2016 Fiscal Year Annual Research Report
大地震後の継続使用を保証する応答制御型建築構造物の研究
| Project/Area Number |
16J04449
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
CHEN XINGCHEN 東京工業大学, 大学院理工学研究科(工学系), 特別研究員(DC2)
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| Project Period (FY) |
2016-04-22 – 2018-03-31
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| Keywords | Continuous spine frame / Segmented spine frame / Key structure properties / Parametric study / Seismic performance / Design procedure |
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| Outline of Annual Research Achievements |
A better understanding on the relation between seismic behavior and key structural properties has been achieved by extensive parametric study for the proposed controlled spine frame system. Based on the results, a simple design procedure has been proposed based on a widely used design method for traditional frame structures, which will better promote application of the proposed system in actual projects.
As a research tool, a simplified dual multi-degree-of-freedom model along with a self-developed nonlinear dynamic analysis program has been established for the proposed system. This tool be very helpful for further study of the proposed system and similar systems.
Besides the continuous spine frame system, a new segmented spine frame system and its optimal configuration has been proposed for tall buildings aiming easier application. The previously proposed design procedure is extended for tall buildings adopting either continuous or segmented spine frames after considering higher-modes contribution to total seismic response. Application scope, clear limitations and recommendations for the use of the design procedure has been provided.
One international journal paper is under publishing. Another one is under construction and will be submitted in two months. This research is expected to drawing interest from both researchers and engineers. The low-damage, high robust performance of the proposed system along with the simple design and construction method is highly promising to be widely applied in new building constructions, hence improving the seismic resilience of urban cities.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Following research results has been achieved from this year’s research as planned in the application form:
1. Seismic behavior of the proposed controlled spine frame system and effect of key structural properties has been well studied by extensive parametric study on both simplified dual multi-degree-of-freedom (DMD) model and original model. Higher-modes contribution to seismic performance of tall buildings adopting the proposed spine frames has been well studied by both static and dynamic analysis along with theoretical explanation. Clear limitation and recommendation has been established for applying the proposed system.
2. Segmented spine frame system has been proposed for tall buildings and the simplified DMD model as well as the nonlinear dynamic analysis program are modified for the segmented system. Study results on seismic performance of the segmented system correct some primary assumptions and reveal a significant effect in reducing strength demand of spine frames, which is beneficial for actual application of the proposed system.
3. Optimal configuration of the segmented spine frame system is figured out by extensive parametric study, including story numbers of each segment, total number of segments, damper amount at each segmented level, et al. Simple design procedure considering higher-modes effect is proposed for tall buildings utilizing either continuous or segmented spine frames and recommendations for key structural parameters are provided.
In conclusion, the research targets have been completed and new studies are going on smoothly.
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| Strategy for Future Research Activity |
Seismic evaluation and design method for buildings adopting the controlled spine frame structural system have be developed based on extensive verification considering various structural properties. However, assumptions involved in the evaluation method, particularly those related with nonlinear modal response combination need more verification by considering a wider variety of ground motion types and intensities. Besides, the main frames concerned in previous studies were all regularly designed. Irregularly designed frames, which are the often cases in actual projects, will be investigated and relation between the sufficient stiffness of spine frames and the irregularity in main frames will be established.
The concerned structural responses in previous study focused on the most essential performance objectives such as the peak deformation and force of the spine frame and the main frame. Residual deformation that reflecting self-centering capacity will be concerned and effect of main frame stiffness corresponding to different damping amount will be investigated. Interaction force between the spine frame and the main frame will be further investigated in order to establish a clear guidance for designing the connecting elements. Based on those study related recommendations will be added to the design method.
The current results indicate that concentrically equipped dampers may be less effective in dissipating earthquake energy. Although segmented configuration can improve this issue to some extent, it worth further study on more distributed dampers layout.
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