scholarly journals Developing Earthquake-Resistant Structural Design Standard for Malaysia Based on Eurocode 8: Challenges and Recommendations

Standards ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 134-153
Author(s):  
Daniel Looi ◽  
Nelson Lam ◽  
Hing-Ho Tsang
Keyword(s):  
Seismic Hazard ◽  
Dynamic Analysis ◽  
Structural Design ◽  
Classification Scheme ◽  
National Standard ◽  
Probabilistic Seismic Hazard Assessment ◽  
Site Classification ◽  
Eurocode 8 ◽  
Natural Period ◽  
Moderate Seismicity

In late 2017, the Malaysian National Annex (NA) to Eurocode 8 (EC8) was released and enacted following some 13 years of deliberations and preparations. The authors of this paper aim to use this article to share their experiences and reflections during this period of developing the first national standard for the seismic design of buildings for Malaysia. To begin with, there were major challenges in implementing the 20-year-old EC8 framework for a country so far away from Europe. The first challenge was adapting the probabilistic seismic hazard assessment (PSHA) methodology in a low-to-moderate seismicity region where the paucity of representative seismic data presented a great deal of uncertainties. To address this situation, imposing a minimum level of seismic hazard was recommended. The second challenge was about dealing with the outdated EC8 site classification scheme, which poorly represents the potential effects of soil amplification in certain geological settings. To address this situation, an alternative site classification scheme in which the site natural period is an explicit modelling parameter was introduced. The third challenge was concerned with difficulties generated by the EC8 provisions mandating Ductility Class Medium (DCM) detailing in certain localities where the level of seismic hazard is predicted to exceed a certain threshold. To address this situation, the viable option of using strength to trade off for ductility was recommended, or in cases where ductility design is needed, a simplified set of code-compliant DCM designs was presented. The fourth challenge was about handling the requirements of EC8 that the majority of buildings are to involve dynamic analysis in their structural design when the majority of practising professionals did not have the skills of exercising proper use of the requisite software. To address this situation, a generalized force method was introduced to control the use dynamic analysis in commercial software. It is hoped that, through sharing the lessons learnt, code drafters for the future would be able to find ways of circumventing the multitude of challenges with clear thinking and pragmatism.

scholarly journals The use of Monte Carlo simulations for seismic hazard assessment in the U.K.

2000 ◽  
Vol 43 (1) ◽  
Author(s):  
R. M. W. Musson
Keyword(s):  
Monte Carlo ◽  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Logic Tree ◽  
The United Kingdom ◽  
The Monte Carlo Method ◽  
Moderate Seismicity ◽  
Seismicity Model

The input required for a seismic hazard study using conventional Probabilistic Seismic Hazard assessment (PSHA) methods can also be used for probabilistic analysis of hazard using Monte Carlo simulation methods. This technique is very flexible, and seems to be under-represented in the literature. It is very easy to modify the form of the seismicity model used, for example, to introduce non-Poissonian behaviour, without extensive reprogramming. Uncertainty in input parameters can also be modelled very flexibly - for example, by the use of a standard deviation rather than by the discrete branches of a logic tree. In addition (and this advantage is perhaps not as trivial as it may sound) the simplicity of the method means that its principles can be grasped by the layman, which is useful when results have to be explained to people outside the seismological/engineering communities, such as planners and politicians. In this paper, some examples of the Monte Carlo method in action are shown in the context of a low to moderate seismicity area: the United Kingdom.

scholarly journals Probabilistic seismic hazard map for Bulgaria as a basis for a new building code

2006 ◽  
Vol 6 (6) ◽  
pp. 881-887 ◽  
Author(s):  
S. D. Simeonova ◽  
D. E. Solakov ◽  
G. Leydecker ◽  
H. Busche ◽  
T. Schmitt ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Attenuation Factor ◽  
Seismic Hazard Assessment ◽  
Building Code ◽  
Probabilistic Seismic Hazard Assessment ◽  
Eurocode 8 ◽  
Probabilistic Seismic Hazard ◽  
Hazard Map ◽  
Intermediate Depth ◽  
Seismic Hazard Map

Abstract. A seismic hazard map proposed as part of a new building code for Bulgaria is presented here on basis of the recommendations in EUROCODE 8. Seismic source zones within an area of about 200 km around Bulgaria were constructed considering seismicity, neotectonic and geological development. The most time consuming work was to establish a homogeneous earthquake catalogue out of different catalogues. The probabilistic seismic hazard assessment in terms of intensities is performed following Cornell (1968) with the program EQRISK (see McGuire, 1976), modified by us for use of intensities. To cope with the irregular isoseismals of the Vrancea intermediate depth earthquakes a special attenuation factor is introduced (Ardeleanu et al., 2005), using detailed macroseismic maps of three major earthquakes. The final seismic hazard is the combination of both contributions, of zones with crustal earthquakes and of the Vrancea intermediate depth earthquakes zone. Calculations are done for recurrence periods of 95, 475 and 10 000 years.

scholarly journals Probabilistic seismic hazard assessment of Bishkek, Kyrgyzstan, considering empirically estimated site effects

2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Shahid Ullah ◽  
Dino Bindi ◽  
Marco Pilz ◽  
Stefano Parolai
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Assessment ◽  
Site Effects ◽  
Response Spectrum ◽  
Seismic Hazard Assessment ◽  
Geological Structure ◽  
Probabilistic Seismic Hazard Assessment ◽  
Site Classification ◽  
Ground Acceleration

<p>It is well known that variability in the surface geology potentially leads to the modification of earthquake-induced ground motion over short distances. Although this effect is of major importance when seismic hazard is assessed at the urban level, it is very often not appropriately accounted for. In this paper, we present a first attempt at taking into account the influence of the shallow geological structure on the seismic hazard assessment for Bishkek, Kyrgyzstan, using a proxy (Vs30) that has been estimated from in situ seismic noise array analyses, and considering response spectral ratios calculated by analyzing a series of earthquake recordings of a temporary seismic network. To highlight the spatial variability of the observed ground motion, the obtained results are compared with those estimated assuming a homogeneous Vs30 value over the whole urban area. The seismic hazard is evaluated in terms of peak ground acceleration (PGA) and spectral acceleration (SA) at different periods (frequencies). The presented results consider the values obtained for a 10% probability of exceedance in 50 years. The largest SA estimated considering a rock site classification of the area (0.43 g) is observed for a period of 0.1 s (10 Hz), while the maximum PGA reaches 0.21 g. When site effects are included through the Vs30 proxy in the seismic hazard calculation, the largest SA, 0.67 g, is obtained for a period of 0.3 s (about 3.3 Hz). In terms of PGA, in this case the largest estimated value reaches 0.31 g in the northern part of the town. When the variability of ground motion is accounted for through response spectrum ratios, the largest SA reaches a value as high as 1.39 g at a period of 0.5 s. In general, considering site effects in the seismic hazard assessment of Bishkek leads to an increase of seismic hazard in the north of the city, which is thus identified as the most hazardous part within the study area and which is more far away from the faults.</p>

scholarly journals Probabilistic seismic hazard map for Romania as a basis for a new building code

2005 ◽  
Vol 5 (5) ◽  
pp. 679-684 ◽  
Author(s):  
L. Ardeleanu ◽  
G. Leydecker ◽  
K.-P. Bonjer ◽  
H. Busche ◽  
D. Kaiser ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Grid Point ◽  
Building Code ◽  
Probabilistic Seismic Hazard Assessment ◽  
Eurocode 8 ◽  
Probabilistic Seismic Hazard ◽  
Hazard Map ◽  
Intermediate Depth ◽  
Attenuation Law ◽  
Seismic Hazard Map

Abstract. A seismic hazard map proposed as part of a new building code for Romania is presented here on basis of the recommendations in EUROCODE 8. Seismic source zones within an area of about 200 km around Romania were constructed considering seismicity, neotectonics and geological development. The probabilistic seismic hazard assessment in terms of intensities is performed following Cornell (1968) with the program EQRISK (see Mc Guire, 1976), modified by us for use of intensities. To cope with the irregular isoseismals of the Vrancea intermediate depth earthquakes a factor Ω is introduced to the attenuation law (Kövesligethy, 1907). Using detailed macroseismic maps of three earthquakes Ω is calculated by fitting the attenuation law to observed intensities, i.e. to local ground conditions. Strong local variation of Ω is avoided by a gridding of 0.5° in longitude and 0.25° in latitude. The contribution of the Vrancea intermediate depth zone to the seismic hazard at each grid point is computed with the corresponding representative Ω. A seismogenic depth of 120 km is assumed. The final seismic hazard is the combination of both contributions, of zones with crustal earthquakes and of the Vrancea intermediate depth earthquakes zone. Calculations are done for a recurrence period of 95, 475 and 10000 years. All maps show the dominating effects of the intermediate depth earthquakes in the Vrancea zone, also for the capital Bucharest.  

scholarly journals A Bayesian Approach to Estimate Weights for GMPE Models in a Logic Tree

2021 ◽  
Author(s):  
Saran Srikanth Bo ◽  
Merlin Keller ◽  
Abhinav Gupta ◽  
Gloria Senfaute
Keyword(s):  
Seismic Hazard ◽  
Bayesian Model Averaging ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Eastern United States ◽  
Logic Tree ◽  
Nuclear Facilities ◽  
Capital Costs ◽  
Precise Knowledge ◽  
Moderate Seismicity

Abstract In current practice, the seismic hazard curves are generated by combining all possible choices for seismotectonic model (SM), earthquake magnitude recurrence models, and ground motion prediction equation (GMPE) models using logic trees. However, studies have shown that significant uncertainties exist in the evaluation of the seismic hazard, especially in low-to-moderate seismicity regions, such as Central \& Eastern United States and Europe, due to the scarcity of the recorded earthquake data and lack of precise knowledge concerning the earthquake generation and propagation mechanisms. Specifically, these uncertainties lead to conservatisms in the seismic hazard which poses a considerable risk for nuclear facilities. Designing or upgrading facilities with such conservative estimates of seismic hazard results in large capital costs. In standard probabilistic seismic hazard assessment (PSHA) practices, the estimate of branch weights for the GMPE models is based on expert judgment and there is no holistic approach for estimating the weights under uncertainty. In this research, we focus on the GMPE part of the PSHA and we propose a statistical methodology that is based on Bayesian inference, to evaluate the GMPE model weights from a list of GMPE models in the logic tree. In this study, Bayesian model averaging (BMA) approach with Bayesian linear models (BLM) is employed to combine GMPE models and the performance of the BMA model is tested against European Strong-Motion (ESM) database. It is shown that the proposed methodology can calculate the weights at different time periods without any approximations using analytical formulas and it is computationally inexpensive.

Probabilistic seismic hazard assessment for the main cities along the continental section of the Cameroon volcanic line

2021 ◽  
Vol 14 (9) ◽  
Author(s):  
Etoundi Delair Dieudonné Ndibi ◽  
Eddy Ferdinand Mbossi ◽  
Nguet Pauline Wokwenmendam ◽  
Bekoa Ateba ◽  
Théophile Ndougsa-Mbarga
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Cameroon Volcanic Line

Probabilistic Seismic-Hazard Assessment in Quito, Estimates and Uncertainties

2014 ◽  
Vol 85 (6) ◽  
pp. 1316-1327 ◽  
Author(s):  
C. Beauval ◽  
H. Yepes ◽  
L. Audin ◽  
A. Alvarado ◽  
J.-M. Nocquet ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard
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