Suppressing wind-induced response of tall buildings by multiple tuned liquid dampers | |
| Author | Apiwat Thaiboonmee |
| Call Number | AIT Thesis no.ST-16-13 |
| Subject(s) | Tall buildings Buildings--Wind stresses |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Structural Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Tall buildings are often susceptible to wind actions because its inherent damping ratio is quite low. With low inherent damping, there are many effects in tall buildings caused by wind-induced vibration which a major concern is discomfort to the occupants. To avoid such problems, the vibration of buildings can be diminished by installing Multiple Tuned Liquid Dampers (MTLD) which using the several number of TLD that the sloshing frequencies are distributed in wider range to cover the controlled structural frequency. In this thesis, a 50-storey building located in Bangkok is selected as a case study to demonstrate the performance of MTLD. The studies of the performance of MTLD including nonlinear damping due to flow-dampening devices are performed through numerical analysis. The harmonic excitation is firstly used to identify the characteristic of MTLD in order to develop a design procedure. Afterwards, time history wind force which is simulated corresponding to the provided data from wind tunnel tests for the case study building is applied to investigate the performance of MTLD. The effective properties of MTLD which are transformed from the generalized properties must be used in design MTLD: size of TLD’s tank and liquid height. With the effective properties, the mass ratio can be obtained in the same form of using Tuned Mass Damper (TMD). The optimal theory of TMD can be applied to estimate the optimal damping of MTLD, since the optimal damping of Multiple Tuned Mass Dampers (MTMD) designed by the same condition as MTLD is found almost equal to the optimal damping of MTLD which is obtained by numerical analysis and the optimal damping of MTMD is in the optimal damping range of MTLD. To achieve the optimal damping of MTLD, the vertical and horizontal circular-section poles which are used as the flow-dampening devices can be applied. The expressions for the damping due to the multiple rows of vertical poles and for the horizontal poles, the design consideration, and the example are presented. Additionally, in design MTLD, it is found that the tuning frequency range is still the most important design parameter as it affects their effectiveness and robustness against estimation error in the structural natural frequency. It is also found that the MTLD with suitable selection of TLD number, tuning frequency range, and damping ratio is more effective and robust than a single TLD and a single TMD. Moreover, the effectiveness and robustness of MTLD which includes the nonlinear damping due to the flow-dampening devices can be compared with MTMD which is design by linear damping. Furthermore, MTLD can efficiently control the dynamic response of the structure induced by wind. The peak acceleration of the structure which is a major concern in along-wind and across-wind direction for the several mean wind speed is significantly suppressed around 50% - 60%. Hence, the results clearly demonstrate the potential of the MTLD in suppressing wind-induced response of the building. |
| Year | 2016 |
| 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) | Anwar, Naveed;Punchet Thammarak; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2016 |