Wind Design and Behavior of Skybridge-Linked Twin Buildings = 스카이브릿지로 연결된 두 고층건물의 풍응답 및 내풍설계에 관한 연구

국문 초록 (Abstract)

본 연구에서는 스카이브릿지로 연결된 두 고층건물의 공기역학적 및 동적 응답을 평가하기 위한 실험적·수치해석적·확률론적 분석 프레임워크를 개발하였다. 본 연구의 목적은 스카이브릿지를 통한 구조적 결합이 국부적 및 전역적 풍응답 특성을 어떻게 변화시키는지를 규명함으로써, 실제 대기 경계층 조건에서의 풍응답 메커니즘 및 내풍설계에 대한 이해를 심화하는 데 있다.
연구는 세 가지 주요 단계로 구성된다. 첫 번째 단계에서는 먼저 새롭게 개발된 모듈형 풍동실험 모형을 활용하여 실험을 수행하였다. 고주파 밸런스법(HFFB)과 고주파 압력적분법(HFPI)을 병행하여 다양한 스카이브릿지 설치 높이 조건 하에서의 전역적·국소적 풍력 및 풍압을 계측하였다. 그 결과, 스카이브릿지에 의한 구조적 결합은 건물 및 스카이브릿지 주변의 유동에 간섭을 유발하여, 건물의 풍직각방향 및 비틀림 응답을 유의미하게 완화하는 것으로 나타났다. 그러나 스카이브릿지 자체에 있어서는 설치 위치가 높아질수록 양력 및 비틀림 응답이 증폭되는 경향이 발생하여, 스카이브릿지의 국부적 파단을 방지하기 위한 연결부 구조설계의 중요성을 시사한다. 스펙트럼 및 상관 분석을 통해 교량부에서의 2차 공진 피크 및 반위상 운동이 확인되어, 구조 간 동적 결합 메커니즘에 대한 새로운 통찰을 제공하였다.
두 번째 단계에서는 연구 범위를 수치해석 영역으로 확장하여, 대와류 모사법(LES)에 적용 가능한 난류 생성기법을 개발하였다. 제안된 기법(SIRFG)은 대기 경계층 난류 특성에 해당하는 왜도와 첨도의 높이방향 프로파일 및 시공간 코히어런스를 통계적 기법을 통해 재현하였다. 풍동실험 결과와의 비교 검증 결과, SIRFG 기반 LES 해석은 단일 건물 및 스카이브릿지로 연결된 건물 구성 모두에서 풍응답이 풍동실험과 유사한 수준으로 재현되어, 물리적으로 일관되고 수치해석으로 신뢰성 있는 난류생성 기법으로서의 타당성을 입증하였다.
세 번째 단계에서는 성능기반 내풍설계와 증분동적해석을 결합한 비선형·확률론적 평가를 수행하였다. 유한요소 모델을 이용한 매개변수 연구 결과, 강체형 스카이브릿지 연결은 전역적 풍응답 저감 효과가 우수하나 연결부에 하중 집중이 발생하였고, 납고무받침(LRB) 연결은 하중 분산이 양호하나 응답 억제 효율이 다소 낮은 것으로 나타났다. 증분동적해석 및 취약도 해석 결과, 스카이브릿지를 통한 두 건물의 구조적 결합은 일반적으로 건물의 풍직각 방향 붕괴 확률을 감소시키지만, 스카이브릿지 및 연결부의 국부적 취약도가 시스템 수준을 초과할 가능성이 존재함이 확인되었다. 이를 통해 스카이브릿지 및 연결부의 보수적 용량 설계가 필요함을 확인하였다.

다국어 초록 (Multilingual Abstract)

This study developed an integrated experimental, numerical, and probabilistic framework for evaluating the aerodynamic and dynamic response of twin high-rise buildings connected by a skybridge. The study aims to identify how structural coupling through a skybridge modifies both local and global wind-induced responses, thereby advancing the understanding of coupled tall-building systems under realistic atmospheric boundary-layer wind conditions.
The research is organized into three major phases. The first phase involved a comprehensive wind tunnel investigation using newly developed modular experimental techniques. High-frequency force balance (HFFB) and high-frequency pressure integration (HFPI) methods were employed to measure global forces and local pressure distributions simultaneously across various skybridge installation height configurations. The results revealed that coupling through the skybridge mitigated crosswind and torsional responses of the buildings by altering wake interference. However, the skybridge itself experienced amplified uplift and torsional loads at higher elevations, indicating the need for careful structural design to prevent premature local failure. Spectral and correlation analyses further identified secondary resonance peaks and anti-phase motions at the bridge level, providing valuable insights into the dynamic coupling mechanisms.
The second phase extended the investigation to the numerical domain by developing a statistically improved random flow generation (SIRFG) method for large eddy simulation (LES). The SIRFG framework reproduced height-dependent skewness, kurtosis, and spectral coherence consistent with atmospheric boundary-layer turbulence observed in wind tunnel tests. Validation against experimental data confirmed that the SIRFG-based LES accurately reproduced mean, fluctuating, and spectral characteristics of wind pressures and aerodynamic forces for both isolated and coupled configurations, thereby establishing a physically consistent and computationally reliable approach for aerodynamic prediction.
The final phase focused on nonlinear and probabilistic evaluation through a performance-based wind design (PBWD) framework integrated with incremental dynamic analysis (IDA). Parametric simulations on finite element models demonstrated that rigid skybridge connections provided greater global response reduction but concentrated local demands, while lead rubber bearing (LRB) connections distributed forces more uniformly with slightly lower suppression efficiency. Fragility analyses revealed that coupling generally reduced collapse probabilities in the crosswind direction. However, local fragilities of skybridge or connector could exceed system-level values, emphasizing the importance of conservative capacity design for both skybridge and connector elements.

목차 (Table of Contents)

• Abstract 5
• Contents 7
• List of Tables 11
• List of Figures 13
• List of Symbols 21
• Chapter 1. Introduction 25
• 1.1 Background and Motivation 25
• 1.2 Research Objectives and Scopes 31
• 1.3 Outline of Dissertation 33
• Chapter 2. Review on Coupled Building Control and Turbulent Inflow Generation 35
• 2.1 Literature Review on Coupled Building Control Systems 36
• 2.1.1 Control of coupled buildings for seismic excitation 36
• 2.1.2 Control of coupled buildings for wind excitation 45
• 2.2 Literature Review on Turbulent Inflow Generation 51
• 2.2.1 Overview of synthetic inflow generation techniques 51
• 2.2.2 Theoretical background of random flow generation 53
• 2.3 Summary 56
• Chapter 3. Aerodynamic Response of Skybridge-Linked Twin Buildings 57
• 3.1 Overview and Objective 58
• 3.1.1 Limitations in previous experimental approaches 58
• 3.1.2 Motivation for experimental investigation 60
• 3.1.3 Development of novel experimental models 62
• 3.1.4 Research significance 64
• 3.2 Experimental Setup and Model Description 65
• 3.2.1 Description of experimental techniques 65
• 3.2.2 Configuration of the proposed experimental models 67
• 3.2.3 Wind tunnel facility and flow conditions 72
• 3.2.4 Validation of the proposed experimental models 77
• 3.3 Experimental Results of HFFB Tests 83
• 3.3.1 Overview of analysis scope and metrics 83
• 3.3.2 Base moment coefficients of building model 83
• 3.3.3 Force and moment coefficients of skybridge model 89
• 3.3.4 Intra-structural aerodynamic correlations 98
• 3.3.5 Inter-structural aerodynamic correlations 104
• 3.3.6 Frequency domain relative motion analysis 106
• 3.3.7 Summary of HFFB test findings 113
• 3.4 Experimental Results of HFPI Tests 116
• 3.4.1 Overview of analysis scope and metrics 116
• 3.4.2 Base moment coefficients of building model 117
• 3.4.3 Force and moment coefficients of skybridge model 123
• 3.4.4 Spectral analysis of the building and skybridge models 129
• 3.4.5 Surface pressure distribution on models 137
• 3.4.6 Correlation analysis of aerodynamic responses 150
• 3.4.7 Summary of HFPI test findings 155
• Chapter 4. Numerical Reproduction of Aerodynamic Responses 159
• 4.1 Overview and Objective 160
• 4.2 Research Significance 161
• 4.3 Statistically Improved Random Flow Generation Method 162
• 4.4 Validation of Proposed Random Flow Generation Method 171
• 4.4.1 Derivation of statistical moments 171
• 4.4.2 Comparative analysis of wind fields 174
• 4.4.3 Mesh independence study and analysis settings 181
• 4.4.4 Comparison of aerodynamic response 187
• 4.4.5 Comparison of dynamic response 194
• 4.5 Application to Skybridge-Linked Twin Buildings 201
• 4.5.1 Comparison of aerodynamic response 201
• 4.6 Summary 208
• Chapter 5. Dynamic Response of Skybridge-Linked Twin Buildings 211
• 5.1 Overview and Objective 212
• 5.2 Research Significance 213
• 5.3 Structural Modeling and Wind Load Construction 215
• 5.3.1 Structural configuration of coupled twin buildings 215
• 5.3.2 Characteristics of time-history wind loads 224
• 5.3.3 Numerical analysis and computational settings 226
• 5.4 Dynamic Response and Performance Evaluation 230
• 5.4.1 System-level performance of baseline twin buildings 230
• 5.4.2 System-level performance of coupled twin buildings 234
• 5.4.3 Component-level performance of coupled twin buildings 249
• 5.4.4 Summary of FEM analysis under PBWD framework 255
• 5.5 Incremental Dynamic Response and Fragility Evaluation of Skybridge-Linked Twin Buildings 258
• 5.5.1 System-level IDA results of baseline twin buildings 259
• 5.5.2 System-level IDA results of coupled twin buildings 263
• 5.5.3 Component-level IDA results of coupled twin buildings 267
• 5.5.4 Fragility analysis of coupled twin buildings 273
• 5.5.5 Limit state for system and component level capacity 274
• 5.5.6 System-level fragility analysis 281
• 5.5.7 Comparative system and component level fragility 283
• 5.5.8 Summary of IDA and fragility analysis 287
• Chapter 6. Conclusions and Recommendations 289
• 6.1 Conclusions 289
• 6.2 Overall Contributions 293
• 6.3 Recommendations and Future Works 293
• 6.3.1 Recommendations 294
• 6.3.2 Future works 295
• References 299
• 국 문 초 록 311
• Acknowledgement 313