This study is a part of the research on the development of safety monitoring system and monitoring program of 3MW offshore wind support structure using fiber optic sensor. In this paper, we propose a maintenance system for offshore wind support structure using fiber optic sensor based on the analysis of current monitoring status and related standards of domestic and overseas offshore wind support jacket structures.

In the case of marine concrete composite structures, damaged by the various environment effect(sea damage, freeze-thaw, carbonation), and then, there is a possibility of going bad in the safety. The purpose of this study is to perform periodic measurements and tests on the durability test site constructed at sea and to provide basic guidelines for future maintenance based on the analyzed data.

In this study, the effect of electromagnetic wave from an electronic device on electric sensor system and optic sensor were analyzed to verify the reduction effect of a optic sensor and applicability to marin structure. Test revealed that optic sensor system was not occurred the noise by electromagnetic waves also had the low range of fluctuation.

There are many cases where large areas of the underground parking lots of residential buildings do not have proper measures against prevention of leakage, resulting in condensation, growth of infectious microogranisms and increase of pollution in the air. This paper discusses a study conducted to understand the awareness of leakage problems and the damage that follows in the underground structures of residential buildings.

This paper aims to develop a wireless unified-maintenance system(WUMS) to obtain real-time structural response of civil structures. The WUMS integrates the GPS module, the strain module and the acceleration module based on the standalone controller, and includes the RF module for remote measurement and the battery for long term operation. In order to evaluate the performance of the WUMS, a response test using a modal shaker and a modal test using a model bridge were performed. The test results using USMS were compared with those measured by wired system. Finally, the developed WUMS was appropriate to obtain the structural response of the civil structure in real-time, unified, and wirelessly.

The internal displacement of the corrugated steel plate structure reduces structural stability. In this study, we evaluated the stability of the corrugated steel plate culvert structure using an inspecting deformation rates between designs and measured 3D shapes. Also, a proper repair and reinforcement method will be proposed through analytical and experimental verification

In reinforced concrete structures, carbonation phenomena associated with deterioration is important. So, this study conducted a visual inspection and a concrete durability test in Precise Safety Diagnosis, analyzed the result, and tried to suggest a reasonable repair method and range of concrete carbonation.

When reinforcing an existing reinforced concrete beam-column building with a precast concrete panel, special connection between the PC member and the RC member is required to solve the time dependent deformation of the RC member and to receive the large shear forces. The aim of this study is to obtain the shear strength of upper connection between the existing RC beam-column and infilled PC wall panels in experimentally and theoretically. Thus, the static shear loading tests were conducted on the 6 specimens with the plate connection. Shear failure was resulted from the weakest portion of interior PC panel, exterior RC, and the connection, when the PC portion which located at the center of specimen was pulled upward from the bottom. The experimental result was compared with analytical result from ACI 318M-14 Chapter 17 for the shear strength of post-installed anchor and PCI Handbook 7th edition 6.8 Structural Steel Corbel (PCI Design Handbook 7th edition, 2010) for the strength of cast-in H-beam. The analytical and experimental results show final failure at the same location. The failure loading of experiment showed larger than average 6% to that of the analysis.

This study presents the structural modelling method for the seismic behavior characteristics evaluation of flat stone bridge. To this end, we select the representative flat stone bridge according to the construction and configuration types. Also, this study provides the discrete element method for the reasonable seismic modelling of discontinuum structures.

This paper addresses simplified method for nonlinear soil–structure interactions (SSI) analysis of base-isolated nuclear power plant (NPP) structure under incident seismic waves. The accuracy and applicability of the method are evaluated by comparing with nonlinear time history responses obtained by the boundary reaction method (BRM).

This study proposed a seismic isolation system which uses the LM guide featuring high hardness and low frictional coefficient and a viscoelastic damper possessing high restitution force and damping force in order that existing seismic isolation systems using conventional sliding bearing way can be applied to a structure, and intended to analyze the proposed seismic isolation system's utilization possibility as a seismic isolation system for rescue through an experiment utilizing 6 earthquake waves being entered according to the reoccurrence cycle on the basis of performance-based design, and the case of Kyungju earthquake and to interpret the results of experiment.

This study evaluates seismic risk of steel ordinary concentrically braced frames. Based on the risk integral concept, the collapse probabilities in 50 years are calculated for the 3-, 5- and 10-story braced frames. The evaluation results present that the collapse probabilities in 50 years are increased for the higher braced frames although they are identically designed according to the current domestic seismic design code.

In this paper, we research about integrated jacket support structure. The connection of the offshore wind support structure was designed based on the DNV-RP-C201 standard and the design of the appropriate type was derived through numerical calculation and finite element analysis of the stress paths of various connecting part type.

All the structures include initial imperfections that can affect the structural behavior and stability, particularly during construction. Therefore, for a concrete beam with an initial lateral deformation, creep analysis was performed to evaluate the influence of the initial imperfection on the creep deformation of the beam in the both vertical and lateral directions.

In this study, We have evaluated the applicability of the substructuring technique to reducing the computational cost of a three-dimensional analysis of a vehicle-track structure dynamic interaction. When the substructuring technique is applied properly to the three-dimensional dynamic interaction analysis, computational cost can be greatly cut down without loss in accuracy.

This paper analyzed the effects of rotational stiffness of wedge connection between vertical and horizontal members of system supports. By simulating the connection condition both a hinge connection, which is considered in the design stage, and a spring with the rotational stiffness reflecting the actual behavior, the critical buckling load and the maximum combination stress ratio are compared. The results show that hinge condition somewhat underestimate the actual behavior of vertical members of system supports. However, it is also noted that the horizontal member represents the increased stress due to the rotational stiffness of the connection.

In this study, a drone based structural health monitoring technique is introduced which uses a piezoelectric (PZT) transducer attached to a drone. With the PZT transducer, the electromechanical impedance (EMI) method is modified to be attached and re-attached onto a structure for damage identification. Since one of the possible principle technology is to keep the tube structure safe from damage, the idea introduced in this study opens up new possibilities of monitoring the integrity of the Hyperloop structure.

This research, concrete materials used SHCC(Strain harding Cementitious Composite) in RC(Reinforced Concrete) shear walls. We tried to identify the performance of developed shear wall. Specimens were only considered gravity load and designed and detailed in compliance to KCI-2012. Based on the loading experiment results, this study was found that the developed shear walls showed improved strength than RC shear wall in controlling bending and shear crack. The developed　shear wall with minimum shear reinforcement increased the more strength than RC wall with nominal shear reinforcement

The goal of this study is to investigate the effectiveness of the use of multiple materials in plate-like structures structure and provide engineers and designers an appropriate view point of multi-material topology optimization when making decision and information in design. Element density distribution contours of mixing multiple material densities are linked to Solid Isotropic Material with Penalization (SIMP) as a design model. The mathematical formulation of multi-material topology optimization problem solving minimum structural compliance is an alternating active-phase algorithm with the Gauss-Seidel version as an optimization model of optimality criteria. Some numerical examples are considered to illustrate the reliability and accuracy of the present design method for multi-material topology optimization.

To understand the changes in physical parameters and phytoplankton size structure caused by tides, a fixed station in the Youngsan River estuary was monitored at 2-h intervals, on April 28, 2012 and August 12, 2012. No clear relationship was observed between the temperature and salinity changes and tidal levels in April. However, in August, temperature decreased during the ebb tide and increased during the flood tide, while salinity showed the opposite trend. In addition, there was no specific change in the phytoplankton biomass corresponding to tidal levels in April. In August, the total chlorophyll a and the biomass of net phytoplankton (>20μm ) increased almost 20 times during the ebb tide and decreased during the flood tide. The biomass of nanophytoplankton (<20μm ) showed a similar variation in response to tidal level changes. In April, the relationship between percent contributions of phytoplankton size structure and tidal levels was not clear. In August, the net phytoplankton was dominant in the early stage and nanophytoplankton was dominant in the later stage, while contribution of nanophytoplankton and net phytoplankton increased at high tide and low tide, respectively. Therefore, in April, other factors such as freshwater discharge were more important than the tide, whereas in August, when no freshwater discharge was recorded, the changes in semidiurnal tides influenced the physical parameters and phytoplankton dynamics. These results could contribute to the understanding of phytoplankton dynamics in the Youngsan River estuary.