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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea institute for structural maintenance and inspection
Journal Basic Information
Journal DOI :
Korea Institute for Structural Maintenance Inspection
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Volume & Issues
Volume 14, Issue 6 - Nov 2010
Volume 14, Issue 5 - Sep 2010
Volume 14, Issue 4 - Jul 2010
Volume 14, Issue 3 - May 2010
Volume 14, Issue 2 - Mar 2010
Volume 14, Issue 1 - Jan 2010
Selecting the target year
Evaluation on Flexural Strength and Shear Strength of RC Beams Extracted from Existing Apartment Housings
You, Young-Chan ; Shin, Hyun-Seop ; Choi, Ki-Sun ; Lim, Byung-Ho ; Kim, Keung-Hwan ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 75~82
The static strengths of the existing RC beams were experimentally investigated in this paper to understand the strength characteristics of existing structural members and to get appropriate data in strengthening RC members in the remodelling construction. Ten RC beams were prepared by cutting and extracting directly from the demolition site of apartment housings and tested in order to evaluate the flexural and shear strengths of existing RC beams by their geometric condition. From the test results, it was found that most of the specimens had a sufficient structural capacity except for some special case, for example, specimens with severe cracks or concrete losses caused by improper casting. Therefore, the severely deteriorated members originated from bad concrete casting or careless construction process should be repaired and strengthened in remodelling construction.
Size Effects in the Failure of Simple Supported Sandwich Slab Bridges
Han, Bong-Koo ; Kim, Duck-Hyun ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 83~90
Composite materials can be used economically and efficiently in civil engineering applications when standards and procedure for analysis, design, construction and quality control are to be established. Bridge systems, including the girders and cross-beams, and concrete decks behave as the specially orthotropic plates. For such systems with sections, boundary conditions other than Navier solution types, it is very difficult to obtain its analytical solution. To design the bridge made by the composite materials, cross-section was used as the form-core shape for economical reason and finite difference method was used for output of the stress value. The Tsai-Wu failure criterion for stress space is used. In this paper, the rate of tensile strength reduction due to increased size was considered. And also numerical study is made for these cases.
Behavior of RC Beam Strengthened with Advanced Lifting Hole Anchorage System
Oh, Min-Ho ; Kim, Tae-Wan ; Park, Sun-Kyu ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 91~99
In order to strengthen RC structures, various strengthening methods have been used. Particularly, external tendon strengthening method is very popular method to strengthen damaged structures in terms of efficiency, ease, economics. In this study, improved anchorage elements using the lifting hole were proposed to strengthen PSC or RC girder without any damage. Two types of anchorage elements were proposed and these elements were applied on six RC beams. Also, three types of existing anchorage elements were applied on three RC beams. Otherwise, any anchorage element was not applied on one RC beam to used as a control beam. To analyse behavior of these elements, static load tests were carried out. Test variables were anchorage shapes, prestressing level on the steel bar and tendon profiles. Deflections, strains and modes of failure were recorded to examine the strengthening effects of the beams. Ductility index and tendon stress were analyzed by comparing cracking load, yielding load and ultimate load. As a result, proposed anchorage elements using lifting hole were superior to existing anchorage elements in terms of strengthening effect and furthermore, they showed ductile behavior based on energy method.
Experimental Study on Bond Performance of RC Beams According to Absorption of Recycled Coarse Aggregates
Kim, Sang-Woo ; Lee, Hyun-Ah ; Jung, Chang-Kyo ; Kim, Kil-Hee ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 100~107
This study evaluates the bond behavior of reinforced concrete (RC) beams using recycled coarse aggregates. A total of four specimens were cast and tested. The test parameter was the type of coarse aggregates, that is, natural and recycled coarse aggregates, and the absorption ratio of recycled coarse aggregate. The recycled coarse aggregates with absorption ratios of 3% and 6% were used in this test. The specimens were simply supported and were subjected to a concentrated load. A test method proposed by Ichinose was adopted to estimate effectively the bond properties of specimens. From the experimental results, it was found that there was no difference of bond characteristics according to the absorption ratio of recycled coarse aggregates.
Development of an Assumed Strain Shell Element for the Three Dimensional Construction Stage Analysis of PSC Bridge
Kim, Ki-Du ; Song, Sak Suthasupradit ; Hwang, Hyun-Jin ; Park, Jae-Gyun ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 108~117
The frame element is commonly used for construction stage analysis PSC bridges. However, the frame element does not show sufficient information in the curved PSC box bridges. For the case of curved PSC bridges, the deformations in the inner and outer web are different. In this case, the different jacking forces are required in the inner and outer webs. And it is impossible to calculate different jacking forces in the inner and outer webs if we use the frame element for construction stage analysis. In order to overcome this problem, the use of shell element is essential for a three-dimensional construction stage analysis of PSC bridges. In the following, the formulation of an assumed strain shell element and its application of PSC box girder bridge analysis are presented.
Time-Temperature Curve for Fire Safety Assessment of Metropolitan Transit Tunnels
Won, Jong-Pil ; Choi, Min-Jung ; Lee, Su-Jin ; Lee, Sang-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 118~122
The study presents a standard time-temperature curve to evaluate the fire performance of subway tunnel structures. The central subway section is 135km long in Korea, the fourth longest in the world. The number of subway tunnels has been increasing rapidly and fire risk is proportional to the tunnel length. However, an adequate time-temperature curve for subway tunnel fires does not exist. Therefore, we studied a proposed foreign fire design model for which the heat rate is based on the traffic, and we present an appropriate time-temperature curve for Korean subway tunnels. The ISO 834 curve was used as a fire design model and the temperature distribution in the tunnel was estimated using numerical analysis. This led to a proposal for effective measures against subway tunnel fires.
Metallic Damper Shape and Cyclic Behavior for the Seismic Capacity Improvement of Building Structures
Lee, Hyun-Ho ; Kim, Seh-Il ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 123~130
The aim of this paper is a seismic performance evaluation of metallic damper devices which are efficient in workability and installation process. For this V shape and S shape dampers is considered. The strut figures of dampers are V shape and S shape and, the research parameters are strut height and angle of the dampers. ABAQUS program is used for nonlinear finite element analysis. The analysis is performed with the hysteretic curve that has maximum displacement with 50mm and has increased progressive. As a results of evaluating the yield strength, maximum strength and energy dissipation capacity of each device, V and S shape have a good strength capacity and the devices with strut angle
and strut height 140 and 200mm are evaluated stable in seismic behaviors. The response of S shape is more efficient than that of V shape. In the yield strength estimation process, proposed formula can not estimate the yield strength of V and S shape dampers. Even though, the formula can not consider the variation of strut heights and strut angles. Finally the S shape damper is recommended in seismic performance than V shape damper.
Design Equation of Reinforced Concrete Walls for Opening Configurations
Lee, Dong-Jun ; Oh, Soon-Taek ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 131~137
12 trial-scale wall panels are tested and evaluated to investigate the ultimate load capacity of axially loaded concrete walls with various opening configurations. The experimental tests have been undertaken to obtain data for the modification of existing equations. A new design equation has been generated using the precise test data and it incorporates the unique length factors. This new design equation for concrete walls with openings is then compared with existing code formulae.
The Diffusion Property of Chloride Ion into Concrete by Electrically Accelerated Method
Bae, Ju-Seong ; Park, Gook-Joon ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 138~143
Recently, as many big marine concrete structures increase, it is necessary that chloride ion diffusion coefficient of concrete shall be evaluated but it will take a long time to evaluate chloride ion diffusion coefficient of concrete. Accordingly, many test methods are suggested to evaluate chloride ion diffusion coefficient in a short period time by the promotion in electro chemical ways but the systematic study for this is insufficient. Therefore, this study evaluates chloride ion penetration and diffusion features by three representative electric promotion tests targeting for three different cements whose ingredients are different and analyzes the correlationship between them. As a result, diffusion features of chloride ion varied according to the cement ingredients and three ingredients cement in which blast furnace slag powder and fly ash are mixed in constant ratio, which shows the most excellent cement diffusion properties. For diffusion properties of chloride ion, the correlationship between test methods are good.
A Fundamental Study on the Material Characteristic of Micro-Admixture for Cement using Phosphogypsum and Kaolin
Oh, Hong-Seob ; Park, Jong-Tak ; Lee, Won-Hong ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 144~151
In this study, it is investigated the mechanical chemical properties of cement matrix using phosphogypsum and kaolin as a admixture for the substitutive materials to silica fume which is so expensive. For the test, phosphogypsum is modified as dihydrate, hemihydrate, type III anhydrite, and type II anhydrite, respectively and furnaced kaolin at
was also manufactured into meta kaolin by air cooling and water cooling method. The chemical characteristic and mechanical properties of various type of blended cements contained above mentioned gypsum and meta kaolin materials analyzed and compared with those characteristics of cement matrix with silica fume. From the test, the cement mixed meta kaolin made in water cooling has more excellent quality than other material.
Mechanical Properties and Flexural Behavior of Recycled PET Fiber Reinforced Eco-Friendly Hwang-toh Concrete
Kim, Sung-Bae ; Yi, Na-Hyun ; Kim, Hyun-Young ; Kim, Jang-Ho Jay ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 152~159
Recently, the public interest in eco-friendly material and structure has been increasing and many Hwang-toh researches are being actively performed. Hwang-toh is one of the traditional environment friendly construction materials used as a construction and plastering material. Hwang-toh has many advantages as construction material due to its high heat storage capacity, auto-purification, antibiotic ability, and infrared ray emission characteristics. But, currently it has not been developed into construction material and used in modern construction due to its low strength and dry shrinkage cracking prone characteristics. According to the recent researches and study results, Hwang-toh can be used as a natural pozzolanic material like fly-ash or pozzolan. In this study, mechanical properties and structural flexure behavior experiments of slag, recycled PET fiber, and Hwang-toh added concrete are carried out. The test results showed that drying shrinkage of concrete mixed with Hwang-toh has lower compressive strength and elastic modulus than those of control cement concrete specimen, but it has the similar flexural behavior in reinforced concrete beams.
Experimental Study on Shear Strength of Steel Fiber Reinforced Concrete Beams
Kal, Kyoung-Wan ; Kim, Kang-Su ; Lee, Deuck-Hang ; Hwang, Jin-Ha ; Oh, Young-Hun ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 160~170
Steel Fiber Reinforced Concrete (SFRC) beams has greater shear strength than typical reinforced concrete beams due to the high tensile strength of steel fibers. In this research, an experiment has been conducted to investigate the shear behavior of SFRC beams, and especially, the portion of shear resistance by uncracked compressive concrete section has been measured. Based on the test results in this study and 87 test data collected from literature, the accuracy of the existing equations for the estimation of shear strength has been evaluated. The shear strength of SFRC beams increased as more steel fibers were mixed. However, it is considered that the most efficient amount of steel fiber for enhancement of shear strength would be between 1% and 2% in that the specimen with 0.5% of steel fibers were abruptly failed after inclined cracking, and that the specimen with 2.0% of steel fibers showed a relatively low efficiency in increasing shear strength. The portion of shear resistance by the uncracked compressive concrete section was measured to be greater than 21%, and the equation proposed by Oh et al. provided the best accuracy on the estimation of shear strength of SFRC beams among the approaches evaluated in this study.
A Study on the Characteristics of Inorganic Polymer Mortar for Concrete Sectional Rehabilitation
Hwang, Tae-Ha ; Song, Tae-Hyeob ; Im, Chil-Soon ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 171~177
As concrete structures are exposed to chemical substances, damaged from salt, or progressed to the neutralization, the surface damage of the structures is generated timely fashion, resulting shortened service life. Especially, the sulfate erosion causes rapid surface defects, and the steel skeleton becomes corroded due to the water infiltration, generating stability deterioration of the concrete structure. In this study, the physical characteristics of the acid-resistant mortar with aluminosilicates was investigated in order to resolve problems of the acid resistance, one of the most serious problems of the cement type repair material. As the result of the experiment, the test specimen turned to exhibit almost equivalent physical characteristics with those of concrete sectional repair materials in terms of compressive and bending strengths. As both the cement sectional repair material and the test specimen were immerged in sulfuric acid solution to examine weight changes, the test specimens exhibited only 4% loss of their weights while the cement sectional repair materials reached at the level of 80% or above, proving the excellence acid resistant characteristics of the test specimens. Consequently, the physical characteristics of acid resistant mortar with aluminosilicates were revealed to be superior than those of concrete sectional repair materials. It can be utilized as a sectional repair material where the acidic erosion is anticipated.
Stability Evaluation Along Interface Loss of a Foundation and the Ground
Kim, Sang-Hwan ; Ji, Tal-Oh ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 178~185
This paper presents the evaluation of foundation stability according to decrease of the foundation contact area on the ground. In order to carry out this research, the experimental and numerical studies are performed. In the experimental study, the carefully controled laboratory model tests are carried out with different foundation size and types. The model test results are analyzed and interpreted by analytical and numerical calculation in order to verify both results obtained from experimental and numerical studies. It is clearly found from the results that the foundation stability is considerably reduced when the foundation contact area ratio is less than 75%. This research may be very useful to develop the economical foundation type.
Flexural Behavior of Steel-Concrete Composite Beams Strengthened by Post Tension Method
Ryu, Soo-Hyun ; Kim, Heui-Cheol ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 186~195
This study has attempted to suggest a proper reinforcement method by strengthening unbonded post -tensioning through height of an anchorage hole, form of a saddle, and loading time point as parameters and evaluating the reinforcement method through a bending experiment. The result of this experiment indicated effects of reinforcement since the maximum strength ratio(the ratio of an experimental value to theoretical value) of SC composite beams before prestressed was 0.97 and after prestress were 1.00~1.21. As a result of analysis on displacement and strain, irrespective of height of an anchorage hole and loading time point, the D120-series specimen where an anchorage hole was installed on the neutral axis after reinforcement showed that its deflection continuously increased without sudden load reduction after maximum load and it stably behaved with relatively low strain of each part. In terms of reinforcement effects, the maximum strength of SCR-UD120 specimen prestressed after pre-loading was increased 1.72 times comparing to SC composite beams so SCR-UD120 specimen prestressed after pre-loading was shown to be the best.
Standard Proposed for Fire Safety Evaluation of Railway Tunnels and Evaluation of Fire Temperature
Won, Jong-Pil ; Choi, Min-Jung ; Lee, Su-Jin ; Lee, Sang-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 196~200
The number of railway tunnels has been increasing rapidly. Although fires in long railway tunnels are rare, the consequences can be devastating. Prior to this study, there were no adequate time-temperature curves for the fire safety assessment of Korean railway tunnels. We studied a standard foreign time-temperature curve for which the heat rate is based on the traffic and the types of vehicles. We then proposed a hydrocarbon curve as a fire design model for railway tunnels in Korea. We examined the implications of this proposed model on railway tunnel structures using numerical analysis.
Field Survey on the Construction Errors for the Members of Reinforced Concrete Structures
Yoon, Sang-Chun ; Jee, Nam-Yong ; Choi, Ki-Bong ;
Journal of the Korea institute for structural maintenance and inspection, volume 14, issue 3, 2010, Pages 201~208
Information on the distribution characteristics of construction errors is very important to determine the member factors, which are to be introduced in a new Korean design code for reinforced concrete structures. The new design code, which is under development for reinforced concrete structures, is based on the performance design concept. The construction errors of reinforced concrete members are mainly caused by the firmness and dimensional accuracy of forms, the arranging condition of reinforcing bars, the pouring and compaction methods of concrete, the skills of field workers, and the experience of supervisors. To find out the construction errors of reinforced concrete structures already built in Korea, a field survey for cover thickness, effective depth of reinforcement, the thickness of slabs and walls, and the dimension of beams and columns has been performed. Based on the survey, which is the first time in Korea, the analysis results are presented. The measuring methods for the construction errors, which have been established through the laboratory tests, are also presented. In addition, the measured construction errors from the survey are compared with the allowable tolerances in the current domestic and foreign specifications.