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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
Editor in Chief :
Volume & Issues
Volume 18, Issue 6 - Nov 2014
Volume 18, Issue 5 - Sep 2014
Volume 18, Issue 4 - Jul 2014
Volume 18, Issue 3 - May 2014
Volume 18, Issue 2 - Mar 2014
Volume 18, Issue 1 - Jan 2014
Selecting the target year
Efficiency Test for Surface Protecting Agents for the Chemical Resistance of Concrete Structures Using Sulfur Polymers
Lee, Byung-Jae ; Lee, Eue-Sung ; Chung, Woo-Jung ; Kim, Yun-Yong ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 1~8
DOI : 10.11112/jksmi.2014.18.5.001
Structures requiring chemical resistance are usually coated with surface protecting agents, but the cost for maintenance and re-construction is incurred due to the low durability. Therefore, in this study, sulfur was polymerized and the performance was examined so that it could be used as the concrete surface protecting agents for structures requiring chemical resistance. The evaluation results indicated that for the spray of the sulfur polymer surface coating agents, the application of the gravity type was appropriate; and for the number of coating times, about 3 cycle spray gave the best results. For the surface condition of the concrete to be coated with the surface protecting agents, outstanding quality was obtained above room temperature (
), and the bond strength increased as the temperature increased. The evaluation results of the strength characteristics depending on the filler content of the surface protecting agents indicated that about 20~40% filler mixing contributed to the strength improvement as it reduced the shrinkage of the sulfur polymer. Also, the mixing of silica showed larger increase in the bond strength than the mixing of fly ash, and the most outstanding bond strength characteristics could be obtained by the mixing of both silica and fly ash. In the case of the chemical resistance, the strength reduction was minimized and outstanding chemical resistance was obtained when the fly ash and silica were substituted by 20%, respectively. The performance evaluation of the chloride ion penetration indicated that for the specimens coated with the sulfur polymer surface protecting agents, the chloride ion penetration resistance increased by 29~48% compared to the specimen without the coating of the surface protecting agent. The examination of the coating condition of the surface protecting agents, compressive strength, bond strength, chemical resistance, and salt damage resistance indicated that in the range of this study, the optimal level was when the silica and fly ash were substituted by 20%, respectively, as the filler for the sulfur polymer.
Interface Behavior of Concrete Infilled Steel Tube Composite Beam
Lee, Yong-Hak ; Lee, Ta ; Jeong, Jong-Hyeon ; Kim, Hyeong-Ju ; Park, Kun-Tae ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 9~18
DOI : 10.11112/jksmi.2014.18.5.009
Interface behavior and confining effects of concrete-infilled steel tube (CFT) composite beam were investigate based on the experimental observations and numerical analyses. For this purpose, laboratory four-points bending tests were performed for the two test specimens of 1,000mm long CFT composite beams. The test beams were made of
and 4.5mm thick steel tube and 10mm thick steel web and bottom flange. Therefore, concrete infilled in steel tube was in compression through the entire cross section due to the web and bottom flange. Two end section conditions, with end section cap and without end section cap, were considered in experiments to monitor the relative slip displacement at ends and induce confining effects at center. In numerical aspects, finite element analysis considering steel-concrete interface behavior was performed and compared to the experimental results.
Study on Cracking Causes and Patterns in Median Barrier and Guardrail Concrete in RC Bridge
Choi, Se-Jin ; Choi, Jung-Wook ; Kwon, Seung-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 19~26
DOI : 10.11112/jksmi.2014.18.5.019
Concrete guide rail and median barrier are an attached RC member, however they are vulnerable to cracking due to slip form construction and large surface of member. In this study, causes and pattern of cracking are analyzed through assessment and NDT (Non-Destructive Technique) evaluation for concrete guide rail and median barrier on highway structure. For this work, analysis on drying shrinkage and hydration heat are performed considering installation period, and plastic shrinkage is also analyzed considering their environmental conditions. From the evaluation, plastic settlement around steel location, drying/ plastic shrinkage, and aggregate segregation are inferred to be the main causes of cracking in the structures. The crack causes and patterns are schematized and techniques of crack-control are suggested. Furthermore concrete guide rail/ median barrier in the bridge on the sea are vulnerable to cracking at early age so that special attentions should be paid at the stages of material selection and construction.
Influence of Carbonation of Concrete on Electrical Resistivity
Yoon, In-Seok ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 27~33
DOI : 10.11112/jksmi.2014.18.5.027
Electrical resistivity of concrete can be measured in a more rapid and simple way for estimating durability of the concrete, however, carbonation causes a result of misleading for durability testing because carbonation leads to a significant reduction in the permeability and porosity of concrete. The purpose of this study is to estimate and quantify the effect of carbonation of concrete on a surface electrical resistivity measurement. Samples of three mixes with difference w/c were prepared and exposed in a carbonation chamber for 330 days. The results show that carbonation leads high electrical resistivity. The increase is substantial and has been shown to proportional to the extent of the carbonation by some of extent. The relationship between electrical resistivity and carbonation depth is taken in the study. Resistivity ratio of carbonated concrete to air concrete decreased significantly from the specific carbonation depth, however, resistivity ratio of carbonated concrete to air concrete had a linear relation with carbonation depth. From the relationship between electrical resistivity and carbonation depth, it is expected that the result should be subsequently used as a calibration curve for estimating carbonated concrete to overcome the interruption effect of carbonation on regular measurements of the electrical resistivity.
Shrinkage Reduction Performance of HPFRCC Using Expansive and Srhinkage Reducing Admixtures
Park, Jung-Jun ; Moon, Jae-Heum ; Park, Jun-Hyoung ; Lee, Jang-Hwa ; Kim, Sung-Wook ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 34~40
DOI : 10.11112/jksmi.2014.18.5.034
High-performance fiber-reinforced cement composite (HPFRCC) shows very high autogenous shrinkage, because it contains a low water-to-binder ratio (W/B) of 0.2 and high fineness admixture without coarse aggregate. Thus, it needs a method to decrease the cracking potential. Accordingly, in this study, to effectively reduce the shrinkage of HPFRCC, a total of five different ratios of SRA (1% and 2%), EA (5% and 7.5%), and a combination of SRA and EA (1% and 7.5%) were considered. According to the test results of ring-test, a combination of SRA and EA (1% and 7.5%) showed best performance regarding restrained shrinkage behavior without significant deterioration of compressive and tensile strengths. This was also verified by performing modified drying shrinkage crack test.
Effect of Pull-out Property by Shape and Mechanical Property of Reinforcing Fiber on the Flexural Behavior of Concrete
Kim, Hong-Seop ; Nam, Jeong-Soo ; Kim, Jung-Hyun ; Han, Sang-Hyu ; Kim, Gyu-Yong ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 41~50
DOI : 10.11112/jksmi.2014.18.5.041
This study evaluated the bonding property of fiber and flexural behavior of fiber reinforced concrete. Amorphous steel fiber, hooked steel fiber and polyamide fiber was used for evaluation of bonding property and flexural behavior. As a result, the hooked steel fiber was pulled out from matrix when peak stress. However amorphous steel fiber occurred shear failure because bonding strength between fiber and matrix was higher than tensile strength of fiber. Polyamide fibers occurred significantly displacement to peak stress because of elongation of fiber. After that peak stress, fiber was cut off. Amorphous steel fiber reinforced concrete had a greater maximum flexural load compared with hooked steel fiber reinforced concrete because bonding performance between fiber and matrix was high and mixed population of fiber was many. However flexural stress was rapidly reduced in load-deflection curve because of shear failure of fiber. Flexural stress of hooked steel fiber reinforced concrete was slowly reduced because fiber was pulled out from the matrix. In the case of polyamide fiber reinforced concrete, flexural stress was rapidly lowered because of elongation of fiber. However flexural stress was increased again because of bonding property between polyamide fiber and matrix. The pull-out properties of the fiber and matrix has effect on the deformation capacity and flexural strength of fiber reinforced concrete.
Evaluation on the Thermal Resistance Capacity of Fire Proof Materials for Improving Fire Resistance of Near-Surface-Mounted FRP in Concrete
Yeon, Jea-Young ; Seo, Soo-Yeon ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 51~58
DOI : 10.11112/jksmi.2014.18.5.051
This paper presents a fire exposure test result to evaluate fire resistance capacity of retrofit method using FRP (Fiber Reinforced Polymer) in reinforcement concrete structure. Especially, this paper focused on near-surface-mounted retrofit method; FRP is mounted into the groove after making a groove in concrete. In the test, main parameters are retrofit method and materials for fire proofing. Spray type of perlite and board type of calcium silicate were considered as external fire proof on surface while particle of calcium silicate and polymer mortar as internal one in groove. By increasing the temperature of inside heating furnace, the transfer of temperature from surface of fire proofing material to groove in specimen was measured. As a result, fire proofing using the board of calcium silicate was more effective to delay the heat transfer from outside than spraying with perlite. It was found that the fire proofing could resist outside temperature of
at maximum to keep the temperature of epoxy below glass transit temperature (GTT).
Experimental Study on Lap Splice of Headed Deformed Reinforcing Bars in Tension
Kim, Seung-Hun ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 59~67
DOI : 10.11112/jksmi.2014.18.5.059
In tension lap splices of straight deformed bars, KCI Code (KCI2012) and ACI Code (ACI318-11) requires that the lap lengths for class B splice are 1.3 times as development length. KCI2012 contains development length provisions for the use of headed deformed bars in tension and does not allow their tension lap splices. The purpose of this experimental study is to evaluate that KCI2012 equation for the development length,
, of headed bars can be used to calculate the lap length,
, of headed deformed bars in grade SD400 and SD500, having specified yield strength of 400 and 500 MPa. Test results showed that specimens with
had maximum flexural strengths as 1.16~1.31 times as the nominal flexural strengths, flexural failure mode, and ductility. These observations indicate that
is suitable to the tensile lap length of headed deformed bars in grade SD400 and SD500.
Analysis Study on Fatigue Stress on the Orthotropic Steel Deck Applied Polymer Concrete Pavement
Han, Bum-Jin ; Yoon, Sang-Il ; Choi, Byung-Jin ; Choi, Jin-Woong ; Park, Sun-Kyu ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 68~77
DOI : 10.11112/jksmi.2014.18.5.068
In this study, polysulfide epoxy polymer concrete was chosen as an ultra thin bridge deck overlay, and the effect of polymer concrete pavement on the fatigue stress range of the orthotropic steel deck was analyzed through the comparative analysis with epoxy asphalt pavement and SFRC pavement. Abaqus was used to estimate the fatigue stress range, and signed von-mises stress was used to estimate fatigue stress range according to pavement materials and thickness, considering there were multi axis stresses which have longitudinal and lateral direction on the welded parts of the steel deck.
Dependency Evaluation According to Damper Strut Type
Lee, Hyun-Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 78~86
DOI : 10.11112/jksmi.2014.18.5.078
The purpose of this study is the displacement and velocity dependence evaluation of I type and S type metallic dampers. For this purpose, 12 metallic damper specimens are prepared and dependence test are performed. Test variables are strut type, displacement and velocity dependence. From the evaluation results of dependence tests, number of cycles are fully exceeded than minimum 5 cycles described in ASCE 7-10. According to displacement dependence test results, larger target displacement (50mm) shows lower cyclic numbers and cumulated energy dissipated area than lower target displacement (25mm). Also it show higher strength and early failure than short target displacement. In velocity dependence evaluation, fast target velocity (60mm/sec) shows lower cyclic numbers and cumulated energy dissipated area than target velocity (40mm/sec). As a results of basic properties, dependence evaluation and cumulated energy dissipated area evaluation, dependence capacity of S type metallic damper is far superior than I type.
A Study on Controlling the Negative Reaction of Cable Stayed Bridge Considering Constructability and Economy : Vam Cong Cable Stayed Bridge in Vietnam
Lee, Yong-Jin ; Lho, Byeong-Cheol ; Kim, Chang-Kyo ; Bae, Sang-Woon ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 87~95
DOI : 10.11112/jksmi.2014.18.5.087
Cable stayed bridge is supported by cables and the negative reaction occurs by cables at anchor pier. To solve this problem, the proper side span ratio and the negative reaction measure of anchor pier are needed. And structural system of cable stayed bridge is determined by solution of the negative reaction as installation of the intermediate pier, counterweight and so on. In feasibility study, Vam Cong bridge was planned as 5 span cable stayed bridge. However, it was changed to 3 span cable stayed bridge in detailed design because of constructability and economy. The intermediate pier was excluded in order to improve the constructability, and side span ratio increased to control the negative reaction. As a result, Vam Cong bridge secure constructability, structural safety, and efficiency.
A Study on the Characteristics of Bridge Bearings Behavior by Finite Element Analysis and Model Test
Lee, Jae-Uk ; Jung, Hie-Young ; Oh, Ju ; Park, Jin-Young ; Kim, See-Dong ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 96~106
DOI : 10.11112/jksmi.2014.18.5.096
The increased vibration level of the railway bridge could make significant noise and, also, cause structural damages such as fatigue cracks. Related to these subjects, a spherical elastomeric bridge bearing, which is layered by hemispherical rubber and steel plates, was investigated in terms of its vibration performance. Several different shape factors could be considered by changing the curvature of hemispherical surface and size in rubber and steel plate thicknesses in the manufacturing stage. The performance of the spherical elastomeric bearing for the reduction in vibration was compared with that of the conventional bearing by performing vibration experiments on a scale-downed model. The rubber material characteristics and spherical shape are found to be important parameters in reducing the bridge vibration.
Seismic Isolation Effects Due to the Difference Between the Center of Mass of the Building and the Center of Stiffness of Isolation Layer
Hur, Moo-Won ; Chun, Young-Soo ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 107~115
DOI : 10.11112/jksmi.2014.18.5.107
In this study, we examined the seismic isolation effects due to the difference between the center of mass of the building and the center of stiffness of isolation layer. Because the base isolation technique is a technique that is highly dependent on the performance of seismic isolation devices installed on the seismic isolation layer, we have to examine the horizontal stiffness of seismic isolation devices after making them. If difference between the design stiffness and the actual stiffness of the seismic isolation device occurred, a big problem may be generated in the upper members on the seismic isolation layer. The analytical results show that the more eccentricity increases, the more maximum response acceleration, story shear and the member forces of the upper part of the structure increases, and the damage is expected to be in excess. Therefore, it is recommended that if possible, isolation devices have to be designed to coincide the center of mass of the building with the center of stiffness of isolation layer. If not after making isolation devices, they need to be relocated to prevent the eccentricity.
Research of Early-age Strength Development Technology for Remove the Steel Form of Large-wide Tunnel Lining Concrete
Kim, Kwang-Don ; Lee, Deuk-Bok ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 116~127
DOI : 10.11112/jksmi.2014.18.5.116
The studies were carried out to process one cycle for a day to the large section tunnel lining concrete. Climatic characteristics of the tunnel inside are changed, when the temperature of the concrete placement is low, the mold remove time is increased that the heat of hydration speed be delayed because affects the strength development, to compensate for this, after installing the curing sheet on both sides of the steel form and installation of tunnel entrance, when it comes to providing the additional heat source of
therein, it was to be achieved early strength development control standards (4.5MPa) presented as a crack control scheme or more, thus, It was able to remove after age of 14hr from mold. On the other hand, under the conditions of
that a natural curing temperature in the tunnel, it was analyzed must ensure the curing time of 36hr or more after concrete placement. Throughout this study, the concrete strength development and the temperature in the early-age concrete, it can find that reverify the curing temperature is greatly affected, even concrete fly ash is mixed 10%, if it is possible to raise the surface temperature for a predetermined time, is not a problem in the early strength development.
An Experimental Study on the Fire Monitoring System for Tunnel Using SMA and Fiber Optic Cable
Hwang, Ji-Hyun ; Park, Ki-Tae ; Lee, Kyu-Wan ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 5, 2014, Pages 128~134
DOI : 10.11112/jksmi.2014.18.5.128
Recently, design and construction of street tunnels tend to focus on cost reduction and preservation of nature. Accordingly, research is actively being carried out to quickly detect fires when they occur in tunnels, which have partially closed structures. Among such research, fire detection methods using optical fiber sensors have a wide bandwidth and fast transmission speed, while using light as a medium. Therefore, it does not receive electrical interference and there is almost no loss of information during transmission, while also having little noise as well. In relation to this, a fire monitoring system that can accurately detect the location of fires in real time using shape memory alloy and optical cables was developed in this study. In order to verify the developed method, light loss measurement test was conducted according to indoor temperature changes, while also conducting fire simulation tests by installing test beds in common underground zones with different external environments of temperature and distance. Upon carrying out experiments, the fire monitoring system developed in this study was found to be able to detect fires in long distance sections in real time.