Nonlinear response spectra of SDOF elasto-plastic systems on Bangkok's soft soils | |
| Author | Chanet Sangarayakul |
| Call Number | AIT Thesis no. ST-97-8 |
| Subject(s) | Earthquake resistant design--Thailand--Bangkok Earthquake hazard analysis--Thailand--Bangkok Earthquake resistant design--Thailand--Bangkok Earthquake hazard analysis--Thailand--Bangkok |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ST-97-8 |
| Abstract | Bangkok, the capital city of Thailand, is at risk of distant earthquakes due to the ability of soft soils to amplify ground motions. To mitigate the risk, buildings must be designed to resist ground motions of relatively long predominant period, harmonic-type time history, and long duration, typically found on soft soil sites. Unfortunately, the appropriate seismic design provisions for buildings in Bangkok have not yet been established. The design curves in various seismic design codes are generally formulated based on the studies of inelastic responses of structures subjected earthquake ground motions and the curves are typically derived from constant-ductility yield strength demand spectra at various levels of displacement ductility. Therefore, in this study, the conventional constant-ductility inelastic response spectra (IRS) as well as the new type of IRS so called constant-damage IRS which directly incorporates the effect of repeated cyclic loading have been computed. The Park-Ang damage model is adopted for the assessment of seismic damage of buildings. Due to the lack of recorded ground motions, they have to be simulated based on five selected input strong ground motion records scaled to 0.03, 0.05, and 0.07g (possible range of probabilistic peak ground acceleration in Bangkok) and an appropriate dynamic model of near-surface soil (SHAKE91 program). In order to cover various characteristics of structures, the Modified Takeda, Clough, Elasto-perfectly plastic, and Bilinear hysteretic models are adopted. The effect of P-Delta is also investigated based on uniformly distributed mass and lumped mass SDOF systems. The sensitivity of seismic damage to absorbed hysteretic energy defined by f3 in Park-Ang damage model is varied to investigate the effect on constant-damage IRS. The results show that the low-rise buildings (4-10 stories) in Bangkok's area is at high risk because they can tune or resonate well with earthquake frequency in Bangkok and respond comparably with the tragic 1985 Mexico earthquake. The results also clearly demonstrate that constantdamage IRS which take into account the effect of repeated cyclic loading give more reliable and conservative results than conventional constant-ductility IRS. Finally, smooth yield strength demand spectra for reinforced concrete and well-designed steel structures are proposed. It is anticipated that the spectra will be adopted in the development of seismic resistant design of buildings in Bangkok in the near future. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ST-97-8 |
| 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;Pennung Warnitchai; |
| Examination Committee(s) | Worsak Kanok-Nukulchai;Gupta, Satyendra P.;Chotchai Charoenngam; |
| Scholarship Donor(s) | Asian Institute of Technology Partial Scholarship; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1997 |