Effect of Design Parameters on the Dynamic Response of Bridges
Effect of Design Parameters on the Dynamic Response of Bridges

Author:

Publisher:

Published: 2000

Total Pages: 39

ISBN-13:

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Engineers and researchers have long recognized the importance of vehicle-induced vibration with regard to the response and service life of bridges. In spite of the recognition of the importance and role of dynamic response in deterioration and fatigue damage, the use of current design practices can still result in bridges with undesirable dynamic response characteristics. The primary objective of this study was to develop a procedure for representing moving loads on a bridge model within the context of a commercially available computer code. Such an evaluation might reveal ways to improve design procedures to mitigate unacceptable dynamic response. To achieve this goal, it was necessary to employ a moving load, and, thus, a secondary objective was to develop a procedure for representing moving loads on a bridge model within the context of a commercially available computer code. A third objective was to evaluate the relative effects of various parameters that have a substantial effect on dynamic response. Finite element models of typical bridge structures were developed using ANSYS, a commercially available computer code. A feature of this program, the ANSYS Parametric Design Language (APDL), was employed to represent moving loads with various characteristics. The algorithm developed to represent transient loads in the finite element beam model solution provided results essentially identical with those determined from theory. The relative influence of various design and load parameters was investigated using a finite element model of a section of an actual bridge. Midspan displacements of the bridge were calculated and normalized with respect to the static displacement. Changes in displacement attributable to modifications of the bridge characteristics and to loading parameters were determined.

Dynamic Response of Highway Bridges Under a Moving Truck and Development of a Rational Serviceability Requirement
Dynamic Response of Highway Bridges Under a Moving Truck and Development of a Rational Serviceability Requirement

Author: Shabnam Darjani

Publisher:

Published: 2013

Total Pages: 164

ISBN-13:

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Through the development and usage of high-strength materials, the design of more flexible bridges is unavoidable. It is assumed that limiting a bridge static deflection would control the excessive vibration caused by more flexible design. However, results of prior studies indicate that deflection limits do not necessarily address bridges vibrational issue. This dissertation addresses the parameters affecting bridge vibration and provides simple equations to compute bridge dynamic acceleration, velocity and displacement in both transient and steady state parts of the vibration. These equations can then be used to control bridges excessive vibration; and provide human comfort and structural performance. A comprehensive analytical study was performed to evaluate dynamic response of bridges under a moving truck load. The effect of bridge dynamic parameters and vehicle moving conditions are investigated, which includes bridge frequency, damping ratio, span length, girders distance, bracing, support conditions, truck speed, load sequence, axle's weight, and number of spans. Bridge and vehicle k-parameters, which represent the number of vibration cycles before the next excitation occurs, are developed to better explain the vibrational behavior of a bridge. The proposed equations include bridge frequency, static deflection for one axle load, and k-parameters. Finally, a case study is presented to highlight the application of the new approach.

Dynamic Impact Factors for Bridges
Dynamic Impact Factors for Bridges

Author: David I. McLean

Publisher: Transportation Research Board

Published: 1998

Total Pages: 72

ISBN-13: 9780309068192

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This synthesis will be of interest to state department of transportation and consulting bridge, structural, and research engineers. The synthesis describes the current state of the practice for determining dynamic impact factors for bridges. Information for the synthesis was collected by surveying U.S. and Canadian transportation agencies and by conducting a literature search using domestic and foreign sources. This report of the Transportation Research Board documents relevant background and recent information with regard to vehicular dynamic load effects on bridges. It provides details on the basic concepts of bridge dynamics, including identification of the main variables affecting bridge dynamic response. In addition, current code provisions for accounting for vehicular dynamic load effects for new bridge design and load evaluation of existing bridges are reported, including a discussion on the background of the provisions. Finally, a discussion of observed field problems associated with vehicular dynamic load effects, as obtained from the survey, are included.

Vehicle-bridge Interaction Dynamics
Vehicle-bridge Interaction Dynamics

Author: Yeong-Bin Yang

Publisher: World Scientific

Published: 2004

Total Pages: 565

ISBN-13: 9812388478

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The commercial operation of the bullet train in 1964 in Japan marked the beginning of a new era for high-speed railways. Because of the huge amount of kinetic energy carried at high speeds, a train may interact significantly with the bridge and even resonate with it under certain circumstances. Equally important is the riding comfort of the train cars, which relates closely to the maneuverability of the train during its passage over the bridge at high speeds.This book is unique in that it is devoted entirely to the interaction between the supporting bridges and moving trains, the so-called vehicle-bridge interaction (VBI). Finite element procedures have been developed to treat interaction problems of various complexities, while the analytical solutions established for some typical problems are helpful for identifying the key parameters involved. Besides, some field tests were conducted to verify the theories established.This book provides an up-to-date coverage of research conducted on various aspects of the VBI problems. Using the series of VBI elements derived, the authors study a number of frontier problems, including the impact response of bridges with elastic bearings, the dynamic response of curved beam to moving centrifugal forces, the stability and derailment of trains moving over bridges shaken by earthquakes, the impact response of two trains crossing on a bridge, the steady-state response of trains moving over elevated bridges, and so on.

Analysis and Design of Bridges
Analysis and Design of Bridges

Author: C. Yilmaz

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 447

ISBN-13: 9400961227

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The Proceedings of the NATO Advanced Study Institute on Analysis and Design of Bridges held at ~e§me, lzmir, Turkey from 28 June 1982 to 9 July 1982 are contained in the present volume. The Advanced Study Institute was attended by 37 lecturers and participants from 10 different countries. The Organizing Committee consisted of Professors P. Gtilkan, A. C. Scordelis, S. T. Wasti and 9. Yl. lmaz. The guidelines set by NATO for the Advanced Study Institute require it to serve not only as an efficient forum for the dissemination of available advanced knowledge to a selected group of qualified people but also as a platform for the exploration of future research possibilities in the scientific or engineering areas concerned. The main topics covered by the present Advanced Study Institute were the mathematical modelling of bridges for better analysis and the scientific assessment of bridge behaviour for the introduction of improved design procedures. It has been our observation that as a result of the range and depth of the lectures presented and the many informal discussions that took place, ideas became fissile, the stimulus never flagged and many gaps in the engineering knowledge of the participants were "bridged". Here we particularly wish to mention that valuable informal presenta tions of research work were made during the course of the Institute by Drs. Friedrich, Karaesmen, Lamas and Parker.

Dynamic Behavior of Composite Adjacent Pre-Stressed Concrete Box Beams Bridges
Dynamic Behavior of Composite Adjacent Pre-Stressed Concrete Box Beams Bridges

Author: Hajir A. Ali

Publisher:

Published: 2022

Total Pages: 0

ISBN-13:

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Composite adjacent box beams have been utilized to construct bridges as accelerated bridge constructions. These bridges are constantly subjected to the effect of a moving load as vehicles passing over them. Dynamic load allowance (DLA) is a reliable approach to show the amount of that vehicle-bridge interaction. The allowable value of the load allowance factor is 1.33 in AASHTO LRFD (2017), the Bridge Design Specifications. Many researchers have shown that the dynamic load allowance (DLA) value of AASHTO LRFD (2017) does not necessarily yield to a satisfactory account for the dynamic response of highway bridges under moving load. In addition, there is no comprehensive data about adjacent box beams bridges regarding the dynamic load allowance (DLA). Therefore, there is a need to perform a detailed dynamic analysis of vehicle-induced vibration to accurately estimate the dynamic load allowance (DLA) values. This dynamic analysis should include the influence of the most important dynamic parameters, which are related to both the vehicle and bridge circumstances. A field assessment platform was implemented; two adjacent concrete box beams bridges that were dynamically evaluated under the effect of the vehicle-bridge interaction. Then, based on the collected field data, the dynamic load allowance (DLA) values were calculated for all installed instruments under the effect of numerous load cases. The influence of vehicle weights, speeds, brakes, and road roughness conditions on the values of the load allowance factor (DLA) was conducted. In addition, a full scale finite element analysis was performed to complement the field investigation by looking at other dynamic parameters. Finite element method was utilized to model the adjacent box beams bridge of Fairmount Rd according to the asconstructed drawing and ODOT bridge design manual. After modeling, the bridge model was calibrated and validated to analytically investigate the effect of other dynamic parameters on the behavior of this bridge when it is subjected to a moving vehicle. Moving load included two kinds of analysis, the model analysis, and the dynamic analysis. Hence, a parametric study was performed to investigate the effect of an adjacent concrete box beams bridge span length, skew angle, depth, width, and the effect of the material properties of its girders on the values of the dynamic load allowance (DLA). Results of this study illustrate that the dynamic effect of adjacent box beams bridges subjected to moving truck is too important. Under the effect of vehicle-induced vibration, the dynamic load allowance (DLA) values undergoing the effect of most of the investigated parameters were higher than the design limit of AASHTO LRFD (2017). The dynamic load allowance (DLA) value is considerably affected by the speed of the vehicle, road roughness condition and truck braking, skew angle, and stiffness. An empty truck can increase the values of the allowance factor (DLA). Furthermore, the longer the span length of a bridge, the lower recoded dynamic load allowance (DLA) values were. Depth and width of an adjacent box beams bridge and deck thickness have no effect on the values of the dynamic load allowance (DLA).

Dynamics of Railway Bridges
Dynamics of Railway Bridges

Author: L. Fryba

Publisher: Thomas Telford Services Limited

Published: 1996-01-01

Total Pages: 332

ISBN-13: 9780727734716

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Provides a comprehensive survey of the dynamic stresses in railway bridges under moving vehicles and summarizes important theoretical and experimental results which has been obtained from various research programs dealing with European railway bridges.