Effects of multiple support earthquake excitation on dynamic responses of elevated railway structures | |
| Author | Sopon Ritdumrongkul |
| Call Number | AIT Thesis no. ST-01-7 |
| Subject(s) | Bridges--Earthquake effects Earthquake resistant design |
| Note | A thesis submitted in partial fulfillment of the-requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Destruction of bridges can be observed in every major earthquake events although these bridges were designed to resist seismic loading. This may be due to neglecting of spatial variability of earthquake in the design of bridges. Therefore, these bridges were designed based on uniform earthquake ground motion. However, in actual situations, bridges, which are large and long structures, are subjected to different ground motion at each support. Non-uniform ground motion, so-called multiple support excitation, can produces quasi-static responses in addition to inertia responses. In conventional seismic resistant design of railway bridges, structures consist of single cell prestressed concrete box girders supported on singlecolumn reinforced concrete piers. Bearing pads and shear keys are installed at the connections between viaduct and piers. Because of the presence of bearing pads and shear keys, eaGh box girder is designed to behave as a hinge-roller beam on the longitudinal direction. Thus, internal forces in conventional design bridges due to the quasi-static force from multiple support excitation may be small because girders are allowed to move freely along the longitudinal axis of bridges. On the other hand,_ one part of Taiwan High-Speed Rail (THSR) bridge will be constructed by using the alternate design system, which box girders are rigidly fixed with alternate piers. The alternate pier consists of an upper portion of twin walls and a lower portion where a stiff wall is added in the longitudinal direction. The two walls are rigidly connected to the viaduct on opposite sides of the expansion joint. By using monolithic connection between viaduct and piers: large quasi-static forces due to multiple support excitation may occur. Due to very contrast characteristics of these two design systems, therefore, effects of multiple support excitation on linear and nonlinear dynamic responses of both conventional and alternate design bridges are studied. Effects of soil-structure interaction, non-uniform pier-height profile of bridges, and imperfection of bridge properties on the responses are also investigated. It is found that multiple support excitation does not create significant d~fferent dynamic responses as compare to uniform excitation for both conventional design and alternate design structures. Soil-structure interaction can increase or decrease internal member forces. Moreover, it significantly affects serviceability and ductility demands. Non-uniform pier-height profile can significantly affect the serviceability. The imperfection has almost no effect on the responses. Finally, it can be concluded response spectrum analysis can be used for estimating the responses for design purpose. |
| Year | 2001 |
| 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) | Takewaka, Koji ;Barry, William |
| Scholarship Donor(s) | STARR Foundation |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2001 |