DOI QR코드

DOI QR Code

Inelastic Displacement Ratio for SDOF Bilinear and Damping Systems

이선형 단자유도 감쇠시스템의 비탄성변위비

  • Published : 2007.12.31

Abstract

This study investigates the effect of site class, post-yield stiffness ratio, damping ratio, yield-strength reduction factor, and natural period on inelastic displacement ratio of bilinear SDF systems located at the sites classified as NEHRP site class B,C,D. The previous studies developed inelastic displacement ratio using equal displacement rule in the intermediate and long period range. But, this approximation overestimates the inelastic displacement ratio. Furthermore, inelastic displacement ratio has not been developed for the systems having a damping ratio less than 5%. This study conducts nonlinear regression analysis for proposing equations for calculating median and deviation of the inelastic displacement ratio of the bilinear SDOF system having damping ratios ranging from 0 to 20%. Using median and deviation of the inelastic displacement ratio, probabilistic inelastic displacement ratio is estimated, which can be used for performance-based seismic evaluation.

NEHRP 지반조건 B,C,D에서 이선형 단자유도 감쇠시스템의 지반조건, 후탄성기울기, 감쇠비, 항복강도 감소계수, 고유 주기 등의 변화가 비탄성변위비에 미치는 영향을 조사하였다. 기존의 제안식은 변위일정 법칙을 따라 일정주기 이상에서 비탄성 변위비를 과대평가하게 된다. 또한 기존식은 5%이상의 감쇠비에 대하여만 제안되었다. 본 연구는 후탄성기울기, 감쇠비 20% 이하의 이선형 시스템의 비탄성 변위비의 평균과 편차를 제안하였고 범용적으로 사용할 수 있음을 보였다. 제안식을 사용하여 비탄성 변위비의 확률적 분포를 계산하여 구조물의 성능기반설계에 이용할 수 있다.

Keywords

References

  1. Applied Technology Council, 'Seismic evaluation and retrofit of concrete buildings,' Report ATC‐40, Redwood City, Calif., 1996
  2. Federal Emergency Management Agency. 'NEHRP guidelines for the seismic rehabilitation of buildings,' Report FEMA 273 (Guidelines) and Report. 274 (Commentary), Washington, D.C. 1997
  3. Whittaker AS et al. 'Displacement estimates for performancebased seismic design'. Journal of Structural Engineering, ASCE, 124(8), 1998, pp. 905-912 https://doi.org/10.1061/(ASCE)0733-9445(1998)124:8(905)
  4. Miranda, E. 'Estimation of inelastic deformation demands of SDOF systems,' Journal of Structural Engineering, ASCE, 127(9), 2001, pp. 1005‐1012 https://doi.org/10.1061/(ASCE)0733-9445(2001)127:9(1005)
  5. Oscar M.Ramirez et al, 'Elastic and inelastic seismic response of building with damping systems', Earthquake Spectra, Vol. 18 No.3, pp. 531‐547
  6. Ruiz‐García, J., and Miranda, E.. 'Inelastic displacement ratios for evaluation of existing structures,' Earthquake Engineering and Structural Dynamics 2003; 32(8) : pp. 1237‐1258 https://doi.org/10.1002/eqe.271
  7. Chopra, A.K. and Chintanapakdee, C., 'Inelastic deformation ratios for design and evaluation of structures : single ‐degree‐of‐freedom bilinear systems,' Report No. EERC 2003‐09, Earthquake Engrg. Res. Ctr., Univ. of Calif. at Berkeley, Berkeley, CA
  8. Ruiz‐García, J., and Miranda, E.. 'Probabilistic estimation of maximum inelastic displacement demands for performancebased design,' Earthquake Engineering and Structural Dynamics 2007; 36(9) : pp. 1235‐1254 https://doi.org/10.1002/eqe.680
  9. Ruiz‐García, J., and Miranda, E.. 'Performance‐based assessment of existing structures accounting for residual displacements,' Report TR‐153, The John A. Blume Earthquake Engineering Center, Stanford University, Stanford, CA, 2005