With recent increasing interest from both safe society expectation and technological advancement in fields of sensors, microelectonics, and wireless communication, nondestructive monitoring technologies based on wireless solutions have been researched in many structures for construction performance evaluation and infrastructure durability inspection. To support robust wireless monitoring system, there are still technical barriers to overcome, such as low power consumption, battery-less operation, robust wiress communication and small system size. In this paper, recent research trends and challenges in infrastructure durability monitoring technology with wireless communication will be reviewed.

The main cause of corrosion in reinforced concrete is diffusion of degradation factors such as chloride ions, carbon dioxide, and sulfate ions. To monitor the extent of the corrosion in reinforced concrete, it is necessary to recognize and track the diffusion of degradation factors. In this paper, we suggest thin-film iron sensorto measure the penetration of chloride ions. The sensor indicates results as electrical resistance and change in electrical resistance. The sensor and contact pad are connected by an anisotropic conducting film (ACF) bonding in order to reduce the influence of the contact electrical resistance. The sensor’s electrical resistance increases with corrosive behavior and external chloride ion concentration. Use of these thin-film iron sensors enables measurement and monitoring of the depth of chloride ion diffusion in concrete.

In this paper, it is described for the technology trends of Durability Health Monitoring (DHM) using sensors and monitoring Methods. Specially, the chloride ion penetration sensor, carbonation depth sensor, corrosion sensors for embeded rebar and wireless sensor monitoring system is described in order to enhance the durability of buildings and infrastructures.

This study is a method to improve the reliability and effectivity of maintenance. It is necessary to build the integrated management system of BIM throughout the design, construction and maintenance of the structure. In order to apply BIM, it was introduced structural record management from the design stage. And It helps to improve the reliability of maintenance.

The number of expressway structure management is continuously increasing, and the aging of structures is proceeding rapidly. In order to secure the safety of expressway structures, we propose improvement methods such as advancement of structure management system, lifetime improvement methods such as prevention of structure deterioration, and the preemptive reflection of the structure maintenance budget.

Recently, steel has been very frequently chosen in building many civil infra-structures including bridges due to its several beneficial advantages as compared to concrete structures. However, for the most cases, damage such as section reduction, that is resulted from corrosion, was natural and inevitable. Therefore, it becomes very important to evaluate the structural safety and to estimate the life for the worst cases. In this study, the corrosion behaviors of mock-up specimen with box girder were examined by visual inspection.

70~80년대 급속한 경제성장기에 구축된 사회자본시설은 최근에 와서 노후화가 급속히 진행되 면서 기존구조물에 대한 유지관리와 활용방안에 대해서 관심이 높다. 지금까지 콘크리트 구조 물의 유지관리에 대해서는 관심이 높은 분야는 아니였지만, 적절하고도 전략적인 유지 관리를 실시하기 위해서는 항상 콘크리트 구조물의 상태에 대해서 주의하고 여러 분야(점검, DB, 분석 및 예측 등)의 고도 기술을 집약하여 콘크리트 구조물을 관리할 필요가 있다. 이러한 배경에서 본 연구에서는 콘크리트 구조물의 효율적 관리 및 사용하기 위한 구조물 자 산관리 시스템에 대해서 제안하고자 한다.

The purpose of this study is to provide basis data that can be used to establish an efficient maintenance system for the corrosion of off-shore structures by comparatively analyzing the present offshore concrete and steel structure corrosion sensors and monitoring techniques under development.

Many of the structures constructed since the 1970s have begun to deteriorate. As a result, safety inspection / diagnosis and maintenance are expected to increase further, and long-term and systematic measures are urgently needed to prepare for the aging of major infrastructures. Currently, the safety inspection and maintenance of the structure is carried out by the method based on the utilization of the measurement data and the manager's experience, but the reliability and the accuracy are still insufficient. In other words, there is a limit to understanding the state change of bridges, such as abnormal behavior and gradual damages, therefore, it is necessary to have an accurate and reliable monitoring process using new techniques and systems. For this reason, I would like to examine the possibility of using cloud and big data in the field of infrastructure safety management.

This study aims to establish design and construction procedure in the fields of the repair and rehabilitation for existing concrete structures. The codes used in this study are ISO 16311 and ACI 562-16. The ISO 16311 and ACI 562-16 focused on maintenance and repair, respectively. After, we will make to design and construction guidelines to meet the domestic situation through analysis the repair and rehabilitation parts of the codes in detail.

In this study, a new strengthening alternative for RC structures, namely wing type steel frames, has been experimentally investigated under reversed cyclic loading. It has been observed that the usage of wing type steel frames considerably improve the capacity and sway stiffness of RC structures.

This study is to evaluate the seismic demand of reinforced concrete structure considering the incident angle of the ground motions. For this purpose, a three-story structure is numerically analyzed under the three ground motion records through a multi-component incremental dynamic analysis (MIDA). The MIDA, an implementation of Incremental dynamic analysis, investigates two components of seismic excitation in which all accelerations are scaled to spectral accelerations at the fundamental natural periods of the buildings. The obtained results indicate the influence of the incident angle should be considered in the assessment response of structures. Maximum inter-story drift of structure will behave in the elastic or inelastic range depending on the variable incident angle

It was studied structural design of nonuniform UHPC concrete structural members. UHPC concrete has the compressive strength of 120-200MPa, the tensile strength of 8-20MPa, and the tensile strain of 1.0-5.0%. There are two types of specimens of nonuniform members improved in bending and shear performances. The specimens were evaluated by beam load test induced by bending and shear failures.

Numerical behavior of GFRP(Fiber Reinforced Polymer) infill panel in steel frame structure was evaluated through the finite element analysis in this study. In order to numerical analysis, a experimental test results was used to develop a three dimensional finite element model of steel frame specimen. Based on the developed three dimensional finite element model of steel frame specimen, the behavior of GFRP infill panel in the steel frame specimen was evaluated. From the numerical analysis results, strength of the steel frame specimen with GFRP infill panel was governed by GFRP infill panel. Also, diagonal compression behavior governed the GFRP infill panel in the steel frame specimen in the numerical analysis results.

Transition piece of offshore wind turbine tower is one of the main parts which takes the direct load and pass on to the lower support structure. In this study, a new design method for the transition piece has been developed. The trasition piece was designed based on the the load flow which was analyzed by approximation and was evaluated by FEM.

Soundless Chemical Demolition Agent (SCDA) has been spotlighted for demolition of concrete structure or rock near or in urban areas and historical places since it does not produce dust or rock fragmentations compared to explosive and gas pressure blasting methods. However, there is no guideline or design code for the demolition of existing structures using SCDA. In this study, numerical analysis using ABAQUS is conducted in order to find a minimum required pressure for the initiation of crack in concrete body with SCDA and obtained results in this study could be a basic data for design of hole spacing for the demolition of the structures using SCDAs.

Recently, as the awareness of safety has become more important, studies on damage assessment techniques for building structures have been actively conducted. The damage of the building structure is caused by the decrease of the stiffness which is inherent dynamic characteristic of the structural system, and the decrease of stiffness acts as a direct variable connected to the collapse of the structure. there have been developed techniques for estimating the inherent dynamics of a structure to identify and evaluate damage to the structure. In this study, we estimate the layer mass due to the modeling error through the optimization algorithm, Genetic Algorithm, and use the optimization algorithm GA to optimize the error covariance matrix, system noise and measured noise covariance matrix We propose an optimal state estimation algorithm. The objective function of the GA algorithm is obtained by the residual which is the difference between the measured values obtained from the EKF calculation and the values obtained from the system model. We verified the feasibility of the algorithm through a 4-DOF system.

The purpose of this study is to evaluate the effect of steel fiber reinforced concrete on structural performance when applied to joints. For this purpose, the development length was designed not to satisfy the concrete structure criterion. Experimental results show that the maximum strength of steel fiber reinforced concrete increases by about 12% in the direction of the settling force. Also, due to the increase of the tensile strength of the concrete, the strength of the cracks increased by 33% in the positive direction.

In this paper, the flexural test of concrete member damaged due to Calcium leaching were performed to evaluate the characteristics of structural behavior. From the results, yield load, maximum load and flexural rigidity of RC member damaged by calcium leaching were decreased and the depth of the neutral axis was increased.

Recently, the use of duplex stainless steel which has a two-phase microstructure consisting of grains of ferritic and austenitic stainless steel has been increased in a variety of industrial fields. Especially, STS329FLD with lower nickel content and higher yield strength compared with austenitic stainless steel has been developed. In this paper, experiments have been conducted to investigate the structural behaviors of single shear duplex stainless steel(STS329FLD) bolted connection with four bolts. Specimens with relatively long end distance failed by block shear fracture accompanied with curling (out-of-plane deformation) and the curling reduced the ultimate strength.