| Author | Agrawal, Pratibha |
| Call Number | AIT Thesis no.ST-19-15 |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Structural Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ST-19-15 |
| Abstract | In this study, seismic assessment of Multi-Span Simply Supported (MSSS) bridge located in high seismic hazard area, Chiang Mai, Thailand is studied. The bridge is conventional, i.e., non-seismically designed. The conventional bridge is then retrofitted by replacing conventional bridge with isolating Lead-Rubber Bearing, with super-structure modification and backfill designed as fuse elements. Realistic seismic behavior of bridge is studied through non-linear 3D models in SAP 2000. The models are capable of simulating flexural yielding of piers, bi-linear behavior of isolation bearings, elastic-perfect behavior of elastomeric bearings of conventional bridge and other important non-linear behaviors of these structures. Seismic response of bridges are evaluated under seven sets of ground motion records, where each set has two horizontal components applied in longitudinal and transverse directions of bridges, but the vertical components are ignored. The representative ground motions are selected such that their average response spectrum approximately resemble to the maximum credible spectrum (MCE) of Chiang Mai, Thailand, site response spectrum. Non-linear time history analysis is conducted to prove that Lead-Rubber Isolator is an effective approach for retrofitting the existing bridge. Lead-Rubber bearing reduces column behavior (Base shear and top displacement) and increases the deck displacement. This increase in deck displacement results in pounding between deck-deck and deckabutment. To prevent severe damage to the whole abutment, the abutment back-wall is designed as a knock-off element with backfill to mobilize at very low yield strength so that abutment can behave as a roller support after the rupture of backwall. Also, the simply supported multi-spans are locked together and made continuous, thus minimizing the deckdeck pounding. This retrofitting scheme results, simply supported bridge to continuous isolated bridge. All these retrofit schemes are very easy to implement and not very expensive. The continuous isolated bridge, results in a much lower demand on the bridge column, large deck displacement, and fixed abutment behaving as roller support with backfill designed with a much lower yield strength. Also, the number of pounding and magnitude of pounding force decreases in the final retrofitted bridge with backfill with lower yield strength. |
| Year | 2019 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ST-19-15 |
| Type | Thesis |
| School | School of Engineering and Technology |
| 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) | Punchet Thammarak;Anwar, Naveed; |
| Scholarship Donor(s) | BRIDGEX BINA SDN BHD, Malaysia; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2019 |