Hee-Ju Kim

A Speed Increasing Test of BIMODALTRAM for Dynamic Response Analysis of Pipe-truss Bridges

A bimodal tram is a new design vehicle introduced to improve a current transportation system, and it has advantages of a bus and a subway. A pipe truss bridge, an exclusive road of the bimodal tram, is constructed for introduction of the bimodal tram. An analysis of dynamic response characteristics is required because this new bridge has never constructed before. A speed increasing test on the pipe truss bridge was conducted with attaching a sensor to bottom of the bridge. Also, Dynamic response characteristics were analyzed by measuring displacements, the maximum vertical and horizontal acceleration about the new bridge through the experiment.

Development of a numerical model for vehicle-bridge interaction analysis of railway bridges

In the field of civil engineering, analyzing dynamic response was main concern for a long time. These analysis methods can be divided into moving load analysis method and moving mass analysis method, and formulating each an equation of motion has recently been studied after dividing vehicles and bridges. In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations for motion. Also, 3 dimensional accurate numerical models was developed by KTX-vehicle in order to analyze dynamic response characteristics. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 18 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by PSD functions of the Federal Railroad Administration (FRA).

The state of the art on innovative monitoring system in Korea

Damage to infrastructure is a real concern at present, caused primarily by worldwide climate anomalies, global warming, and natural disasters. Korea has begun research to develop a high precision patch/implant system using new IT techniques since 2011 and technologies which must be developed for this research are those which measure and evaluate the soundness and safety of structures based on the measurements of an attached sensor. During the research period since 2011, optical fiber sensor patches and wireless sensor capsule implants along with various sensor technologies, stress sensing and structural condition evaluation algorithm have been developed effectively for network hardware technologies as prototype version. Similarly high precision image processing for automatic crack extraction have been developed along with radiation sensor application technologies, combined management/control technologies for developed systems, and practical technologies for building and large scale structure. Through the results, it is expected that we acquire higher sensor system performance with a measurement scope (for precision, etc.) goal at least 200% better than conventional sensor systems.