Man-induced vibration on pedestrian bridges | |
| Author | Nguyen Nguyen Minh |
| Call Number | AIT Thesis no. ST-95-20 |
| Subject(s) | Bridges--Vibration Bridges--Design and construction |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ST-95-20 |
| Abstract | One of the major serviceability problem in many modern footbridges is the excessive vibrations which can annoy or even alarm people. The vibrations are basically caused by the resonance of the fundamental mode of bridges with periodic load produced by walking pedestrians. In this study, analytical solution of the resonant response of damped footbridge structures under one-pedestrian walking load is derived by an approximation technique, and the solution agrees well with the numerical results obtained from direct integration. The Dynamic amplification factor of resonant response is analytically proved to be a function of structural damping and the number of steps needed to pass the bridge. The findings are very useful for establishing acceptance criteria since there have been no such analytical solution so far. In the second part of the study, the efficiency of Tuned Mass Damper (TMD) in suppressing pedestrian induced vibration is evaluated for a wide range of applications. The efficiency is limited due to the transient nature of human walking load. Since there is no available optimal design of TMD for n·ansient loads, trial and error numerical method is used to determine the optimal parameters. It is found that the efficiency is not as high as that of harmonic steady state response, and the efficiency is approaching that of harmonic steady state response when the number of steps needed to pass the bridge increases. In the final part of the study, an investigation on man-structure interaction is made by an energy approach. The approach is based on the assumption that people walk in such a manner that their metabolic energy cost is minimized. A walking model is formulated based on this assumption, and it is then extended to the case where the bridge is vertically vibrating. From the model, it is found that walking in the same frequency and phase with vertical vibration of structure is the most favorable manner to minimize metabolic energy cost. The greater amplitude of the structural vibration, the less metabolic energy cost for walking in such manner, and the more disturbance to walking steps if walking in different frequencies. Then, the synchronization of pedestrian footsteps with the vibration of structure can be explained. |
| Year | 1995 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ST-95-20 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pennung Warnitchai |
| Examination Committee(s) | Pichai Nimityongskul;Wijeyewickrem, Anil C.;Sutat Weesakul |
| Scholarship Donor(s) | Norwegian Agency for Development Cooperation (NORAD) |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1955 |