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Ground motion record selection is a standard step in state‐of‐the‐art performance‐based earthquake engineering (PBEE) applications. It links the structural response to seismic hazard of the site of interest. In this process, suites of hazard‐consistent ground motion recordings of a wide range of intensity levels are selected (and often scaled) from a database of ground motions to be used as input to nonlinear dynamic response analysis. The ideal practice would be to select ground motions from a database of recorded accelerograms in such a way that they are consistent with the seismic hazard at as many intensity measure (IM) levels as possible and for all important causative scenarios. However, the available databases are not heavily populated, especially for the large‐magnitude short‐distance scenarios. Therefore, synthetic ground motions are the natural candidates to enlarge the database of recordings for scenarios that are important to the site hazard but lack, completely or partially, recorded accelerograms. The usage of such recordings, however, can be recommended only after they are proven to be "realistic" through a battery of seismological and statistical tests. In this study, we propose and implement a multi‐fold testing framework for such an evaluation. We first generate a ground motion database of simulated ground motions (SDB) whose values of the parameters of the causative earthquakes are, to the extent possible, the same of those that caused the ground motions in a mirror database of recorded ground motions (RDB). We then utilize the conditional spectrum (CS) approach computed for a hypothetical rock site in Perugia, Italy, to select hazard consistent records separately from the RDB and SDB databases. A comprehensive set of comparisons of distributions of several IMs, computed from the selected sets, and of distributions of engineering demand parameters (EDPs), that such record sets induce on simple SDoF structures suggests the adequacy of using the proposed simulated ground motions for structural response analyses of structures on stiff and rock sites. [ABSTRACT FROM AUTHOR]

Recent seismic design approaches developed under the umbrella of performance-based earthquake engineering (PBEE) pursue pre-defined performance objectives in terms of structural response, economic losses, or casualties. The earlier PBEE methods were mainly concerned with the deterministic evaluation of performance at a single ground motion intensity level. This premise, however, provides little insight into the long-term risk-based performance of a structure, and limits the ability to make informed design decisions. Given the inherent sources of uncertainty in all aspects of seismic design, probability theory needs to be employed to enable reliable design solutions. However, applying a risk-oriented design approach is not currently feasible for most practitioners, making it essential to understand how the current deterministic applications of these intensity-based PBEE approaches perform in terms of risk. Specifically, the aim is to investigate the capability of the direct displacement-based design (DDBD) method in producing reliable, risk-consistent designs. A probabilistic PBEE assessment framework is applied as the benchmark to determine the risk of exceeding performance objectives for multiple DDBD-based reinforced-concrete-wall and dual reinforced-concrete-wall/steel-frame buildings located at three different sites. The significant variation in the achieved risk estimates related to the limit states of damage limitation, life safety and global collapse for the buildings considered, questions the ability of DDBD—or any other intensity-based design method that does not account for uncertainty—to offer risk consistency. [ABSTRACT FROM AUTHOR]

This study applies the latest probabilistic performance-based earthquake engineering tools in terms of nonlinear dynamic analyses in tandem with hazard-consistent record selection to assess the risk of collapse of RC tall buildings in the Istanbul metropolitan area and to quantify their seismic safety margin with respect to acceptable risk levels. Statistically representative archetype buildings selected from an extensive inventory form the basis for this assessment study. Accordingly, we chose five hypothetical building sites in Istanbul where tall buildings are densely populated to estimate the risk of collapse for 5 × 5 = 25 building-and-site specific cases. The results showed an average 10% probability of collapse under the ground-motion intensities with 2% probability of exceedance in 50 years. The mean annual rates of collapse range between 0.1 × 10–4 and 6.1 × 10–4 with an average of 1.7 × 10–4, which remains below the tolerable risk threshold value of 2.0 × 10–4 envisioned by the FEMA's Building Seismic Safety Council. However, 36% of the analyzed cases yielded collapse rates higher than this tolerable risk. Among the considered cases, the core walls and frame building was identified as the best design choice from a collapse safety point of view while the tunnel form archetype raised concern by exhibiting substantially higher collapse risk compared to other archetypes. [ABSTRACT FROM AUTHOR]

Summary: Pulse‐like records are well recognized for their potential to impose higher demands on structures when compared with ordinary records. The increased severity of the structural response usually caused by pulse‐like records is commonly attributed to the spectral increment around the pulse period. By comparing the building response to sets of spectrally equivalent pulse‐like and ordinary records, we show that there are characteristics of pulse‐like records beyond the shape of the acceleration response spectrum that affect the results of nonlinear dynamic analysis. Nevertheless, spectral shape together with the ratio of pulse period to the first‐mode structural period, Tp/T1, are confirmed as "sufficient" predictors for deformation and acceleration response metrics in a building, conditioned on the seismic intensity. Furthermore, the average spectral acceleration over a period range, AvgSA, is shown to incorporate to a good proxy for spectral shape, and together with Tp/T1, form an efficient and sufficient intensity measure for response prediction to pulse‐like ground motions. Following this latter route, we propose a record selection scheme that maintains the consistency of Tp with the hazard of the site but uses AvgSA to account for the response sensitivity to spectral shape. [ABSTRACT FROM AUTHOR]

Average spectral acceleration, AvgSA, is defined as the geometric mean of spectral acceleration values over a range of periods and it is a ground motion intensity measure used for structural response prediction. One of its advantages stands on the assumption that its distribution is computable from the available GMPEs for spectral acceleration, GMPE- SA, (called here indirect method) without the need for deriving new specific GMPEs for AvgSA, GMPE- AvgSA, (called here direct method). To what extent this assumption is valid, however, has never been verified. As such, we derived an empirical GMPE- AvgSA based on RESORCE ground motion dataset and we compared its predicted values with those from a GMPE- SA via the indirect approach. As expected, the results show that the indirect approach yields median AvgSA estimates that are identical to those of the direct approach. However, the estimates of AvgSA variance of the two methods are identical only if both the GMPE- SA and their empirical correlation coefficients among different SA ordinates are derived from the same record dataset. [ABSTRACT FROM AUTHOR]

This study compares the performance of the bare and infilled frames of RC buildings based on incremental dynamic analysis (IDA) and fragility analysis in the Performance Based Earthquake Engineering framework. Inter story drift ratio (IDR), maximum inter-story drift ratio (MIDR) and absolute peak floor acceleration (PFA) are chosen as engineering demand parameters (EDPs). Comparing the response of such different frames is always problematic because of their very different dynamic characteristics, a feature that to ensure efficiency imposes selecting different sets of accelerograms for response assessment. To bypass this problem as common intensity measure for both types of frames we used here the spectral acceleration averaged in a period range (AvgSA) that include the first mode periods of both frames. We further derived fragility curves for six case study buildings of regular 4-, 5-, 6-, 8- and irregular 6-, and gravity designed 6-story buildings. Except for the gravity designed 6-story building, we observed that the infilled frame buildings have slightly better performance at less severe limit states. For the gravity designed building performance, however, ignoring URM infill walls resulted in un-conservative collapse capacity estimates. Finally, exploring the comparison of the PFA response of the bare and infilled frames for the 6 case study buildings confirms that significantly higher demands are to be expected for the latter, suggesting the necessity of accounting for the infills when performing detailed building-specific loss estimation analysis or designing acceleration sensitive equipment. Hence, it is recommended to account for the infill elements in both design and assessment procedure to ensure the safety of structural and nonstructural elements. [ABSTRACT FROM AUTHOR]

A risk-consistent approach is proposed for the evaluation of behaviour factors that are compatible with Eurocode 8, using nonlinear static and dynamic analysis. It comprises seven discrete steps, involving hazard assessment and record selection at multiple sites, designing and modelling multiple archetype buildings and assessing their performance vis-à-vis target safety objectives. In all cases, uncertainty is incorporated and propagated to the final results whereby a flexible verification procedure is offered to account for the confidence of the investigator on the data available. An example application is offered on steel concentrically braced frames, highlighting the need for selecting appropriate performance targets for Europe. The overall added value goes beyond the current state of art, offering a consistent risk basis for the seismic design of different systems that is compatible with current uniform hazard design spectra and can benefit from future risk-targeted hazard maps. • A risk-consistent approach is proposed for deriving EN1998 compatible behaviour factors. • Hazard assessment, record selection and incorporation of uncertainty are important aspects of the approach. • Setting appropriate performance targets is required to achieve consistency with current EN1998 implied safety. • An example is shown for steel concentrically braced frames. [ABSTRACT FROM AUTHOR]