MODELING THE FREQUENCY RESPONSE OF A BRIDGE SUPERSTRUCTURE
Open Access
- Author:
- Haddat, Mohamed
- Graduate Program:
- Civil Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- November 11, 2019
- Committee Members:
- Shashidhara S Marikunte, Thesis Advisor/Co-Advisor
Seroj Mackertich-Sengerdy, Program Head/Chair
Sofia Margarita Vidalis, Committee Member
Seroj Mackertich-Sengerdy, Committee Member - Keywords:
- Bridge frequency response
Dynamic response of bridges - Abstract:
- With the evolution in technology there has been a rise of remote electronic monitoring of structures in the transportation industry. These advanced monitoring systems are usually non-destructive, meaning there is no need to disrupt the structure by drilling into it or taking samples, which is a major benefit to use. One of the most easily available non-destructive testing systems is accelerometers that can measure the dynamic response of a structure in real-time. Another is a strain gage, which measures the flexure of a member. Using that strain, and known values of the system such as length, depth, and centroid, total bridge deflection can be calculated. There are different methods by which the test could be conducted. It should be apparent by the results. In this research, the purpose was to determine if data from a non-destructive testing system could be used to calculate the acceleration, velocity, and displacement at the testing location, as well as determine an impulse response model to estimate these reactions to future loading. It is complicated and time consuming to design bridges to resist dynamic loads produced by high speed motor vehicles. It is strongly advisable to reduce the degrees of freedom in the structural system to a single one. An approach of a single degree of freedom system is used for different simple loading cases. It focuses on comparing the response of displacement and bridge span for selected load combinations according to the governing standards and specifications. Oscillations and their effect on the bridge structural integrity are examined to provide some basic understanding on how to reduce and eliminate these undesirable outcomes. Using input data and system output based on the real-world testing of I-80E over Interstate I-287N in New Jersey, it was possible to determine an impulse response model for the system. Using that model, it was possible to convolve a new system output using a new input function converted into a vector. This showed how different load cases affected the structure. After seeing the long settling times, it was determined that the dynamical behavior of the bridge could be improved by using tuned mass dampers.