Benefits of site-specific hazard analyses for seismic design in New Zealand

2015 ◽  
Vol 48 (2) ◽  
pp. 92-99 ◽  
Author(s):  
Brendon A. Bradley
Keyword(s):  
New Zealand ◽  
Seismic Design ◽  
Site Response ◽  
Hazard Analysis ◽  
Seismic Source ◽  
Design Guidelines ◽  
Assessment Process ◽  
Site Specific ◽  
Comparative Examination

This paper summarizes the role site-specific seismic hazard analyses can play in seismic design and assessment in New Zealand. The additional insights and potential improvements in the seismic design and assessment process through a better understanding of the ground motion hazard are examined through a comparative examination with prescriptive design guidelines. Benefits include the utilization of state-of-the-art knowledge, improved representation of site response, reduced conservatism, and the determination of dominant seismic source properties, among others. The paper concludes with a discussion of these relative benefits so that the efficacy of site-specific hazard analysis for a particular project can be better judged by the engineer.

Capturing epistemic uncertainty in site response

2020 ◽  
pp. 875529302097097
Author(s):  
Adrian Rodriguez-Marek ◽  
Julian J Bommer ◽  
Robert R Youngs ◽  
Maria J Crespo ◽  
Peter J Stafford ◽  
...  
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Epistemic Uncertainty ◽  
Hazard Analysis ◽  
Discrete Distribution ◽  
Seismic Source ◽  
Site Specific ◽  
Underlying Distribution ◽  
Response Characteristics ◽  
Motion Models

The incorporation of local amplification factors (AFs) determined through site response analyses has become standard practice in site-specific probabilistic seismic hazard analysis (PSHA). Another indispensable feature of the current state of practice in site-specific PSHA is the identification and quantification of all epistemic uncertainties that influence the final hazard estimates. Consequently, logic trees are constructed not only for seismic source characteristics and ground-motion models (GMMs) but also for the site AFs, the latter generally characterized by branches for alternative shear-wave velocity ( VS) profiles. However, in the same way that branch weights on alternative GMMs can give rise to unintentionally narrow distributions of predicted ground-motion amplitudes, the distribution of AFs obtained from a small number of weighted VS profiles will often be quite narrow at some oscillator frequencies. We propose an alternative approach to capturing epistemic uncertainty in site response in order to avoid such unintentionally constricted distributions of AFs using more complete logic trees for site response analyses. Nodes are included for all the factors that influence the calculated AFs, which may include shallow VS profiles, deeper VS profiles, depth of impedance contrasts, low-strain soil damping, and choice of modulus reduction and damping curves. Site response analyses are then executed for all branch combinations to generate a large number of frequency-dependent AFs. Finally, these are re-sampled as a discrete distribution with enough branches to capture the underlying distribution of AFs. While this approach improves the representation of epistemic uncertainty in the dynamic site response characteristics, modeling uncertainty in the AFs is not automatically captured in this way, for which reason it is also proposed that a minimum level of epistemic uncertainty should be imposed on the final distribution.

scholarly journals Determination of Local Site-Specific Spectra Using Probabilistic Seismic Hazard Analysis for Bitlis Province, Turkey

2015 ◽  
Vol 19 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Ercan Işık ◽  
Mustafa Kutanis
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Response Spectra ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Source Characterization ◽  
Site Specific ◽  
Attenuation Relationships

<p>In this study, site-specific earthquake spectra for Bitlis province in Lake Van Basin has been obtained. It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage data from geological studies and records from the instrumental period were compiled to make a seismic source characterization for the study region.The probabilistic seismic hazard curves for Bitlis were developed based on selected appropriate attenuation relationships, at rock sites, with a probability of exceedance 2%, 10% and 50% in 50 year periods. The obtained results were compared with the spectral responses proposed for seismic evaluation and retrofit of the building structure in Turkish Earthquake Code, Section 2. At the end of this study, it is apprehended that the Code proposed earthquake response spectra are not sufficient for the performance evaluation of the existing structures and the current estimations show that the potential seismic hazard research of the Turkey is underestimated in the code.Therefore, site- specific design spectra for the region should be developed, which reflect the characteristics of local sites.</p><p> </p><p><strong>Determinación de espectros de sitio específico locales a través del análisis probabilístico de amenazas sísmicaspara la provincia de Bitlis, Turquía</strong></p><p> </p><p><strong>Resumen</strong></p>En este estudio se obtuvieron espectros de terremoto de sitio específico para la cuenca del Lago de Van, en la provincia de Bitlis, al este de Turquía. La primera fase del trabajo consistió en una evaluación probabilística de riesgo sísmico donde se compilaron los estudios geológicos y registros del período instrumental para hacer una caracterización de fuente sísmica en la región de estudio. Las curvas de amenaza sísmica para la provincia de Bitlis se desarrollaron con base en las relaciones de atenuación apropiada seleccionadas en los sitios rocosos, con una probabilidad de exceso de 2 %, 10 % y 50 % durante 50 años. Los resultados obtenidos se compararon con las respuestas de espectro propuestas para la evaluación sísmica y modernización de estructuras contempladas en el Código de Terremoto de Turquía, en la sección 2. En la parte final de este trabajo se comprende que las respuestas de espectros de terremoto propuestos en el código no son suficientes para la evaluación de desempeño de las estructuras existentes y que las estimaciones actuales muestran que la investigación de amenazas potenciales sísmicas en Turquía está subestimada en el código. Por lo tanto, el diseño de espectros de sitio específico para la región se debe desarrollar, ya que permitiría conocer las singularidades locales.</p>

Fault Source Characterization of Probabilistic Seismic Hazard Analysis for the Sites of Offshore Wind Turbine in Taiwan

2015 ◽  
Vol 764-765 ◽  
pp. 1085-1089
Author(s):  
Cheng Yu Pan ◽  
Yuan Chieh Wu
Keyword(s):  
Wind Turbine ◽  
Seismic Design ◽  
Hazard Analysis ◽  
Active Faults ◽  
Seismic Source ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Source Characterization ◽  
Heavy Damage

During seismic hazards, offshore wind turbine structures do not have direct effects on people's safety; however, the seismic design is still important to prevent heavy damage on structure. The seismic design of offshore wind turbine has been discussed in some previous studies. Based on the result of those studies, we further modified the seismic source, especially on active faults in west foot hill zone. Of all the active faults in this area, we choose five which lie nearby the sites to make the modification. A logic tree has been set to avoid overlapping and derive an accurate recurrence model of the seismic source used in PSHA. This study is just a preliminary result of PSHA in wind turbine sites, Chunan and Chanbin, there are still several adjustments need to be done.

scholarly journals Insights and challenges associated with determining seismic design forces in a loading code

1995 ◽  
Vol 28 (3) ◽  
pp. 224-246 ◽  
Author(s):  
A. C. Heidebrecht
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Seismic Design ◽  
Ground Motions ◽  
Performance Expectations ◽  
Hazard Parameters ◽  
Seismic Hazard Parameters ◽  
Frequent Reference

This paper presents and discusses a number of important topics which affect the determination of seismic design forces in a loading code. These range broadly from seismic hazard through to design philosophy and include the following aspects: influence of uncertainty in determining seismic hazard, seismic hazard parameters, site effects, probability level of design ground motions, role of deformations in seismic design, performance expectations and level of protection. The discussion makes frequent reference to the seismic provisions of both the National Building Code of Canada (1995) and the New Zealand Loading Standard (1992). Also, comparisons are made of seismic hazard and seismic design forces for several Canadian and New Zealand cities.

Seismic Design Factors for Steel Moment Frames with Masonry Infills: Part 2

2012 ◽  
Vol 28 (3) ◽  
pp. 1205-1222 ◽  
Author(s):  
Shiv Shanker Ravichandran ◽  
Richard E. Klingner
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Design Guidelines ◽  
Structural Systems ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Systematic Procedure ◽  
Masonry Infills ◽  
Design Factors

In this second part, archetypical steel moment frames with masonry infills are evaluated using the ATC-63 methodology, which is a systematic procedure for the determination of seismic design factors of structural systems. The ATC-63 methodology is briefly reviewed. Procedures in the ATC-63 methodology are specialized for application to infilled steel moment frames. Results from the ATC-63 evaluation of the archetypical infilled steel moment frames are presented, and are used to propose seismic design factors and design guidelines for steel moment frames with masonry infills. The applicability of the proposed seismic design factors and guidelines for reinforced concrete infilled frames is discussed.

Determination of Design Ground Motion for Potential GEN III and Plus Plants in China: A Regulatory Level Review

2017 ◽  
Author(s):  
Ziduan Shang ◽  
Yugang Sun ◽  
Hongliang Gou ◽  
Lutong Zhang ◽  
Meng Chu ◽  
...  
Keyword(s):  
Ground Motion ◽  
Seismic Design ◽  
Probabilistic Approach ◽  
Time History ◽  
Response Spectra ◽  
Regulatory Requirements ◽  
Site Specific ◽  
Motion Time ◽  
Standard Design

The determination of Design Ground Motion time history (or response spectra) is the primary and critical step to derive correct Seismic Design Inputs for a Nuclear Power Plant (NPP) design. Historically Design Ground Motion (design SSE input) for a NPP was determined by early version procedure provided in RG 1.60. It was based on a theory of deterministic approach; the resulting ground motion is given in acceleration response spectra located at free surface of a site. As a transition point, 1997 was the year where new procedure was developed and recommended in RG 1.165 based on the new theory of SSE ground motion probabilistic approach. RG 1.165 was authorized for application on all new NPPs’ design after 1997. With the advancing of PSHA approach, RG 1.165 was withdrawn and replaced with new RG 1.208 in 2008. RG 1.208 established an effective way through the similar probabilistic approach used in RG 1.165 by improving PSHA method. Both RG1.165 results and RG 1.208 results are focused on addressing site-specific design, its Ground Motion Response Spectra (GMRS) and Ground Motion Time History (converted from GMRS) are used as design inputs to specific Nuclear Island (NI) seismic design. To accomplish a Standard Design Certification, the RG 1.60 DRS is used to develop the Certified Seismic Design Response Spectra (CSDRS) by modifying control points on original RG 1.60 curves to broaden the spectra in higher frequency range. In reality, CSDRS serves as a good approach to define DRS and Design Ground Motion Time History for standard design of new NPPs in current timeframe, hence envelop the site-specific GMRS given in RG 1.208. In this paper, through the comparison of above US NRC regulatory requirements and Chinese regulatory requirements, gives recommendations on the determination of Design Ground Motion Response Spectra (or Time History), which serves as the basis for deriving seismic design inputs at required specific location (e.g. the bottom of NI foundation level) for potential “GEN III & Plus” plants in China.

scholarly journals New Zealand seismic hazard analysis

1985 ◽  
Vol 18 (4) ◽  
pp. 313-322
Author(s):  
T. Matuschka ◽  
K. R. Berryman ◽  
A. J. O'Leary ◽  
G. H. McVerry ◽  
W. M. Mulholland ◽  
...  
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Seismic Design ◽  
Hazard Analysis ◽  
Response Spectra ◽  
Seismic Hazard Analysis ◽  
Return Periods ◽  
Acceleration Response ◽  
Ground Shaking ◽  
Horizontal Acceleration

The results of a seismic hazard analysis for the country by the Seismic Risk Subcommittee (SRS) of the Standards Association are presented. The SRS was formed in 1979 to advise the Standards Association Loadings Code Amendments Committee on the frequency and level of earthquake ground shaking throughout New Zealand. Results of the SRS study are in terms of estimates of five percent damped horizontal acceleration response spectra for 50, 150, 450 and 1000 year return periods. It is intended that these results will form the basis for developing seismic design response spectra for the proposed new Loadings Code (NZS 4203).

scholarly journals Site Specific Response Analysis (SSRA) Kampus UNP Air Tawar, Kota Padang

2017 ◽  
Vol 14 (1) ◽  
pp. 20-29
Author(s):  
Merley Misriani
Keyword(s):  
Wave Propagation ◽  
Seismic Design ◽  
Hazard Analysis ◽  
Response Spectra ◽  
Rock Properties ◽  
Soil Conditions ◽  
Response Analysis ◽  
Specific Response ◽  
Site Specific ◽  
Local Soil

In general, the seismic design provisions around the world present different criteria for local soil conditions depending on soil and rock properties to determine the design spectra representing seismic design. On the other hand, site-specific analysis results not only show the main characteristics of soil-rock profiles but also local soil characteristics where detailed studies are needed to review the earth response to earthquakes. In this study conducted Site Specific Response Analysis (SSRA) is to analyze the earthquake wave propagation from the bedrock to the surface layer. The data needed are ground stratification data and shear wave velocity parameters obtained from empirical correlation to N-SPT test drilling data. In addition, the required data is ground motion synthetic at baserocks used for the earthquake wave propagation obtained by Probabilistic Seismic Hazard Analysis (PSHA) 3-dimensional earthquake source referring from the results of previous research. SSRA is based on the theory of single-dimensional wave propagation in time domain using NERA (Non-linear Earthquake Response Analysis) program. Various inputs of earthquake movement are taken by considering suitable for Padang area. The results of this analysis are shown in the form of historical time acceleration graph and peak acceleration from each bore point location which is then processed to obtain amplification and response spectra design factors for the re-quake period of 475 years and 2475 years.

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