Dynamics of Highway Bridges, Iowa Highway Research Board Bulletin 17, 1960

Joint Publications from Iowa Engineering Experiment Station - Bulletin No. 188 and Iowa Highway Research Board - Bulletin No. 17. 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 it is an integral part of a dynamic load distribution problem. 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.

Annual Report of Iowa Highway Research Board Research and Development Activities FY 08

RESEARCH AND DEVELOPMENT The Highway Division of the Iowa Department of Transportation (Iowa DOT) engages in research and development for two reasons: first, to find workable solutions to the many problems that require more than ordinary, routine investigation; second, to identify and implement improved engineering and management practices. This report, entitled "Iowa Highway Research Board Research and Development Activities FY2008" is submitted in compliance with Sections 310.36 and 3 I2.3A, Code of Iowa, which direct the submission of a report of the Secondary Road Research Fund and the Street Research Fund respectively. It is a report of the status of research and development projects in progress on June 30, 2008; it is also a report on projects completed during the fiscal year beginning July 1, 2007, and ending June 30, 2008. Detailed information on each of the research and development projects mentioned in this report is available in the Research and Technology Bureau in the Highway Division of the Iowa Department of Transportation. IOWA HIGHWAY RESEARCH BOARD In developing a progressive, continuing and coordinated program of research and development, the Highway Division is assisted by the Iowa Highway Research Board. This advisory group was established in 1949 by the Iowa State Highway Commission to respond to the research denoted in Section 310.36 of the Code of Iowa and now is denoted by 312.3A. The Research Board consists of 15 regular members: seven Iowa county engineers, four Iowa DOT engineers, one representative from Iowa State University, one from The University of Iowa, and two engineers employed by Iowa municipalities. Each regular member may have an alternate who will serve at the request of the regular member. The regular members and their alternates are appointed for a three-year term. The membership of the Research Board as of June 30, 2008, is listed in Table I. The Research Board held nine regular meetings during the period ofJuly 1, 2007, to June 30, 2008. Suggestions for research and development were reviewed at these meetings and recommendations were made by the Board.

Annual Report of Iowa Highway Research Board Research and Development Activities 2007

RESEARCH AND DEVELOPMENT The Highway Division of the Iowa Department of Transportation (Iowa DOT) engages in research and development for two reasons: first, to find workable solutions to the many problems that require more than ordinary, routine investigation; second, to identify and implement improved engineering and management practices. This report, entitled "Iowa Highway Research Board Research and Development Activities FY2008" is submitted in compliance with Sections 310.36 and 3 I2.3A, Code of Iowa, which direct the submission of a report of the Secondary Road Research Fund and the Street Research Fund respectively. It is a report of the status of research and development projects in progress on June 30, 2008; it is also a report on projects completed during the fiscal year beginning July 1, 2007, and ending June 30, 2008. Detailed information on each of the research and development projects mentioned in this report is available in the Research and Technology Bureau in the Highway Division of the Iowa Department of Transportation. IOWA HIGHWAY RESEARCH BOARD In developing a progressive, continuing and coordinated program of research and development, the Highway Division is assisted by the Iowa Highway Research Board. This advisory group was established in 1949 by the Iowa State Highway Commission to respond to the research denoted in Section 310.36 of the Code of Iowa and now is denoted by 312.3A. The Research Board consists of 15 regular members: seven Iowa county engineers, four Iowa DOT engineers, one representative from Iowa State University, one from The University of Iowa, and two engineers employed by Iowa municipalities. Each regular member may have an alternate who will serve at the request of the regular member. The regular members and their alternates are appointed for a three-year term. The membership of the Research Board as of June 30, 2008, is listed in Table I. The Research Board held nine regular meetings during the period ofJuly 1, 2007, to June 30, 2008. Suggestions for research and development were reviewed at these meetings and recommendations were made by the Board.