Download or read book Advanced Numerical Techniques for Dynamic and Aerodynamic Analysis of Bridges written by Hamidreza Naderian and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To meet the economic, social and infrastructure needs of the community for safe and efficient transportation systems, long span bridges have been built throughout the world. Long span bridges are one of the most challenging kinds of structures in civil engineering. The cable-stayed bridges are of great interest mainly as an alternative and a more economic solution than the one of suspension bridges. In addition, the fiber reinforced polymer (FRP) composites are, nowadays, successfully used for constructing modern bridges, where the significant weight saving provides additional benefits. Because of the great flexibility, modern long-span cable-stayed bridges are usually very susceptible to dynamic loads especially to the earthquake and strong winds. Therefore, the earthquake-resistant and wind-resistant designs become one of key issues for successful construction of bridges. The objective of the present research is to develop a very efficient spline finite strip technique, for modelling and analysis of both conventional and hybrid FRP cable-stayed bridges. The study falls into the categories of bending, free vibration, seismic, and aerodynamic flutter analysis. The spline finite strip method (SFSM) is one of the most efficient numerical methods for structural analysis of bridges, reducing the time required for estimating the structural response without affecting the degree of accuracy. In the finite strip method, the degrees of freedom could be significantly reduced due to the semi-analytical nature of this method. However, the previous versions of SFSM are not able to model the entire bridge system. For that reason, the structural interactions between different structural components of the bridge could not be handled. In addition, the vibrations and displacements of the towers and cables could not be investigated. In the present formulation, all these obstacles have been eliminated. Moreover, the proposed finite strip technique is very efficient and accurate due to the drastic reduction in the formulation time, simplicity of data preparation, rapid rate convergence of the results, and the semi-analytical nature. Last but not least, and for the first time, a fully finite strip solution is extended to the area of wind engineering. Using the spline finite strip discretization, the aerodynamic stiffness and mass properties of the long-span cable-stayed bridge are derived. The aerodynamic properties along with the structural properties of long-span plates and bridges are formulated in the aerodynamic equation of motion and are used to analyze the flutter problem. The accuracy and efficiency of the proposed advanced finite strip method is verified against the finite element and field measurement results. The results demonstrate that this methodology and the associated computer code can accurately predict the dynamic and aerodynamic responses of the conventional and FRP long-span cable-stayed bridge systems. The outcome of the present research will lead to a comprehensive structural analysis of bridges in the framework of the proposed discretization which is more efficient and straightforward than the finite element analysis.
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 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 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 Dynamic Analysis of Bridges Using the Finite Strip Method written by Abdulkarim Hassan Ali and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamic analysis of highway bridges is very complex because of the interaction between the moving vehicle load and the bridge response. Analytical methods such as beam theory and orthotropic plate theory are applicable only to simple structures and highly simplified moving vehicle load models. The beam theory is applicable only to long and narrow bridges since it neglects the effect of transverse flexibility of the bridge. The orthotropic plate theory is only applicable to slab bridges under simple vehicle load models as complex vehicle models render the differential equation of equilibrium difficult or impossible to solve. The finite element method is a very powerful and versatile technique which can be applied to deal with any specific configuration of bridge structure, supports and vehicle load models. However, the efficiency of the method needs to be improved because the finite element solutions usually require too much computer time, too large core storage and too much data input. In addition to these deficiencies, in order to simulate the local of the moving concentrated wheel loads the finite element mesh should be refined in both directions. The finite strip method has already proven to be the most efficient numerical technique for the static analysis of bridges. In fact the method is even more efficient for dynamic analysis of bridges. The structure can be divided into a number of finite strips. In each strip the displacement components at any point are expressed in terms of the displacement parameters of nodal lines by means of simple polynomials in the transverse direction and a continuously differentiable smooth series in the longitudinal direction. Thus, the number of dimensions of the analysis is reduced by one. The minimum number of degrees of freedom along a nodal line in the finite strip method is equal to twice times the number of terms used in the series and this is normally much less than that for finite element method, which requires a minimum of three times the number of nodes along the same line. Hence the size and the bandwidth of the matrices are greatly reduced, and consequently it can be handled by personal computers and solved in much shorter time. In this study the finite strip method is applied to dynamic analysis of simply supported single span slab bridges, slab-on girder bridges, box girder bridges and multi-span bridges by using various vehicle load models. Harmonic analysis of beams is covered in Chapter Two as an introduction for the finite strip method. A FORTRAN computer program capable of analyzing all the topics covered in this thesis is also developed.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Advanced Materials and Structural Engineering written by Jong Wan Hu and published by CRC Press. This book was released on 2016-02-03 with total page 996 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ICAMEST 2015 Conference covered new developments in advanced materials and engineering structural technology. Applications in civil, mechanical, industrial and material science are covered in this book. Providing high-quality, scholarly research, addressing developments, applications and implications in the field of structural health monitoring, construction safety and management, sensors and measurements. This volume contains new models for nonlinear structural analysis and applications of modeling identification. Furthermore, advanced chemical materials are discussed with applications in mechanical and civil engineering and for the maintenance of new materials. In addition, a new system of pressure regulating and water conveyance based on small and middle hydropower stations is discussed. An experimental investigation of the ultimate strength and behavior of the three types of steel tubular K-joints was presented. Furthermore, real-time and frequency linear and nonlinear modeling performance of materials of structures contents were concluded with the notion of a fully brittle material, and this approach is implemented in the book by outlining a finite-element method for the prediction of the construction performance and cracking patterns of arbitrary structural concrete forms. This book is an ideal reference for practicing engineers in material, mechanical and civil engineering and consultants (design, construction, maintenance), and can also be used as a reference for students in mechanical and civil engineering courses.
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 320 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 Bridge Aerodynamics written by Allan Larsen and published by Taylor & Francis. This book was released on 1998 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the May 1998 Symposium. Twenty-five contributions present state-of-the-art and future development trends in optimization, bridge aerodynamics and ship collision analysis, and operation and maintenance. Topics include probabilistic methods, aeroelastic analysis, cable dynamics, cross wind on vehicles, and numerical methods. Contains an author index but no subject index. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Numerical Analysis of Aerodynamic Stability of Cables of Long span Suspension Bridges written by Naoki Toyama and published by . This book was released on 2009 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1988 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP written by and published by . This book was released on 1990 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Scientific and Technical Reports written by United States. National Aeronautics and Space Administration Scientific and Technical Information Division and published by . This book was released on 1968 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Selected Listing of NASA Scientific and Technical Reports written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Division and published by . This book was released on 1968 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Safety and Reliability Safe Societies in a Changing World written by Stein Haugen and published by CRC Press. This book was released on 2018-06-15 with total page 3202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safety and Reliability – Safe Societies in a Changing World collects the papers presented at the 28th European Safety and Reliability Conference, ESREL 2018 in Trondheim, Norway, June 17-21, 2018. The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk management Safety and Reliability – Safe Societies in a Changing World will be invaluable to academics and professionals working in a wide range of industrial and governmental sectors: offshore oil and gas, nuclear engineering, aeronautics and aerospace, marine transport and engineering, railways, road transport, automotive engineering, civil engineering, critical infrastructures, electrical and electronic engineering, energy production and distribution, environmental engineering, information technology and telecommunications, insurance and finance, manufacturing, marine transport, mechanical engineering, security and protection, and policy making.
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1989 with total page 1676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
