A Proposal of Damping Correction Formula Considering Period-Dependent Characteristics of the Design Response Spectra of Long-Period Ground Motions for the Hypothetical Nankai Trough Earthquake

Abstract

MLIT has announced a countermeasure against the Nankai trough long period ground motions. However, the response spectrum method, indicated by the Ministry of Construction notification Vol. 2009, is out of the countermeasure, because this method was considered to be difficult to reflect the influence by long period ground motions. Therefore, in this study, the damping correction formula for long period ground motions, which considers periodic characteristics of the design earthquake response spectra, was proposed. Moreover, the applicability for the seismic isolation buildings was verified by comparing with the results by the time history analysis using SDOF models.

Feasibility Study on Evaluating Required Seismic Capacity for Safety Limit Design of High-Rise Rc Buildings in Os1 and Os2 Regions and Its Estimation Based on the Equivalent Linearization Method

“…Therefore, it was modified based on Eq. (12) presented by Kobayashi et al 16) Consequently, the base shear coefficients required by the earthquake response analyses were well estimated by the proposed procedure with Eq. (12a), as shown in Table 8.…”

Earthquake response prediction of seismically isolated buildings based on the response spectrum method considering changes in characteristics of lead rubber bearings due to repeated deformations

“…The damping correction formula F h uses the proposed Equation (4), considering the periodic characteristics of the response spectra of the LPGMDs. 12,13 If the damping factor is less than 5%, the same type of Equation as in MCN included in the Appendix of Ref. [12] and [13] should be used.…”

“…12,13 If the damping factor is less than 5%, the same type of Equation as in MCN included in the Appendix of Ref. [12] and [13] should be used.…”

“…where h is the damping factor, h 0 is the initial damping factor (h 0 = 0.05), T eq is the equivalent period, T 1 and T 2 are boundary periods of periodic ranges 1, 2, and 3 based on the simplified spectra of the LPGMDs, 12,13 and α, β, and γ are the regression coefficients given for each area. 12,13 The equivalent damping factor h eq for a steady-state loop at peak response displacement of the LRB was evaluated from Equation ( 5). 1 The reduction coefficient α R shown in Equation ( 6) is multiplied, and 0.8 is used in MCN to take into account the effect of irregularity of the response.…”