Research Interest

I. Real-Time Aeroelastic Hybrid Simulation (RTAHS)

In a conventional section-model wind tunnel test the dynamic properties of the target bridge are fixed by the physical spring suspension, so changing the mass, frequency or damping means rebuilding the rig. Real-time aeroelastic hybrid simulation (RTAHS) removes that limit. The deck section model in the wind tunnel is kept as the physical substructure, the structural system is solved numerically, and the two are coupled within a single time step: load cells measure the instantaneous wind force, the equation of motion is integrated with a central-difference scheme, and linear motors impose the computed displacement back on the model. Mass, damping, frequency — and even mode-shape effects — become software parameters, so one physical model can represent many bridges and many design conditions, and states that a passive suspension cannot reach (very low or negative damping, an arbitrary mode shape, a deck carrying a damper) become experimentally accessible. Just as importantly, because the model is driven by motors rather than springs, the load cells measure the wind force itself while the deck is moving. I developed the first version of this system during my Ph.D. and I am continuing to extend it at PKNU.

• Development of the RTAHS system

SNU – University of Toronto collaboration, ‘Hybrid simulation of a suspended bridge deck subjected to wind load.’ Four linear motors drive the deck section model while load cells measure the wind force directly; actuator-delay compensation and the stability of the real-time loop were the core problems. 

Visiting student with Prof. Oh-sung Kwon, University of Toronto, Jan 2018 – Feb 2019. 

Frontiers in Built Environment 6, 560672 (2020) - base-pivoting building models. 

Journal of Structural Engineering 149(5), 04023024 (2023) — formulation and experimental verification of the real-time loop.

Journal of Structural Engineering 150(10), 04024149 (2024) — deck flexibility and mode-shape effects reproduced numerically.

Development of a Novel Real-Time Aeroelastic Hybrid Simulation Wind Tunnel Testing Technology. Sejong Science Fellowship, National Research Foundation of Korea (RS-2025-00520228), Mar 2025 – Feb 2030.

• Exploring wind engineering knowledge using RTAHS devices

Vortex-induced force measured directly during lock-in. - Shim, Hwang, Kwon, Cho and Kim (under review), Journal of Wind Engineering and Industrial Aerodynamics.)

II. Wind-Resistant Design of Real Bridges

Wind-resistance verification is most useful while a bridge is still on the drawing board, when the deck shape, the guardrail and the erection sequence can all still be changed. Since 2011 I have taken part in the design stage of cable-supported bridges and pedestrian suspension bridges, running section-model tests — free vibration, forced vibration, wind pressure and PIV — not only to check the code criteria but to explain why a given section behaves as it does and to propose the smallest shape modification that fixes it. Recent work concentrates on lightweight, very flexible pedestrian suspension bridges, where the conventional reduced-scale test procedure itself turns out to need re-examination.

• Yeong Gwang cable-stayed bridge (POSCO / DM Engineering, 2011–2012). Two-dimensional section model tests for construction-stage wind stability and extraction of the aero-static and dynamic coefficients.

• Jido–Imja cable-stayed bridge (POSCO, 2013–2014). The deck shape was modified with an extended lower plate and a flap; free-vibration tests and PIV were used to explain why the modification worked.

• Sheik Jaber Al-Ahmad Al-Sabah Causeway, Kuwait (Hyundai E&C, 2013–2014). Section model and free-standing pylon wind tunnel tests for wind-resistant design.

• Twin-deck aerodynamics (COWI A/S, 2015–2016). Aeroelastic and wind-pressure model tests on the wind distribution and aero-elastic parameters as a function of the gap distance.

• Taeha–Hwangtogumi pedestrian bridge (2017). Section model tests to extract the aero-static and dynamic coefficients.

• Pedestrian suspension bridges, 2019–2023. Ganhyeon Tourist Site, Daewangam Suspension Bridge and Hantan River Suspension Bridge — section model tests and flutter instability assessment in the frequency and time domains. → Coupled flutter of a flexible pedestrian footbridge, Wind and Structures 40(2), 93–105 (2025).

• Daecheoncheon Nuri-gil pedestrian suspension bridge (2026). Wind tunnel testing and analysis for the Daecheoncheon Nuri-gil footbridge.

III. Solving Vibration Problems Observed in the Field

Structures vibrate for reasons that rarely appear in the design report: a temporary screen added during repaving, a cable whose damping turned out lower than assumed, a walkway that feels alive under a crowd. In these cases the question is not whether the code is satisfied but what exactly drives the motion, and what the smallest effective intervention is. My approach combines field measurement, wind tunnel or shaking table testing of the actual configuration, and numerical reproduction of the observed response, so that a countermeasure can be justified rather than guessed.

• Yi Sun-sin Bridge (이순신대교), vortex-induced vibration, 2015. Temporary screens installed over the guardrails to shield the curing surface during the replacement of the epoxy-coated pavement excited the mode with the lowest damping. A series of wind tunnel tests and field records identified the mechanism. → 2 SCI(E) papers and 4 international conference papers, including High-mode vortex-induced vibration of a long-span suspension bridge, Structure and Infrastructure Engineering (2020).

• Cheonsa Bridge (천사대교), stay-cable vibration, 2023–2024. Investigation of large-amplitude, low-frequency cable vibration and of the effectiveness of the countermeasures. → Engineering Structures 322, 119082 (2025).

• Interlocking-brick masonry walls, shaking table tests (KICT, 2026). Full-scale wall specimens tested at the KCL seismic facility (18–19 Aug 2026) with vision-based displacement measurement, to quantify how far interlocking bricks improve overturning stability over conventional masonry.

• Member, IABSE WG10 Super-Long Span Bridge Aerodynamics (2016–2017) and IAWE TG1 (2025–).