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In performance-based design and assessment, there are prescriptive limits based not only on element-based performance evaluation but also on comparing story drifts with limit values. The process of determining performance levels at the element level involves obtaining the required data through numerous calculation steps, followed by evaluation, which makes it a time-consuming process. The iterative nature of this process emphasizes the importance of selecting the structural system, element dimensions, and target performance levels during the preliminary design stage to ensure they are consistent with the final analysis results. For this purpose, the determination of story drifts, which is widely accepted in the literature, is a critical aspect of performance evaluation studies, particularly for high-rise buildings, within the framework of deformation-based calculation assumptions. The continuum model is a practical approach for the approximate analysis of high-rise buildings including moment-resisting frames and shear wall-frame systems. In the continuum model, discrete buildings are simplified such that their overall behavior is described through the contributions of flexural and shear stiffnesses at the story levels. In this study, the aim is to enhance the Miranda and Taghavi (2005) model, which is classified among the approximate methods in the literature for determining story drifts and is developed within the framework of continuum model approaches. [ABSTRACT FROM AUTHOR]

The Performance-Based Seismic Design (PBSD) is an advanced approach to designing earthquake-resistant structures, ensuring that a building meets specific performance objectives under seismic impacts. Unlike traditional design codes, PBSD aims to predict and control the damage to structures based on defined earthquake levels, minimizing damage and repair costs after an earthquake. The PBSD process includes defining performance objectives, selecting appropriate analysis models, conducting nonlinear analyses, and evaluating damage levels. Analytical methods such as nonlinear static pushover analysis and dynamic time history analysis are commonly applied in this process. Due to the need for in-depth knowledge and complex calculations, implementing PBSD can present significant challenges. This paper aims to present the details of PBSD based on seismic design codes and applies this approach to seismic design for bridges under earthquakes. [ABSTRACT FROM AUTHOR]

This study presents the development and analysis of high damping rubber bearings (HDRBs) with enhanced stiffness properties to improve seismic isolation performance. The proposed HDRBs exhibit displacement-dependent nonlinear stiffness and significant damping effects, especially under large deformations caused by various seismic events. A deformation history integral model, calibrated with experimental data, is employed to accurately simulate the mechanical behavior and stiffness-damping characteristics of the HDRBs. The numerical simulations are validated through experimental tests, providing a solid basis for parameter design and performance assessment. The results show that the equivalent stiffness coefficient of the HDRBs increases with deformation amplitude, effectively limiting extreme deformations. Parametric analyses and case studies across a wide range of earthquake scenarios demonstrate that the enhanced stiffness and high damping effects of HDRBs significantly improve seismic isolation efficiency while controlling isolation layer displacement. The performance-based design methodology developed in this research effectively limits bearing deformation, thereby preventing potential superstructure failures. Moreover, the adaptive characteristics of the HDRBs allow for the adjustment of deformation levels according to seismic intensity, ensuring the structural safety of buildings under varying earthquake conditions. [ABSTRACT FROM AUTHOR]

Functional recovery is a new, nonstandardized building design objective, intended to improve a building's capacity to maintain or rapidly restore basic intended functions after a natural hazard event. Current building seismic design standards, which target life-safety performance objectives, provide limited requirements to ensure buildings maintain, or rapidly recover, function after earthquakes. Therefore, the expected functional recovery performance that is provided by current building codes is unclear. To provide clear and systematic insights to inform the development of prescriptive and performance-based design standards, this study documents the functional recovery performance for a set of 60 reinforced concrete archetype buildings. The results indicate that the estimated functional recovery time for reinforced concrete buildings designed to life-safety standards may approach 1 year, on average, for design-level earthquakes. Additionally, while increased strength and stiffness requirements significantly reduce the likelihood of a building being marked as unsafe due to structural damage, additional design provisions for nonstructural components are required to ensure a high confidence of rapid recovery. The findings from this study clarify the expected post-earthquake recovery of modern reinforced concrete buildings and identify key trends in underlying damage and response mechanisms required to improve future building performance. [ABSTRACT FROM AUTHOR]

This paper presents the physics based ground motion synthetics and its earthquake engineering consequences in the National Capital Territory (NCT) Delhi, India due to the Mw8.2 scenario earthquake on the Nahan segment of the western Himalaya. In order to fulfill the aim, a state-of-the-art pseudo-dynamic rupture is implemented in a 3D fourth-order staggered-grid viscoelastic time-domain finite-difference code. The ground motion is simulated in a frequency bandwidth of 0–2.5 Hz at the basement level at 158 locations of the NCT Delhi. The computed transverse component of velocity time series at the basement level is numerically transferred to the free surface taking into account the rheological parameters of the sediment deposit. Upon first inspection, the estimated range of peak ground acceleration, between 0.017–0.12 g, indicates that all the buildings in the NCT Delhi will remain safe in the event of an Mw8.2 Nahan earthquake, provided they are constructed in accordance with Indian building codes. But, the computed acceleration response spectra (Sa) depicts that some of the high-rise buildings of the NCT Delhi may suffer minor damage to collapse under partial or complete double resonance condition due to Sa exceeding the DBE and MCE levels. The obtained range of pseudo-spectral displacements (Sd) reveals the need of performance-based design for high-rise buildings in the NCT Delhi, so that they can withstand under partial or complete double resonance condition during the occurrence of Nahan earthquakes. The developed contour maps of Sa and Sd at different periods can be used for the retrofitting and forced-based and displacement-based designs of the high-rise buildings. [ABSTRACT FROM AUTHOR]

Sustainable seismic design (SSD) is the first step towards next-generation earthquake engineering. SSD of mixed multiple seismic systems (MMSSs), in which more than one earthquake-resisting structure is used, is a challenging structural engineering issue. Seismic sustainability implies survivability during and after an earthquake, preceded by post-earthquake realignment and repairs (PERR). Purpose-specific MMSSs are ideally suited for SSD. However, contemporary codes address neither the sequences nor the failure mechanisms of the earthquake-resisting structures of MMSSs. The difference between conventional design and SSD is their approach to expected behaviour during and after an earthquake. Earthquakes are natural and dynamic occurrences, whereas PERR is a manual and static process. SSD does not favour unreal detailing or oversimplifying assumptions; it is a multi-faceted effort that involves realistic structural analysis and planned manual operations. In this context, design implies operability with a view to PERR and requires a change from damageability assessment and performance-based seismic design to performance control and reparability-based design, including the development of new analytic tools and purpose-specific details. This article presents graphical solutions and theoretical principles to help achieve practical SSD for MMSSs. These new techniques may be used for practical reliability, economy and environmental protection. [ABSTRACT FROM AUTHOR]

The long-period transition period (TL) is an important parameter in both seismological theory and seismic design. Current estimates of the parameter used for design are based on seismological model data from 2006, and presumably are for nonsubduction earthquakes. ASCE 7-16, which contains standards for seismic design, provides mapped estimates for TL based on the maximum considered seismic ground shaking. To expand the data considered for TL , this study used the NGA-Sub flatfile obtained from the NGA Subduction Portal at the B. John Garrick Institute for the Risk Sciences. For each record, TL was interpreted as the period at which spectral displacement is a maximum, an interpretation which becomes evident upon close examination of the two-point design response spectra in modern codes. The rationale for this interpretation is the very definition of TL in ASCE 7-16. As performance-based design for multiple hazard levels has evolved and continues to gain acceptance by the engineering community, there is a need for a method to estimate TL for multiple levels of ground shaking at a given site. The primary purposes of this study were to develop estimates for TL for subduction zones and to facilitate the estimation of TL for lower-magnitude, more-frequent subduction events in subduction zones for performance-based seismic design, as opposed to using a single mapped value for a particular region. In this study, other methods for estimating TL also were explored. The long-period transition parameter, TL , for subduction zones was found to vary with moment magnitude as the primary influence. A model in tabular form, similar to that used to develop maps in ASCE 7, was developed for subduction zones. [ABSTRACT FROM AUTHOR]

Chile, recognized as one of the world's most earthquake-prone nations, has gained valuable insights from significant earthquakes, such as those in 1985 and 2010, which have influenced updates to the nation's design codes. Although Chile's seismic design approach has been largely effective in recent earthquakes and demonstrated an "operational" performance level in most structures, performance-based design (PBD) methods have not yet been officially incorporated as valid approaches in the Chilean seismic design codes for buildings. However, in 2017, the Chilean Association on Seismology and Earthquake Engineering (ACHISINA) introduced a PBD approach, primarily for verification purposes, based on the Los Angeles Tall Buildings Structural Design Council (LATBSDC) framework. In this work, firstly, we provide an overview of Chile's PBD methodology, focusing on the thresholds for various performance levels. These levels are established through experimental and numerical analysis, correlating performance with permissible damage levels. The second part of the paper examines the seismic performance of a residential building, designed before the 2010 Maule earthquake and subsequently damaged, using Chile's PBD guidelines. This case study highlights the implementation and effectiveness of PBD for assessing seismic resilience in Chilean structures. [ABSTRACT FROM AUTHOR]

We use a method based on Uniform Hazard Spectrum (UHS) to compile seismic microzonation maps for the broader area of Novi Sad, a city in Serbia. The maps are intended for use in the performance-based design (PBD) of earthquake-resistant structures. At present, PBD requires the use of two sets of spectral amplitudes, one in which the structure remains linear and the other in which it may respond nonlinearly. These PBD requirements cannot be met by using only one (same) fixed-shape spectrum and scaling by peak ground acceleration alone for varying probabilities of exceedance. The alternative we present in this paper is based on UHS and describes a combined contribution from (a) seismic excitation by local earthquakes, for which region-specific attenuation equations are used, and (b) seismic excitation by large, distant earthquakes, for which different attenuation equations are used. Our maps also take into account the influences of site geology and site soil conditions in a balanced manner. [ABSTRACT FROM AUTHOR]

A reliable assessment of earthquake-induced permanent displacements is a fundamental step for both displacement-based and force-based methods applied to the seismic design of embedded anchored walls. Acceleration reduction factors recommended by the codes for a force-based design of these structures derive from parametric studies of the performance of gravity walls or slopes. This may lead to either conservative or unconservative results and is certainly misleading from the point of view of the physics of the problem. Based on the results of an extensive numerical study, this work clarifies the mechanisms by which anchored walls accumulate permanent displacements during earthquakes, showing that full mobilization of soil passive strength requires displacements of the order ur/H≈1%–2% , making the assumption of rigid-perfectly plastic behavior of the system unsuitable. Moreover, both the critical acceleration and the pattern of final displacements depend on the plastic mechanism effectively activated within the soil-wall-anchor system. The issue of the proper choice of performance factors to be used in a force-based design of anchored walls is also addressed, and a new method is outlined for a preliminary calculation of the permanent displacements of the wall. Finally, the paper critically reviews two methods recently proposed in the literature to compute earthquake-induced wall displacements. All three methods account for the soil-wall system nonlinearity and hardening during the earthquake. The results discussed herein, together with the complementary work presented by the same authors in a companion paper, provide a thorough conceptual framework for the performance-based seismic design of anchored walls. [ABSTRACT FROM AUTHOR]

The code-based response modification factors are mainly developed based on engineering judgments and experiences from past earthquakes, and hence, they may not lead to reliable solutions considering different performance targets and hazard levels. On the other hand, the uncertainties associated with these proposed values are more significant for new lateral load-carrying systems, such as tunnel-form buildings, due to insufficient information about their performance against seismic events. To address these challenges, this study aims to propose a multi-level approach for the estimation of response modification factors for tunnel-form building structures by taking into account the site seismicity and the damage level defined as the target performance. Using the proposed approach, the modification factors corresponding to different ranges of earthquake intensity and damage levels are obtained for 2-, 5-, 7-, and 10-storey tunnel-form buildings. The results are then used to verify the efficiency of the response modification factors proposed by design codes for the preliminary design (code-based factors) of such systems. It is shown that, in general, by adopting a response modification factor between 4 and 6, the tunnel-form structural systems exhibit excellent seismic performance and can satisfy the requirements of the Immediate Occupancy (IO) performance level even under the Maximum Considered Earthquake (MCE). The outcomes of this study could be useful for performance-based design of tunnel-form building structures aligned with the new generation of seismic design codes. [ABSTRACT FROM AUTHOR]

The potentially large spatial footprint of earthquake disasters and the increased concentration of population and values in dense urban areas call for an explicit consideration of seismic risk at a regional, building portfolio level. The relation between the building‐level seismic risk and the portfolio‐level seismic risk is helpful if one wants to meet a specific regional seismic risk tolerance level by specifying seismic risk targets for individual buildings. We examine four types of common risk measures and point to the importance of subadditivity, a risk measure mathematical property, for deriving a conservative upper‐bound relation between the building‐specific and the building portfolio seismic risks. Subadditive risk measures, such as the Expected Shortfall, allow estimates of conservative upper bounds of the portfolio‐level seismic risk. In a case study, we show that nonsubadditive risk measures commonly used in earthquake engineering can lead to counter‐intuitive and nonconservative perceptions of the regional seismic risk, especially when one extrapolates from individual buildings to the entire building portfolio. We also illustrate the advantages of subadditive risk measures for regional seismic risk assessment. [ABSTRACT FROM AUTHOR]

In order to study seismic design process of RC (reinforced concrete) column components considering the effect of earthquake duration, the degradation law of capacity under random amplitude hysteresis history was conducted by the research group, and the estimation method for the energy dissipation capacity of RC column components was suggested. Furthermore, the correlation between the stiffness decay index and energy dissipation capacity, hysteresis histories, and structural parameters was proposed, and the performance classification criteria based on the stiffness decay index was established. On this basis, the connection between the stiffness decay index and structural parameters and seismic parameters was established, and the seismic design process of RC column components in SDOF (single degree of freedom) system was proposed. The research indicated that the proposed seismic design process based on stiffness decay index can effectively consider the effect of earthquake duration. The stiffness decay index is more suitable for defining structural damage than deformation index and Park-Ang index. The stiffness decay index establishes quantitative relationships with seismic parameters and structural parameters, facilitating performance-based design in engineering practice. The increase in earthquake duration exacerbates the damage of RC column components, and this effect is more pronounced at the beginning of the earthquake and gradually decreases over time. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A centrifuge experiment of the crane-wharf structure in liquefiable stratum is implemented. • The damage state of the crane-wharf structure is analysed by calibrated 3D numerical model. • The framework for structural damage characteristics extraction and identification is proposed. The damage state of the crane-wharf structure is difficult to describe quantitatively in earthquake, which brings great challenges to its emergency rescue and post-earthquake repair. At present, the criterion for evaluating the crane-wharf structure damage reflect a certain section or point, such as bending moment, axial force, displacement, stress, strain curvature, etc., which cannot reflect the overall performance and can be easily obtained. In addition, in the current popular performance-based seismic design concepts, the definition of damage degree is an indispensable part, which shows that the extraction and identification of damage characteristics is imminent. Therefore, on the basis of results of centrifuge experiment that have been carried out under different damage conditions, the basic damage law of the crane-wharf structure in liquefiable stratum is analysed first in the study, and it is clear that the existing means cannot distinguish the damage degree in detail. Furthermore, the proven numerical modelling techniques and the Hilbert-Huang transform theory are applied to extract and identify damage characteristics of the crane-wharf structure, Finally, the corresponding damage index is constructed and damage criterion are developed, which provided a reference for damage evaluation of similar structures in liquefiable stratum. [ABSTRACT FROM AUTHOR]

As structural safety emerges as a paramount concern and with the advancement in vibration control technology, a notable gap persists in accurately simulating structural state nonlinearity, especially within the field of inerter-based seismic control technology. Dealing with the need to upgrade the seismic performance of practical nonlinear structures, this study proposes a structural state nonlinearity-based design method for inerter-incorporated civil structures by incorporating the target seismic performance, structural nonlinearity level, and ground motion effects. By establishing mechanical models of inerter-based systems with straightforward parameters and a prototypical bilinear model for the primary structure, governing equations for inerter-incorporated structures were derived. Later, structural state nonlinearity-based design method for inerter-based systems, including optimization criteria and parameter distribution pattern, is elaborated. Simultaneously, this study also provides structural state nonlinearity-based design curves and modification formulae related to structural state nonlinearity and peak ground acceleration of earthquake. Validated using a 10-story multiple-degree-of-freedom (MDOF) structure subjected to earthquakes, the results highlight the effectiveness of the method, emphasizing its potential in controlling seismic responses of structures within the predetermined performance target. In addition, the absolute acceleration mitigation effect of inerter-based systems is investigated. The efficiency and robustness of the proposed method are also verified under near-fault and far-fault earthquakes. In essence, this research pioneers an approach in inerter-based design, bridging structural state nonlinearity, and potentially reshaping seismic control strategies to align with diverse structural states. • Design framework and formulae for inerter-incorporated nonlinear structure. • Structural state nonlinearity and ground intensities for inerter-based design. • Easy-to-use design curves given to efficiently determine parameters. • Effectiveness verified by structural acceleration and displacement evaluations. • Robustness of the method are discussed under near-fault and far-fault earthquakes. [ABSTRACT FROM AUTHOR]

• A multi-hazard approach is developed to coherently compare the structural performance under wind and earthquake. • A true multi-hazard method for preliminary probabilistic structural design is presented for mid-rise buildings. • The method leads to a uniform risks design solution for the structure under the considered design hazards. Focusing on natural hazards as wind and earthquake, the goal of this work is to understand if interference occurs in the design choices for steel buildings of a certain height, thus determining which design requirement and hazard is predominant, between Ultimate Limit State (ULS) requirements under earthquakes, or comfort of the occupants and the Serviceability Limit State (SLS) of the structure under wind. Thus, in order to compare structural responses, both in linear (i.e., SLSs) and non-linear field (i.e., ULS) a simplified analysis procedure that could be also implemented in Standards and in design practice (so-called SAC-FEMA method, originally introduced in the seismic field by Cornell in the early 2000s and more recently extended to the wind) is adapted, leading to a true optimal Performance-Based Multi-Hazard Design (PB-MH-D) of the structure considering the two hazards. The procedure is applied to two case-study steel buildings, 17 and 60 floor heigh; the approach is shown to efficiently lead to a design solution who consistently tackles with the same level of reliability with the two hazards. [ABSTRACT FROM AUTHOR]

This study investigates the inelastic displacement of structures subjected to earthquake-tsunami loadings. The relative intensity is defined as the ratio of the tsunami force per unit mass to the Sa of the corresponding ground motion. The effects of the hysteretic model, soil condition, post-yield stiffness, damping, and relative intensity on the inelastic displacement ratios are investigated. The results show that, compared to earthquakes alone, earthquake-tsunami loadings can enlarge the inelastic displacement ratio demands, especially for higher relative intensities. A predictive model is developed by considering several parameters, which may be used in the framework of performance-based seismic design. [ABSTRACT FROM AUTHOR]

In recent decades, a variety of self‐centering braces (SCBs) have been developed to address the limitations of conventional frames by decreasing residual drift due to earthquakes. However, the initial construction cost of self‐centering (SC) structures is expected to be higher and the study about its cost‐effectiveness over the life‐cycle span is limited. This paper presents a seismic life‐cycle cost evaluation of emerging friction spring‐based self‐centering braced frames (SCB‐Fs) compared with traditional buckling restrained braced frames (BRB‐Fs) when an existing structure is upgraded. Particular focus is on the effect of residual deformation, initial construction cost, and high fatigue performance of the SCB. Following the performance‐based design of the SCB‐F and BRB‐F, system‐level analyses are conducted. Numerical results of case‐study buildings indicate that the total expected annual loss (EAL) of the BRB‐F increases by approximately three times when the effect of residual deformation is considered, while its effect on the total EAL of the SCB‐F is negligible. Besides, the superior performance of the SCB‐F compared to BRB‐F is highlighted by a substantial reduction in EAL induced by earthquakes. In addition, the acceleration‐related seismic losses of SCB‐F constitute approximately 44% of the total EAL. Its contribution is significantly larger in the case of the SCB‐F compared to the BRB‐F. From the perspective of economic benefit, increasing the structural life‐cycle span is beneficial to the SCB‐F compared to the BRB‐F. The high fatigue performance of the SCB is favorable to increase the economic benefit of the SCB‐F, especially when the reduction of repair time is considered. The economic benefit of the SCB‐F compared to the BRB‐F is highly related to the initial construction cost. Taking the 100 years as an expected life‐cycle span, the high initial construction cost of the SCB‐F would not be paid off when the unit cost of the SCB is about 2.1 times that of the BRB. [ABSTRACT FROM AUTHOR]

In nonlinear dynamic structural analysis, a suite of pulse-like ground motions is required for the performance-based design of structures near active faults. The dissimilarity in the amplitude and frequency content of the earthquake time series referred to nonstationary properties in temporal and spectral, respectively. An approach is proposed based on the nonstationary properties of the far-field records and the seismological information in an event for simulating pulse-like records. The pulse-like earthquake time history is estimated via the superposition of the residual part of the earthquake with the estimated pulse. The wavelet-based Hilbert transform is utilized to characterize the nonstationary properties, the instantaneous amplitude, and frequencies of far-field records to model residual part. The effects of near-fault and pulse are estimated based on the seismological properties of the region. The validation of the procedure is indicated by comparing simulated time-series, response spectra, and Arias intensity with recorded pulse-like records in two different earthquakes in California; the Mw 6.7 1994 Northridge and the Mw 6.5 1979 Imperial valley. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A look at the evolution of Seismology and Engineering Construction from the mid-1700s until the mid-1900s is presented to understand the main accomplishments achieved. Then, we perspective the new advancements toward future mitigation of earthquake impacts with a clear proposal for sustainability and ecological challenge. We will concentrate on analysing the phase 1755–1950 because not enough attention has been paid recently to this exciting period. Next, we jump to our days to look into a few significant problems that require the involvement of the scientific, technical and political communities. In particular: (i) We will look into the developments Intensity Scales should pursue to reduce uncertainties since more than 20 years have passed since the last upgrade. Today, the information from new events is much more extensive and reliable than in the past. Several examples will be presented to illustrate how the frequency of motion should be included in the main characteristics/categories (Building typologies and Vulnerabilities; Damage Grade; Quantity definition) and how it could be beneficial to add a few more descriptors to the Scale, namely shaking of objects and sloshing of water in recipients. (ii) We will analyse the lines of development to mitigate earthquake impacts, and respond to present and future needs, concentrating on the new scientific results that are changing seismology from a "back-analyst" science (indirect contribution to earthquake engineering) into a more pro-active one, with direct impact to reduce risks, such as the EEWS, and low-cost instrumentation. And adding to earthquake engineering the revolutionising health monitoring, as a precautious indicator of malfunction of structures, and a rapid system for evaluation of post-earthquakes, complemented with the citizen science. Finally, all these ingredients need to be merged into simple recommendations for which only data mining will be able to extract new reliable information. Five Highlights's for the future: MEMS EEWS Performance-based design Field trips Citizen Science All these new developments under the umbrella of Machine Learning. [ABSTRACT FROM AUTHOR]

This paper aims to apply a performance-based earthquake engineering approach to assess the assurance of flexural frames whose members are jointed together by using new modified RBS connections, namely, semi-rigid welded steel connections, which obey a progressive failure mechanism. First, the structural members and connections are modeled and predesigned in ETABS software, and then, using OpenSees software, a series of nonlinear progressive failure analyses are performed on the built models extracted from ETABS. To this end, three types of multi-story structures with 3, 10, and 15 are modeled. The models are subjected to 15 earthquakes, such as Northridge (1994), Kobe (1995), Chichi (1999), Bam (2003), Tabas (1978), and so on. The connections are modeled by a series of rotational springs whose nonlinear behavior is estimated by a three-line curve that is established based on the modified Ibarra–Krawinkler deterioration model. Finally, obtaining the maximum ground acceleration versus the maximum relative drift of the floors, the fragility curves of the structures for a collapse level (CP) are determined, through which the seismic performances of the models are evaluated. The results show that by reducing the number of structural floors, the ductility of structures was reduced, and by increasing the ductility of structures, higher drifts in structures were achieved at the same seismic level. The average amount of ductility reduction coefficient in structures with RBS was 1.06 times those without RBS, which indicates that the energy dissipation capacity in structures without RBS connection is higher than in those with RBS. Local analysis of connections shows a 9% increase in the plastic rotation capacity if RBS connections are used. The ductility of all frames with RBS connection increased slightly compared to frames without RBS. [ABSTRACT FROM AUTHOR]

Current investigations on performance-based seismic design of structures generally employed story drift as performance objectives. However, the story drift could only partially reveal the global damage of a structure and not control the damage of important components. In order to control the damage of various components in a structure, this paper proposed a new damage-controlled seismic design method using the Park & Ang indexes of components. Firstly, the Park & Ang damage index was simplified as an equivalent ductility damage index for various components. The energy balance concept was used to observe the hysteretic energy demand which was subsequently distributed to all stories. Thus, the components of each story could be designed based on their damage indexes under design-based and maximum-considered earthquakes. Four concrete filled double skin tubular (CFDST) moment resisting frames equipped with metallic dampers with various layouts were designed based on the proposed design method. Time history analyses on these four structures were performed after validating the accuracy of nonlinear model by Opensees. Analysis results showed that the components in four structures exhibited expected damage states as illustrated by the design method. It also verified that proposed seismic design method was effective to control the damage of various components, which was beneficial for protecting the important components in a structure by setting low damage indexes for them. The seismic design method and analysis results also provided a reference for the design of moment resisting frame with energy devices. • A novel damage-controlled seismic design method was proposed. • Time-history analyses were performed to validate the proposed seismic method. • Damage distributions of different components were assessed. [ABSTRACT FROM AUTHOR]

The performance-based design (PBSD) begins with defining performance goals. Performance-based seismic design accurately predicts the structure's performance during an earthquake. Recognizing and analyzing the structure's performance capacity is critical in performance-based design. This project was to do a PBSD on a (G+10) RCC construction. The building is first studied and built in STAAD PRO. Then, it was imported into the ETABS 2019 program to do a more detailed analysis of the displacement-controlled pushover analysis. The ETABS yields the structure's performance point, story displacement, capacity spectrum, Story drift, and demand spectrum. After the original design, a nonlinear pushover analysis is done to find out how well the building can withstand earthquakes and whether or not the goal was met, as well. In this research, we looked at the seismic code IS 1893 (Part 1) and the concrete design code IS 456: 2000 in order to make sure the building was safe. After obtaining all of the results, the structure's performance was compared for the various scenarios investigated and the optimal combination was determined. [ABSTRACT FROM AUTHOR]

Historical city centres are critical-built environments prone to earthquake risk because of the features of the complex network of Architectural Heritage, facing Open Spaces (OSs) and the users hosted by them. Structural measures, such as building retrofitting actions, and non-structural measures, like emergency and evacuation planning, could be jointly set up to improve the safety of the Historical Built Environments since they aim to face the effects of damage across the OSs and so on the users' movement. This work adopts a simulation-based approach to assess the individual and combined efficiency of these structural and non-structural measures. Risk indices focused on the evacuation process are used to this end, considering the final effects on the users' movement and safety. Results show how seismic retrofitting strategies could be located in critical "hot-spots" in the urban fabric to additionally support the evacuation plan, thus reducing implementation efforts for the stakeholders. [ABSTRACT FROM AUTHOR]

One of the efficient methods for seismic design of structures is Performance-based Plastic Design (PBPD) in which by choosing the desired yield mechanism and the target drift at the beginning of the design, unlike that in conventional design methods, there is no need for a time-consuming process of trial and error to achieve the desired performance. On the other hand, recent earthquakes have shown that aftershocks can increase the damage to a building after the main earthquake and thereby threaten the safety of the inhabitants. However, the seismic hazard of aftershocks is still not explicitly included in the current design codes. In this study, attempts have been made to develop the PBPD method for considering the effects of aftershocks. For this purpose, by performing an incremental dynamic analysis (IDA), the ductility factor μ and the ductility reduction factor Rμ of six PBPD frames (2-, 4-, 6-, 8-, 10-, and 12-story) were calculated under mainshock and mainshock-aftershock sequences. Then, the energy modification factor γ, which is related to the two parameters μ and Rμ, was calculated for both the mainshock and the mainshock-aftershock sequences. An equation is presented in order to calculate the ratio of the energy modification factor of the mainshock-aftershock sequence to the mainshock energy modification factor ( γ m s + a s γ m s ) according to the design period, and the factor obtained is multiplied by the energy modification factor γ so that the effect of aftershock can be considered for the frame design, and by using this modification, the performance of the frame under the mainshock-aftershock sequence can be improved. The results of the time-history analysis performed on the modified PBPD frames show better performance by the frames designed on the basis of modified PBPD than the frames designed on the basis of the original PBPD method under MS-AS sequences in terms of inter-story drift and rotation of plastic hinges. [ABSTRACT FROM AUTHOR]

Current building code requirements for seismic design are primarily intended to minimize life-safety risks due to structural damage under extreme earthquakes. While tall buildings designed under current standards are expected to achieve the life-safety goal, this study estimates that they may require up to 7.5 months of repair to return to functionality after a design-level earthquake (roughly equivalent to ground motion shaking with a 10% probability of exceedance in 50 years), and over 1 year after a risk-targeted maximum considered earthquake (roughly equivalent to ground motion shaking with a 2%–4% chance of exceedance in 50 years). These long downtimes, which correspond to median predictions, far exceed recovery goals for major employers and other recovery-critical uses and can have disproportionately harmful effects on businesses and residents. To address such extensive downtime risks, we evaluate the impact of recovery-based design guidelines for reducing recovery times through (1) more stringent drift limits under expected ground motions and (2) measures to mitigate externalities that impede recovery. The results suggest that by combining these strategies, expected recovery times following a design-level earthquake can be reduced to roughly 1 month, and to 2 months following a risk-targeted maximum considered earthquake. These findings are illustrated for an archetype 42-story reinforced concrete shear wall residential building and a 40-story steel buckling-restrained braced frame office building in San Francisco, CA. [ABSTRACT FROM AUTHOR]

Ground‐motion simulations for infrequent earthquake scenarios are gaining increasing interest in the engineering community for their potential to inform performance‐based structural design and assessment, particularly in regions where major earthquakes are expected, but recordings from consistent historical events are not available. However, the absence of empirical data makes the evaluation of such scenarios and the interpretation of the simulation results very challenging. In this context, this paper presents the evaluation of the first EQSIM (v.1.1.0) ground‐motion simulations generated for the San Francisco Bay Area (SFBA) region. The current database, which is at the first stages of development, includes eight realizations of a Hayward Fault Mw7 event. The evaluation of the simulated motions is first conducted on the average ground‐motion amplitudes through comparison against the NGA‐W2 GMPEs and a selected population of real records. A methodology for selecting a population of real records consistent with the simulated event is proposed. The objective of the proposed evaluation is twofold: (1) build confidence in the realistic character of the simulated motions for their use in engineering applications and (2) offer a critical physics‐based interpretation of the simulation results that can help improve key features of the simulation models. To further investigate the implications of using the simulated ground motions for site‐specific structural assessments, the ASCE7‐16 approach is employed for the analysis of two hazard‐consistent near‐field sites in the SFBA. Results are discussed. This study offers a critical review of the EQSIM (v.1.1.0) SFBA ground‐motion simulations and suggestions for improving the earthquake rupture models. [ABSTRACT FROM AUTHOR]

Thanks to its variable mechanical properties, the sliding isolator with variable curvature (SIVC) has recently attracted significant attention in seismic isolation research. Nevertheless, designing an SIVC is a challenging task, as it usually involves more design parameters than a conventional sliding isolator. To expedite the application of SIVCs, this study proposes a systematic design method that enables SIVCs to achieve multiple performance objectives corresponding to dual earthquake levels. The method comprises linear and nonlinear design stages. During the linear design stage, the linearized isolator parameters that comply with the design-basis-earthquake (DBE) and maximum-considered-earthquake (MCE) seismic demands specified in a design code are determined. Subsequently, in the nonlinear design stage, the isolator geometric parameters are determined based on the linearized parameters. While the linear design procedure is generic and applicable to all types of SIVCs, the derived formulas for determining the isolator geometric parameters in the nonlinear design stage are tailored for the polynomial friction pendulum isolator (PFPI). Finally, the proposed method is demonstrated by implementing a PFPI design for a 5-story reinforced-concrete (RC) building. The effectiveness of the proposed design method is validated through dynamic analysis of a hysteretic structural model representing the RC building with two different types of PFPIs subjected to 23 spectrum-compatible ground motions. The results demonstrate that, despite their different mechanical features, both types of PFPIs can accomplish the "preset" DBE and MCE design objectives. Additionally, the simulated results highlight the advantages of using different types of PFPIs. • A SIVC is an adaptive passive sliding isolator with more design parameters. • A systematic performance-based design method is proposed for SIVCs. • The proposed method can achieve preset performance-objectives in dual seismic levels. • The method is demonstrated via the design of a polynomial friction pendulum isolator. • Dynamic analysis of a RC-building with PFPI shows the effectiveness of the method. [ABSTRACT FROM AUTHOR]

Summary: Outriggers, which should be systematically analyzed and designed based on seismic performance methods in the different seismic level actions, can improve the lateral stiffness of irregular high‐rise structures. In this paper, a concrete‐filled steel frame‐core tube‐outrigger structural system is adopted for a practical overrun high‐rise building with an obviously asymmetrical vertical setback in a high‐intensity seismic region. To ensure the seismic safety of irregular high‐rise building structures, the members of the outrigger are designed based on the seismic performance analysis method, and the complex joint region and slab of the outrigger floor are also refined and analyzed. In addition, the effect of outrigger on the damage states of the structural and member is evaluated using the elastic–plastic analysis method in the rare earthquake action. Finally, the seismic mitigation efficiency of the high‐rise structure with the viscous dampers installed on the outrigger floor is analyzed. The results indicate that the member size of the outrigger should be determined based on the performance objectives of the moderate earthquake action rather than the frequent earthquake action. The shear force distribution ratio of the outer frame located at the outrigger floor is obviously amplified, which shows that the cooperative bearing ability of the outer frame and the core tube is improved because of the outrigger action. The stress in the complex joint region of the outrigger, which satisfies the material strength requirement, is analyzed by the refined finite element analysis method. The slab of the outrigger floor, which should be strengthened to effectively transfer larger horizontal seismic shear force, has obvious damage in the rare earthquake action. The region of the structure with an outrigger that experiences significant damage in the rare earthquake action is located at the outrigger floor and adjacent upper domains rather than the bottom domains, which is different from that of a structure without an outrigger. The internal force of the outrigger member can be reduced by considering viscous damper action, but the seismic mitigation efficiency is not significant because of the limited number of dampers. [ABSTRACT FROM AUTHOR]

A holistic evaluation of a building's environmental impact must include a thorough accounting of both its operating and embodied energies, inclusive of the influence of hazard-induced damage and repairs. Unfortunately, these considerations are notoriously absent in today's practice owing to a traditionally segmented approach to the design process that has perpetuated interoperability challenges between existing commercial tools. In response to this and other limitations of existing approaches, this paper offers an integrated life-cycle assessment (iLCA) that (1) considers the effects of site-specific climate and exposure to wind and seismic hazards on a building's embodied and operating energy, (2) adopts an assembly-based approach to reveal the specific components influencing performance outcomes, (3) accommodates both risk-neutral and risk-adverse perspectives, and (4) addresses interoperability challenges that limit access to the data stored within commercial building information models. The resulting iLCA is partitioned into a sustainability workflow, with modules dedicated to embodied and operating energy, and a resilience workflow, sequencing modules for hazard characterization, structural response, damage, and repair/loss. A custom parser leverages semantic technologies to efficiently extract geometry and material information from the underlying data structures of Revit building information models; this parser ultimately supplies the required building data to each module. A unifying probabilistic framework is then adopted to quantify life-cycle performance, in terms of repair costs and total (embodied and operating) energy, with emphasis placed on expanding the statistical descriptions of performance to support both risk-neutral and risk-averse decision-making. The iLCA is applied to a case study office building at two sites to demonstrate the effects of climate and wind and seismic hazards on the performance of specific components over different service lives, inclusive of potential performance variability due to hazard exposure. The framework is further leveraged to examine how different sources of uncertainty, or assumptions surrounding the quantification of this uncertainty, impact life-cycle performance estimates. [ABSTRACT FROM AUTHOR]

Performance-based earthquake engineering requires the harmonization of performances between structural and nonstructural elements. This paper discusses the performance-based seismic design of nonstructural elements through a direct displacement-based methodology applicable to nonstructural elements attached to a single location in the supporting structure and for which damage is the result of excessive displacements. The fundamentals of direct displacement-based seismic design are presented along with a description of the modifications required for its application to nonstructural elements. As an example, the direct displacement-based seismic design of a suspended piping restraint installation is presented. The design approach is appraised by nonlinear dynamic time-history analyses. [ABSTRACT FROM AUTHOR]

An accurate evaluation of structural damage is essential to performance-based seismic design for the structure across the earth fissure. By comparing the calculation results from three commonly used damage models and the experimental results, a weighted combination method using Chen model was selected in this paper as the seismic damage evaluation. A numerical model considering the soil-structure interaction (SSI) was proposed using ABAQUS software. The model was calibrated by comparing with the experimental results. The results from the analysis indicated that, for the structure across the earth fissure, the existence of earth fissure changed the damage distribution of the structural members. The damage of structural members in the hanging wall was greater than that in the foot wall. Besides, the earth fissure enlarged the damage degree of the structural members at the same location and changed the position of the weak story. Moreover, the damage degree of the structure across the earth fissure was greater than that of the structure without the earth fissure under the same excitation. It is expected that the results from this research would enhance the understanding of the performance-based seismic design for the structure across the earth fissure. [ABSTRACT FROM AUTHOR]

Gravity caisson wall is a common waterfront construction that were severely damaged by soil liquefaction in previous earthquakes. The deep mixing method is regarded as effective in liquefaction remediation. Meanwhile, an easily-executable remedial design procedure of using the deep mixing method for caisson walls exposed to seismic liquefaction risk has not been well developed for routine constructions. To solve the issue by following the philosophy of the Performance-Based Design method, the deep mixing method is examined within a framework of a well-calibrated case history to provide hypothetical mitigation to a damaged caisson wall to reach the acceptable level under the identical cyclic loadings as recorded in the case history. The study is divided into two steps: (1) a case history of damaged caisson wall by seismic-induced soil liquefaction was verified; (2) the deep mixing method is hypothetically applied to the caisson wall before the occurrence of earthquake, and the remedial design is optimized based on the improved wall structure deformation under seismic loading. The remedial design including the locations and configurations of deep mixing elements are optimized. Insights and recommendations on the establishment of liquefaction mitigation design and optimization process for caisson quay walls are provided to the practice. [ABSTRACT FROM AUTHOR]

Due to the stable hysteretic behavior, buckling-restrained braces (BRB) have been increasingly adopted in reinforced concrete (RC) frame structures to develop a dual structural system. This investigation aims to quantify the seismic behavior of newly-constructed reinforced concrete BRB frames (RC-BRBFs). The force–deformation characteristic of dual RC-BRBFs is firstly presented and the yield displacement is derived using the story shear ratio resisted by BRB system. The seismic design procedure of dual systems for different BRB configurations (including single diagonal, V-type and inverted V-type), is developed using the performance-based plastic design approach by considering BRB postyield behavior, design target drift and global yield mechanism. 126 RC-BRBF structures corresponding to different story numbers, BRB configurations and story shear ratios are designed. The influence of story shear ratios on the design results is analyzed. The seismic response of structures subjected to 22 ground motions is investigated and compared in terms of yield mode, maximum interstory drift ratio, BRB maximum ductility and cumulative ductility, and residual drift ratio. The relationship between actual and design normalized story shear of BRBs is demonstrated and a fitting equation is proposed to quantify the actual story shear ratios. The analytical results of the present study can provide quantified insights to the seismic design of RC-BRBF structures. [ABSTRACT FROM AUTHOR]

• A new seismic resilient design method that considers extremely rare earthquakes is proposed. • The proposed method achieves both the roof drift ratio and inter-story ratio design targets. • The predetermined yielding mechanism and anticipated performance goals for all four seismic levels are achieved. • TYBLSFS can be effectively utilized as a seismic resilient system against very strong earthquakes. Current design methods for achieving seismic resilience of structures are limited to hazard levels of service level earthquake, design-based earthquake and maximum considered earthquake, but they do not account for the risk of extremely rare earthquake (ERE) that poses a significant challenge to structural and human safety. To address this issue, this paper proposes a new seismic resilient design method that considers ERE by incorporating two-level yielding dampers as the primary structural fuse while satisfying the performance objectives of all four seismic hazard levels. The paper presents a detailed derivation of the proposed design method and outlines a step-by-step design procedure. The proposed design method is applied to a seismic resilient system called the two-level yielding beam linked steel frame system (TYBLSFS), and two TYBLSFSs with three and six stories are designed and numerically modeled. Nonlinear dynamic analyses are then conducted to validate the effectiveness of the proposed design method. The results show that the two TYBLSFSs achieve the designed targets of roof drift ratio (RDR) and inter-story drift ratio (ISDR) and that the RDR-base shear curves obtained from the dynamic analyses match the design curves. The predetermined yielding mechanism and anticipated performance goals for all four seismic levels have been achieved. And the presented TYBLSFS can be effectively utilized as a seismic resilient system against very strong earthquakes. [ABSTRACT FROM AUTHOR]

Evaluating the failure probability of a slope under the seismic condition during a given exposure time is important for performance-based assessment of slope stability. In this paper, a two-stage method is suggested to study the seismic stability of a slope during a given exposure time. In the first stage, the exceedance probability of the horizontal pseudo-static acceleration is evaluated. In the second stage, the vulnerability curve of the slope, which shows the relationship between the horizontal pseudo-static acceleration and the failure probability of the slope, is established. The failure probability of the slope during a given exposure time is then assessed by combining the exceedance probability curve of the horizontal pseudo-static acceleration and the vulnerability curve of the slope. Examples investigated show that the reliability of a slope under the seismic condition is controlled by multiple slip surfaces. A slope may have different failure probabilities during the same exposure time when it is at different locations because of different levels of ground shaking. Event at the same site, different slopes may have different failure probability because of the difference in factors like slope geometries and geological conditions. The method suggested in this paper can be used to quantify the effect of the above factors on the reliability of a slope. [ABSTRACT FROM AUTHOR]

This paper describes a pseudo-static approach developed for geosynthetic-reinforced earth ( GRE ) retaining walls, calibrated against given levels of wall performance defined by specified values of earthquake-induced displacements. The GRE walls generally show a good performance under severe seismic loading due to the capability of reinforcements to redistribute the deformations induced by the seismic actions within the reinforced zone. This can be achieved by promoting the activation of internal plastic mechanisms involving the reinforcements strength, providing that they are characterised by adequate extensional ductility. In the proposed procedure, the seismic coefficient k to be used in a pseudo-static calculation is assumed equal to the internal seismic resistance of the wall k c int , related, through the kinematic theorem of limit analysis, to the maximum strength demand of geosynthetic reinforcements. The seismic coefficient is then calibrated against given levels of seismic wall performance, defined by threshold values of earthquake-induced displacements that result by the temporary activation of plastic mechanisms during severe seismic loading. Permanent displacements induced by earthquake loadings are evaluated through empirical relationships based on a parametric integration of a large number of Italian seismic records and are expressed as a function of the critical and the maximum horizontal accelerations. A procedure is finally proposed to conceive a reinforced-earth retaining wall with an internal seismic resistance lower than the external one, so that a prescribed level of seismic performance and the activation of internal mechanisms are ensured during severe seismic shaking. [ABSTRACT FROM AUTHOR]

This paper proposes a performance-based seismic design (PBSD) method for self-centering moment-resisting frames with shape memory alloy (SMA)-bolted endplate connections. PBSD can be used to achieve different performance objectives, resulting in several benefits, such as cost-effectiveness and customization of the design. This study develops a PBSD framework by establishing a relationship between the fundamental period, ductility demand, and seismic force reduction factor and using an energy-balanced concept. The design method is facilitated using an artificial neural network (ANN)-based predictive tool and an efficient experimentally-validated phenomenological model for SMA-bolted endplate connections. Maximum drift and ductility ratios are adopted as performance objectives. Two 3- and 6-story prototype frames are designed and evaluated to illustrate the proposed PBSD method. The seismic response and collapse safety of the prototype frames at different shaking intensities are evaluated. The results show that the prototype frames designed using the proposed PBSD framework meet the prescribed design objectives and the collapse safety requirements in FEMA P695. The illustrative examples confirm that the designed moment frames possess the intended self-centering capability with negligible residual deformations as low as 0.05% at the maximum considered earthquake (MCE) hazard level. The results also confirm that the designed frames exhibit uniform drift distribution along their height. • Developing a performance-based seismic design framework for SMA-based self-centering moment resisting frames. • Investigating seismic performance of SMA-based moment resisting frames through nonlinear response history analyses. • Illustrating the application of a predictive tool for SMA-bolted endplate connections in seismic design and analysis. • Showing the effectiveness of the developed design method to achieve the prescribed design objectives. [ABSTRACT FROM AUTHOR]

Various durations of Endurance Time Acceleration Functions (ETAFs) associated with different seismic hazard levels are presented to enable Endurance Time (ET) method for use in probabilistic seismic demand assessment studies. Various Intensity Measures (IMs) were, first, considered for establishing multiple "IM-duration" relationships. A set of 30 RC moment resisting frames were, then, subjected to IDA analysis using 44 ground motion records and the median IM values corresponding to different structural response levels were extracted. These values were compared with the ET-derived IMs by computing the errors corresponding to various demand levels and summating these errors over a complete range of response levels to derive an overall error index. The error indices were then averaged over all structural models and were compared for different IMs, revealing that maximum compatibility with the ETAF generation method dominated selection of the best IM. [ABSTRACT FROM AUTHOR]

It is well-known that in order to decrease displacements and accelerations in a frame structure during earthquakes, purely viscous dampers can be effectively employed, allowing for a remarkable dissipation of seismic input energy. The design of such devices, however, is still an open issue, since it is often carried out by means of inefficient trial-and-error procedures, or simplified analytical approaches which do not guarantee the optimal exploitation of the dampers. This work investigates the use of an optimisation-based approach for the design of nonlinear purely viscous dampers, aimed at improving the seismic behaviour of frame structures. The potential and the flexibility of the method are shown through an illustrative example displaying how different structural requirements (limitation or minimisation of inter-storey drifts and/or forces transferred by the devices) can be easily taken into account by means of a suitable formulation of a constrained optimisation problem. [ABSTRACT FROM AUTHOR]

Seismic microzonation maps for Belgrade (Serbia) and its surroundings are presented based on the uniform-hazard-spectrum (UHS) methodology. Such mapping must satisfy the guidelines for performance-based design (PBD), which at present requires the specification of two sets of spectral amplitudes, one in which the structure would remain essentially linear, and one in which it would undergo nonlinear response. These requirements cannot be achieved by specifying the design spectra using only one (same) fixed spectral shape, and such spectra cannot be scaled by the peak ground acceleration alone. Another source of difficulties in the selection of the design amplitudes for PBD occurs when the standard spectrum shape is not capable of describing excitation by large, distant earthquakes. Furthermore, scaling the site dependent design ground motion only via soil site classification ignores the effects of site geology and thus leads to biased results. The maps we present in this paper avoid these shortcomings and include the effects of near and distant large earthquakes, spatial distribution of seismic activity, site geology, and site soil properties in a balanced way. [ABSTRACT FROM AUTHOR]

An optimized seismic performance-based design (PBD) methodology considering structural and nonstructural system performance and seismic losses is considered to optimize the design of a steel structure. Optimization objectives are to minimize the initial construction cost associated with the weight of the structural system and the expected annual loss (EAL), considering direct economic losses. A non-dominated sorting genetic algorithm method is implemented for the multi-objective optimization. Achieving the desired confidence levels in meeting performance objectives of interest are set as constraints of the optimization problem. Inelastic time history analysis is used to evaluate structural response under different levels of earthquake hazard to obtain engineering demand parameters. Hazus fragility functions are employed for obtaining the damage probabilities for the structural system and nonstructural components. The optimized designs and losses are compared for the structure located in two geographic locations: one in the central United States and another in the western United States. [ABSTRACT FROM AUTHOR]

An important consideration in the design of structures for seismic effects is residual displacement. However, few design specifications have residual displacement criteria. As performance-based design gains popularity, the need arises to estimate residual displacements in structures from strong ground shaking. A total of 16,896 nonlinear analyses of single-degree-of-freedom bilinear oscillators were performed to estimate residual displacement ratios. Comparisons were made to previously developed models for estimating residual displacement demand. [ABSTRACT FROM AUTHOR]

By employing two or more types of braces, hybrid braced frames (HBFs) combine the merits of the adopted braces and offsets their drawbacks. However, the corresponding seismic design method is still under development. To this end, this paper develops a performance-based seismic design (PBSD) method, based on the performance-based plastic design (PBPD) method. In current work, the buckling-restrained braces (BRBs) and shape memory alloy braces (SMABs) are introduced, because they are known for high energy-dissipating capacity and excellent self-centering capability, respectively. The participation extent of BRBs and SMABs is controlled by the stiffness contribution factor. The equations governing the design results are derived and the step-by-step procedure is detailed. A six-story benchmark frame is selected to demonstrate the design method. The designed HBF is subjected to a suite of earthquake ground motions, and the mean demands of seismic responses are compared against performance targets. It indicates that the HBF designed by the design method can well meet the design targets. A parametric analysis is conducted to reveal the effect of changing the stiffness contribution factor on the seismic demands of the HBF. This study validates the proposed design method for HBF, and it may also shed light to the PBSD method of the structures equipped with the other types of displacement-dependent damping braces. • It proposes a seismic design method for hybrid braced frames. • The hybrid braced frames can meet the requirements of multiple EDPs simultaneously. • The optimal value of stiffness contrition factor of BRB system to the hybrid system is 0.7. [ABSTRACT FROM AUTHOR]

The ability of aging shore structures to resist design seismic forces located in high-seismicity regions has been a subject of interest for many researchers. Seismic design codes have become more stringent and suggest the use of new design methods, such as performance-based design. According to the Turkish Code for Shore Structures (TCSS 2008), a pile-wharf structure is expected to withstand a D1 level of ground motion (corresponding to a return period of 72 years) with minor or no damage and a D2 level of ground motion (corresponding to a return period of 475 years) with short-term loss of serviceability. In this study, nonlinear static analyses of the seismic performance of two existing pile-wharf structures were performed (pushover analyses) according to TCSS (2008). The results are presented here. [ABSTRACT FROM AUTHOR]

Post-earthquake fire (PEF) is considered one of the most high risk and complicated problems affecting buildings in urban areas and can cause even more damage than the earthquake itself. However, most standards and codes ignore the implications of PEF and so buildings are not normally designed with PEF in mind. What is needed is for PEF factors to be routinely scrutinized and codified as part of the design process. A systematic application is presented as a means of mitigating the risk of PEF in urban buildings. This covers both existing buildings, in terms of retrofit solutions, and those yet to be designed, where a PEF factor is proposed. To ensure the mitigation strategy meets the defined criteria, a minimum time is defined – the safety guaranteed time target – where the safety of the inhabitants in a building is guaranteed. [ABSTRACT FROM AUTHOR]

This study aims to compare the seismic performance of two 42-story reinforced concrete buildings located in Los Angeles, California: a coupled core wall building and a similar core wall building with perimeter moment resisting frames (i.e. dual system). The buildings were designed using two different approaches. The first approach followed the traditional code prescriptive design approach as outlined in the International Building Code (2006), whereas the other approach followed a performance-based design approach outlined in the seismic design guideline published by the Pacific Earthquake Engineering Research Center. Detailed finite element models were developed for both systems with the different design approaches. The models were used to evaluate the seismic performance of the prototype model at five different earthquake shaking intensities. Detailed comparisons of the design approaches, seismic responses, and initial and annualized repair costs of these buildings are presented. Analysis results show that both structural systems generally achieved excellent performance, whereas the dual system performed slightly better (smaller inter-story drifts and lower core wall stresses). Although repair costs were lower in the dual system building (which is attributed to lesser degree of damage), total costs were higher than the core wall building due to the higher initial costs. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]