Performance-based Seismic Design Approach Research Articles

Machine learning modelling of structural response for different seismic signal characteristics: A parametric analysis

The present study investigates the best seismic parameters for modeling the dynamic response of various non-linear structural systems by comparing different Machine Learning (ML) algorithms. A total of 400 synthetic excitations were generated and analyzed against 23 seismic parameters. These signals were used in a step-by-step numerical analysis to calculate the dynamic responses of 1000 single-degree-of-freedom (SDOF) systems with varying mechanical properties. The data obtained from these responses were processed using 20 ML algorithms, including linear regression, tree, support vector machine (SVM), boosted and bagged trees, and artificial neural network (ANN). Each ML algorithm used a single seismic parameter as input to determine the most predictive parameters for modeling structural responses, defining the high predictive seismic parameters (HPSP) set. To validate the obtained results, the most effective model predictions have been compared with the results of the parametric step-by-step analyses performed for a new group of natural ground motions. The findings demonstrate that with a properly calibrated training phase, considering the specific site hazard and selecting seismic parameters from the HPSP set, the ML model can accurately estimate seismic responses whit a significantly reduced computational effort. This study underscores the potential of integrating ML techniques into the performance-based seismic design approach.

Response Modification Factor of High-Strength Steel Frames with D-Eccentric Brace Using the IDA Method

The design innovation of high-strength steel frames paired with D-eccentric bracing exhibits remarkable resistance to plastic deformation during seismic events. This method strategically combines regular steel connections (with yield strengths below 345 MPa) and high-strength steel beams and columns (such as Q460 or Q690, with yield strengths over 460 MPa), effectively reducing cross-sectional sizes while preserving the elasticity of non-energy-dissipating members. This configuration results in substantial ductility and superior energy dissipation capabilities. The response modification factor (R) is vital for achieving both effective and economical seismic resilience, particularly in the development of efficient and cost-effective seismic designs. However, the 2016 edition of the Code for Seismic Design of Buildings (GB50011-2010) fails to incorporate the concept of R, opting instead to apply a uniform value to all structural systems. This oversight is fundamentally flawed, necessitating a comprehensive investigation into the R value specifically for the high-strength steel frame with a D-eccentric brace. This research primarily aims to improve structural performance design, provide guidance for future projects, and encourage the adoption of this advanced seismic performance structure in earthquake-prone areas. To achieve these objectives, a performance-based seismic design approach is employed. This method involves designing structures with varying numbers of stories (4, 8, and 12), different link lengths (900, 1000, and 1100 mm), and various steel strengths (Q460 and Q690). This study uses the Incremental Dynamic Analysis (IDA) method to determine the R values for each prototype. The derived performance coefficients act as crucial references for the development of future innovative structural designs. This research greatly enhances seismic design practices and facilitates the wider adoption of high-strength steel frames with D-eccentric braces due to their outstanding seismic performance.

Response modification factor of high strength steel frame with D-eccentric brace using improved pushover analysis method

The high-strength steel frame with D-eccentric brace presents a novel structural system that demonstrates exceptional plastic deformation capabilities when exposed to high levels of earthquake hazards. This system employs ordinary steel links with a yield strength below 345 MPa, while the frame beam and column utilize high-strength steel (yield strength above 460 MPa, such as Q460 or Q690 steel) to reduce cross-sectional dimensions while ensuring elasticity of non-energy consuming components. The resulting structure exhibits outstanding ductility and energy-dissipating capacity. The response modification factor (R), a crucial parameter in performance-based seismic design, plays a significant role in achieving appropriate and cost-effective seismic designs. Unfortunately, the 2016 edition of China's code for Seismic Design of Buildings (GB50011-2010) did not consider the concept of R and instead employed a constant value for all structural systems, which is unreasonable. Therefore, a comprehensive investigation of the R value for the high-strength steel frame with D-eccentric brace is imperative to enhance structural performance design, provide guidance for future designs, and promote the widespread implementation of this structure in seismic regions, where it exhibits superior seismic performance. This study utilizes the performance-based seismic design approach to design structures with varying numbers of stories (4, 8, and 12), link lengths (900, 1000, and 1100 mm), and different steel strengths (Q460 and Q690). An improved pushover analysis method is employed to calculate the R values for each prototype, considering the number of structural stories (N) and the link length (e). The derived values of each performance coefficient serve as valuable references for future performance designs of novel structural systems.

Thermography Investigation and Seismic Vulnerability Assessment of a Historical Vaulted Masonry Building

Typically, historical masonry constructions were only designed due to gravity loads. The structural detailing, aimed at improving the seismic performance, was introduced thanks to the advancement in performance-based seismic design approaches in recent decades. In this context, the vaults play a key role. Depending on the construction technology, material, shape and constraints, the vault can modify the load patterns both in static and/or dynamic conditions. Furthermore, in heritage buildings, the possible presence of frescos or decorations increase the difficulties in assessing the technological nature of the vault. Non-destructive in situ investigation techniques, such as thermography, can be a powerful tool to improve the level of knowledge with respect to structural detailing and increase the prediction capability of the numerical model. The present paper discusses the results of a large thermography campaign performed in a cultural masonry building located in the south of Italy. The extensive investigation was aimed at identifying the typologies of vaults covered by worth frescos. This peculiarity was considered in the structural analysis in order to investigate the influence of the vault typology, in terms of plan stiffness versus the global seismic vulnerability. The outcomes demonstrated that thermography was decisive in improving the level of knowledge and obtaining a more reliable prediction of the seismic response.

Two-level performance-based seismic design approach for steel frames with novel self-centring seismic base isolators

A two-level performance-based seismic design (PBSD) approach for frame structures isolated by self-centring isolators (SCIs) is proposed in this study. Unlike the traditional PBSD process that generally designs a structure for a specific seismic intensity level first and then checks structural performance for other levels, the proposed PBSD approach considers both the design basis earthquakes (DBE) and maximum considered earthquakes (MCE) by analysing two different nonlinear equivalent structural models, thereby enabling the accurate control of structural performance objectives at two different seismic intensity levels during the design process. The design method combines the fundamental displacement-based design process and the widely-accepted nonlinear response spectra. A four-storey frame structure, equipped with novel SCIs consisting of rubber bearing, steel U-shaped dampers, and shape memory alloy U-shaped dampers, is designed as an example. Seismic analysis results demonstrate that the two-level PBSD approach can satisfactorily achieve the predefined performance objectives at both DBE and MCE levels. Although the design process is applied to SCI-isolated structures in this study, the design framework can be easily extended to other types of isolated structures to enable the advanced design that can achieve the target performances at DBE and MCE levels simultaneously.

Seismic Analysis of Irregular Reinforced Concrete Building Considering Soil Structure Interaction

Abstract: According to several studies on past earthquakes, Dynamic loading influences the seismic reaction of buildings. Sudden distress and failures in structures have been seen as a result of soil-structure interaction. Soil-structure interaction increases shear stresses in the structure's bottom storeys, making it less rigid and increasing lateral displacements such as storey drift, inter-storey drift, and roof displacements. Increased lateral displacements in high-rise buildings cause occupant discomfort. The interaction between soil and structure lengthens the building's natural time period. Three modelling approaches, fix foundation building, medium stiff base building, and low stiff base building, have been investigated and analysed using SAP2000 V14, taking into account soil-structure interaction (SSI). The results can be used to build a detailed performance-based seismic design approach that considers the influence of soil structure interaction. Keywords: Seismic Analysis, Soil Structure Interaction, Seismic Response, SAP2000

Seismic design and performance of self-centering precast concrete frames with variable friction dampers

This paper presents the numerical investigation of the seismic performance of post-tensioned self-centering precast concrete (SCPC) frames with variable friction dampers (VFDs) and hidden corbels (HCs). The VFDs are characterized by the combination of flat and grooved plates, where the friction forces change as the connection deformation increases, which enables designs to meet target seismic performance objectives at different seismic hazard levels. Theoretical and numerical models for the connection are proposed based on connection geometry, and a performance-based seismic design approach for the SCPC frames is outlined to meet target performance objectives at two common seismic hazard levels, the design basis earthquake (DBE) and the maximum considered earthquake (MCE). SCPC frames for a six-story prototype building located in a high seismic zone in California were designed using this procedure. Three frames with HC-VFD-SPSC connections were designed using various methods to mitigate concentration of drifts in the first story, and one frame was designed with conventional constant friction devices (CFDs) for comparison. Nonlinear time-history analyses were performed for these different designs using two sets of ground motions representing the DBE and MCE seismic hazard levels. The analysis results indicate that the frames with the HC-VFD-SCPC connections achieved the target performance objectives. The proposed approaches of modifying post-tensioning and VFD design parameters or column stiffness in the first story were effective in mitigating the concentration of drifts. Additionally, through comparison with the results of the frame with CFDs, it was found that the VFDs are effective in decreasing overall drift demands at the MCE level, as well as mitigating detrimental higher mode effects observed in SCPC frames with CFDs.

Performance of battery rack auxiliary power systems under FEMA 461 quasi-static seismic loading protocol

The performance of nonstructural components in nuclear power plants (NPPs), which is primarily based on experience and historical data, has been attracting increased interest from researchers following the Fukushima Daiichi nuclear disaster in 2011. This disaster demonstrated the importance of using batteries in NPPs as an auxiliary power system, where such systems can provide the necessary power to mitigate the risk of serious accidents. However, little research has been conducted on such nonstructural components (e.g., auxiliary battery power systems) to evaluate their performance following the post-Fukushima safety requirements, recommended by several nuclear regulators worldwide [e.g., Nuclear Regulatory Commission (NRC), and Nuclear Safety Commission (NSC)]. To address this research gap, the current study investigates the lateral performance of an auxiliary battery power system similar to those currently existing/operational in NPPs in Canada. The rack system was experimentally tested under displacement-controlled quasi-static cyclic fully-reversed loading that simulates lateral seismic demands, following the FEMA 461 guidelines “Interim testing protocol for determining the seismic performance characteristics of structural and nonstructural components”. Following a brief summary of the experimental program, the test results are presented in terms of the rack hysteretic response, damage sequence, stiffness degradation, ductility capacity, member strains, and local deformations. Subsequently, a simplified mechanistic model and a concentrated plasticity model in OpenSees have been developed and calibrated using the experimental results. The results show that without detailed modeling of the rack system connections (i.e., L-shaped connection and sliding nuts), incorrect performance prediction of such systems may result. The findings of the current study can be utilized, within the next generation of performance-based seismic design approaches, to enhance the robustness and improve the reliability of damage state predictions of auxiliary battery power systems in critical facilities.

Analysis of performance-based seismic design method for super high-rise frame-supported shear wall structure

In this paper, the advanced performance-based seismic theory is introduced, and combining with the seismic codes and high-rise building codes, a performance-based seismic design approach is established for high-rise frame-supported shear wall structure. Firstly, the performance objective is determined, and then calculation under frequent earthquakes, fortification earthquake and rare earthquake is carried out, finally, the performance analysis is carried out to see whether it achieves the predetermined performance objective. Then taking a high-rise frame-supported shear wall structure as an example, based on the performance-based seismic design method, YJK and ETABS software were used to carry out the performance-based seismic design under the action of frequent earthquakes and fortification earthquakes. Next, Perform3D software was used to analyze dynamic elastic-plastic time-history analysis under the action of rare earthquakes. In addition, the analysis of transfer component performance were conducted for quantitative control of the bearing capacity and deformation of reinforced concrete structures and structural members. The calculation results show that relevant parameters can meet code requirements and the seismic performance of the whole structure and components can reach the expected performance objectives. Finally, we present a summary of the proposed seismic strengthening measures and make suggestions for the whole structures, by which the structure can meet the seismic fortification code requirements and be safe and reliable.

Sensitivity analysis of the influence of ground motion intensity levels on the seismic behavior of steel frames in assessment of the target displacement considering near-fault effects

Nonlinear time-history analysis conducted as part of a performance-based seismic design approach often require that the ground motion records are selected and then scaled to a specified level of seismic intensity. In such analyses, besides an adequate structural model, a set of acceleration time-series is needed as the most realistic representation of the seismic action. In this paper, the effects of scaling procedure on seismic demands of steel frames are investigated. To this, two special steel moment-resisting frames with considerable higher mode effects, and two sets of ground motions, including near-fault and far-fault motions are considered. Moreover, three scaling procedures are introduced for performing nonlinear dynamic time-history analysis of structures. Among different demands, lateral roof displacement and interstory drift are selected as seismic demands. The height-wise distribution of demands shows that the inelastic seismic demands of the near-fault pulse-like ground motions differ considerably from those of far-fault ones. These results show that the story drifts are mostly larger for far-fault motions in the upper story levels in comparison to near-fault records and in the lower floors, the reverse is true. Thus, the scaling procedures directly affect the results of seismic demands and choosing different methods would result in varying responses. Moreover, a low-cost and fairly effective procedure is proposed to estimate the target displacement demands of buildings from response-spectrum analyses, considering near-fault effects. The precision of this method is verified by nonlinear time-history analysis results, as the benchmark solution, and acceptable improvements have been achieved.

On the structural energy distribution and cumulative damage in soil-embedded foundation-structure interaction systems

Repeated cyclic loading is well-known to have detrimental effects on inelastic response of structures. Distribution of structural energy and quantification of cumulative damage effects are very important components in performance-based seismic design approach. On the other hand, soil-foundation-structure interaction effects significantly influence inelastic response of structures through the soil contribution to modification of dynamic characteristics of the structure. Hence, this study focuses on structural energy distribution and cumulative damage effects in structures with embedded foundations considering collective effects of kinematic and inertial interactions. To achieve this goal, a soil-foundation-structure interaction system well suited for parametric study was considered: the soil surrounding the rigid foundation was modelled as a half-space, the embedded foundation was modelled using a stack of discrete disks and applying double cone model concept, and the structure was considered as a single-degree-of-freedom structure. The soil-foundation-structure interaction systems were defined according to key interaction dimensionless parameters and were then analysed subjected to 40 non-pulse far-fault ground motions. It is found that SFSI effects significantly alter total energy, viscous damping energy, and hysteretic damping energy of the structure. The results also show that considering only inertial interaction increases cumulative damage index of the structure while inclusion of kinematic interaction has a decreasing effect. Furthermore, practice-oriented correction factors to cumulative damage index of fixed-base structures are proposed to return cumulative damage index of soil-foundation-structure systems. This study can find use in damage evaluation of existing structures with embedded foundation on soft soils.

Performance-Based Seismic Design of High-Rise Buildings: Incorporating Nonlinear Soil-Structure Interaction Effects

This project aims to understand better how to incorporate nonlinear soil-structure interaction (SSI) effects into high-rise building performance-based seismic design approaches. The primary goals are to determine how important it is to include nonlinear SSI effects, create integration methods for them, and analyze how they affect seismic resilience. In terms of methodology, the study uses case studies and an analysis of current literature to show real-world applicability. Important discoveries highlight how critical nonlinear SSI analysis is for precisely forecasting structural reactions, locating weaknesses, and creating focused mitigation strategies. The policy implications emphasize the necessity of modern building regulations, research and development expenditures, and advancements in site characterization methods to facilitate the implementation of performance-based design methodologies. To improve the resilience and safety of high-rise buildings in earthquake-prone areas, this study's findings highlight the significance of considering nonlinear SSI effects during seismic design procedures.

Evaluating the consistency between prescriptive and performance-based seismic design approaches for reinforced concrete moment frame buildings

The performance of 4- and 8-story reinforced concrete (RC) moment frame buildings designed in accordance with ASCE/SEI 7–10 is assessed using ASCE/SEI 41. Practicing engineers are increasingly using ASCE/SEI 41 as the standard to implement performance-based seismic design and to demonstrate the adequacy of the seismic performance of new buildings. However, ASCE/SEI 41 was originally developed to assess the structural performance of existing buildings. On the other hand, ASCE 7 is a prescriptive standard that has been used for the design of new buildings for several decades. The correlation between the target performance of the ASCE/SEI 41- and ASCE 7-code compliant buildings is unknown for RC moment frames. In order to compare the anticipated structural performance between ASCE/SEI 7 and ASCE/SEI 41, the seismic performance of 4- and 8-story ASCE/SEI 7 code-compliant special reinforced concrete moment frame buildings is assessed based on the four evaluation methodologies defined in the Tier 3 analysis of ASCE/SEI 41 for the collapse prevention and life safety performance levels. The evaluation results show that depending on the ASCE/SEI 41 evaluation approach employed, the buildings designed per ASCE/SEI 7 may not meet the expected performance in ASCE/SEI 41 and need to be retrofitted.

Seismic Response Reduction in Liquid Storage Tanks by Simple Smart Base Isolation Systems

In this paper, a nonlinear autonomous algorithm is proposed to control the variable dampers and to provide semi-active control of a liquid storage tank by taking advantage of similarity to friction models and avoiding demerits. Friction mechanism in sliding bearings shows rigid-perfectly plastic behavior with limited damping force. However, transition of vibrations of high frequencies and appearance of residual displacements after the excitation are the drawbacks of such systems. Considering a performance-based seismic design approach, the proposed damping mechanism is capable of controlling the system in a two-level seismic design criterion. The performance and applicability of both the proposed algorithm and a variable oil damper under this command were experimentally verified in previous research. The effect of passive and semi-active seismic control of a liquid storage tank on the response of the structure and sloshing liquid is analytically investigated. Three base isolation systems with passive viscous or sliding dampers are applied and compared with three hybrid semi-active base isolation systems. Pseudo-negative stiffness, skyhook and a proposed control strategy by author are utilized as the control systems. A lumped mass–spring model is employed to represent the dynamic behavior of the tank and the contained liquid. The structural response and sloshing are calculated and compared. It is shown that the smart base isolation system is effective in reduction in the base shear and displacement of the structure. The sloshing response observed through the displacement and kinetic energy of the convective mass is reduced by the hybrid control systems.

Scoring models for reinforced masonry shear wall maximum displacement prediction under seismic loads

In the past decade, there has been an increased shift towards performance-based seismic design (PBSD) approaches to meet the requirements for the next generation of seismic codes worldwide. Displacement-based seismic design (DBSD) is key for implementing PBSD approaches as structural performance is typically linked to damage which in turn is associated with component displacements and deformations. Available reinforced masonry shear wall (RMSW) displacement prediction models in the literature are found to be unreliable when compared with published experimental results. This study outlines the use of a statistical multivariate analysis technique and applying it to develop a reliable model for the maximum displacement capacity prediction of RMSW systems. This approach is subsequently used to build scoring models based on an experimental database of 81 flexurally dominated RMSW tested under simulated seismic loads. The models are further utilized to investigate the influence of altering the wall design characteristics on their maximum displacement capacities. The developed models are considered a major step to facilitate DBSD codification of RMSW systems for the next generation of PBSD codes.

Life-cycle cost optimization of steel moment-frame structures: performance-based seismic design approach

In recent years, along with the advances made in performance-based design optimization, the need for fast calculation of response parameters in dynamic analysis procedures has become an important issue. The main problem in this field is the extremely high computational demand of time-history analyses which may convert the solution algorithm to illogical ones. Two simplifying strategies have shown to be very effective in tackling this problem; first, simplified nonlinear modeling investigating minimum level of structural modeling sophistication, second, wavelet analysis of earthquake records decreasing the number of acceleration points involved in time-history loading. In this paper, we try to develop an efficient framework, using both strategies, to solve the performance-based multi-objective optimal design problem considering the initial cost and the seismic damage cost of steel moment-frame structures. The non-dominated sorting genetic algorithm (NSGA-II) is employed as the optimization algorithm to search the Pareto optimal solutions. The constraints of the optimization problem are considered in accordance with Federal Emergency Management Agency (FEMA) recommended design specifications. The results from numerical application of the proposed framework demonstrate the capabilities of the framework in solving the present multi- objective optimization problem.

A Framework for Performance-Based Seismic Design Approach for Developing Countries, A Case study of Syria

A Framework for Performance-Based Seismic Design Approach for Developing Countries, A Case study of Syria

Performance-based seismic analysis and design of code-exceeding tall buildings in Mainland China

Design codes provide the minimum requirements for the design of code-compliant structures to ensure the safety of the life and property. As for code-exceeding buildings, the requirements for design are not sufficient and the approval of such structures is vague. In mainland China in recent years, a large number of code-exceeding tall buildings, whether their heights exceed the limit for the respective structure type or the extent of irregularity is violated, have been constructed. Performance-based seismic design (PBSD) approach has been highly recommended and become necessary to demonstrate the performance of code-exceeding tall buildings at least equivalent to code intent of safety. This paper proposes the general methodologies of performance-based seismic analysis and design of code-exceeding tall buildings in Mainland China. The PBSD approach proposed here includes selection of performance objectives, determination of design philosophy, establishment of design criteria for structural components and systems consistent with the desirable and transparent performance objectives, and seismic performance analysis and evaluation through extensive numerical analysis or further experimental study if necessary. The seismic analysis and design of 101-story Shanghai World Financial Center Tower is introduced as a typical engineering example where the PBSD approach is followed. The example demonstrates that the PBSD approach is an appropriate way to control efficiently the seismic damage on the structure and ensure the predictable and safe performance.

Fragility Curves for Architectural Glass in Stick-Built Glazing Systems

Fragility functions are presented for 15 glazing system configurations in support of Applied Technology Council efforts to develop a performance-based seismic design approach for building performance assessment. The study includes seismic evaluation of curtain wall and storefront systems in terms of probability and the consequences of damage, including economic and life safety consequences. Defined damage states consist of gasket degradation, initial glass cracking and crushing, and glass fallout. Alternatives are offered to the provided prototype fragilities for configurations with differing glazing characteristics, which account for varying glass-to-frame clearance, aspect ratio, and glass panel dimensions. Issues related to applying laboratory-based fragility data to actual glazing systems in the field are addressed.

Performance-Based Seismic Design Approach for High Speed Railway Bridge

Performance objectives and contents of resistance verification for high speed railway bridge are embodied and quantified based on the theory of performance-based seismic design. The resistance verification is proposed, which can control the damage under design earthquake and ensure safety of the pier under low-level earthquake. The simplified capacity spectra method for calculating displacement ductility factor is proposed by using strength reduction factor. The method for evaluating damage of RC bridge pier in high-level earthquake is presented by using maximum displacement and hysteretic energy. The proposed approach and procedures for performance-based seismic design are easily to implement. The performance-based seismic design procedure is demonstrated by using an example.