Article

Development of Maximum Considered Earthquake Ground Motion Maps

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Abstract

The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings use a design procedure that is based on spectral response acceleration rather than the traditional peak ground acceleration, peak ground velocity, or zone factors. The spectral response accelerations are obtained from maps prepared following the recommendations of the Building Seismic Safety Council's (BSSC) Seismic Design Procedures Group (SDPG). The SDPG-recommended maps, the Maximum Considered Earthquake (MCE) Ground Motion Maps, are based on the U.S. Geological Survey (USGS) probabilistic hazard maps with additional modifications incorporating deterministic ground motions in selected areas and the application of engineering judgement. The MCE ground motion maps included with the 1997 NEHRP Provisions also serve as the basis for the ground motion maps used in the seismic design portions of the 2000 International Building Code and the 2000 International Residential Code. Additionally the design maps prepared for the 1997 NEHRP Provisions, combined with selected USGS probabilistic maps, are used with the 1997 NEHRP Guidelines for the Seismic Rehabilitation of Buildings.

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... However, these fault sources will tend to contribute proportionately more to seismic hazard at higher return periods, as is demonstrated for the kp curve for Adelaide. 68,73]. It is also worth noting that variability in the kp factor (or return period factor, RS) is also noted between sites in New Zealand [70,74]. ...
...  In low-to-moderate seismicity regions, there is a larger difference between 1/475 and 1/2475 AEP groundmotions than in more tectonically active regions [e.g., 106]. Transitioning to lower exceedance probabilities in the national design provisions reduces the risk in low-tomoderate seismicity regions due to rare extreme ground motions [68]; ...
... It should be noted that neither Canada nor the United States use the 2% in 50-year hazard values directly calculated from their national-scale probabilistic hazard assessments for defining the seismic loading for building design, and use methods such as deterministic capping of ground motions for near-fault sites, or 2/3 of the risk-targeted maximum considered earthquake ground motions for assigning design levels [i.e., 68,113,114]. Nevertheless, the application of these adjustments would still yield higher seismic loading requirements, relative to the AS1170. ...
Article
Damaging earthquakes in Australia and other regions characterised by low seismicity are considered low probability but high consequence events. Uncertainties in modelling earthquake occurrence rates and ground motions for damaging earthquakes in these regions pose unique challenges to forecasting seismic hazard, including the use of this information as a reliable benchmark to improve seismic safety within our communities. Key challenges for assessing seismic hazards in these regions are explored, including: the completeness and continuity of earthquake catalogues; the identification and characterisation of neotectonic faults; the difficulties in characterising earthquake ground motions; the uncertainties in earthquake source modelling, and; the use of modern earthquake hazard information to support the development of future building provisions. Geoscience Australia recently released its 2018 National Seismic Hazard Assessment (NSHA18). Results from the NSHA18 indicate significantly lower seismic hazard across almost all Australian localities at the 1/500 annual exceedance probability level relative to the factors adopted for the current Australian Standard AS1170.4–2007 (R2018). These new hazard estimates have challenged notions of seismic hazard in Australia in terms of the recurrence of damaging ground motions. This raises the question of whether current practices in probabilistic seismic hazard analysis (PSHA) deliver the outcomes required to protect communities and infrastructure assets in low-seismicity regions, such as Australia. This manuscript explores a range of measures that could be undertaken to update and modernise the Australian earthquake loading standard, in the context of these modern seismic hazard estimates, including the use of alternate ground-motion exceedance probabilities for assigning seismic demands for ordinary-use structures. The estimation of seismic hazard at any location is an uncertain science, particularly in low-seismicity regions. However, as our knowledge of the physical characteristics of earthquakes improve, our estimates of the hazard will converge more closely to the actual – but unknowable – (time independent) hazard. Understanding the uncertainties in the estimation of seismic hazard is also of key importance, and new software and approaches allow hazard modellers to better understand and quantify this uncertainty. It is therefore prudent to regularly update the estimates of the seismic demands in our building codes using the best available evidence-based methods and models.
... Afghanistan, following ASC-10, takes the Maximum Considered Earthquake (MCE) for 0.2s spectral response acceleration as the starting point (2%PE 50y ). The mapped MCE values are then scaled by two-thirds, which represents a close approximation of the life-safety design level of 10%PE 50y (Leyendecker et al., 2000). IND-16 has a similar approach but defines the design earthquake at 50% of MCE. ...
... Set limitations of the design values correspond with an SDC which defines the method of analysis. To transform these set values into representative PGA levels (although not utilized as such in the US-based approach), they are to be divided by the spectral amplification (S DS /2.5), which is a close and acceptable approximation for initial design purposes (Leyendecker et al., 2000). TUR-18 also accepts PGA S DS /2.5 and has adopted a system of site-specific hazard coordinates, which includes spectral acceleration (as well as PGA) values for 10% PE 50y . ...
Article
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Full base shear seismic demand analyses with calculated examples for heavy stone masonry buildings are not present in the literature. To address this shortcoming, analyses and calculations are performed on nominally reinforced rubble stone masonry house and school designs, as typically built in Nepal. The seismic codes are literally applied for countries where the technique is still allowed (Nepal, India, China, Tajikistan, Iran, Croatia), or should be reintroduced based on current practices (Pakistan, Afghanistan, Turkey). First, this paper compares the base shear formulas and the inertia forces distributions of these codes, as well as material densities, seismic weights, seismic zoning, natural periods of vibration, response spectra, importance factors and seismic load combinations. Large differences between approaches and coefficients are observed. Then, by following Equivalent Lateral Force-principles for Ultimate Limit State verifications (10%PE50y), the base shear and story shears are calculated for a design peak ground acceleration of 0.20 g, as well as the effects of critical load combinations on the forces and moments acting on the lateral-resisting elements. It is concluded that Pakistan has the most tolerant code, Nepal represents an average value, whereas India and China are most conservative toward the case study buildings. Overall, it is observed that heavy-masonry-light-floor systems with negligible diaphragm action behave different under seismic motion than most other building typologies. Given the observations in this paper, the applicability of conventional ELF, S-ELF and S-Modal methods for heavy masonry buildings is questionable. The codes however do not introduce modified approaches that address these differences. Possible implications of the exclusion of plinth masonry and large portions of seismic weight need further assessment and validation, for which different (possibly more sophisticated) concepts must be considered, such as the equivalent frame method or distributed mass system. Since Nepal allows stone masonry in areas with higher seismic hazard levels >0.40 g (opposed to India <0.12 and China <0.15 g), their code is taken as the reference and starting point for follow-up research, which aims to verify the seismic demand by performing seismic capacity checks of the masonry piers and spandrels. The paper ends with an appeal for global collaboration under the research project SMARTnet.
... Analisis untuk mendapatkan nilai spektra percepatan tanah dengan menggunakan kombinasi hazard gempa probabilistik (probabilitic seismic hazard analysis/PSHA) dan deterministik (deterministic seismic hazard analysis/DSHA) pertama kali diperkenalkan oleh Leyendecker et al. (2000). Perhitungan percepatan gerakan tanah di batuan dasar pada satu titik dengan pendekatan PSHA dilakukan dengan menggunakan metode total probability theorem dari McGuire (1995). ...
... Nilai "c" pada persamaan tersebut merupakan nilai percepatan sedangkan "c10%" adalah nilai 10 th percentile kapasitas keruntuhan bangunan. Gambar 1 menunjukkan skema perhitungan MCER yang merupakan kombinasi dari hasil perhitungan RTGM dan DSHA dan dikembangkan dari metode yang diperkenalkan oleh Leyendecker et al. (2000). ...
Article
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SNI 1726:2012 states that surface spectral accelerations SMS (0.2 second) and SM1 (1 second) can be calculated by multiplying site factors Fa (0.2 second) and Fv (1 second) with spectral accelerations SS (0.2 second) dan S1 (1 second). All site factors used by SNI 1726:2012 are adopted from ASCE/SEI 7-10. In 2013 Stewart and Seyhan proposed new and different site factors compared to ASCE/SEI 7-10. These site factors are then used for developing ASCE/SEI 7-16 with minor improvement for site class SE (soft soil). ASCE/SEI 7-16 states that the site factors for site class SE with SS greater than 1g or S1 greater than 0.2g, shall be calculated using Site Specific Analysis (SSA). The SSA method used for calculating site factor is difficult for ASCE/SEI 7-16 to be implemented in Indonesia. This paper describes the result of SMS and SM1 study at five cities (Jakarta, Bandung, Semarang, Yogyakarta and Surabaya) for site class SC, SD and SE using site factors proposed by Stewart and Seyhan and site factor SNI 1726:2012. The SMS and SM1 at five cities calculated using site factors proposed by Stewart and Seyhan are ±15% differences compared to SMS and SM1 calculated usingSNI 1726:2012 site factors.
... The final accelerations to be adopted in the map are the lesser between the deterministic and the probabilistic values. Interested readers should refer to Leyendecker et al. [23] and Stewart et al. [30] for further information on this. The deterministic accelerations are not considered in this study because of the lack of knowledge regarding existent faults (e.g., Costa et al. [31]) and the absence of a discussion regarding any predefined values for Brazil. ...
... (iii) In [26], design accelerations are multiplied by 2/3. This is based on an existent safety margin, due to code design conservatism [23], [30], which, to the best of our knowledge, has never been stated for buildings in Brazil. Therefore, this is not explored in the results of this paper. ...
Article
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Given the tendency of risk-targeted seismic design maps worldwide, it is important that Brazil is inserted in this context as well. This study aims to apply the risk-targeting methodology for Northeastern Brazil, more specifically the region within Zone 1 of the Brazilian earthquake-resistant design code ABNT NBR 15421:2006. Different inputs for the methodology are explored and combined with existing hazard studies for the region, and their impact in the final map are evaluated. The results outline that, depending on the safety level required, the provisioned design accelerations could be lower than the commonly used in codes, but may as well be much higher. The results are also compared with the current code provisions and their differences are discussed, providing insights on the code provisioned level of safety.
... Allen and Luco, 2018). Transitioning to lower exceedance probabilities in the national design provisions reduces the risk in low-to-moderate seismicity regions due to rare extreme ground motions (Leyendecker et al., 2000); The rate of attenuation of earthquake ground-shaking is generally lower in SCRs like Australia (e.g. Bakun and McGarr, 2002;Frankel et al., 1990). ...
... It should be noted that neither Canada nor the United States uses the 2% in 50-year hazard values directly calculated from their national-scale probabilistic hazard assessments for defining the seismic loading for building design, and use methods such as deterministic capping of ground motions for near-fault sites, or 2/3 of the risk-targeted maximum credible earthquake ground motions for assigning design levels (i.e. Leyendecker et al., 2000;Luco et al., 2007;Malhotra, 2005). Nevertheless, the application of these adjustments would still yield higher seismic loading requirements, relative to the AS 1170.4-2007 ...
Article
Full-text available
Seismic hazard assessments in stable continental regions such as Australia face considerable challenges compared with active tectonic regions. Long earthquake recurrence intervals relative to historical records make forecasting the magnitude, rates, and locations of future earthquakes difficult. Similarly, there are few recordings of strong ground motions from moderate-to-large earthquakes to inform development and selection of appropriate ground-motion models (GMMs). Through thorough treatment of these epistemic uncertainties, combined with major improvements to the earthquake catalog, a 2018 National Seismic Hazard Assessment (NSHA18) of Australia has been undertaken. The resulting hazard levels at the 10% in 50-year probability of exceedance level are in general significantly lower than previous assessments, including hazard factors used in the Australian earthquake loading standard ( AS 1170.4–2007 (R2018)), demonstrating our evolving understanding of seismic hazard in Australia. The key reasons for the decrease in seismic hazard factors are adjustments to catalog magnitudes for earthquakes in the early instrumental period, and the use of modern ground-motion attenuation models. This article summarizes the development of the NSHA18 explores uncertainties associated with the hazard model, and identifies the dominant factors driving the resulting changes in hazard compared with previous assessments.
... As described below, in some cases, this probabilistic MCE R ground motion is capped by a deterministic ground motion. The actual design ground motion is reduced from MCE R using a 2/3 factor that was introduced in Project 97 for reasons described subsequently (BSSC, 1997;Leyendecker et al., 2000). ...
... Near such faults, deterministic caps are applied to limit the ground motions to the 84th percentile level, given the occurrence of a characteristic earthquake. Deterministic caps were introduced in Project 97 and the 1997 NEHRP Provisions (BSSC, 1997;Leyendecker et al., 2000), at which time the general basis for design ground motions was uniform hazard ground motions computed using probabilistic seismic hazard analyses (PSHAs). The practice has continued since then, for reasons described here, but was reconsidered in Project 17. ...
Article
Since their inception over 20 years ago, the maximum considered earthquake ground motion maps in U.S. building codes have capped probabilistic values with deterministic ground motions from characteristic earthquakes on known active faults. This practice has increasingly been called into question both because of spatially non-uniform risk levels that are produced (risk being higher mainly in coastal California) and practical difficulties in defining characteristic earthquakes from recent earthquake rupture forecast models. We describe two proposals developed to enable phase-out of deterministic caps. One approach modestly increases collapse risk targets nationwide based on recent information on return periods of characteristic earthquakes on major central and eastern U.S. seismic sources; adoption of this approach would remove the perceived need for caps in California. The second approach uses geographically varying collapse risk targets, being higher near the highly active faults in California and unchanged elsewhere. Neither approach was adopted for the 2020 National Earthquake Hazards Reduction Program recommended seismic Provisions for new building structures, but they are described in a Part 3 document to accompany the Provisions and Commentary.
... The return time of a ground motion is the reciprocal of the annual probability of exceeding that ground motion and is not the same as the repeat time of an earthquake (see also Frankel, 2004), because of the variability of ground motions from any particular earthquake. The 2000–2009 versions of the International Building Code (IBC) applied in the U.S. were based, in most areas, on design ground motions equal to 2/3 times the ground-motion values with a 2% probability of being exceeded in 50 years, which on average represent a 1500 year return time of ground motion (Leyendecker et al., 2000). ...
Data
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... However, as a national-scale model, a key require- ment is that these models must portray similar information across widely differing seismotectonic regions to allow direct comparison of hazard in different parts of the country ( Frankel et al., 2000;Moschetti et al., 2015;Rezaeian et al., 2015). Since 1996, the hazard maps have directly formed the basis for the seismic provisions in U.S. building codes ( Leyendecker et al., 2000;Frankel, Petersen, et al., 2002;Petersen et al., 2008Luco et al., 2015). The connection between U.S. build- ing codes and the NSHM represents one critical way in which knowledge about earthquake occurrences and effects can be used to reduce seismic risk. ...
... Based on the latest researches and investigations, revised seismotectonic models for Indonesia were developed and to be used in developing new seismic hazard For the purpose of geotechnical calculation, it combines both the results from probabilistic seismic hazard analysis for 2% probability of exceedance in 50 years (2500 years earthquake) and deterministic seismic hazard analysis for area located near active fault. Both approaches were utilized according to the procedure proposed by Leyendecker et al. (2000) and the result of combining both probabilistic and deterministic analyses is called MCE G . In order to evaluate the seimic hazard for low and high risk structure (e.g. ...
Chapter
This paper presents the recent efforts in Indonesia to mitigate the impacts of earthquake hazards. The actions includes as follows: updating of the seismic hazard maps of Indonesia 2010 and 2016; revision and continuous updating of building and infrastructure design codes; development of microzonation maps for big cities in Indonesia; development of academic draft of Indonesian Earthquake Master Plan; development of design guidelines for tsunami vertical evacuation; development of a national design code for geotechnics and earthquake; and establishment of the national center for earthquake studies. Revision of seismic hazard maps for Indonesia 2010 has been developed based upon updated: seismotectonic data, fault models, and GMPEs up to 2010. The updating of infrastructure design codes related to earthquakes activities are being performed for buildings, bridges, dams, harbors and others special structures. The development of microzonation map of seismic risk has been initiated for Jakarta city. The academic draft for Indonesian earthquake master plan has been prepared based on assessment from several aspects, i.e. basic sciences, engineering and risk analysis, and social and legal aspects. The guidelines for tsunami evacuation had been finished and submitted to BNPB in 2013. Lastly, the Indonesia National Research Center for Earthquake has been initiated in June 2016.
... ASCE 7-10 [6] defines MCE as the earthquake having a 2% probability of exceedance in 50 years, i.e. a return period of 2475 years and which is 1.5 times higher than the design earthquake (DE). According to some studies [11], DE can be considered as an earthquake having 10% probability of exceedance in 50 years for some areas in United States, which can be correlated to the seismic hazard defined in EN 1998-1 [1] for no-collapse requirement. Accordingly, the design response spectrum of EN 1998-1 obtained for each seismic location is multiplied by 1.5 in order to define a level similar to MCE for each archetype Fig. 3 shows the scaled design response spectrums of EN 1998-1 used in this study and the seismic Design categories (SDC) of ASCE 7-10 based on MCE. ...
Conference Paper
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The study presented herein is centred around the behaviour factor evaluation of cold-formed steel strap braced stud walls following the methodology of FEMA P695. A set of fourteen archetypes, are designed with an initial assumption of behaviour factor and following the capacity design approach. Numerical models possessing the ability to simulate the non-linear response of archetype buildings are developed and analysed using non-linear static and dynamic analysis procedures. Performance of archetypes is then evaluated by measuring their collapse fragility against the performance criterions of FEMA P695. Based on results, it is concluded that the design method used in this study and a behaviour factor (q) of 2.5 are appropriate for CFS strap-braced stud walls.
... DE is defined in ASCE 7-10 [2] as 2/3 times of MCE, while MCE is defined as the earthquake having 2% probability of exceedance in 50 years, i.e. a return period of 2475 years. According to some studies [30], DE can be considered as an earthquake of 10% probability of exceedance in 50 years for some areas in United States, which corresponds to No-collapse requirement of EN 1998-1 [1]. Since FEMA P695 methodology use MCE in its formulations, therefore it was necessary to define a level similar to MCE for locations in this study, which can be obtained by simply multiplying the elastic response spectrum of EN 1998-1 by 1.5. ...
Article
An upgrade of the construction standards is required to promote the use of lightweight steel structures in seismic areas of Europe. European earthquake standard EN1998-1 does not provide seismic design guidelines for the energy dissipative structural typologies in lightweight steel constructions. CFS strap-braced stud wall is an all-steel solution to dissipate the seismic energy in lightweight steel constructions. In this regard, a numerical study is performed to provide suitable value of the behaviour factor (q) for CFS strap-braced stud wall following the procedures of FEMA P695. A set of fourteen archetypes, which represented the range of design parameters and building configurations are designed following the capacity design approach. Numerical models with the ability to simulate the non-linear response of archetype buildings are then developed and analysed using non-linear static and dynamic analysis procedures. A suite of 44 normalized and scaled earthquake records, representing the probable seismic hazard to the buildings, is used for the incremental dynamic analysis. Performance of archetypes is evaluated by measuring their collapse fragility. Based on the results, it is concluded that the design method used in this study and a behaviour factor (q) of 2.5 for CFS strap-braced stud wall are appropriate to be include in next edition of the Eurocodes.
... The several analytical methods usually adapted for earthquake analysis are mentioned in DSLS-1977, however only detailed steps of, the coefficient method employing equivalent static method ESLF is available. for determining earthquake, snow and wind loads [5], hence the "equivalent lateral force" analysis (ELF) ...
... U.S. code defines only one explicit level of seismic action based on a recommended probability of exceedance of 2% in 50 years or a return period of 2475 years, namely maximum considered earthquake (MCE) ground motion, and stipulates that structures are designed to provide an approximately uniform margin against collapse under such level of ground motion throughout the United States [28]. The so-called seismic margin is set at 1.5; consequently, the design level ground motion is defined as 2/3 of MCE and is used to formulate the design response spectrum. ...
... Differences in regional seismicity can produce significant differences in ground motions at different return periods. Leyendecker et al. ͑2000͒ showed that short-period ͑0.2 s͒ spectral acceleration, for example, increased by about 50% when going from return periods of 475 years to 2,475 years in Los Angeles and San Francisco but by 200-500% or more in other areas of the country. The position and slope of the peak acceleration hazard curve clearly affect the return period of liquefaction. ...
Thesis
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The paper describes a performance-based approach to the evaluation of liquefaction potential, and shows how it can be used to account for the entire range of potential ground shaking. The result is a direct estimate of the return period of liquefaction, rather than a factor of safety or probability of liquefaction conditional upon ground shaking with some specified return period. As such, the performance-based approach can be considered to produce a more complete and consistent indication of the actual likelihood of liquefaction at a given location than conventional procedures. In this paper, the performance-based procedure is introduced and used to compare likelihoods of the initiation of liquefaction at identical sites located in areas of different seismicity. The results indicate that the likelihood of liquefaction depends on the position and slope of the peak acceleration hazard curve, and on the distribution of earthquake magnitudes contributing to the ground motion hazard. The results also show that the consistent use of conventional procedures for the evaluation of liquefaction potential produces inconsistent actual likelihoods of liquefaction.
... Also shown for comparison in Figure 25are the " firm rock " 10%-in-50 yr values (black line) reflected in the 1996 CDMG/USGS hazard maps (Petersen et al., 1996;). These latter values are close to, but not exactly the same as those applied in the 1997 NEHRP building code provisions (BSSC, 1998;Leyendecker et al., 2000). The effect of applying the NEHRP amplification factors (Tables 2 and 3) to the rock-site exceedance levels, as specified in the code, is also plotted in Figure 25(blue line). ...
Article
This article presents an overview of the Southern California Earthquake Center (SCEC) Phase-III effort to determine the extent to which probabilistic seismic hazard analysis (PSHA) can be improved by accounting for site effects. The contributions made in this endeavor are represented in the various articles that compose this special issue of BSSA. Given the somewhat arbitrary nature of the site-effect distinction, it must be carefully defined in any given context. With respect to PSHA, we define the site effect as the response, relative to an attenuation relationship, averaged over all damaging earthquakes in the region. A diligent effort has been made to identify any attributes that predispose a site to greater or lower levels of shaking. The most detailed maps of Quaternary geology are not found to be helpful; either they are overly detailed in terms of distinguishing different amplification factors or present southern California strong-motion observations are inadequate to reveal their superiority. A map based on the average shear-wave velocity in the upper 30 m, however, is found to delineate significantly different amplification factors. A correlation of amplification with basin depth is also found to be significant, implying up to a factor of two difference between the shallowest and deepest parts of the Los Angeles basin. In fact, for peak acceleration the basin-depth correction is more influential than the 30-m shear-wave velocity. Questions remain, however, as to whether basin depth is a proxy for some other site attribute. In spite of these significant and important site effects, the standard deviation of an attenuation relationship (the prediction error) is not significantly reduced by making such corrections. That is, given the influence of basin-edge-induced waves, subsurface focusing, and scattering in general, any model that attempts to predict ground motion with only a few parameters will have a substantial intrinsic variability. Our best hope for reducing such uncertainties is via waveform modeling based on first principals of physics. Finally, questions remain with respect to the overall reliability of attenuation relationships at large magnitudes and short distances. Current discrepancies between viable models produce up to a factor of 3 difference among predicted 10% in 50-yr exceedance levels, part of which results from the uncertain influence of sediment nonlinearity.
... Hazard Curves for West Coast and Mid-America(Leyendecker and Hunt, 2000) Figure 3.5 shows the seismic effects of the two earthquakes in the West Coast, 1906 San Francisco and 1971 San Fernando, and the two in Mid-America, 1811 New Madrid and 1886 Charleston. The estimated moment magnitudes of the 1906 San Francisco and the 1971 San Fernando earthquake are 8.3 and 6.3, respectively. ...
Data
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... The design-response spectrum of horizontal ground motion in the 2003 IBC (ICC, 2003) and ASCE 7 (2002) is constructed from 5% damping SAs at 0.2 sec S DS , and at 1 sec S D1 , which are based on probabilistic seismic hazard analysis (Cornell, 1968;Reiter, 1991;Frankel et al., 1996;Petersen et al., 1996;Leyendecker et al., 2000;McGuire, 2004). First, the control period defining the transition between the acceleration-and velocity-sensitive regions is computed: ...
Article
An improved method of constructing a smooth-response spectrum from peak values of ground acceleration, velocity, and displacement (PGA, PGV, and PGD) is presented. Improved dynamic amplification factors are presented for applying damping adjustments to the spectral accelerations or to backcalculate PGA, PGV, and PGD from spectral accelerations. Horizontal-to-vertical spectral ratios are analyzed for rock and soil sites to allow the construction of a vertical design spectrum from a given horizontal design spectrum.
... Relative displacement is the maximum absolute displacement of a SDOF system relative to its base. Response spectra can be developed from PGA alone or from PGA, PGV, and PGD (Newmark and Hall, 1982;Campbell, 2002; see also Chapter 67 by Jennings), or they can be developed from one or two key response-spectral ordinates, such as PSA at T n = 0.2 and T n = 1 sec (Leyendecker et al., 2000; see also Chapter 68 by Borcherdt et al.). Such procedures are typically used in building codes and other seismic regulations where a simple prescribed method for estimating a seismic design spectrum is required. ...
... The design hazard levels are associated with the desired performance and a probability of occurrence. IBC (Merritt, 1996) associates the design hazard to the Maximum Considered Earthquake (MCE) which corresponds to 2% probability of exceedance in 50 years in most parts of the US, except in coastal California (Leyendecker et al., 2000). IBC recommends a factor of 2/3 to reduce the MCE to obtain the design hazard level. ...
Thesis
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Design philosophy refers to a set of assumptions and procedures, which are used to meet the conditions of serviceability, safety, economy, and functionality of structures. The application of the current introduced “Risk-targeted maximum considered earthquake” ground motion maps enables engineers to incorporate a more consistent and better-defined level of seismic safety into their building designs. It requires that buildings be designed to provide the same level of seismic performance, meaning that they will be equally (un)likely to collapse in earthquakes. The new maps are referred to as risk-targeted because the likelihood of collapse is known as the seismic risk level. The main aim of this thesis is to undertake a comparative study on representative buildings to discuss the current state of design philosophies and applied/considered limit states for different international seismic standards and with respect to modern risk-targeted seismic design analysis.
... However, as a national-scale model, a key require- ment is that these models must portray similar information across widely differing seismotectonic regions to allow direct comparison of hazard in different parts of the country ( Frankel et al., 2000;Moschetti et al., 2015;Rezaeian et al., 2015). Since 1996, the hazard maps have directly formed the basis for the seismic provisions in U.S. building codes ( Leyendecker et al., 2000;Frankel, Petersen, et al., 2002;Petersen et al., 2008Luco et al., 2015). The connection between U.S. build- ing codes and the NSHM represents one critical way in which knowledge about earthquake occurrences and effects can be used to reduce seismic risk. ...
... The scaling factor of 1.5 can be considered as MCE (Maximum Considered Earthquake) intensity earthquake. This is due to the fact that the MCE is 1.5 times the DE [32]. Figs. ...
Article
The current edition of Eurocode 8 (EN 1998 (CEN (2004))) does not explicitly cover the earthquake-resistant design of the Lightweight steel (LWS) buildings made with cold-formed steel (CFS) frame. Extensive research has been carried out in the past decade on this topic that provides a solid background for an update of the current provisions and the development of a new edition of the code. As part of the revision process of Eurocode 8, several activities are currently under development. Within this framework, this paper presents a set of design rules for the seismic design of LWS buildings based on background studies carried out at the University of Naples “Federico II”. A critical review of the provisions given by international design standards for the seismic design of LWS systems is also presented. The proposed design rules include a set of provisions for achieving the dissipative behaviour of Lateral Force Resisting System (LFRS) and predicting their design strength, together with behaviour factor values and geometrical and mechanical limitations. Different types of LFRS are analysed, namely CFS strap-braced walls and CFS shear walls with steel sheets, wood, or gypsum sheathing. Worked examples are also presented to show the applicability of the proposed design rules on a set of building archetypes. Validation numerical study is performed using both nonlinear static and incremental dynamic analysis approaches. Finally, the collapse performance of the archetypes is assessed following the seismic performance evaluation protocol of FEMA P695.
... MCE is an earthquake having 2% probability of exceedance in 50 years, i.e. a return period of 2475 years. Moreover the Design Earthquake (DE) in ASCE 7-10 is defined as the 2/3rd of the MCE, which according to Leyendecker et al. [36] can be associated to seismic intensity level with probability of exceedance as 10% probability of exceedance in 50 years, i.e. 475 years return period for some sites in U.S. and hence can be considered equal to the 5% damped elastic design response spectrum of [27]. ...
Article
Keywords: Cold-formed steel Shear walls Gypsum board sheathing Seismic design Incremental dynamic analysis Behaviour factor FEMA P695 A B S T R A C T Earthquake standards around the globe are progressing towards adopting an advanced performance based seismic design approach, providing the guidelines for the newer innovative seismic force resisting systems and codifying the seismic performance of already in use structural systems. Gypsum board panels are among one of the many types of panels currently widely used in the Light Weight Steel (LWS) constructions made of the Cold Formed Steel (CFS) frames primarily for sheathing the studs to form an envelope of the building. Contrarily, there choice as the sheathing panel for shear walls resisting the seismic loads in LWS construction is rather limited due the lack of guidelines on their seismic performance in European standards. The work presented here in attempts to bridge this gap by evaluating a suitable value of their behaviour factor, which is one of the significant measures for quantifying the seismic response, through a numerical study performed following the procedures of FEMA P695. A set of fourteen archetypes, which represent a range of design parameters and the building configurations are designed following the capacity design approach and their response is idealized by the nonlinear models. The performance of archetype models is evaluated systematically through the static pushover and the incremental dynamic analysis under a suite of forty-four normalized and scaled earthquake records, representing the probable seismic hazard to the buildings. Finally, by calculating the collapse probability while also considering the uncertainties from various sources, the suitability of trial value of behaviour factor used in the design phase of archetypes is evaluated. Based on the results, it is concluded that a behaviour factor (q) of 2.0 for the CFS shear walls with gypsum board sheathing is appropriate.
... The schematic approach employed in combining PSHA and DSHA was first illustrated by [16], with this model adopted in the present study to calculate the MCE R values (2018). Fig. 3 Seismic microzonation of Semarang was carried out based on the obtained national MCE R analysis results by combining risk targeted ground motion analysis (RTGM) for a 1% probability of collapse in 50 years and 84 th percentile deterministic seismic hazard analysis with an adjusted direction factor of 1.1 for 0.2 second period and 1.3 for 1 second period spectral acceleration. ...
... After defining the code-based design spectrum, the design acceleration coefficients (S DS = design spectral response acceleration at short periods; and S D1 = design spectral response acceleration at a 1-s period) were multiplied by a 1.50 scale-up factor to match the maximum considered earthquake (MCE) level (i.e., a 2% probability of exceedance within a 50-year period). The scaled-up response spectrum was set as the target response spectrum [66]. Fig. 14 compares the mean value of the individual response spectra for the original earthquake records to the target response spectrum (the scaled-up response spectrum). ...
Article
Piloti-type reinforced concrete building structures have vertically irregular configurations composing a moment frame for parking spaces in the lower story and heavyweight shear wall system for residential spaces in the upper stories. Due to these vertically irregular configurations, such building structures are governed by a soft-story mechanism, damage concentration on the first story. Since the 2017 Pohang earthquake led to severe damage to the piloti-type building structures on a regional level, a decision-making tool mitigating the seismic damage for future events is needed. This paper aimed to propose a rapid decision-making tool promptly estimating seismic damage with simple information and determining a retrofit scheme using a pre-developed extensive database, i.e., multi-dimensional structural parameter surfaces. The multi-dimensional surfaces were created using a simplified modeling approach with five structural parameters: period, strength ratio, and ductility controlling failure modes as the input, and peak inter-story drift ratio and demand-to-capacity ratio as the output. The proposed methodology was validated using a finite element model for the piloti-type building structure with a soft-story mechanism. The seismic responses detected from the multi-dimensional surfaces have a slight difference from those of the numerical model. Nevertheless, the rapid tool predicted a reasonable agreement with performance evaluation from the finite element simulation. In addition, the rapid tool provided feasible retrofit options to meet target performance using brief structural information. Due to its simplified process, the proposed tool can be implemented to the regional seismic assessment for the residential areas where the piloti-type building structures were highly concentrated.
... The scaling factor of 1.5 can be considered as MCE (Maximum Considered Earthquake) intensity earthquake. This is due to the fact that the MCE is 1.5 times the DE [40]. Figure 3 shows the results of IDA results for the DC2 Class building archetype braced with CFS steel sheathed shear wall. ...
... DE is taken as 2/3rd of MCE, while MCE is an earthquake, which has a return period of 2475 years, i.e. 2% probability of exceedance in 50 years [30]. For some sites in USA, DE can be considered equivalent to an earthquake of 10% probability of exceedance in 50 years [33]. Based on this, a correspondence can also be established between DE and an earthquake corresponding to No-collapse requirement of EN 1998-1 [1]. ...
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Cold formed steel (CFS) wood sheathed shear walls are one of the most often used type of shear walls applied as the main lateral force resisting system (LFRS) in a lightweight steel (LWS) building. This paper evaluates the behavior factor used in the seismic design according to Eurocodes for buildings equipped with CFS wood sheathed shear walls as the main LFRS. FEMA P695 methodology is used to evaluate the behavior factor. A set of archetypes are selected and designed, which reflected the applicable building heights, seismic hazard and occupancies for LWS buildings in Europe. Nonlinear three-dimensional finite element (FE) models of building archetypes are developed in OpenSees software using the individual shear wall models, which are calibrated on results from tests on individual shear wall specimens. The resilience of building models against collapse is checked by analyzing the models using lateral static (pushover) and incremental dynamic analysis (IDA). Uncertainties arising from test and design information, numerical modelling and archetype response variability to different ground motions is also taken into account. Based on the collapse performance evaluation results, a value of 2.5 for behavior factor, used in the design, is found to provide appropriate level of safety against the collapse in LWS buildings equipped with CFS wood sheathed shear walls.
... Pada perhitungan MCEG, nilai PSHA tidak mempertimbangkan probabilitas kehancuran bangunan atau tidak menggunakan nilai logarithma standar deviasi. Gambar 1 menunjukkan model analisis gabungan DSHA dan PSHA untuk perhitungan MCEG (Leyendecker et al., 2000). Tabel 1 menunjukkan contoh hasil analisis untuk mendapatkan nilai MCEG yang dilakukan pada tiga titik koordinat di Kota Semarang. ...
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Surface peak ground acceleration (PGAM) needs for seismic forces of basement and retaining structures design. The PGAM value can be calculated using bedrock peak ground acceleration (MCEG) and multiplied it with site coefficient FPGA. For building design purposes, the MCEG value can be calculated based on the combination of DSHA (Deterministic Seismic Hazard Analysis) and PSHA (Probabilistic Seismic Hazard Analysis). Compared to the previous 2012 website response spectrum design which is displayed the PGAM value, only MCEG value at site position can be obtained from the new 2021 response spectrum design website. This paper describes the development of PGAM distribution of Semarang using Visual Basic programming language software. The distribution of DSHA and PSHA (2500 return periods) combination analysis for developing MCEG value also describes in this paper. The analysis was performed based on the earthquake record data from 1900 to 2016. The PGAM analysis was performed at 203 soil boring investigation positions and using FPGA site coefficients of SNI 1726:2019. The minimum and maximum PGAM distribution values at the study area are in between 0.45 through 0.55 g and the maximum PGAM is distributed at the northern part of the study area.
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A review of seismic hazard description in United States design codes and procedures is presented in this paper. This review includes: history of seismic hazard maps; development and use of seismic hazard maps; and use and adoption of seismic building codes in the US. The review includes discussion of two paradigm shifts. The first paradigm shift occurred in the 1970s when seismic hazard was described as contour maps of probabilities of peak ground accelerations being exceeded. The second paradigm shift occurred in the 1990s and led to the development of a new concept for describing the use of seismic hazard maps in US seismic design codes.
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Earthquake Resistant Design and Risk Reduction, 2nd edition is based upon global research and development work over the last 50 years or more, and follows the author's series of three books Earthquake Resistant Design, 1st and 2nd editions (1977 and 1987), and Earthquake Risk Reduction (2003). Many advances have been made since the 2003 edition of Earthquake Risk Reduction, and there is every sign that this rate of progress will continue apace in the years to come. Compiled from the author's wide design and research experience in earthquake engineering and engineering seismology, this key text provides an excellent treatment of the complex multidisciplinary process of earthquake resistant design and risk reduction. New topics include the creation of low-damage structures and the spatial distribution of ground shaking near large fault ruptures. Sections on guidance for developing countries, response of buildings to differential settlement in liquefaction, performance-based and displacement-based design and the architectural aspects of earthquake resistant design are heavily revised. This book: Outlines individual national weaknesses that contribute to earthquake risk to people and property Calculates the seismic response of soils and structures, using the structural continuum "Subsoil - Substructure - Superstructure - Non-structure" Evaluates the effectiveness of given design and construction procedures for reducing casualties and financial losses Provides guidance on the key issue of choice of structural form Presents earthquake resistant design methods for the main four structural materials - steel, concrete, reinforced masonry and timber - as well as for services equipment, plant and non-structural architectural components Contains a chapter devoted to problems involved in improving (retrofitting) the existing built environment This book is an invaluable reference and guiding tool to practising civil and structural engineers and architects, researchers and postgraduate students in earthquake engineering and engineering seismology, local governments and risk management officials.
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Only engineering models that directly predict ground-motion amplitude or that predict the modulation of this amplitude from such effects as fault geometry and source directivity are discussed in this chapter. Duration is an important aspect of strong ground motion, especially for the inelastic response of structures, but much less attention has been paid to predicting duration and, therefore, no consensus engineering models are available. Generally speaking, the inelastic behavior of structures is included in structural design through the use of time histories and structural ductility factors, which are the topics of other chapters in this book.
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This paper outlines seismic guidelines of both Japan and U.S. Building Codes. Each country has its own types of seismic provisions. Japan has the allowable stress-based design and the performance-based design, while the U.S. has 1997 UBC seismic provisions and IBC 2000 seismic provisions. Each item shown below as keywords is further explained for each of the four types of Japan and U.S. seismic provisions. Both of Japan two provisions are two-step design methods for moderate and major earthquakes, while both of two U.S. provisions are single-step methods for major earthquakes, based on elastic analysis combined with response modification factors. Finally it is stated that design base shear coefficient levels are much higher in Japan than in U.S., reflecting the difference of building damages caused by past earthquakes as well as structural characteristics of buildings used for each country. and that the comparison will be, in a separate article, made on the seismic resistance of two approximately 45 high multi-story office buildings designed by Japan and U.S. seismic provisions respectively.
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Based on probabilistic seismic risk analysis result of 8181 grids in Sichuan and adjacent region, we summed up the features of ratios between peak ground accelerations of different risk levels. We focused our research on the statistical and spatial distribution characteristics of the ratio (K2-value) between rare and medium seismic action and made a preliminary analysis on the factors affect K2-value. The result could provide not only a significant basement for determining criteria and methodology for compiling seismic zonation maps against collapse of structures, but also a reference to aseismic design and checking computation for different industries and engineering.
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Procedure of standard Seismic Hazard Assessment (PSHA) has a problem with over simplifying recurrence since being represented by a linear relationship. However, the relationship will be satisfied only if the size of the study area is large enough with respect to linear dimensions of sources.. PSHA lies in attenuation relations are usually not translation invariant in the phase space. Regarding the problem of completeness data, instead of using recurrence relationship DSHA select the most credible earthquakes. However, the DSHA remain lies in attenuation relations, assume the same propagation model for all the events, but such a hypothesis is not very realistic. On the contrary, NDSHA procedure has advantages in calculation strong ground motion from the realistic model of synthetic seismograms from source specific properties and cooperates with the available structural model. Additionally, The NDSHA produced more information such as PGD, PGV, PGA for horizontal and vertical components each. Using realistic computation for Banda Aceh, NDSHA provides an accurate value for each of those components, achieving probability of exceedance in the range between 10% to 2% probability of exceedance PGA from PSHA computation. Regarding some limitation from PSHA, Indonesia needs to establish research on NDSHA for the area has critical infrastructures to face the seismic hazard.
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The renewal of Indonesian seismic code from SNI 1726-2002 into SNI 1726-2012 brings significant change in the design spectrum. Focused on several regular plan concrete building which have been design using displacement based design method, the aim of this study is to verify their performance using nonlinear time history analysis based on parameters: drift, damage indices, and plastic mechanism determined by FEMA 356. The excitation is spectrum consistent accelerogram based on El-Centro 1940 N-S, to match with the new Indonesian response spectrum for soft soil in low- and high intensity area. It is found that the code-designed buildings are not suitable for the targeted design of level-2 with maximum drift of 2.5% due to major. This is caused by improper selection of SNI spectrum as the design major earthquake. In fact, it is only equivalent to small earthquake. Although buildings survive up to a very rare earthquake without collapse but they suffer excessive damage and rotation due to small- to major-earthquake. The capacity design procedure is able to maintain ductile mechanism, but some columns experience yielding at prohibited locations.
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An important difference between ASCE 7-16 or ASCE 7-10 with ASCE 7-05 is the definition of the response spectrum for horizontal shaking. In ASCE/SEI 7-05, the spectrum is the geometric mean of the two horizontal components. In ASCE 7-16 and ASCE 7-10, the spectrum is defined as the maximum rotated component, where the ratio of maximum to geometric mean spectral demand can be taken as 1.1 at 0.2 second and 1.3 at 1.0 second. Huang et al. (2008a, 2010) provide the technical basis for these multipliers.
Chapter
Website software (WS) for Risk-targeted Maximum Considered Earthquake (MCER) acceleration calculation was announced in 2019. Single user non website software (stand-alone software/SAS) was also released in June 2020. The MCER acceleration is divided into three different values MCEG (peak ground acceleration), MCER-SS (short period) and MCER-S1 (1-s period) spectral acceleration. The purpose of the SAS software development is to help civil engineers living in areas having no internet connection or internet connection problems. Both software packages should yield the same MCER result when the same building location or position or coordinate is entered as an input. This paper describes the evaluation of SAS in calculating the MCER compared to the result calculated using the WS. The evaluation was performed at three different islands in Indonesia; Sumatra, Java and Sulawesi islands and at 154, 115 and 81 coordinate positions on these islands, respectively. More than 10% difference in the data was observed when the MCER acceleration was calculated at the area having (MCEG and MCER-S1) greater than 0.6 g (g is gravitational acceleration). The minimum 10% difference in data was also observed when the MCER-SS was greater than 1.5 g. The largest difference was also observed when the coordinate positions were located close to seismic sources (fault source traces).KeywordsMCERWebsite softwareStand-alone software
Chapter
Baugruben sind Ingenieurbauwerke, welche im Wesentlichen aus einem oder zwei Bauteilen bestehen, und zwar der Baugrubenwand und einer ggf. erforderlichen Dichtsohle. Baugrubenwände können als Böschungen oder als Stützbauwerke ausgeführt werden. In diesem Kapitel werden die verschiedenen möglichen Stützbauwerke vorgestellt. Bei der Ausführung von weitgehend wasserdichten Baugrubenkonstruktionen sind bei durchlässigen Böden auch Abdichtungssohlen herzustellen, auf die ebenfalls detailliert eingegangen wird.
Chapter
Yogyakarta Province is located close to two active seismic sources, Opak Fault which crosses the province area and the South Java subduction source which is located at the south of Java island. The province is located at the southern part of Java island. Based on the Indonesian earthquake database, from 1984 to 2015 at least seven earthquakes struck this province. The 2006 earthquake with 6.2 Mw magnitude was the largest earthquake to hit this area, causing approximately 88,249 buildings to be totally destroyed and 98,343 buildings to collapse. Most of the destroyed and collapsed buildings were constructed based on the old version of the seismic design code. Improvements in earthquake research have already been conducted in this area and the latest research was conducted at 2016. According to the New Indonesian seismic code 2019, improvements in seismic acceleration for building design need to be adjusted in this area. This paper described the seismic microzonation of Yogyakarta Province based on the New Indonesian seismic maps and 2019 seismic code in terms of the Risk-targeted Maximum Considered Earthquake. The analysis was performed by conducting a combination of three seismic hazard analysis, namely probabilistic, deterministic and Risk-targeted Ground Motion. Based on the Risk-targeted Maximum Considered Earthquake data calculated and its distribution in this area, an area with a maximum 10 km radius from the Opak Fault trace was detected as the largest acceleration area. This area can be used as an indicator of a dangerous area of the province when subject to earthquake ground motion.KeywordsDeterministicProbabilisticRisk-targeted maximum considered earthquakeRisk-targeted ground motion
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Current trends in code development in North America and Western Europe are toward the implementation of probability-based limit states design methods. Structural design of buildings and other facilities to withstand the effects of strong earthquake ground motion requires special considerations that are not normally a part of design for other occupancy, service and environmental loads. This paper reviews some of these special considerations specifically as they pertain to probability-based codified design. The role of structural reliability methods in providing an improved basis for design provisions that are suitable for code implementation is evaluated, and the treatment of uncertainty in code safety checking is described. Difficulties experienced in implementing structural reliability principles in the first-generation probability-based limit states codes are summarized. Prospects for improving current earthquake-resistant design procedures based on a more rational probability-based treatment of uncertainty are assessed.