi and Shin) is used to validate the damaged models of the deck in which a good coincide was seen between them. The results revealed that the TFSI models and the coupled thermal-stress models are significant in detecting earlier vortex induced vibration and lock-in regions in addition to predicting damages and fatigue of the deck and identifying the role of wind-induced vibrations in speeding up the damage generation and the collapse of the structure in critical situations.

Download or read book Aerodynamics of Large Bridges written by Allan Larsen and published by Routledge. This book was released on 2017-10-19 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: As bridges spans get longer, lighter and more slender, aerodynamic loads become a matter of serious study. This volume of proceedings reflect the co-operation between civil and mechanical engineering and meteorology in this field.

Download or read book Aeroelastic Phenomena and Pedestrian structure Dynamic Interaction on Non conventional Bridges and Footbridges written by Claudio Borri and published by Firenze University Press. This book was released on 2010 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid-structure and pedestrian-structure interaction phenomena are extremely important for non-conventional bridges. The results presented in this volume concern: simplified formulas for flutter assessment; innovative structural solutions to increase the aeroelastic stability of long-span bridges; numerical simulations of the flow around a benchmark rectangular cylinder; examples of designs of large structures assisted by wind-tunnel tests; analytical, computational and experimental investigation of the synchronisation mechanisms between pedestrians and footbridge structures. The present book is addressed to a wide audience including professionals, doctoral students and researchers, aiming to increase their know-how in the field of wind engineering, bluff-body aerodynamics and bridge dynamics.

Download or read book System Based Vision For Strate written by Franco Bontempi and published by CRC Press. This book was released on 2003-01-01 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: Objective of conference is to define knowledge and technologies needed to design and develop project processes and to produce high-quality, competitive, environment- and consumer-friendly structures and constructed facilities. This goal is clearly related to the development and (re)-use of quality materials, to excellence in construction management and to reliable measurement and testing methods.

Download or read book Experimental Investigation of Effect of Windshield Barriers on the Aerodynamic Properties of the Multi box Bridge Decks written by Chen, xi and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulations of the Aerodynamic Characteristics of Circulation Control Wing Sections written by Yi Liu and published by . This book was released on 2003 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Action Phenomena Associated with Large Span Bridges written by Daniel C. Vaz and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past, the design of bridges over increasing distances was limited by construction techniques and, as always, by economics. As technological advances have turned possible cable-supported bridges of incredible spans, a new challenge has been added to the equation: that of withstanding the action of winds without developing undesirable dynamic responses. In this chapter, the several aerodynamic phenomena of relevance to long-span bridges are classified and discussed. This will interest both experts and non-experts in the field, thanks to the overview that is given. For certain cases, codes of practice recommend wind tunnel tests. The reader is introduced to these, as well as to numerical simulations, which are currently gaining increasing importance. Next, measures for attenuating susceptibility for undesirable dynamic responses are reviewed. The chapter ends with a discussion of the Vila Real Bridge deck section, based on wind tunnel tests and numerical simulations carried out by the authors: the aerodynamics was effectively improved with geometrically subtle modifications that were proposed and adopted still in the design phase.

Download or read book Numerical Bridge Deck Aerodynamics Investigation written by C. Marni and published by . This book was released on 2024-01-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical Bridge Deck Aerodynamics Investigation" is a comprehensive and insightful book that focuses on the study of aerodynamics specifically related to bridge decks through numerical analysis. Written by experts in the field, this book presents an in-depth exploration of the complex interactions between bridge decks and the surrounding wind flow, utilizing advanced computational techniques. The book begins by establishing a strong foundation in the fundamental principles of aerodynamics and bridge engineering. It then delves into the numerical methods and simulation models employed to accurately predict and analyze the aerodynamic behavior of bridge decks under various wind conditions. The authors present in detailed with simulations, providing practical insights into the flow patterns, wind pressures, and structural responses experienced by bridge decks. Throughout the book, the authors highlight the significance of accurate aerodynamic analysis in the design and maintenance of bridges, emphasizing the importance of considering aerodynamic loads to ensure structural safety and serviceability. They discuss various factors influencing the aerodynamic performance of bridge decks, such as bridge geometry, wind direction, wind turbulence, and wind-induced vibrations. This book serves as an invaluable resource for researchers, engineers, and professionals involved in bridge design, construction, and maintenance. By employing numerical techniques, the book offers a systematic approach to evaluating and optimizing the aerodynamic performance of bridge decks, leading to more efficient and reliable bridge designs. It bridges the gap between theory and practice, offering practical guidance and solutions for mitigating the potential risks associated with wind effects on bridges.

Download or read book Bridge Aeroelasticity written by J. A. Jurado and published by WIT Press. This book was released on 2011 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is dedicated to the study of an aeroelastic phenomenon of cable supported long span bridges known as flutter, and proposes very innovative design methodologies, such as sensitivity analysis and optimization techniques, already utilized successfully in automobile and aerospace industries. The topic of long-span suspension and cable-stayed bridges is currently of great importance. These types of bridge pose great technical difficulties due to their slenderness and often great dimension. Therefore, these bridges tend to have problems caused by natural forces such as wind loads, some of which we have witnessed in our history, and we are currently seeing a very high incidence of bridge construction to overcome geographical obstacles such as bays, straits, or great estuaries. Therefore, it seems very appropriate to write a book showing the current capability of analysis and design, when up until now, the information could only be found partially in technical articles. This book will be useful for bridge design engineers as well as researchers working in the field. This book only requires previous knowledge of structural finite element models and dynamics, and it is advisable to have some previous knowledge in bridge engineering. Nevertheless, this book is very self-contained in such a way that all the information necessary to understand the theoretical developments is presented without the need of additional bibliography.

Download or read book Aerodynamic Characteristics of Long span Twin deck Bridges written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Xxii, 206 leaves : ill. ; 30 cm.

Download or read book Aerodynamic Characteristics of Long span Twin deck Bridges written by Chin Hong Fok and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Small Scale Transonic Investigation of the Effects of Partial Span Leading Edge Camber on the Aerodynamic Characteristics of a 50 Deg 38 Sweptback Wi written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A small-scale transonic investigation of two semispan wings of the same plan form was made in the Langley high-speed 7- by 10-foot tunnel through a Mach number range of 0.70 to 1.10 and a mean-test Reynolds number range of 745,000 to 845,000 to determine the effects of partial-span leading-edge camber on the aerodynamic characteristics of a swept-back wing. This paper presents the results of the investigation of wing-alone and wing-fuselage configurations of the two wings; one, was an uncambered wing and the other had the forward 45 percent of the chord cambered over the outboard 55 percent of the span. The semispan wings had 50deg 38ft sweepback of their quarter-chord lines, aspect ratio of 2.98, taper ratio of 0.45, and modified NACA 64A-series airfoil sections tapered in thickness ratio. Lift, drag, pitching moment, and root-bending moment were obtained for these configurations. The results indicated that, for the wing-alone configuration, use of the partial-span leading-edge camber provided an increase in maximum lift-drag ratios up to a Mach number of 0.95, after which no gain was realized. For the wing-fuselage combination, the partial-span leading-edge camber appeared to cause no gain in maximum lift-drag ratio throughout the test range of Mach numbers. The lift-curve slopes of the partial-span leading-edge camber configurations indicated no significant change over the basic configurations in the subsonic range but resulted in slight reductions at the higher Mach numbers. No significantly large changes in pitching-moment-curve slopes or lateral center of additional loading were indicated because of the modification.

Download or read book Pareto and Reliability Oriented Aeroelastic Shape Optimization of Bridge Decks written by Zouhour Jaouadi and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the development of new technologies and materials, optimized bridge design has recently gained more attention. The aim is to reduce the bridge components materials and the CO2 emission from the cement manufacturing process. Thus, most long-span bridges are designed to be with high flexibility, low structural damping, and longer and slender spans. Such designs lead, however, to aeroelastic challenges. Moreover, the consideration of both the structural and aeroelastic behavior in bridges leads to contradictory solutions as the structural constraints lead to deck prototypes with high depth which provide high inertia to material volume ratios. On the other hand, considering solely the aerodynamic requirements, slender airfoil-shaped bridge box girders are recommended since they prevent vortex shedding and exhibit minimum drag. Within this framework comes this study which provides approaches to find optimal bridge deck cross-sections while considering the aerodynamic effects. Shape optimization of deck cross-section is usually formulated to minimize the amount of material by finding adequate parameters such as the depth, the height, and the thickness and while ensuring the overall stability of the structure by the application of some constraints. Codes and studies have been implemented to analyze the wind phenomena and the structural responses towards bridge deck cross-sections where simplifications have been adopted due to the complexity and the uniqueness of such components besides the difficulty of obtaining a final model of the aerodynamic behavior. In this thesis, two main perspectives have been studied; the first is fully deterministic and presents a novel framework on generating optimal aerodynamic shapes for streamlined and trapezoidal cross-sections based on the meta-modeling approach. Single and multi-objective optimizations were both carried out and a Pareto Front is generated. The performance of the optimal designs is checked afterwards. In the second part, a new strategy based on Reliability-Based Design Optimization (RBDO) to mitigate the vortex-induced vibration (VIV) on the Trans-Tokyo Bay bridge is proposed. Small changes in the leading and trailing edges are presented and uncertainties are considered in the structural system. Probabilistic constraints based on polynomial regression are evaluated and the problem is solved while applying the Reliability Index Approach (RIA) and the Performance Measure Approach (PMA). The results obtained in the first part showed that the aspect ratio has a significant effect on the aerodynamic behavior where deeper cross-sections have lower resistance against flutter and should be avoided. In the second part, the adopted RBDO approach succeeded to mitigate the VIV, and it is proven that designs with narrow or prolonged bottom-base length and featuring an abrupt surface change in the leading and trailing edges can lead to high vertical vibration amplitude. It is expected that this research will help engineers with the selections of the adequate deck cross-section layout, and encourage researchers to apply concepts of optimization regarding this field and develop the presented approaches for further studies.