Conditional Mean Spectrum of Aftershocks

2017 ◽  
Author(s):  
Rui‐Guang Zhu ◽  
Da‐Gang Lu ◽  
Xiao‐Hui Yu ◽  
Guang‐Yuan Wang
Keyword(s):  
Conditional Mean ◽  
Conditional Mean Spectrum

A Generalized Conditional Mean Spectrum and Its Application for Intensity-Based Assessments of Seismic Demands

2017 ◽  
Vol 33 (1) ◽  
pp. 123-143 ◽  
Author(s):  
N. Simon Kwong ◽  
Anil K. Chopra
Keyword(s):  
Computational Effort ◽  
Seismic Demands ◽  
Earthquake Scenario ◽  
Conditional Mean ◽  
Conditional Mean Spectrum ◽  
Accuracy And Precision ◽  
Target Spectrum ◽  
Hazard Level ◽  
Vector Valued

When the response of a structure is influenced significantly by multiple vibration modes, the seismic demands determined by response history analyses with ground motions selected to match a single conditional mean spectrum (CMS) may be unconservative for several response quantities. An existing solution to this problem is to determine the demand as the maximum of mean demands from several CMSs. To reduce the computational effort while maintaining accuracy and precision, we introduce an alternative engineering solution that is based on a simplified version of the generalized CMS, where two specified conditioning spectral accelerations share a common hazard level. vector-valued disaggregation is developed herein to provide a single earthquake scenario for the target spectrum. The results from a realistic case study suggest that the proposed spectrum provides seismic demands that are as accurate and precise as those obtained from analyzing the structure with multiple CMSs while simultaneously reducing the computational effort by a factor of 2 or more.

Conditional mean spectrum for Bucharest

2014 ◽  
Vol 7 (2) ◽  
pp. 141-157
Author(s):  
Radu Vacareanu ◽  
Mihail Iancovici ◽  
Florin Pavel
Keyword(s):  
Conditional Mean ◽  
Conditional Mean Spectrum

scholarly journals Site Specific Response Analysis Kota Padang dari Input motion Conditional Mean Spectrum (CMS) Menggunakan Software NERA

2017 ◽  
Vol 14 (2) ◽  
pp. 28-38
Author(s):  
Merley Misriani
Keyword(s):  
Ground Motion ◽  
Time Domain ◽  
Earthquake Response ◽  
Response Analysis ◽  
Specific Response ◽  
Site Specific ◽  
Conditional Mean ◽  
Conditional Mean Spectrum ◽  
Input Motion ◽  
Earthquake Response Analysis

Dalam perencanaan struktur bangunan tahan gempa, tujuan umum dari analisa struktur dinamis adalah memprediksi respons dari struktur terhadap pengaruh ground motion yang memiliki Spectral Acceleration (Sa) pada periode tertentu berdasarkan tingkat kemungkinan terlampui (Probability of Excedence/PE) 10% atau 2% masa layan bangunan 50 tahun.  Prediksi respons struktur ditentukan dengan memilih ground motion yang cocok dengan beberapa target spektra dan nantinya ground motion tersebut digunakan sebagai input dalam analisis dinamis struktur. Pada paper ini menyajikan analisis perambatan gelombang gempa dari batuan dasar ke lapisan permukaan (Site Specific Response Analysis/ SSRA). Data-data yang diperlukan adalah data stratifikasi tanah dan parameter kecepatan gelombang geser yang didapatkan dari korelasi empiris terhadap data hasil pemboran dan uji N-SPT. Ground motion synthetic batuan dasar yang digunakan untuk perambatan gelombang gempa diperoleh dari hasil penelitian sebelumnya yang mengadopsi pendekatan statistik Conditional Mean Spectrum (CMS) agar ground motion  yang dihasilkan dipermukaan cocok dengan prediksi masalah respon struktur yang sebenarnya. SSRA dilakukan berdasarkan teori perambatan gelombang geser satu dimensi dalam time domain dengan menggunakan program Non-linear Earthquake Response Analysis (NERA). Hasilnya diperoleh percepatan maksimum gempa dipermukaan (peak surface acceleration/ PBA) berbeda-beda di kedua lokasi tergantung pada faktor amplifikasi, karakteristik dan jenis gempa yang terjadi. Direkomendasikan respons spectra desain untuk periode ulang 475 tahun dan 2475 tahun wilayah 4 kelas tanah sedang (SD) untuk kedua lokasi tersebut. Data-data tersebut digunakan sebagai input dalam penentuan beban gempa pada bangunan dalam analisis struktur dinamis.

Selecting, scaling, and orienting three components of ground motions for intensity-based assessments at far-field sites

2020 ◽  
Vol 36 (3) ◽  
pp. 1013-1037 ◽  
Author(s):  
N. Simon Kwong ◽  
Anil K. Chopra
Keyword(s):  
Three Dimensional ◽  
Vertical Component ◽  
Uniform Hazard Spectrum ◽  
Conditional Mean ◽  
Conditional Mean Spectrum ◽  
Scale Factors ◽  
Target Spectrum ◽  
Wide Range ◽  
Orthogonal Components ◽  
Three Components

This article develops a methodology for selecting, scaling, and orienting three orthogonal components of ground motion (GM) when conducting intensity-based assessments of structures. Target spectra for selecting multicomponent GMs are critically examined and strategies for selecting hazard-consistent GMs are investigated. The Conditional Mean Spectrum–Uniform Hazard Spectrum (CMS-UHS) Composite Spectrum is proposed as an alternative to several Conditional Mean Spectra for selecting multicomponent GMs when conducting intensity-based assessments of complex three-dimensional (3D) structures. To ensure hazard consistency, multicomponent GMs should be selected using (a) the target spectrum for the vertical component of GM, (b) a wide range of vibration periods, and (c) scale factors that are constrained. With constrained scale factors, all three components of a GM can be reasonably scaled either by the same scale factor or by different scale factors.

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