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Deepshikha Nair

Bio: Deepshikha Nair is an academic researcher from Tokyo Institute of Technology. The author has contributed to research in topics: Structural engineering & Substructure. The author has an hindex of 1, co-authored 2 publications receiving 1 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the seismic response characteristics of 150m-span domes supported by multi-storey substructures are investigated, and the effects of the post- yield stiffness of multistore structures are also analyzed by considering two structural systems, buckling- restrained braced frames and damped spine frames.
Abstract: This paper investigates the seismic response characteristics of long-span domes. The natural periods of the prominent modes are longer than medium-span domes, which leads to a greater contribution from the higher modes to the response of the long-span dome. The acceleration distributions, particularly the vertical acceleration distributions are sensitive to the dominant mode shapes of these higher modes. This leads to inaccuracies when applying the previously proposed response evaluation methods. The vibration modes of multi-storey supporting substructures also affect the excited vibration modes of the roof. In this paper, the dynamic characteristics and seismic response of 150m-span domes supported by multi-storey substructures are studied. The effects of the post- yield stiffness of multi-storey substructures are also analysed by considering two structural systems, buckling- restrained braced frames (BRBF) and damped spine frames. A simple design procedure to evaluate the equivalent static loads using amplification factors and incorporating the effects of higher modes is proposed based on response spectrum analysis and equivalent linearisation procedures. The accuracy of the proposed method is evaluated by comparing the responses with those obtained from non-linear response history analysis.

6 citations

Journal ArticleDOI
TL;DR: In this article, a parametric study was conducted on steel gridshell domes with 60, 100 and 150m spans and six-storey substructures to investigate the interaction between the higher substructure modes and dominant roof modes.

5 citations

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TL;DR: In this article , the authors investigated the applicability of ductility reduction factors (or Rμ factors) to estimate the inelastic response spectra and an alternative equivalent linearisation approach to compute the peak horizontal acceleration of multistorey substructures with buckling-restrained braces.
Abstract: Curved gridshells are excited not only in the horizontal direction but also experience large anti-symmetric vertical accelerations when subjected to horizontal earthquake ground motions. In addition to the coupled response, gridshells exhibit closely spaced modes and substructure-roof interaction. Nevertheless, previous studies have proposed elastic horizontal and vertical equivalent static seismic forces considering these complex dynamic response characteristics. These are determined from the input horizontal acceleration at the substructure’s roof level, an assumed acceleration distribution, nodal roof masses and amplification factors derived from the dynamic characteristics of the dome and substructure. To extend this methodology to nonlinear substructures with displacement-dependent damping devices, this paper investigates the applicability of ductility reduction factors (or Rμ factors) to estimate the inelastic response spectra and an alternative equivalent linearisation approach to compute the peak horizontal acceleration of multistorey substructures with buckling-restrained braces. This is achieved by modelling the curved roof as a rigid mass for the substructure model, and using its idealised base shear-roof displacement relationship obtained from modal pushover analyses. The peak horizontal acceleration of the substructure is then used to obtain the equivalent static loads of the curved roof using amplification factors, and the accuracies are verified against the results from nonlinear response history analyses. It was confirmed that the Rμ R μ factors combined with the roof amplification factors provide a simple way to estimate the peak roof response with sufficient accuracy for preliminary design of domes with multistorey substructures having low post-yield stiffness.
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TL;DR: In this paper , a generalized response spectrum analysis based computational morphogenesis method is presented to obtain form-found shell structures by considering the dynamic seismic loads and the response reduction effects of seismic energy-dissipating devices.
Journal ArticleDOI
TL;DR: In this paper , the authors proposed a method to solve the problem of the lack of a suitable curriculum for Japanese students in the field of computer science, and they proposed a curriculum for teaching Japanese to Japanese students.
Abstract: — 194 — * 1 東京工業大学建築学系 助教・博士(工学) * 2 東京工業大学建築学系 大学院生・修士(工学) * 3 東京工業大学建築学系 大学院生 * 4 東京工業大学建築学系 教授・博士(工学) Assist. Prof., Dept. of Arch. and Build. Eng., Tokyo Institute of Technology, Dr.Eng. Grad. Student, Dept. of Arch. and Build. Eng., Tokyo Institute of Technology, M.Eng. Grad. Student, Dept. of Arch. and Build. Eng., Tokyo Institute of Technology Prof., Dept. of Arch. and Build. Eng., Tokyo Institute of Technology, Dr.Eng. 【カテゴリーII】

Cited by
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Journal ArticleDOI
TL;DR: In this article , a numerical analysis of the seismic behavior of asymmetric low-rise reinforced concrete (R/C) frames is performed considering the deformability of the supporting soil.
Abstract: A numerical investigation of the seismic behaviour of asymmetrical low-rise reinforced concrete (R/C) frames is performed considering the deformability of the supporting soil. The typical rigid base assumption is adopted by most current seismic design codes for ordinary buildings, implicitly assuming that the “beneficial” influence of the Soil-Structure Interaction (SSI) effects results in a decrease of the internal forces of a structure. However, in recent research works, SSI is found to affect the structural response in not always a beneficial manner and occasionally in a detrimental one. In the current study, the non-linear time-domain seismic analyses of selected 2D and 3D symmetric and asymmetric R/C framed buildings are presented considering initially the fixed base assumption. Subsequently, these R/C building models, subjected to the same seismic excitations, are analysed considering SSI, by applying a set of orthogonal footings with tie beams which interact with the soil medium. In addition, in the 3D models, the case of a foundation mat supporting the frames is examined. Comparisons between the numerical response results obtained for the examined supporting conditions yield useful conclusions regarding the modified elastoplastic estimated behaviour of common low-rise R/C buildings due to SSI, which can be used for the improvement of the seismic design codes.

8 citations

Journal ArticleDOI
TL;DR: In this article, a parametric study was conducted on steel gridshell domes with 60, 100 and 150m spans and six-storey substructures to investigate the interaction between the higher substructure modes and dominant roof modes.

5 citations

Journal ArticleDOI
TL;DR: In this article , the authors investigated the effectiveness of buckling restrained braces (BRBs) adopted for reducing dynamic responses of a grid dome to severe earthquakes, and the results indicated the feasibility of constructing large reticulated domes of this type in regions prone to severe seismicity using such BRBs.

4 citations

Journal ArticleDOI
TL;DR: In this article , a super-elastic bracing system comprising parallel spine frames with buckling-restrained dampers and steel elastic braces was proposed to enhance the seismic performance of multistory buildings.

4 citations

Journal ArticleDOI
TL;DR: In this article , the acceleration response spectra of a single-layer spherical reticulated shell structure are compared with those described in the current seismic design codes of the nonstructural components.
Abstract: In recent years, earthquake disasters have seriously damaged nonstructural components, so it is necessary to study their seismic performance. However, the existing scholarly research mainly concentrates on multistorey and high-rise buildings, and there are still deficiencies in the analysis of the seismic performance of the nonstructural components in large-span structures under seismic action. In this paper, the acceleration responses of a single-layer spherical reticulated shell structure are compared with those described in the current seismic design codes of the nonstructural components, and it is found that the current codes are not fully applicable to the seismic design of the nonstructural components in reticulated shell structures. The calculation formulas of the acceleration response spectra of single-layer spherical shell nodes are theoretically derived, and the shell node acceleration response spectra are affected by higher-order modes, orthogonal horizontal seismic input directions, and the membrane stiffness of the shell nodes. The variations in the acceleration responses of the shell nodes with node position and rise-to-span ratio are analysed, and a design method for the equivalent seismic action of the nonstructural components in a single-layer spherical reticulated shell with a roofing system is proposed.

4 citations