• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.203-210
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• 2019

A recent earthquake on the Korean Peninsula caused much damage to masonry buildings, and research on performance evaluation has been underway. A masonry building is generally constructed using wet construction and is affected by temperature, which reduces the efficiency of the construction. In this study, we propose a dry construction technique for assembling concrete blocks without using mortar and evaluated its performance through experimental and analytical research. To evaluate the performance, experiments were carried out for the prismatic compressive strength, direct terminal strength, and diagonal tensile strength of the dry construction wall. The adequacy of the cross section shape was also reviewed through FEM analysis. The results show that the compressive strength and diagonal tensile strength could exert a certain intensity or higher. Furthermore, the H-type module of a key block acted as a shear key for the entire concrete block, which resulted in excellent shear strength performance. In addition, the shape and thickness of the main block have a major effect on the strength performance of each block. Therefore, an optimal shape and the proposed dry construction method could be applied to replace the wet method by studying the construction or seismic performance of the proposed method.

• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.458-465
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• 2018

Purpose: Concrete track that affects on railway safety can detect cracks using image processing technique. However, since a condition of concrete track and surface noisy are obstructed to detect cracks, there is a need for a way to remove them effectively. Method: In this study, we proposed an image processing to detect cracks effectively for Korean railway and verified its performance through experiment. We developed image acquisition system for capture a railway concrete track and acquired railway concrete track images, randomly selected 2000 images and detected cracks in the image process using proposed Gabor Filter Bank methods. Results: As a result, 94% of detection rate are matched to the actual cracks in same quality and format railway concrete track image. Conclution: The crack detection method using Garbor Filter Bank was confirmed to be effective for crack image including noise in the Korean railway concrete track. This system is expected to become an automated maintenance system in the existing human-centered railway industry.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.129-138
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• 2008

The finite element method(FEM) was one of tools used to solve problem of previous Concrete Pavement and was applied to Korea Pavement Research Program Study. This study used the ABAQUS and the fortran analysis program to calculate the critical stress on jointed concrete pavement and compared and analyzed the results by using neural networks and linear regression model. In that case, which are not enough analysises by using FEM programs though many input variables, when the results of FEM with NN and linear regression models are compared, there are some differences. The other cases, which are reduced input variables and a lot of analysises each of them, results of Neural Networks(NN) and linear regression models are simulated to them of FEM. But, the result of NN is more exact than them of linear regression at the (0,0), (1,1). On the results of this study, it is suggested that the calculation of stress using NN is more compatible to Korea Pavement Research Program Study.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.5
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• pp.23-32
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• 2012

Research on steel plate concrete (SC) structures for the modularization of nuclear power plants have been performed recently in Korea. In this study, the seismic capacity and stiffness characteristics of unstiffened SC shear walls under the effects of earthquakes were investigated through static pushover tests. Failure modes, sectional strength, and stiffness characteristics of SC structures under lateral loads were inspected by analyzing the experimental results. The strengths obtained by the experiments were also compared with those derived by the design code of the SC structures. One of the main failures of unstiffened SC shear walls was found to be the type of bending shear failure due to the debonding of the steel plate at the concrete interface. The ductility capacity of SC structures was also confirmed to be improved, which is considered to be a confining effect on steel plates in the longitudinal behavior of SC structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.60-67
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• 2021

In lately, it's been developed and used a system of using deck plates as formwork in order to solve various problems caused by conventional formwork system. This system is more economical and has higher constructability than the conventional system by permanently embedding most of deck plates into the members. However, for this kind of embedded deck plates formwork system, it's been reported that it is difficult to verify filling of concrete in members like beams with narrow width and complicated rebar arrangement. In addtion, there are several problems such as corrosion of deck plates in terms of constructability and maintenance. Therefore, in this study, it is attempted to develop a removal-deck plate formwork system for beams by removing deck plates after concrete curing. The system consists of a deck plate module that acts as form, a frame preventing deformation by concrete lateral pressure, stirrup frame, and connector that combines these. As a result of this research, it is verified that it has higher constructability, efficiently prevents deformation caused by concrete lateral pressure and could be easily removed in the developed formwork system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.61-68
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• 1999

This paper is the study of methodology for development of preliminary structural design modules for an intergated system for reinforced concrete structures. To develop the modules. it is used that the iteratived and incremental development process of object-orientied methodology and affects. The aspect is a tool to capture characteristics of the objects. The aspects consists of .user, structure, and system. By using aspects, we can find that objects and relationships between the objects consisting of the modules in the phases of process. In this paper, UML(Unified Modeling Language) is used to the notation. It serves as the language for communicating decisions that are not obvious and provides semantics to capture all important stategic and tactical decisions. Therefore such a series of mothods is valuable to development of preliminary structural design modules. Then preliminary structural design modules were programed by using Visusl C++, a windows environmental development tool.

• Journal of Korean Association for Spatial Structures
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• v.20 no.3
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• pp.35-42
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• 2020

The purpose of this study is to develop precast concrete modules that can be used as a booth and a single-story building with a large space. This precast concrete module is originally designed to have a hexagonal facade when the upper and lower parts, which are symmetrical about horizontal connection line, are combined. A structural design was conducted to ensure structural safety of these precast concrete modules and to extend the slope of the inclined members as far as possible. Then the finite element analysis was performed to estimate the lateral and vertical deflection of complete precast concrete modular structures. And to verify the structural safety of these precast concrete modules, weight loading tests were conducted on the upper and lower modules respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.10-19
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• 2013

Recently, researches related to precast modular construction have been actively conducted for nuclear power plant, LNG gas tank, and small-medium PCCV as well as bridges and buildings. In this study, the precast panel cast with steel mesh reinforced mortar (SRM) which is similar reinforced ferrocement was developed for efficient precast construction, construction time reduction, and easy transportation. Mortar mixture with high strength and flowability was obtained from various case studies using silica fume and GGBS. Also, $1,200{\times}600{\times}150mm$ SRM and reinforced concrete (RC) panels were manufactured with reinforcing ratio of 2% and 4%. To verify structural performance of the SRM specimen, the basic material tests, free shrinkage test, and 3-point flexural test with a line loading were carried out. From the test results, it was determined that SRM specimens showed outstanding flexural capacity and ductility. However, the 4% reinforced SRM specimens must consider shear reinforcing to be used as a precast modular member.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.459-467
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• 2016

Recently, new open-cut modular construction method, which is built within a 5~7m depth below the road, was proposed for the near-surface transit system to ensure the economic feasibility of underground structures. In this paper, the precast modular construction method was developed for the low-cost and rapid construction of underground structures. For the experiment on the flexural performance of the modular slab connections, a total of eleven specimens were fabricated according to the test variables; section shape, joint type, lap length, and transverse reinforcement. The test results were compared with those of the specimens without loop joints. To verify the performance of the slab connections, the 4-point loading tests of precast RC members with loop joints were conducted. As a result of the test, the flexural performance of the half-depth specimens with a 200mm lap length of loop joints were confirmed to be similar to those of the specimens without joints.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.677-684
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• 2012

In recent years, extension of life span of buildings is becoming an important issue in our society. To improve the life span of buildings, rhamen structure construction and long-spanned structures are advantageous. And in order to achieve this goal, structural elements of buildings must be light and slender. As an alternative method, general porous slabs are used frequently domestically and internationally. But the study on the porous slabs using T-deck plate and assembly of light weight precast construction is insufficient at present. In this study, flexural and fatigue tests were performed on six specimens to verify structural performance and serviceability. The main parameters of the specimens were light weight and T-deck plate construction possibility as well as slab thickness. The test results indicated that the strength of porous slabs using T-deck plate and assembly of light weight were much better than general RC slabs and porous slabs without T-deck plate. And stiffness was much better than that of other tested slabs.