Performance-based Seismic Design Method Research Articles

Analysis of Bridge Tests on Sandy Overburden Site with Fault Dislocating

Performance-based seismic design methods for bridges are advancing, yet limited research has explored the damage mechanisms of bridges subjected to extreme seismic effects, such as those near or across faults. To investigate the damage mechanisms under bedrock dislocation and bridge rupture resistance, providing essential insights for the standardized design and construction of bridges in close proximity to seismic rupture sites, we developed a large-scale device to model bridges in the immediate vicinity of tilted-slip strong seismic rupture sites. This included a synchronous bedrock dislocation loading system. Four sets of typical sandy soil modeling tests were concurrently conducted. The results indicate: (1) The overall shear deformation zone of the foundation and surface uneven deformation primarily concentrate the overburdened soil body along the fault dip. The damaged area under the low-dip reverse fault is lighter on the surface and inside the soil body compared to the high-dip-positive fault. (2) The presence of bridges reduces the width of the main rupture zone and avoidance distance to some extent. However, this reduction is not as significant as anticipated. The damage to the bridge pile foundation along the fault dislocation tendency notably leads to the bending damage of the bridge deck. (3) Input parameters for fracture-resistant bridge design (surface rupture zone location, extent, maximum deformation, etc.) can be deduced from the free site. Within the rupture zone, a “fuse” design can be implemented using simply supported girders. Additionally, combining the “fuse” design with simple supported girders on both sides and utilizing simple support beams for “fuse” design within the rupture zone, along with structural “disconnection”, allows for reinforcing measures on the bridge structure’s foundation platform and pile in the soil body.

Performance-based seismic design method for disc spring-based self-centering viscous dissipative braced steel frame

Disc spring-based self-centering viscous damper (SCVD) has emerged as a novel technology, offering velocity-dependent energy dissipation and exceptional self-centering capabilities. Integrating this damper in structural bracing systems can effectively enhance passive control over critical structural demands such as peak deformation, residual displacement, and floor acceleration. Nevertheless, a seismic design method specifically tailored for self-centering viscous dissipative braced steel frames (SCVDFs) needs further refinement. This study proposes a performance-based seismic design (PBSD) method for SCVDFs, which is grounded in the performance-based plastic design (PBPD) approach. The proposed procedure primarily considers the effects of two critical hysteresis parameters: the post-activation stiffness ratio and the viscous damping ratio. To verify the effectiveness of the design method, a set of SCVDFs was designed, each utilizing different combinations of design parameters. Nonlinear static and dynamic analyses were performed on these archetypes to evaluate their seismic performance. The evaluation findings demonstrated that the properly designed SCVDFs can achieve the expected design performance and effectively suppress the peak inter-story drift, residual inter-story drift, and peak absolute floor acceleration of the structure, thereby achieving a favorable trade-off in the design outcome and maximizing the advantages of the SCVDF in seismic resilience.

Research on seismic design methods for high-rise building structures

In recent years, with the increase of the number of high-rise buildings and the increase of the frequency of earthquakes, the requirement of seismic design of high-rise buildings is getting higher and higher. Therefore, this paper mainly studies the requirements of the existing seismic design code and the basis of designing the seismic performance of high-rise buildings. The results of this paper show that the performance-based seismic design method is the most popular and practical seismic design method at present. It also concluded that the seismic capacity of high-rise buildings can be improved by changing the calculation method of bearing capacity and adopting stable lightweight materials. In addition, this paper also introduces the new seismic methods such as preset yield mode, so as to improve the seismic ability of tall buildings as a whole. In the future, more new and innovative technologies will be applied to the seismic design of high-rise buildings to provide a stable and safe environment for peoples production and life.

Seismic Design of Large-Span, Heavy-Load Transfer Truss for Zhanjiang Bay R&D Building

The Zhanjiang Bay Laboratory R&D Building project aims to create a favorable working, research, and living environment. Zone II of the Zhanjiang Bay Laboratory R&D Building is equipped with a large-span, heavy-load transfer truss to obtain a large space on the ground floor. The overall structure adopts a steel frame-core tube structure system. In order to reduce the deflection of the large-span, heavy-load transfer truss, eight diagonal pull rods are installed between the large-span, heavy-load transfer truss and the core tube. The Q235 cross-shaped replacement section can consume construction load energy. Adopting replacement methods can reduce the stress and damage of diagonal pull rods caused by construction loads. The structure adopts a performance-based seismic design method for seismic calculation and analysis. In addition, a special analysis was conducted on the single frame structure. The major results can be summarized as follows: during small earthquakes, all structural components are in the elastic stage; during large earthquakes, frame beams yield first, but frame columns and core tubes do not yield; even without considering out-of-plane constraints, the structure can still meet the requirements.

Seismic design and performance evaluation of hybrid braced frames having buckling-restrained braces and self-centering viscous energy-dissipative braces

Hybrid braced frames (HBFs) emerge as an innovative seismic-resilient system, synergizing the strengths of buckling-restrained braces (BRBs) and self-centering viscous energy-dissipative braces (SCVDBs). This novel system has the potential to simultaneously manage three key seismic demand parameters: peak inter-story drift (PID), residual inter-story drift (RID), and peak absolute floor acceleration (PFA). Nevertheless, a dedicated seismic design method for HBFs is yet to be developed. This research proposes a performance-based seismic design (PBSD) method specifically tailored for HBFs. The method's core relies on energy decoupling in the HBFs using a proposed energy distribution factor (η). To validate the proposed design method, sets of 4-, 8-, and 12-story braced frames are designed using varied η. A comprehensive seismic performance evaluation is conducted, utilizing nonlinear static and nonlinear time-history analyses. The findings indicate that the HBFs, designed utilizing different values of η, consistently meet predefined performance objectives. Within the scope of this study, the η value of 0.5 is shown to be optimal, enhancing the structural resilience of HBFs against PIDs and PFAs while exhibiting excellent self-centering performance comparable to the self-centering viscous energy-dissipative braced frame (SCVDF). Additionally, the HBFs demonstrate superior control over PFA compared to pure buckling-restrained braced frame (BRBF) and SCVDF.

Substructure Mass Participation Effect on the Performance-Based Seismic Design Method for Isolated Bridges

Substructure Mass Participation Effect on the Performance-Based Seismic Design Method for Isolated Bridges

Performance-based seismic design of self-centering steel moment frames with SMA-bolted connections

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.

Peak and residual deformation-based seismic design for multi-story hybrid concentrically braced frames

Recently, using two and more types of braces in a concentrically braced frame (CBF) has been demonstrated to be effective for developing seismic resilient structures. The hybrid CBF with the combination of buckling-restrained braces (BRBs) and self-centering braces (SCBs) is promising to realize the desirable seismic performance. However, the seismic design method for the hybrid CBFs can rarely be found. To this end, the general behavior of the hybrid CBF is first introduced. Through nonlinear time history analysis (NLTHA) on single-degree-of-freedom (SDOF) systems, the seismic responses of the hybrid CBFs are investigated comprehensively. Based on the SDOF analytical results, a performance-based seismic design (PBSD) method is introduced to size the hybrid CBFs. The essential advantage of the PBSD method is that the peak and residual inter-story drift ratios can be jointly selected as the performance targets. A benchmark six-story CBF was selected as the example building to demonstrate the method. The system-level NLTHA under a suite of ground motion earthquakes was conducted to examine the accuracy of the method. The results indicated that the hybrid CBF designed by the PBSD method could well meet the prescribed performance targets, i.e., both the peak and residual inter-story drift ratios are well controlled within performance limits. Moreover, the optimal design hysteretic parameters are suggested to eliminate the residual inter-story drift ratios and minimize the peak floor accelerations.

Nonlinear seismic performance of RC bridges using the ESA, EDA, DDBA, and nonlinear analysis with various viscous damping models

Modern bridge seismic design follows a performance-based seismic design (PBSD) philosophy where the structure is designed to achieve a prescribed limit state under a defined hazard. Nevertheless, the demands may substantially diverge depending on the PBSD method applied in the assessment. This article presents a demand sensitivity analysis using the elastic (ESA) and dynamic (EDA) procedures of the AASHTO Seismic Guide Specifications and direct displacement-based assessment (DDBA). The investigation was conducted using 81 reinforced concrete (RC) bridges and ten multi-period spectra from a shallow tectonic regime. Moreover, these demands were compared with nonlinear time history analysis (NLTHA) using five viscous damping models. Seven compatible records were employed to calculate the envelopes of transverse displaced shapes and cumulative distribution functions of the column with the highest displacement ductility. These average inelastic responses were contrasted with the predictions from the ESA, EDA, and DDBA. For regular bridges, this study found that the elastic procedures considerably underestimate the deformations, while DDBA compares well with NLTHA, especially for high ductility levels. Also, a discussion about the impact of the viscous damping models is included. We expect these findings may encourage practitioners to use DDBA as a reliable alternative to evaluate the seismic performance of RC bridges.

Simplified Risk-Targeted Performance-Based Seismic Design Method for Ordinary Standard Bridges

Simplified Risk-Targeted Performance-Based Seismic Design Method for Ordinary Standard Bridges

Performance-based plastic design of multi-story hybrid braced frames with buckling-restrained braces and shape memory alloy braces

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.

Machine learning-driven performance-based seismic design of hybrid self-centering braced frames with SMA braces and viscous dampers

A hybrid self-centering braced frame equipped with shape memory alloy-based self-centering braces (SMA-SCBs) and viscous dampers is proposed to achieve enhanced seismic performance. Based on the proposed hybrid strategy combining the contributions of SMA-SCBs and viscous dampers, this paper investigates the advantages of such hybrid self-centering braced frames in achieving the desired maximum inter-story drift under a considered seismic intensity. To this end, the influence of design parameters of SMA-SCBs and viscous dampers on hybrid self-centering braced frames is examined through parametric dynamic analyses of equivalent single-degree-of-freedom systems. The analysis results indicate that the post-yield stiffness ratio α and energy dissipation factor β of SMA-SCB, and the contribution of viscous damper show significant influence on the peak displacement responses of hybrid self-centering braced frames. The constant inelastic displacement ratio prediction model for hybrid self-centering braced frames is developed using machine learning algorithms. A performance-based seismic design method is subsequently proposed for the hybrid self-centering braced frames to achieve the target displacement responses based on the developed machine learning models. Two hybrid self-centering braced frames are designed based on the proposed design method. Nonlinear dynamic analyses are conducted to investigate the seismic performance of the designed structures. To highlight the advantages of the hybrid self-centering braced frames, another six-story self-centering braced frame with SMA-SCBs only is also studied in this paper. The analysis results indicate that all the designed hybrid self-centering braced frames can achieve the desired performance objective. Compared to the self-centering braced frame with SMA-SCBs only, the hybrid self-centering braced frames can achieve much smaller base shear demand and absolute floor acceleration responses.

Performance-based seismic design method for retrofitting steel moment-resisting frames with self-centering energy-absorbing dual rocking core system

This research intends to propose an upgraded strategy for steel moment-resisting frames (SMRFs) by implementing Self-Centering Energy-absorbing Dual Rocking Core (SEDRC) systems to achieve enhanced seismic performance, improved seismic resilience, and avoid inter-story drift concentration. A performance-based method is developed to design the SEDRC system for upgrading the existing SMRF. The maximum inter-story drift and drift concentration factor are adopted as the design performance objectives. Two prototype SMRFs with three and nine stories are introduced to validate the proposed performance-based design procedure. Nonlinear static analyses were first performed for the original SMRFs and the updated ones (denoted as SEDRC-MRFs) to investigate the efficiency of the proposed retrofit strategy. The pushover curves of the analytical structures confirm that the SEDRC systems can increase the stiffness and strength of SMRFs, and SEDRC-MRFs upgraded through the proposed design procedure show no strength deterioration before the fracture of the brace in the SEDRC system. A set of 18 ground motions were chosen to study the seismic performance of the designed SEDRC-MRFs. The analysis results indicate that SEDRC-MRFs can obtain the desired performance objectives. The SEDRC system could reduce the maximum and residual inter-story drifts of SMRFs and promote uniform inter-story drift distribution. Moreover, the designed SEDRC-MRFs can be used immediately without the need for repairing structural members after the design basis earthquakes and can be repaired economically after the maximum considered earthquakes.

Response modification factor and displacement amplification factor of K-shaped eccentrically braced high-strength steel frames

ABSTRACT A K-shaped eccentrically braced high-strength steel frame is a novel structure. For such structures to exhibit good plastic deformation under severe earthquakes, the links are made of ordinary steel (fy≤345 MPa), whereas high-strength steel (fy≥460 MPa) is used in the frame beams and columns to reduce the cross section while ensuring the elasticity of the nonenergy consuming components. The response modification factor R is crucial to the performance-based seismic design. For an appropriate and economical seismic design, the R value and displacement amplification factor Cd should be reasonably selected. In China’s code for Seismic Design of Buildings R is uniform without considering high-strength steel, which is unreasonable. It is important to study R and Cd of K-shaped eccentrically braced high-strength steel frame. Therefore, structures with different stories (5, 10, 15, and 20 stories) and link lengths (900, 1000, 1100, and 1200 mm) were designed via the performance-based seismic design method. A static nonlinear pushover analysis and an increment dynamic analysis (IDA) were conducted. The R and Cd of each prototype were calculated using the capacity spectrum method. The effects of various factors in terms of the number of stories and link length were evaluated.

Seismic performance design of energy-dissipated structure system based on damage control and time-varying damping ratio

The installation of energy dissipation devices on building structures can significantly reduce seismic damage. A brief review of first, second and third generation performance-based seismic design (PBSD) theories, and a comparative analysis of existing PBSD methods for energy-dissipated structure systems confirms that design methods based on force, displacement, and energy are inadequate. A more comprehensive approach is the damage-based design method, which can evaluate the seismic performance of structures. However, due to the lack of an analytical relationship between the additional equivalent damping ratio (AEDR) of dampers and the damage degree of the main structure, the current performance design method can only predict the expected damage via an iterative adjustment analysis of damper's design parameters. The authors addressed this problem by analyzing the damage mechanism of the energy-dissipated structure system's core area from the perspective of energy dissipation. It is established an analytical relationship between the AEDR and the damage index of the main structure with dampers via a damage model based on the energy difference ratio and the time-varying AEDR calculation of dampers subjected to ground motions. With this new approach to seismic vulnerability analysis, the performance design flow of the seismic structure system is based on damage control. A case study verifies the accuracy of the damage-degree based AEDR calculation. The proposed damage-based method effectively controls the damage degree of the main structure to the expected damage target. This method is compatible with the displacement-based design method, and which also enriches the research contents of structural seismic design and damage analysis in the third generation PBSD.

Seismic performance of self-centering glulam frame with friction damper

The self-centering structure has good recentering capacity and seismic performance, and its application in timber structures can significantly reduce the residual displacement of the structure. In this paper, the seismic performance of the self-centering glulam (SCG) frame with friction damper (FD) is studied from three aspects: the test of beam-to-column joint, the seismic design method of frame and the dynamic time history analysis of frame. Firstly, a low-cycle reversed loading test was carried out on the glulam beam-to-column joint with the initial post-tensioned (PT) force as a variable. According to the test results, the beam-to-column joint showed both good self-centering capacity and hysteretic behavior. Then, a simplified performance-based seismic design method of the FD-SCG frame was proposed, with a 6-story self-centering frame structure as the design example. The nonlinear dynamic time history analysis and parametric analysis of the frame were conducted by the OpenSees. The dynamic time history analysis proves from both the global and local response that the frame has a good seismic response under the design basis earthquake (DBE) and the maximum considered earthquake (MCE), while the frame also has safety reserve under the MCE level. The average values of the maximum inter-story drift of the frame under the DBE and MCE levels are 0.31% and 1.92%, respectively, which are less than the design limitation. The parametric analysis results showed that the increase of the PT tendons number, that is, the increase of the second stiffness can reduce the damage of acceleration-sensitive nonstructural components.

Energy-balance based plastic design and analysis of hybrid coupled wall system

The hybrid coupled wall (HCW) system consists of steel coupling beams that connect adjacent reinforced concrete (RC) wall piers. In order to minimize or even eliminate the lengthy design iterations of conventional performance-based seismic design method and directly account for inelastic structural behavior, the modified energy-balance based plastic design (EBPD) method is proposed and developed for the seismic design of HCW systems with the consideration of influences of the degradation of hysteretic behavior and pinching effects. The design base shear can be obtained by solving the modified energy balance equation analytically. Twelve HCW prototype structures with different structural heights and coupling ratio (CR) were designed and evaluated by conducting a series of push-over analyses and nonlinear dynamic time-history analyses with the proved-reliable program of PERFORM-3D. The analysis results indicate that all HCW prototype structures exhibit the favorable yield mechanism and satisfactory seismic performance. Particularly, the influences of CR on the deformation characteristics, bending moment distribution among wall piers and vertical distribution of overturning moment are revealed. Suggestions are made in terms of the appropriate selection of CR for different structural heights.

Seismic Performance Assessment of a Multistorey Building Designed with an Alternative Capacity Design Approach

The actual seismic building codes have a prescriptive nature, and they are principally aimed to guarantee a prescribed life-safety level against a design-level earthquake even if some methods have been proposed to evaluate the seismic performance of a building along its entire service life. Among these, the performance-based seismic design method permits the design of buildings with a more realistic understanding of both risk of life for occupants and economic losses that may occur in future earthquakes. On the other side, the capacity design method, providing criteria to properly spread the inelastic deformation demand between the different structural elements, allows to establish a ductile collapse mechanism avoiding undesired brittle failures. In this context, modern building codes consider the adoption of a single value for the behaviour factor q to be used in the design process. All this should be argued since, especially for buildings characterized by storeys with different uses and occupancy ratios, the adoption of a single value for q could guide the design process to a solution not minimizing the seismic loss. With reference to these aspects, the paper shows the comparison of the seismic responses of a multistorey framed building designed following two different approaches. The first approach, suggested by many international codes, follows the capacity design rules and considers a single value for the behaviour factor valid for the whole building. In this first case, the damage mechanisms could affect, theoretically, every storey of the building. The second approach, proposed here, considers instead the possibility to adopt different behaviour factors to attribute to different storeys. In this way, it is possible to concentrate and localize the most severe earthquake-induced structural damage on (few) storeys, selected by the designers. By means of the seismic performance assessment methodology, the comparison between the two building responses is provided in terms of expected losses during the whole building service life and is reported in terms of both economical loss and human life loss. The results in the paper show that, if different behaviour factors are properly selected for different storeys, the design process can provide a solution characterized by lower values of seismic loss with respect to the case of the design assuming a single-q value.

Direct displacement-based design of the linked column steel frame System, Part 1: Modeling and yield drift evaluation

The linked column frame (LCF) system is a load resisting system in which replaceable link beams are used to provide the desired structural behavior at various performance levels. The optimal performance of this system can be achieved by controlling the successive yielding pattern of its structural fuse elements using performance-based seismic design methods. This paper derives some analytical relationships for the yield drift estimation of the LCF system required to its direct displacement-based design developed in the companion paper. The obtained results show the high accuracy of the proposed relationships to estimate the yield drift of the LCF system.

Integrating expected loss and collapse risk in performance-based seismic design of structures

With the introduction of performance-based earthquake engineering (PBEE), engineers have strived to relate building performance to different seismic hazard levels. Expected annual loss (EAL) and collapse safety described by mean annual frequency of collapse (MAFC) have become employed more frequently, but tend to be limited to seismic assessment rather than design. This article outlines an integrated performance-based seismic design (IPBSD) method that uses EAL and MAFC as design parameters. With these, as opposed to conventional intensity-based strength and/or drift requirements, IPBSD limits expected monetary losses and maintains a sufficient and quantifiable level of collapse safety in buildings. Through simple procedures, it directly identifies feasible structural solutions without the need for detailed calculations and numerical analysis. This article outlines its implementation alongside other contemporary risk-targeted and code-based approaches. Several case study reinforced concrete frame structures are evaluated using these approaches and the results appraised via verification analysis. The agreement and consistency of the design solutions and the intended targets are evaluated to demonstrate the suitability of each method. The proposed framework is viewed as a stepping stone for seismic design with advanced performance objectives in line with modern PBEE requirements.