Optimizing Seismic Resilience in High-Rise Structures: A Comprehensive Review of Advanced Outrigger System Design

The rapid growth of high-rise buildings has intensified the need for structural systems capable of resisting seismic forces while maintaining safety, serviceability, and economic efficiency. Among the various lateral load-resisting systems, outrigger systems have become one of the most widely adopted solutions because they effectively improve building stiffness, reduce inter-story drift, and enhance overall structural stability. The reviewed study investigates how different outrigger design parameters—including their height, location, stiffness, and dimensions—affect the seismic performance of tall steel buildings through comprehensive numerical simulations using ABAQUS. By systematically comparing multiple design configurations, the research identifies strategies for minimizing seismic responses such as displacement, base shear, and acceleration. The findings provide valuable guidance for structural engineers seeking optimized outrigger designs for earthquake-resistant high-rise buildings while contributing to ongoing developments in performance-based seismic engineering.

Bibliographic Information

Item	Information
Article Title	Optimizing Seismic Resilience in High-Rise Structures Through Comprehensive Evaluation and Enhancement of Outrigger Systems: A Comparative and Multifaceted Study
Authors	Aqdas Shehzad; Wang Xiu-Xin; Muhammad Baqi Billah; Muhammad Sajawal; Ambe Harrison; Pradeep Jangir; Wulfran Fendzi Mbasso; Mohammad Khishe
Journal	Engineering Reports
Volume	7
Issue	12
Publication Year	2025
Article Number	e70439
Pages	e70439
DOI	https://doi.org/10.1002/eng2.70439
Publisher	John Wiley & Sons Ltd.
ISSN	2577-8196
License	Creative Commons Attribution License (CC BY)
Keywords	comparative study; lateral stability; numerical simulations; optimization framework; outrigger systems; seismic activity; seismic design; tall buildings

Research Background

The continued expansion of urban populations and the scarcity of available land have encouraged cities worldwide to construct increasingly taller buildings. While vertical development improves land-use efficiency, it also introduces significant structural challenges because tall buildings are particularly susceptible to lateral forces generated by earthquakes and strong winds. As building height increases, structural flexibility also increases, making effective lateral load-resisting systems an essential requirement for ensuring occupant safety and maintaining structural integrity.

Among modern structural solutions, outrigger systems have emerged as one of the most effective approaches for enhancing the lateral stiffness of high-rise buildings. These systems connect the central structural core to the exterior columns through horizontal trusses or walls, allowing overturning moments to be distributed more efficiently throughout the structural frame. Numerous previous studies have demonstrated the benefits of outrigger systems in reducing building displacement and improving seismic performance. However, existing research has not fully established how different design parameters—including outrigger height, vertical location, stiffness, truss dimensions, and configuration—interact to influence seismic behavior under varying loading conditions.

The authors identify an important research gap in the absence of comprehensive optimization frameworks capable of systematically evaluating multiple outrigger design variables simultaneously. Previous investigations often focused on individual parameters or specific structural configurations without providing comparative analyses that could guide practical engineering decisions. Furthermore, many existing optimization approaches do not adequately consider regional seismic characteristics or evaluate how combinations of design variables influence structural performance.

To address these limitations, the study develops an integrated numerical investigation using finite element simulations to compare multiple outrigger system configurations within a representative forty-story steel building. By examining seismic responses such as inter-story drift, base shear, and acceleration response spectra under controlled variations of critical design parameters, the research aims to establish practical recommendations for improving the seismic resilience of tall buildings while supporting more efficient structural design strategies.

Research Objective

To systematically evaluate the seismic performance of tall steel buildings equipped with different outrigger system configurations using advanced numerical simulations.
To investigate how key design variables—including outrigger height, vertical location, stiffness, structural strength, and truss dimensions—influence seismic response.
To identify optimal outrigger system configurations capable of minimizing inter-story drift, base shear, and acceleration response during earthquake loading.
To compare alternative outrigger design strategies through a comprehensive parametric investigation rather than evaluating individual variables independently.
To provide engineering recommendations that contribute to safer, more economical, and more resilient seismic design of high-rise buildings.
To enrich the existing body of knowledge regarding performance-based optimization of outrigger systems for earthquake-resistant tall structures.

Why This Research Matters

Addresses increasing seismic risks in urban development. As cities continue constructing taller buildings, improving earthquake resistance becomes increasingly important for protecting occupants and reducing structural damage.
Provides a systematic evaluation of multiple design variables. Rather than investigating a single design factor, the study simultaneously evaluates several critical parameters affecting outrigger performance.
Supports evidence-based structural optimization. Engineers can use the findings to select outrigger configurations that improve seismic performance while avoiding unnecessary structural complexity or material use.
Improves structural safety. Reducing lateral displacement, acceleration, and inter-story drift directly contributes to improved building stability during major seismic events.
Promotes cost-effective engineering design. Identifying optimal outrigger configurations enables designers to achieve better structural performance without excessive construction costs.
Contributes to sustainable infrastructure development. More resilient buildings typically experience lower repair requirements, longer service lives, and reduced lifecycle costs following earthquakes.
Advances numerical simulation methodologies. The study demonstrates how finite element modeling using ABAQUS can support comprehensive performance evaluation of complex structural systems during seismic loading.

Research Methodology

The study employed a computational structural engineering approach based on finite element analysis to investigate the seismic behavior of high-rise buildings equipped with various outrigger system configurations. Numerical simulations were conducted using ABAQUS, allowing the researchers to systematically evaluate how modifications to key design parameters influence seismic performance. Rather than comparing existing buildings, the research adopted a controlled parametric investigation in which one design variable was modified while maintaining other structural characteristics constant. This methodology enabled a direct comparison of the influence of each parameter on structural response.

Research Design

The research followed a comparative numerical simulation framework. A forty-story steel building served as the reference structural model, and multiple simulation scenarios were developed by modifying the characteristics of the outrigger system. Each numerical model was subjected to identical earthquake loading conditions to ensure that observed differences in structural behavior resulted solely from changes in the outrigger design parameters.

Structural Model

A three-dimensional steel building consisting of forty stories with an overall height of 160 meters was selected as the representative high-rise structure. The building was modeled using beam elements for columns and shell elements for slabs and walls. The structural core was connected to the exterior columns through outrigger beams that provided additional lateral stiffness during seismic excitation.

The primary structural characteristics included:

40 stories
Total structural height of 160 meters
Story height of 4 meters
Floor plan dimensions of 25 m × 25 m
Steel moment-resisting frame with reinforced concrete core
Beam-column finite element representation
Shell element modeling for slabs and structural walls

Material Properties

Material properties were assigned according to commonly accepted structural engineering values for steel and reinforced concrete. These parameters allowed the numerical model to realistically simulate the stiffness and strength characteristics of modern tall buildings.

Material	Property	Value
Steel	Modulus of Elasticity	200 GPa
Steel	Density	7850 kg/m³
Steel	Yield Strength	350 MPa
Concrete	Modulus of Elasticity	25 GPa
Concrete	Density	2400 kg/m³
Concrete	Compressive Strength	30 MPa
Structural Damping	Critical Damping Ratio	5%

Design Parameters Investigated

The study evaluated several engineering variables that directly influence the seismic behavior of outrigger systems. Each parameter was varied independently across multiple simulation scenarios in order to determine its contribution to lateral stability and earthquake resistance.

Vertical position of the outrigger system
Height of the outrigger installation
Stiffness of outrigger members
Strength of structural components
Dimensions of outrigger trusses
Number of outrigger systems
Structural configuration of the outrigger system

Ground Motion Selection

Earthquake loading records were obtained from the Pacific Earthquake Engineering Research (PEER) Ground Motion Database. Only records satisfying predefined engineering criteria were selected to ensure consistency throughout the comparative simulations.

Earthquake magnitude between 6.5 and 7.5
Epicentral distance ranging from 10 to 30 kilometers
Firm soil site conditions
Ground motions scaled to design basis earthquake levels
Bidirectional seismic loading applied along the principal structural axes

Analysis Procedures

Several complementary structural analyses were performed to evaluate the seismic response of the building under different outrigger configurations.

Modal Analysis to determine natural vibration characteristics and mode shapes.
Nonlinear Time History Analysis to simulate structural response during earthquake excitation.
Sensitivity Analysis to evaluate the influence of individual design variables.
Comparative Parametric Analysis to identify optimal outrigger configurations.

Performance Indicators

The seismic effectiveness of each numerical model was evaluated using several structural response indicators commonly employed in earthquake engineering.

Inter-story drift
Lateral displacement
Base shear
Acceleration Response Spectra (ARS)
Overall structural stiffness
Dynamic response characteristics

Model Validation

To improve confidence in the simulation results, the numerical models were validated by comparing the predicted seismic responses with experimental findings and previously published investigations involving high-rise buildings equipped with outrigger systems. Following validation, the numerical models were used to conduct extensive parametric analyses across the various design scenarios.

Key Findings

1. Outrigger Systems Significantly Improve Seismic Performance

The numerical simulations consistently demonstrated that incorporating outrigger systems substantially improves the seismic performance of tall buildings. Compared with conventional structural systems lacking outriggers, buildings equipped with optimized outriggers experienced lower lateral displacement, reduced inter-story drift, and improved overall structural stability during earthquake loading.

The results confirm that effective interaction between the structural core and perimeter columns enables lateral forces to be distributed more efficiently, thereby reducing deformation throughout the height of the building.

2. Outrigger Location Strongly Influences Structural Response

One of the most influential variables investigated in the study was the vertical location of the outrigger system. Different installation heights produced noticeably different seismic responses. Proper positioning of the outrigger significantly reduced lateral displacement and improved load transfer between the core and perimeter columns.

The simulations indicate that selecting an inappropriate outrigger elevation can reduce structural efficiency even when other design parameters remain unchanged, emphasizing the importance of optimizing vertical placement during structural design.

3. Structural Stiffness Plays a Critical Role

Increasing the stiffness of outrigger members consistently enhanced seismic resistance by reducing structural flexibility. Stiffer outrigger systems produced lower inter-story drift and smaller building displacements during earthquake excitation.

However, the research also demonstrates that stiffness optimization should be balanced with practical design considerations because excessive stiffness may increase construction requirements without proportional improvements in structural performance.

4. Truss Dimensions Affect Earthquake Resistance

The dimensions of the outrigger trusses significantly influenced the effectiveness of lateral load transfer. Larger and properly proportioned trusses generally improved seismic performance by increasing overall structural rigidity and distributing seismic forces more efficiently throughout the structural frame.

The comparative simulations allowed the researchers to identify truss dimensions that provided improved structural performance while avoiding unnecessary increases in structural weight and material consumption.

5. Multiple Design Variables Interact Simultaneously

Rather than acting independently, the investigated design variables exhibited strong interactions during seismic loading. Improvements achieved by modifying one parameter often depended on the values assigned to other structural characteristics. Consequently, optimal seismic performance cannot be achieved by optimizing only a single design variable.

This finding supports the need for integrated optimization strategies that simultaneously consider outrigger location, stiffness, geometry, and structural configuration.

6. Numerical Simulation Supports Structural Optimization

The ABAQUS finite element simulations successfully captured the dynamic behavior of the forty-story building under various earthquake scenarios. The numerical framework proved capable of comparing alternative structural configurations while providing detailed information regarding displacement, acceleration, and force distribution throughout the structure.

The study demonstrates that advanced finite element modeling represents a practical engineering tool for evaluating and optimizing seismic design before actual construction begins.

Scientific Contribution

The study makes several important contributions to the field of structural and earthquake engineering by presenting a comprehensive evaluation of outrigger system optimization for tall buildings. Unlike many previous investigations that focused on a single structural parameter, this research adopts a multifaceted approach that simultaneously examines the effects of outrigger location, height, stiffness, strength, and truss dimensions on seismic performance. This integrated perspective provides a broader understanding of how multiple design variables collectively influence the dynamic behavior of high-rise structures.

Another significant contribution is the application of advanced finite element simulations to perform systematic parametric analyses under consistent seismic loading conditions. The study demonstrates how computational modeling can be used to identify structural configurations that reduce inter-story drift, lateral displacement, base shear, and acceleration response without relying solely on empirical design recommendations.

The research also contributes practical engineering knowledge by providing comparative evidence regarding the effectiveness of alternative outrigger configurations. These findings support the development of more rational performance-based seismic design strategies and establish a useful reference for future optimization studies involving high-rise structural systems.

Provides a comprehensive comparative evaluation of multiple outrigger design parameters.
Demonstrates the capability of finite element analysis for structural optimization under seismic loading.
Expands current knowledge regarding the interaction between outrigger geometry and seismic response.
Supports performance-based structural design through numerical evidence.
Provides engineering guidance for optimizing lateral load-resisting systems in tall buildings.

Industrial Implications

The findings of this research have direct implications for structural engineering practice, particularly in regions where earthquake-resistant high-rise construction is becoming increasingly important. By identifying design variables that most strongly influence seismic performance, the study provides practical guidance that can improve both structural safety and construction efficiency.

Structural consultants and design engineers may utilize the comparative results during the conceptual design stage to determine suitable outrigger configurations before detailed structural analysis begins. Optimized designs can reduce unnecessary material usage while maintaining or improving seismic resistance, thereby contributing to more economical construction projects.

The numerical methodology demonstrated in this study also illustrates how modern simulation software can support digital structural engineering workflows. Integrating finite element analysis into design optimization enables engineers to evaluate numerous design alternatives rapidly, reducing dependence on conservative assumptions and extensive physical testing.

Structural Design Firms
Can use the findings to optimize outrigger placement and stiffness during conceptual building design.
Construction Companies
May reduce construction costs by selecting efficient structural configurations that achieve desired seismic performance without excessive material use.
Software-Based Engineering Practice
Demonstrates the practical value of advanced finite element software such as ABAQUS for performance-based structural evaluation.
High-Rise Building Developers
Can improve occupant safety and long-term structural resilience through optimized lateral load-resisting systems.
Structural Consultants
Gain comparative engineering evidence that supports decision-making during seismic design optimization.
Infrastructure Owners
More resilient buildings are expected to experience reduced earthquake damage, lower maintenance requirements, and longer service lives.

Research Limitations

Although the study provides valuable insights into outrigger system optimization, several limitations should be considered when interpreting the findings. These limitations arise primarily from the controlled numerical modeling approach adopted in the investigation rather than deficiencies in the research itself.

The investigation is based entirely on numerical simulations using a representative forty-story steel building model. Actual building behavior may vary depending on construction quality, material variability, and site-specific conditions.
Only one structural configuration was employed as the reference model. Buildings with substantially different heights, structural systems, geometries, or materials may exhibit different seismic responses.
The study evaluates specific ranges of design parameters rather than every possible outrigger configuration used in engineering practice.
Ground motion records were selected according to predefined criteria, and therefore may not represent the full diversity of earthquake characteristics experienced worldwide.
The investigation primarily focuses on structural response indicators such as displacement, inter-story drift, base shear, and acceleration response spectra. Broader considerations including construction cost, constructability, lifecycle assessment, and maintenance requirements were outside the scope of the research.
Dedicated supplemental energy dissipation devices such as viscous dampers, tuned mass dampers, or base isolation systems were not incorporated into the analyzed structural models.

Future Research Opportunities

The results establish several directions for future investigations aimed at further improving the seismic resilience of high-rise buildings equipped with outrigger systems.

Investigate outrigger optimization for reinforced concrete, composite, and hybrid structural systems.
Evaluate the interaction between outrigger systems and supplemental energy dissipation devices such as viscous dampers, friction dampers, tuned mass dampers, or base isolation systems.
Develop automated optimization algorithms that integrate artificial intelligence, machine learning, or evolutionary optimization techniques for outrigger design.
Conduct probabilistic seismic performance assessments considering multiple earthquake scenarios and regional seismic uncertainties.
Study lifecycle cost optimization by integrating construction cost, maintenance requirements, repair costs, and structural resilience into the design process.
Investigate the seismic behavior of irregular, asymmetric, twisted, and super-tall buildings equipped with optimized outrigger systems.
Perform large-scale experimental validation using laboratory testing to complement numerical simulation results.
Develop performance-based design guidelines that incorporate optimized outrigger configurations into future structural engineering standards.

Potential for Public Policy Citation

The findings have potential relevance for organizations responsible for developing seismic design regulations, urban development policies, and resilient infrastructure strategies. As cities continue to expand vertically, evidence-based recommendations regarding optimized lateral load-resisting systems become increasingly valuable for improving public safety.

Building regulatory agencies may use the study as supporting scientific evidence when updating earthquake-resistant design provisions for tall buildings. Likewise, municipal authorities responsible for urban planning may consider these findings when establishing structural performance requirements for high-rise developments located in seismically active regions.

Although the research does not propose new engineering standards, it provides comparative numerical evidence that may support future revisions of performance-based seismic design guidelines and encourage greater adoption of optimization-based structural engineering practices.

National seismic design code development.
Performance-based building regulations.
Urban resilience and disaster risk reduction policies.
Guidelines for high-rise structural safety.
Infrastructure resilience planning.
Government-supported earthquake mitigation programs.

Who Should Read This Paper?

Structural engineers involved in high-rise building design.
Earthquake engineering researchers.
Civil engineering academics.
Finite element modeling specialists.
Performance-based structural design practitioners.
Graduate students in structural and earthquake engineering.
Engineering consultants working on tall buildings.
Urban infrastructure planners.
Government agencies responsible for seismic regulations.
Professionals interested in resilient infrastructure development.

Final Thoughts

This study presents a comprehensive numerical investigation into one of the most important structural systems used in modern high-rise buildings. Through systematic comparison of multiple outrigger design parameters, the research demonstrates that seismic performance depends not on a single design variable but on the combined interaction of location, stiffness, geometry, and structural configuration. The extensive finite element simulations provide convincing evidence that optimized outrigger systems can substantially reduce lateral displacement, inter-story drift, and other critical seismic responses.

Beyond its technical findings, the research illustrates the growing importance of computational structural optimization in modern engineering practice. Advanced simulation tools enable engineers to evaluate numerous design alternatives efficiently before construction begins, supporting safer, more economical, and more resilient buildings. As urban skylines continue to expand, the insights provided by this study offer valuable guidance for engineers seeking to improve earthquake resistance through scientifically informed structural design.

Suggested Citations

Teknomekanik (UNP) Style

Shehzad A, Wang X-X, Billah MB, Sajawal M, Harrison A, Jangir P, Mbasso WF, Khishe M. Optimizing seismic resilience in high-rise structures through comprehensive evaluation and enhancement of outrigger systems: A comparative and multifaceted study. Engineering Reports. 2025;7(12):e70439. https://doi.org/10.1002/eng2.70439

APA (7th Edition)

Shehzad, A., Wang, X.-X., Billah, M. B., Sajawal, M., Harrison, A., Jangir, P., Mbasso, W. F., & Khishe, M. (2025). Optimizing seismic resilience in high-rise structures through comprehensive evaluation and enhancement of outrigger systems: A comparative and multifaceted study. Engineering Reports, 7(12), e70439. https://doi.org/10.1002/eng2.70439

IEEE Style

A. Shehzad, X.-X. Wang, M. B. Billah, M. Sajawal, A. Harrison, P. Jangir, W. F. Mbasso, and M. Khishe, "Optimizing seismic resilience in high-rise structures through comprehensive evaluation and enhancement of outrigger systems: A comparative and multifaceted study," Engineering Reports, vol. 7, no. 12, Art. no. e70439, 2025, doi:10.1002/eng2.70439.

Harvard Style

Shehzad, A., Wang, X.-X., Billah, M.B., Sajawal, M., Harrison, A., Jangir, P., Mbasso, W.F. & Khishe, M. (2025) 'Optimizing seismic resilience in high-rise structures through comprehensive evaluation and enhancement of outrigger systems: A comparative and multifaceted study', Engineering Reports, 7(12), e70439. Available at: https://doi.org/10.1002/eng2.70439.

Vancouver Style

Shehzad A, Wang XX, Billah MB, Sajawal M, Harrison A, Jangir P, Mbasso WF, Khishe M. Optimizing seismic resilience in high-rise structures through comprehensive evaluation and enhancement of outrigger systems: A comparative and multifaceted study. Engineering Reports. 2025;7(12):e70439. doi:10.1002/eng2.70439.

Chicago (Author–Date)

Shehzad, Aqdas, Wang Xiu-Xin, Muhammad Baqi Billah, Muhammad Sajawal, Ambe Harrison, Pradeep Jangir, Wulfran Fendzi Mbasso, and Mohammad Khishe. 2025. "Optimizing Seismic Resilience in High-Rise Structures Through Comprehensive Evaluation and Enhancement of Outrigger Systems: A Comparative and Multifaceted Study." Engineering Reports 7 (12): e70439. https://doi.org/10.1002/eng2.70439.

MLA (9th Edition)

Shehzad, Aqdas, et al. "Optimizing Seismic Resilience in High-Rise Structures Through Comprehensive Evaluation and Enhancement of Outrigger Systems: A Comparative and Multifaceted Study." Engineering Reports, vol. 7, no. 12, 2025, article e70439. Wiley, https://doi.org/10.1002/eng2.70439.

Editorial Note

This review has been prepared exclusively for the Engineering Research Insights blog based on the peer-reviewed article published in Engineering Reports. The scientific analysis presented in this review is derived solely from the contents of the published research article. Bibliographic metadata have been verified against the official publisher's webpage to ensure consistency with the published record. The review aims to summarize the research objectively while preserving the original scientific context. Readers are encouraged to consult the original publication for complete methodological details, numerical formulations, datasets, figures, and supplementary technical information.

SEO Meta Description

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SEO Keywords

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Conclusion

This review highlights the growing importance of optimized outrigger systems in improving the seismic resilience of modern high-rise buildings. By systematically evaluating multiple design parameters through finite element simulations, the study demonstrates that the effectiveness of an outrigger system depends on the interaction of its location, stiffness, dimensions, and overall structural configuration rather than on any single variable. The research offers valuable engineering insights for developing safer, more efficient, and performance-based structural designs capable of withstanding severe earthquake loading. As computational structural analysis continues to evolve, studies of this nature provide an important scientific foundation for future innovations in resilient tall-building engineering and optimization-driven structural design.

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