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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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 19, Issue 6 - Nov 2015
Volume 19, Issue 5 - Sep 2015
Volume 19, Issue 4 - Jul 2015
Volume 19, Issue 3 - May 2015
Volume 19, Issue 2 - Mar 2015
Volume 19, Issue 1 - Jan 2015
Selecting the target year
A Suggestion of Blasting Patterns of a Mine closed to Railway Line for Securing Safety of High Speed Train
Kim, Hyun-Ki ; Lee, Sung-Hyeok ; Lee, Jin-Wook ; Choi, Chan-Yong ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 1~9
DOI : 10.11112/jksmi.2015.19.5.001
Recently Honam high-speed railroad line is constructed in southern part of Korea. This line is for next generation HST named HEMU-430X. But there is a limestone mine near this line and this mine will make a process to dig a passageway under the railway line. In this case, safety of railroad system and stability of mine are crucial problems on both sides. By measuring mine blasting vibration and calculating regression equation, effect of mine blasting to train running is investigated quantitatively. 0.5 kine (cm/sec) is applied as a management specification of vibration based on field measurement. In this study, changes of blasting patterns are suggested to control vibration of mine blasting. And the effect of train vibration to mine is also invesitigated by numerical analysis.
Strengthening Effect of Axial Circular Concrete Members Wrapped by CFRP sheet
Moon, Kyoung-Tae ; Park, Sang-Yeol ; Kim, Moon-Kwan ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 10~21
DOI : 10.11112/jksmi.2015.19.5.010
Many studies have been carried out on carbon fiber-reinforced plastic sheet(hereafter CFRP sheet)-confined concrete specimens for improve structural performance of concrete structures. To complement the existing studies, a parametric study is conducted to examine the effect of various design parameters such as layers of CFRP sheet, size and aspect ratio of specimens, and overlap length. The behavior of CFRP-confined concrete is compared using stress-strain curves of each specimen. And the strengthening effect of CFRP sheet is examined by maximum compressive strength. As the layers of CFRP sheet increases, structural performance of CFRP-confined concrete is significant increased. If the overlap length is more than 5% of circumstance, strengthening effect is not affected. In addition, a test database assembled from test results and existing studies is presented. Using these test database, accuracy and reliability of the existing strength models for CFRP-confined concrete are verified.
Lightweight Concrete Fracture Energy Derived by Inverse Analysis
Lee, Kyeong-Bae ; Kwon, Min-Ho ; Seo, Hyun-Su ; Kim, Jin-Sup ; Cho, Jae-Young ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 22~29
DOI : 10.11112/jksmi.2015.19.5.022
Modern structures is the tendency of being increasingly taller and larger. The concrete with large weight has the disadvantage of increasing the weight on the structure. therefore, the method of carrying out the weight saving of the concrete is required. one of such method is to use a lightweight aggregate. However, studies on structural lightweight concrete, lacking for the recognition of the lightweight concrete, so also is lacking. therefore it is necessary to study on the physical characteristic value of the lightweight concrete. In this study, in order to investigate the tensile properties of lightweight concrete, Crack mouth opening displacement (CMOD) experiments were carried out. the fracture energy of the lightweight concrete subjected to inverse analysis were derived from the CMOD experimental results.
Estimation of System Damping Parameter Using Wavelet Transform
Lee, Seok-Min ; Jung, Beom-Seok ; Hong, Seok-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 30~37
DOI : 10.11112/jksmi.2015.19.5.030
The estimation of system damping parameter of the response signal with lower natural frequency and higher damping parameter from free vibration is affected by the wavelet center frequency. This study discusses these considerations in the context of the wavelet's multi-resolution character and includes guidelines for selection of wavelet center frequency. The experiment with H-Beam and numerical examples with respect to three cases (i)single mode, (ii)separated modes and (iii)close modes demonstrate the validity of method to improve the accuracy of the estimated damping parameter. The localization of the corresponding scale for the total scales is determined by the natural frequency of the analysing mode and is affected by the wavelet center frequency. Thus, the reliability for the accuracy of the estimated damping parameter can be improved by the corresponding scale of the natural frequency for the analysing mode is localized at the half of the total scales.
Vibration Control Effect of the Framed Building Structures according to the Stiffness Ratio of Exo-type Damping System and Damper Device Yield Ratio
Hur, Moo-Won ; Lee, Sang-Hyun ; Chun, Young-Soo ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 38~44
DOI : 10.11112/jksmi.2015.19.5.038
In this paper, the vibration control effect of the Exo-type damping system was investigated by applying the Kagome dampers to 15-story and 20-story frame structure apartment. A new Exo-type damping system composed of the dampers and supporting column was proposed in the previous work and numerical analysis were performed to investigate the effects of optimum stiffness ratio between controlled structure and supporting column, the size of damper and yield ratio of the damper. The numerical analysis results of a structure with Exo-type damping system up to the third story showed that the stiffness ratio should be higher than 7.0 and the damper device yield ratio be at least 8.0% (
) to effectively reduce the base shear and the maximum drift of the uppermost story. When the Exo-type damping system was installed up to the fifth story, the stiffness ratio should be higher than 2.5 and damper device yield ratio needs to be at least 3.5% (
) for obtaining the target performance.
Performance Based Evaluation of Concrete Carbonation from Climate Change Effect on Curing Conditions of Wind Speed and Sunlight Exposure Time
Kim, Tae-Kyun ; Shin, Jae-Ho ; Choi, Seung-Jai ; Kim, Jang-Ho Jay ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 45~55
DOI : 10.11112/jksmi.2015.19.5.045
Currently, extreme weather events such as super typhoon, extreme snowfall, and heat wave are frequently occurring all over the world by natural and human caused factors. After industrial growth in the 1970s, earth's temperature has risen sharply. due to greenhouse effect. Global warming can be attributed to gases emitted from using fossil fuel such as average carbon dioxide, perfluorocarbons, nitrous oxide, and methane. Especially, carbon dioxide has the highest composition of about 90%. in the fossile fuel usage emitted gas. Concrete has excellent durability as a building material climate change. However, due to various of physical and chemical environmental effect such as conditions during its curing process, the performance degradation may occur. Carbon dioxide in the atmosphere causes steel corrosion and durability decreases by lowering the alkalinity of concrete. Therefore, in this study, concrete durability performance with respect to carbonation from curing conditions change due to wind speed and sunshine exposure time. Concrete carbonation experiment are performed. using wind speed (0, 2, 4, 6) m/s and sunlight exposure time (2, 4, 6, 8) hrs. Also, performance based evaluation through the satisfaction curve based on the carbonation depth and carbonation rate test results are performed.
Analysis on the Flexural Behavior of Existing Reinforced Concrete Beam-Column Structures Infilled with U-Type Precast Wall Panel
Son, Guk-Won ; Yu, Sung-Young ; Lim, Cheol-Woo ; Ju, Ho-Seong ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 56~66
DOI : 10.11112/jksmi.2015.19.5.056
This study aims at developing a new seismic resistant method by using precast concrete wall panels for existing low-rise, reinforced concrete beam-column buildings such as school buildings. Three quasi-static hysteresis loading tests were performed on one unreinforced beam-column specimen and two reinforced specimens with U-type precast wall panels. Seismic resistant test of anchored and welded steel plate connections manifested an average of 2.8 times increase in the maximum loading (average 591.8 kN) in comparison to unreinforced beam-column specimen. The maximum drift ratios were also shown between 1.4% and 2.7%. An analytical study was performed while assuming the RC column on the right side and the vertical element of the reinforced PC panel to behave in completely composite manner and the RC column on the left side and PC panel to behave in completely non-composite manner when loading was exerted from upper right end of RC frame of specimen to its left side. It was found with the assumptions that the overall flexural behavior in principle agreed with the experimental result.
Evaluation of Service Life in RC Column under Chloride Attack through Field Investigation: Deterministic and Probabilistic Approaches
Kwon, Seung-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 67~74
DOI : 10.11112/jksmi.2015.19.5.067
RC (Reinforced Concrete) structures are considered as cost-benefit and durable however performances of structural safety and durability are degraded due to steel corrosion. Service life in RC structure is differently evaluated due to different local environmental conditions even if it is exposed to the same chloride attack. In the paper, 25 concrete cores from field investigation are obtained from 4 RC columns with duration of 3.5~4.5 years exposed to sea water. Through total chloride content measurement, surface chloride contents and apparent diffusion coefficients are evaluated. Service life of the target structure is estimated through deterministic method based on Fick's
Law and probabilistic method based on durability failure probability, respectively. Probability method is evaluated to be more conservative and relatively decreased service life is evaluated in tidal zone and splash zone over 40.0 m. Chloride penetration behavior with coring location from sea level and the present limitations of durability design method are investigated in the paper.
Development Length Effects of High Strength Headed Bar
Moon, Jeong-Ho ; Oh, Young-Hun ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 75~82
DOI : 10.11112/jksmi.2015.19.5.075
An experimental study has been carried out to examine development length effects for high strength headed deformed bars. Current design codes limit the specified yield strength of headed bars to 400 MPa. Such the limit is due to the lack of experimental studies on headed bars made of high strength materials. Thus a test program was planed with headed bars with the yield strength of 600 MPa. The threaded head type with head shapes of round plate and circular cone was selected in this study. The experimental variables were development length, number of bars, and head shape. Specimens were classified into L-type and S-type depending on the development length. The development length of L-type was computed according to the design code without considering the limit. S-type specimens had shorter development lengths than the L-type. Further classification was made depending on the shape of heads. A-types have the head shape of round plate and B-types have the shape of circular cone. Three L-type specimens were fabricated with the variable of number of bars (1, 2, and 3). Four specimens for each of SA and SB types were made with development lengths of 50%, 45%, 40%, and 35% compared with L-type. Pullout tests was carried out with 11 specimens. The test results were compared with computed strengths with the design code equations (Appendix II). Based the current studies, it can be said that high strength headed deformed bars used in this study be able to provide such strengths computed with the current design code without considering the yield strength limit.
Analysis Technique for Chloride Penetration using Double-layer and Time-Dependent Chloride Diffusion in Concrete
Mun, Jin-Man ; Kim, Jin-Yeong ; Kim, Young-Joon ; Oh, Gyeong-Seok ; Kwon, Seung-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 83~91
DOI : 10.11112/jksmi.2015.19.5.083
With varying conditions of concrete surface, induced chloride contents are changed and this is a key parameter for steel corrosion and service life in RC (Reinforced Concrete) structures. Many surface enhancement techniques using impregnation have been developed, however the evaluation techniques for chloride behavior through doubly layered media and time-dependent diffusion are rarely proposed. This paper presents an analysis technique considering double-layer concrete and time-dependent diffusion behavior, and the results are compared with those from the previous test results through reverse analysis. The chloride profiles from the surface-impregnated concrete exposed to atmospheric, tidal, submerged zone for 2 years are adopted. Furthermore surface chloride contents and diffusion coefficients are obtained, and are compared with those from Life365. Through consideration of time effect, the relative error decreases from 0.28 to 0.20 in atmospheric, 0.29 to 0.11 in tidal, and 0.54 to 0.40 in submerged zone, respectively, which shows more reasonable results. Utilizing the diffusion coefficients from Life365, relative errors increases and it needs deeper penetration depth (e) and lower diffusion coefficient ratio (
) due to higher diffusion coefficient.
Box-Wilson Experimental Design-based Optimal Design Method of High Strength Self Compacting Concrete
Do, Jeong-Yun ; Kim, Doo-Kie ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 92~103
DOI : 10.11112/jksmi.2015.19.5.092
Box-Wilson experimental design method, known as central composite design, is the design of any information-gathering exercises where variation is present. This method was devised to gather as much data as possible in spite of the low design cost. This method was employed to model the effect of mixing factors on several performances of 60 MPa high strength self compacting concrete and to numerically calculate the optimal mix proportion. The nonlinear relations between factors and responses of HSSCC were approximated in the form of second order polynomial equation. In order to characterize five performances like compressive strength, passing ability, segregation resistance, manufacturing cost and density depending on five factors like water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content, the experiments were made at the total 52 experimental points composed of 32 factorial points, 10 axial points and 10 center points. The study results showed that Box-Wilson experimental design was really effective in designing the experiments and analyzing the relation between factor and response.
Mechanical Properties of Granulated Ground Blast Furnace Slag on Blended Activator of Sulfate and Alkali
Kim, Tae-Wan ; Jun, Yu-Bin ; Eom, Jang-Sub ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 104~111
DOI : 10.11112/jksmi.2015.19.5.104
This study shows the mechanical properties of alkali-activated slag cement (AASC) synthesized using sulfate with NaOH solution. The used sulfates were calcium sulfate (
, denoted CS) and sodium sulfate (
, denoted SS). The replacement ratio of sulfates was 2.5, 5.0, 7.5 and 10.0% by weight of slag. NaOH solution of 2M and 4M concentration was used. A sample was activated with sulfate and activated with blended activator (blending NaOH solution with sulfate) respectively. 24 mix ratios were used and the water-binder weight ratio for the test was set 0.5. This research carried out the compressive strength, flexural strength, ultrasonic pulse velocity (UPV), absorption and X-ray diffraction (XRD). In the case of samples with CS, sample with 7.5% CS, sample with 2M NaOH+5.0% CS and sample with 4M NaOH+5.0% CS showed the good performance in the strength development. In the case of samples with SS, sample with 10.0% SS, sample with 2M NaOH+7.5% SS and sample with 4M NaOH+2.5% SS obtained good performance in strength. The results of UPV and water absorption showed a similar tendency to the strength properties. The XRD analysis of samples indicated that the hydration products formed in samples were ettringite, CSH and silicate phases. In this study, it is indicated that when compared to the use of sulfate only, the use of both sulfate and NaOH solution makes mechanical properties of AASC better.
Capacity Development of Existing Frame by Aramid Sheet and Energy Dissipation Device
Lee, Hyun-Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 19, issue 5, 2015, Pages 112~119
DOI : 10.11112/jksmi.2015.19.5.112
In this paper, the strengthening method was proposed for improving the seismic performance of the vulnerable structural frames. To improve the brittle characteristics of columns, aramid fiber sheet was used for the lateral confinement of columns. And to introduce the energy dissipation capacity, a steel damper with S-shaped struts was installed. By making the unreinforced and reinforced specimens with full size specimens were evaluated for lateral load resistance capacity. It was confirmed the strengthening effects by the evaluation of failure shape, strength, stiffness degradation, and energy dissipation capacity. Also from the FE analysis using ABAQUS, the hysteretic behavior of the specimens were predicted and evaluated.