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:

DOWNLOAD EBOOK

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.

Moving Loads - Dynamic Analysis and Identification Techniques
Moving Loads - Dynamic Analysis and Identification Techniques

Author: Siu-Seong Law

Publisher: CRC Press

Published: 2011-02-18

Total Pages: 332

ISBN-13: 0203841425

DOWNLOAD EBOOK

The interaction phenomenon is very common between different components of a mechanical system. It is a natural phenomenon and is found with the impact force in aircraft landing; the estimation of degree of ripeness of an apple from impact on a beam; the interaction of the magnetic head of a computer disk leading to miniature development of modern c

Dynamics of Highway Bridges
Dynamics of Highway Bridges

Author: Don Albert Linger

Publisher:

Published: 1960

Total Pages: 115

ISBN-13:

DOWNLOAD EBOOK

In the design of highway bridges, the static live load is multiplied by a factor to compensate for the dynamic effect of moving vehicles. This factor, commonly referred to as an impact factor, is intended to provide for the dynamic response of the bridge to moving loads and suddenly applied forces. Many investigators have published research which contradicts the current impact formula 1, 4, 17. Some investigators feel that the problem of impact deals not only with the increase in over-all static live load but that is an integral part of a dynamic load distribution problem 24. The current expanded highway program with the large number of bridge structures required emphasizes the need for investigating some of the dynamic behavior problems which have been generally ignored by highway engineers. These problems generally result from the inability of a designer to predict the dynamic response of a bridge structure. Many different investigations have been made of particular portions of the overall dynamic problem. The results of these varied investigations are inevitably followed by a number of unanswered questions. Ironically, many of the unanswered questions are those which are of immediate concern in the design of highway bridges, and this emphasizes the need for additional research on the problem of impact.

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

DOWNLOAD EBOOK

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.