이 연구에서는 철근콘크리트 부재에서 일반콘크리트를 대신하여 고인성 섬유보강 콘크리트를 사용하였을 때의 내진성능 향상효과를 평가하고자 하였다. 일정한 크기의 축하중을 받는 상태에서 단자유도 RC기둥 부재의 비선형 Push-Over 해석 방법을 적용하여 내진성능평가를 실시하였다, 일반콘크리트를 사용한 경우와 안장변형률성능에 따라 네 가지 고인성 섬유보강 콘크리트를 적용하여 그 거동을 비교하였다. 해석결과, 고인성 섬유보강 콘크리트를 사용한 철근콘크리트 기둥부재는 인장변형률성능이 거의 없는 일반 콘크리트를 사용한 철근콘크리트 기둥부재와 비교했을 때, 항복하중은 25~37% 크게 나타났으며, 변위연성도도 6.0~8.3% 크게 나타나는 것을 확인하였다.

In this study, concrete box structure was analyzed for reinforcement of the corner using the proposed pre-flexed steel members, Numerical results confirmed that the proposed reinforcement method can enhance the load capacity of the concrete box structures.

In this study, perfectly matched discrete layers with analytical wavelengths is applied to concrete gravity dam analyses. The validation of the proposed procedure is made by comparing the results with a previous study and the results obtained from SASSI,

Acoustic Emission (AE) technique applied to detect the crack occurrence of the actual beam element. An optimum position for a limited number of AE transducer was considered to accurately detect the location of the cracks in the three-dimensional space. Six AE transducer was used to detect cracks in the L400mm×H200mm×T100mm region, and several position combinations were applied. Considerable six position combinations were selected, and the weak or incorrect position detection was investigated. The optimum position applied to the experiment for actual beam element and the detected crack position was compared with the visual inspection location. A reliable crack position detecting was confirmed for loadings.

The old electric transmission tunnel over thirty years old in northern Seoul is operated with Ttukdo substation as its starting point and 41km-length since March, 1980, and the trend is an icrease in embedded electric power structures over thirty years old beyond sixty kilometers. If the corrosion occur in reinforced concrete structures, it is considered as the important factor among deterioration factors .By examing the seventy-two cases of concrete carbonation and covering depth in order to analyze the concrete carbonation of electric power structures over thirth years old in Gangbuk-gu, this paper atempts to analyze carbonation coefficient, remaning service life, and concrete carbonation of old embedded electric power structures for reference to predict the concrete carbonation progress.

Most apartment houses have been constructed with concrete structures. However, underground parking lots and rooftops in apartment buildings frequently have cracks due to drying shrinkage and various degradation factors. The leakage caused by this cracks has a problem that the durability of the structure and the waterproof performance is deteriorated. Therefore, the development of a proper crack repairing materials is continuously required. The purpose of this study is to apply chemically bonded ceramics (CBC) as a repair material to repair cracks in concrete, which has strong adhesion, durability, rapid hardening performance. Therefore, it was applied to the roof crack of the apartment(mock-up test) and the performance was evaluated. As a result, the compressive strength and the bond strength showed excellent performance. In the case of the dry shrinkage characteristics, the performance was stable in the range of -35 to 43 × 10 -6 until 20 days of age. In addition, the mock-up test results showed good workability and surface condition, and surface polishing is possible after 2 hours of consruction, which is considered to be very effective for Reducing work time.

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

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.

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.

Recently, Earthquake occurrence in korea has become frequent, and the seismic safety of low-rise piloti buildings becomes more and more important. In this study, the differences in seismic performance between before and after reinforced by concrete filled steel tube (CFT) of low-rise central core type piloti building structures were compared.

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.

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.

Recently, Earthquake occurrence in korea has become frequent, and the seismic safety of low-rise piloti buildings becomes more and more important. In this study, the differences in seismic performance between before and after reinforced by concrete filled steel tube (CFT) of low-rise central core type piloti building structures were compared.

In the current concrete structure of the highway is still the major problem most of concrete deterioration caused by the freeze-thaw and deicing salt, which is of issues that are not completely resolved. In particular, a single freezing event does not cause much harm, durability of concrete under multi-deterioration environment by repeated freeze-thaw and deicing salt is rapidly degraded and reduce its service life. In this study, the exposure environmental condition according the regional highway points were established. The damage condition and chloride content of the concrete at general and severe environmental exposure condition were also investigated. In addition, the experimental test of chloride ion permeability, scaling resistant and freeze-thaw resistance were carried out to improve the durability of the mechanical placing concrete of subsidiary structure. According to the results of this study, in observation of concrete surface condition, the concrete exposed by severe environmental condition showed broad ranges of damage with high chloride contents. Meanwhile, the water-binder(W/B) ratio and the less water content, and fly ash concrete than the specified existing mix proportion is significantly improved the durability. Also, the optimal mix proportion derived for test is satisfied the strength and air contents, water-binder ratio, and durability criteria of concrete specifications, as well as service life seems greatly improved.

In order to understand the seismic performance of weir structure under seismic events, concrete weir structure with infinite foundations was modeled in ABAQUS. Additionally, this study conducted the three different design response spectra based on KBC 2009, ASCE 7-05, and EuroCode 8. The results from numerical analyses showed that the seismic behavior of weir structure subjected to seismic ground motions was sensitive to natural frequency and mass participation factors.

Concrete behaves as a brittle material with low tensile strain capacity. By adding fibers, the cracking in concrete matrix is controlled, and the durability is improved. In this study, the microstructure and Chloride diffusion resistance of fiber reinforced concrete are compared with fiber type and fiber volume fraction. From the results, the fiber mixed in concrete must be at least 0.5% regardless fiber type, in order to ensure the chloride diffusion coefficient higher than OPC at 91days. However, the micro structure distribution is affected with fiber volume fraction and fiber type at range 10~100nm.

In this research, we carried out design and analysis with joint of concrete supporting structure for offshore wind energy. We developed load transfer mechanism about applied load induced from steel tower to concrete foundation. Also, a commercially available finite element program, ABAQUS 6.10, is used to analyze behavior of structure.

In the current concrete structure of the highway is still the major problem most of concrete deterioration caused by the freeze-thaw and de-icing salt, which is of issues that are not completely resolved. In particular, a single freezing event does not cause much harm, durability of concrete under multi-deterioration environment by repeated freeze-thaw and de-icing salt is rapidly degraded and reduce its service life. In this study, to considering environmental characteristics when design and construction of concrete structures, the exposure environmental guidelines were established by investigation the application rates of de-icing salt, temperatures and snowfall characteristics during five years (2004∼2008) by regions. Also, damage condition and chloride content of the structural at regions of moderate and severe environmental exposures were investigated.

The purpose of this study is to evaluate the impact on flexural strength and compressive strength of the concrete, the mixing rate of the amorphous fibers.

Traditional methods for concrete structure demolition is not adequate specially for urban areas and historical places due to hazard of explosive and noise. Therefore, Soundless Chemical Demolition Agents (SCDA) is useful in urban area and historical places. In this study, a analysis for SCDA is performed depending on boundary conditions.