Recently, accidents caused by the aging of structures are occurring frequently in the world. As a result, maintenance and accident prevention of structures are required. In this study, for the purpose of addressing these issues to solve these problems, we developed a non - destructive inspection technique using thermal imaging and planned damage detection process. we set up a scenario to detect the invisible excursions, cracks, and internal damage by sensing and analyzing the thermal energy radiated by the stainless steel test piece (STS304) with infrared thermal imaging equipment.

The target in the design of base isolated structures is the selection of isolation system properties so that optimal performance is achieved among seismic levels and performance metrics. To withstand very rare ground motions, isolation system are frequently designed with significant strength or damping, and as a result such devices provide reduced isolation effect for more frequent seismic events. To investigate improvements to the design of isolated structures, a lot of research program is performed. Experimental investigations are presented to characterize smart base isolation capable of progressively exhibiting different hysteretic properties at different stages of response. Shear tests are conducted along the ISO standard, including harmonic characterizations tests. These tests included various input intensities, multi-component excitation. Behavior of the new smart base isolation system is compared with that of linear isolation systems with both nonlinear viscous and bilinear hysteretic energy dissipation mechanisms.

In this study, we propose a structural modeling method to analyze the seismic behavior characteristics of arched stone bridge. For this purpose, we select the representative model of arched stone bridge, and various arch types are set in consideration of the width and height. Accordingly, this study applies the discrete element method for the modelling of discontinuum structure to analyze the seismic behavior characteristics according to the various arched types.

This paper presents the seismic performance of the steel damper under reversed cyclic loading. The U-shaped steel damper used in this study was designed to have energy dissipation zone with an external diameter of 120 mm, a width of 15 mm, and a thickness of 15 mm. The cyclic loading test was carried out using an uniaxial universal testing machine with a capacity of 2,000 kN. The test results indicated that no strength deterioration of the specimen was found as well as the equivalent damping ratio of the specimen was excellent.

In this paper, structural behavior of internal and external connection of modular system was evaluated by finite element analysis(FEA). As a result of FEA, results of experiment and analysis were nearly similar to validate analysis model. Parametric analysis will be necessary using this valid analysis model

The purpose of this study was to experimentally evaluate seismic performance of connection of modular system. As a result of experiment study, two specimens did not show the strength reduction and brittle fracture at connection until 2% story drift. Thus, requirements for intermediate moment frame(IMF) was satisfied in two specimens.

In this study, the explosion resistance on the normal strength concrete and HPFRCC structure members were evaluated. As a result of TNT ignition test, blow out occurred in normal strength concrete structure member, but HPFRCC structure member only cracked slightly. The structure member with 180 MPa HPFRCC has excellent resistance against explosive load. Therefore, HPFRCC is considered to be applicable to national main facilities and major military facilities.

Frequent unstable natural disasters worldwide in recent year caused damage to large power plants, high-rise buildings, dams and public facilities, resulting in a growing sense of anxiety among people. This is result in the increase of concern for the safety of residential as well as public infrastructure. Considering this growing concern for the public infrastructure a systematic safety evaluation is require. Thus, in this paper, the fragility of weir structure by considering the scour effect of flood was the focused of study. The weir structure in this study was located in Daegu city; it served as the power and water supply and flood prevention. The study was performed by conducting penetration analysis on the variables of the adjacent ground.

Blast-resistant doors are installed to protect human life, precious equipments and materials in the plant and other similar industrial facilities, national important SOC, evacuation facilities and military shelter. In this study structural behavior according to the boundary condition is analyzed. For the simulation the FE program LS-DYNA is used. Anaylsis results will be used to design blast-resistant door in detail.

Blast-resistant doors are installed to protect human life, precious equipments and materials in the plant and other similar industrial facilities, national important SOC, evacuation facilities and military shelter. In this study structural type and design consideration for blast-resistant doors are reviewed to design a bullet- and blastproof structures including doors.

In this research, new structural design and manufacturing method of atypical irregular UHPC structural members were newly introduced. The atypical irregular UHPC member was optimized to design from the conventional rectangular section and a method of nonuniform formwork system was newly created to manufacture the irregular member. The specimens were evaluated by analysis and the newly designed member was improved in bending performance by 2.6 times compared to conventional rectangular concrete beams.

The transition piece of the offshore wind power support structure transmits the load of the tower stably to the support structure on the lower side. The transition piece of the offshore wind power support structure should solve the stress concentration problem in design. In this paper, in order to solve the stress concentration problem occurring at the transition piece of the offshore wind power support structure, the location and the mitigation of the stress concentration have been studied.

In the KEPIC-SNG, the domestic technical standard of the SC structure, the condition that the baseplate supporting the reinforcing bars is not bonded to the surface plate is suggested. However, if the baseplate is bonded only to the wingplate, all of the rebar loads generated on the baseplate will be transferred to the wingplate. The wingplate is expected to be conservatively designed in spacing and thickness to support the rebar load. In this study, the finite element analysis was carried out according to bonding conditions between surface plate and baseplate. As a result, it was confirmed that the overall structural strength was increased when the baseplate and the surface plate were bonded. Based on this result, it is possible to propose an economical design for the RC-SC connection such as increasing the wingplate spacing.

Recently, the frequency of natural disasters in Korea is increasing due to the influence of global climate change, and the importance of quick and accurate monitoring and corresponding response is frequently and strongly stressed in terms of disaster management. In this regard, this study describes a development of realtime safety evaluation system (RSEE) which enables to carryout real-time measurement and safety evaluation of some important SOC water infrastructures (dams, weirs, cut slopes, retaining walls, levees and bridges) installed along the nation registered large scale rivers.

The Integrated Water Infrastructures Safety Management Platform(WINS+) provides safety information of water infrastructures such as dams, weirs, bridges, cut slopes, retaining walls and levees designated as the first class infrastructures to be maintained according to the nations’s safety law. The WINS+ is incorporated with a computerized Standard Operating Procedure (SOP) system that provides crisis warning level (green/blue/yellow/orange/red) to central and individual disaster response managers of waterside structures. Thus it is expected that by using the WINS+ we may strengthen disaster responsiveness and reduce the time for recovery and response at emergency.

In the case of the port mooring facility, jetties with piles are mainly applied in soft ground conditions. In the three-dimensional modeling for the structural analysis of jetties with piles, the boundary conditions between the pile and the ground are universally applied to the Approximate depth of pile supported method and Elastic subgrade reaction spring method. In this study, p-y curve data for the pile ground condition was generated using the LPILE program, and then the nonlinear spring considering the p-y curve as the pile and ground boundary condition was input and analyzed in the 3D modeling of jetties with piles using the MIDAS civil And the necessity of applying the Nonlinear subgrade reaction spring method by comparison with the result and the analysis result according to the existing analysis method is suggested.

The extent damages of concrete structures due to fire occurrence are evaluated. The evaluation of fire safety is evaluated by using the inspection, non-destruction test, fracture test(concrete SEM analysis, concrete heat analysis, rebar fracture test. The criteria for determining the safety of concrete structures are presented using evaluation results.

In this study, an experimental study of Impulse Thermography was carried out on a concrete specimen with in-placed artificial defects at different depths and dimensions. Then, all the data were processed by Pulse Phase Thermography technique by performing Fast Fourier Transformation. The results were compared with the absolute contrast method.

We have identified the subway of structures as subway station users complained of vibrations from a structures when they walked through middle stairs of escalator. As a result of converting the vibration level to the conversion rate, it was measured at 3.846mm/s(82.7dB) on the B1st floor and 0.966mm/s(70.7dB) on the B2nd floor. These results are higher than the domestic standard of 65dB and lower than the international standard of under 5mm/s. It is felt well with the human body, but the structure is considered to be harmless. Therefore, it is deemded the structure is safe to usue. As the result of measuring the national frequency, the stairs on the B1st floor to be 3.01Hz and the stairs B2nd floor to be 5.36Hz. We consider that the users feel discomfort and anxiety on the B1st floor, where displacement and vibrations are higher.

In this study, Integrity evaluation of offshore wind turbine substructure was carried out. The strain values obtained by strain gauges circularly installed on upper part of the substructure was converted into vertical and moment load. Considering directions of the moment load through FEM, the most conservative P-M interaction diagram of the model was graphed. Obtained load values were evaluated by utilizing P-M interaction diagram.