Higher mode effects of multistorey substructures on the seismic response of double-layered steel gridshell domes

Nair, Deepshikha; Ichihashi, Keita; Terazawa, Yuki; Sitler, Ben; Takeuchi, Tōru

doi:10.1016/j.engstruct.2021.112677

Cited by 12 publications

(34 citation statements)

References 12 publications

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“…In the case of relatively thin lattice domes, a large number of vibration modes with similar periods significantly participate in the response. 14 Nevertheless, it has been observed that when the out-of-plane stiffness of the roof is large (typical of double-layered domes 5 ), the response characteristics are predominated by four prominent modes which are denoted as O1, O2, O2.5, and I shown in Figure 1(b), 7,13,16 where O1 is the fundamental mode and has an asymmetric modeshape with one crest and one trough (Figure 1(b)). The O2 mode is the next higher mode with two crests and two troughs with high amplitude in the centre wave, followed by the O2.5 mode that is similar to the O2 mode but has lower amplitudes.…”

Section: Seismic Response Characteristics Of Double-layered Domesmentioning

confidence: 99%

“…7 To extend this method to multistorey substructures, horizontal and vertical amplification factors were proposed to estimate the roof response generated by higher multistorey substructure modes in interaction with the four roof modes. 16 Finally, a generalised equivalent static design procedure was developed (Figure 2) for domes with multistorey substructures and validated against RSA, comparing against both the nodal displacements and member forces. 15,16…”

Section: Seismic Response Characteristics Of Double-layered Domesmentioning

confidence: 99%

“…7 Further increasing the height of the substructure leads to increased participation from the higher substructure modes and the interaction between the higher substructure modes (in linear range) and dominant roof modes have also been quantified as higher mode amplification factors. 16…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Equivalent static loads for double-layered domes supported by multistorey buckling-restrained braced frames

Nair

Terazawa

Takeuchi

2022

International Journal of Space Structures

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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 [Formula: see text]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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Section: Seismic Response Characteristics Of Double-layered Domesmentioning

confidence: 99%

Section: Seismic Response Characteristics Of Double-layered Domesmentioning

confidence: 99%

See 1 more Smart Citation

Equivalent static loads for double-layered domes supported by multistorey buckling-restrained braced frames

Nair

Terazawa

Takeuchi

2022

International Journal of Space Structures

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“…Fan et al [30] investigated the applicability of the provisions of the current seismic codes for the non-structural components of singlelayer spherical reticulated shells considering a direct fixed connection of the boundary shell nodes to the ground, i.e., neglecting SSI. Double-layered steel grid-shell domes were analysed by response spectrum seismic analyses by Nair et al [31], considering the fixed base assumption. Roopa et al [32] conducted response spectrum seismic analysis of a single layer latticed geodesic steel dome comparing the SSI consideration to the fixed base assumption.…”

Section: Introductionmentioning

confidence: 99%

“…Figure31. T(s)/T versus J(wall)/J(col) (a) on the 1st storey for footings to rigid soil and φ = 45°, ( on the 3rd storey for footings to rigid soil and φ = 0° (Lixouri earthquake).…”

mentioning

confidence: 99%

The Modification of the Estimated Seismic Behaviour of R/C Low-Rise Buildings Due to SSI

Askouni

Karabalis

2022

Buildings

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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.

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Importance of higher modes for dynamic soil structure interaction of monopile‐supported offshore wind turbines

Sah,

Yang

2024

Earthq Engng Struct Dyn

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Offshore wind turbines (OWTs) have emerged as one of the most sustainable and renewable sources of energy. The size of OWTs has been increasing, which creates more challenges in the design of foundations due to the potential higher‐mode effects involved in the dynamic soil‐structure interaction (DSSI) response. Several foundation modeling techniques are available for calculating the OWT fundamental frequency; however, their capability to predict the higher modes by considering real geometric configurations is unclear. The main aim of this study is to perform a rigorous modal analysis of the NREL 5MW reference OWT to investigate the higher mode effects using the 3D finite element method. A detailed parametric analysis is also performed to study the effects of soil inhomogeneity, initial soil modulus, and the monopile dimensions (diameter, thickness, and embedded pile depth) on higher modes' natural frequencies and effective mass participation ratios. The study shows that dynamic soil‐structure interaction has a significant role in modal response and the simplified foundation models are not accurate enough. Given the significant contribution from higher modes, they should not be simply ignored in the OWT design, particularly in earthquake‐prone zones.

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Higher mode effects of multistorey substructures on the seismic response of double-layered steel gridshell domes

Cited by 12 publications

References 12 publications

Equivalent static loads for double-layered domes supported by multistorey buckling-restrained braced frames

Equivalent static loads for double-layered domes supported by multistorey buckling-restrained braced frames

The Modification of the Estimated Seismic Behaviour of R/C Low-Rise Buildings Due to SSI

Importance of higher modes for dynamic soil structure interaction of monopile‐supported offshore wind turbines

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