김호경 교수

A significant vortex-induced vibration (VIV) was observed in a suspension bridge under a wind velocity of approximately 6 and 7 m/s, and with a maximum amplitude that exceeded the serviceability limitations. Since the observation of VIV in an operating bridge was an infrequent event, this study investigated the cause of unexpected VIV. A series of wind tunnel tests revealed the main cause of the VIV was temporary screens applied over the guardrails to shield the curing surface during replacement

This study reports on the assessment of the vibrational serviceability performance of a parallel cable-stayed bridge, which was subjected to a vortex-induced vibration (VIV) in 2011, by identifying modal damping ratios from the operational monitoring data that were obtained. The natural excitation technique (NExT) combined with the eigen realization algorithm (ERA) was applied for the output-only modal analysis. Parameters regarding the NExT and ERA procedures were determined from a sensitivity

A new procedure to assess the crosswind hazard of operating a vehicle over a bridge deck has been developed using a probabilistic approach that utilizes long-term wind data at bridge sites as well as the aerodynamic properties of bridge decks and vehicles. The proposed procedure for safety assessment considers the probabilities of two accident types: sideslip and overturning. The vulnerability of vehicles to crosswinds is represented by the number of days for traffic control that would be requir

In this study, wind-tunnel testing was used to evaluate how side-winds interact with the geometric characteristics of the truss girders of a double-deck bridge and how this impacts vehicle stability. The aerodynamic coefficients of three vehicle types—sedans, trucks, and tractor-trailers—were obtained using force-balance sensors placed on each traffic lane and deck. The two girder shapes of the main and approach spans were tested for an in-depth assessment of the effects of the structural and no

A geometrically nonlinear buffeting analysis of a cable-stayed bridge in the time domain is described. The bridge structure is modeled with three-dimensional thin-walled beam elements and three-dimensional elastic catenary cable elements. Spatially correlated wind velocity fluctuations are modeled and simulated using an algorithm for generating sample functions of a stationary, multivariate stochastic process according to its prescribed cross-spectral density matrix. Aerodynamic damping and aero