Optimal reduction of inelastic seismic demands in high-rise RC core wall buildings using energy dissipating devices | |
| Author | Ahmed, Munir |
| Call Number | AIT Diss. no.ST-11-02 |
| Subject(s) | Seismic Walls Energy dissipation |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Structural Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ST-11-02 |
| Abstract | High-rise RC core wall buildings are being constructed in high seismic areas because they offer advantages of lower costs, faster construction, and more open and flexible architecture compared to high-rise buildings with other lateral-force-resisting systems. Conventionally, a plastic hinge is normally confined at the base of the core wall to control the seismic demands in these structures. However, recent studies show that inelastic seismic demands obtained from the more rigorous non - linear response history analysis (NLRHA) are much larger than those obtained from the well known response spectrum analysis (RSA) procedure. If the designer follows the RSA procedure, he might end up with an unsafe design of the building. On the other hands, if the correct but high seismic demands from the NLRHA procedure are used, the design might lead to uneconomically thick wall with a very high amount of steel reinforcement and expensive foundation structures to withstand very large lateral loading, etc. It is therefore crucial to understand why the seismic demands are such high and why the RSA procedure fails to predict the demands. The improved understanding could lead to more effective design of measures to reduce the seismic demands to acceptable levels. To understand the reasons for the large inelastic seismic demands, total inelastic responses are decomposed into the contributions from each vibration mode. Uncoupled modal response history (UMRHA) is modified to suit the case of the high - rise RC core wall buildings and used for this purpose. A realistic case study building is examined in detail. The modes responsible for the large inelastic seismic demands are identified. The identification of dominant modes and mean elastic design spectra of represent ative ground motions for different damping ratios have led to identification of three control measures: plastic hinges (PHs), buckling restrained braces (BRBs), and fluid viscous dampers (FVDs). The identified control measures are designed to suppress the dominant modes responsible for the large inelastic seismic force demands. Comparison of the modal as well as the total responses of the case study building with and without the control measures shows that all the control measures are effective and able to reduce the inelastic seismic demands. A reduction of 33%, 22%, and 27% in the inelastic shear demand at the base and a reduction of 60%, 22%, and 26% in the inelastic moment demand at the mid height are achieved using the PHs, BRBs, and FVDs respectively. Whereas, a reduction of about 30 - 40% in the inelastic seismic deformation demands is achieved for the case of the BRBs and FVDs. The study enables us to gain insight to the complex inelastic behavior of the high - rise wall buildings with and without the con trol measures |
| Year | 2011 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ST-11-02 |
| Type | Dissertation |
| 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) | Park, Kyung-Ho ;Anwar, Naveed; |
| Scholarship Donor(s) | Higher Education Commission, Pakistan ;Asian Institute of Technology Fellowship; |
| Degree | Thesis (Ph. D.) - Asian Institute of Technology, 2011 |