Test-bed was constructed in Honam High-speed railway due to evaluate the suitable infrastructure for operation of 400km/h level speed. To evaluate performance of roadbed in test-bed, several sensors installed in the standard roadbed, soft ground, transition zone as bridge and earthwork. In contrast to existing long-term monitoring, system developed was designed and builted on site to log-time operation automatically. Therefore, the measured data collected monitoring system and analysis results can be databased continuously from construction to operation of railway for study design criteria about long-term behavior of roadbed.

Based on the test run of next generation high speed train which is called HEMU-430X, bridge serviceability is investigated through measurements of vertical displacements of a steel composite bridge. In the present paper, a steel composite bridge which has 50m span length are reported. Vertical displacements of the bridge according to the gradually increasing speed are investigated and compared with interaction analysis results.

In this paper, we presents overview of performance qualification and testing method for new OCL (overhead contact line) up to 400 km/h. The track-side and on-board monitoring system are proposed to measure current collection performance. The proposed systems will be capable of measuring abnormal behavior quality of current collection between pantograph and contact wire.

For the water content measurement in thr unapproachable site, moisture content monitering sensor was developed. It was compared with another conventional sensor and verified according to the standard procedures proposed in this study. The proposed standard procedures was also modified using data analysis through laboratory test.

The aim of this study is to experimentally verify the feasibility of the vibration control system to be implemented on 1/10 scale down floating structure with rigid body motion and propose a control algorithm to effectively control the dynamic responses of a floating structure. For this, active mass damper system was constructed and evaluated the function of each component consisting of the mass damper system.

In this study, a noncontact NDT method is implemented to detect the damage of pipeline structures and to identify the location of the damage. To achieve this foal, an Nd:YAG pulsd laser system is used to generate guided waves and a galvanometer-based laser scanner scans a specific area to find damage location. Then, a piezoelectric sensor is installed to measure structural responses. The measured time and spatial responses are transformed to data in frequency and wavenumber domain through 3-dimensional Fourier transform. Finally, damages can be detected by extracting reflected signals due to damage using wavenumber filter which eliminated strong incident waves.

This study presents a practical approach for imaging concrete pavement and bridge deck slabs for the presence of delamination defects. Air-coupled impact resonance (i.e. impact-echo) test data are presented as a fused image using stacked spectral C-scans of the tested deck surface. The low frequency (less than 6 kHz) dynamic vibrational response of delamination defects, principally caused by the behavior of flexural vibration modes, clearly and accurately reveals the presence of internal shallow delamination defects. Images are constructed with data from air-coupled impact resonance tests carried out on laboratory and field concrete deck samples and an in-service concrete bridge deck.

The depth of a surface-breaking crack in a concrete slab is characterized by using non-contact surface wave transmission measurements. Two air-coupled sensors are used to measure surface waves across surface-breaking cracks with varying depths from 0mm to 100mm in a concrete slab (1500X1500X180mm3). Resulting transmission coefficient and crack depth relation from a series of experimental studies shows a good agreement with theoretical results previously obtained by the author.

Displacement is one of the most fundamental responses, containing useful information regarding dynamic behavior of a structure. Traditional displacement measurement devices such as LVDT have disadvantages in their high cost and few options on installation locations. For the sake of economic reason, vision-based displacement measurement systems using low cost cameras have been developed, yet these systems still have difficulties in finding appropriate camera positions; camera should be placed perpendicular to targets. This study presents a new vision-based displacement measurement system using the planar homography method that results in accurate displacement measurement, allowing the camera to face targets with an arbitrary angles. The proposed vision-based system was experimentally validated from a laboratory test.

System identification was performed on the swing span of a steel truss bridge using a wireless sensor network. The swing span can rotate 360° to allow river traffic to pass through the locks located under the bridge. The twenty-two wireless sensor nodes were installed on the span to measure synchronized tri-axial acceleration. Modal properties of the bridge according to its different positions were successfully obtained using frequency domain decomposition method, and compared with the ones from the FE model of the bridge.

The FBG sensor responses simultaneously to changes in thermal strain as well as elastic strain. Thus the total strain measured from a single FBG sensor shall be corrected to obtain the elastic strain by removing the temperature effect. This paper addresses how the temperature effect can be removed when the FBG sensor is encapsulated in a 7-wire steel strand. For this purpose, fundamental properties of the FBG sensor are identified through tests using a controlled temperature chamber. Then field measurements on a UHPC pi girder with the size of 11.0 m long, 5.0 m wide, and 0.6 m high have been conducted for about one year, and the prestressing force is estimated using the raw data from the FBG sensor and by applying temperature correction technique proposed in this study. Estimated results indicate that the proposed correction technique is executable for extracting the elastic strain from monitoring data using the FBG sensor in civil infrastructures.

「Special Act for the Safety Control of Public Structures」is for the periodical inspection and maintenance on the main structures. It is based on the reactive measures for the found faults and the maintenance budget is allotted with a ceiling. Therefore decision makers cannot establish long-term strategies and connot consider the serviceability from a user's point of view. The infrastructure maintenance system has to be renewed considering for the efficiency in the face to the rapid increase of the rate of deteriorated facilities.

This study introduces the role of level of service in the asset management for social infrastructures. An overall process to determine the level of service and performance measures were also described. The developed process was applied for actual road infrastructures, pavements, bridges and tunnels and the results were shown briefly.

Maintenance cost of bridges is calculated by the scenario that represented reactive maintenance and preventive maintenance strategy. Preventive maintenance strategy is more life cycle cost-effective than reactive maintenance strategy because bridge life is extended through preventive maintenance work.

In this study, We estimated a life time of the expansion joint using survival functions on reliability theory. The sample data were extracted in the Highway Bridge Management System(HBMS). It were about six thousands of bridges from 1999 to 2013. the average life of all the expansion was 16~20years, type and figure type were superior in life.

This study presents investigations on infrastructure report cards published regularly in developed countries such as U.S. and Australia. Each of the report cards has its unique evaluation method and characteristics reflecting their current state of infrastructure and political and social situation. The report cards are analyzed in terms of infrastructure evaluating methods, and features included in each report card are compared each other to derive implications to the infrastructure maintenance system of Korea. Also, several recommendations to successfully introduce and develop the report card system to Korea are given in this paper.