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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 20, Issue 5 - Sep 2016
Volume 20, Issue 4 - Jul 2016
Volume 20, Issue 3 - May 2016
Volume 20, Issue 2 - Mar 2016
Volume 20, Issue 1 - Jan 2016
Selecting the target year
Estimating the Compressive Strength of High-Strength Concrete Using Surface Rebound Value and Ultrasonic Velocity
Kim, Min Wook ; Oh, Hongseob ; Oh, Kwang Chin ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 1~9
DOI : 10.11112/jksmi.2016.20.2.001
The authors performed the experimental work to propose the strength prediction equation for high strength concrete based on the non-destructive test methods. The concrete specimens that the range of design compressive strength was 40~80 MPa was produced in laboratory, and then tested rebound test and ultrasonic velocity methods and also compressive test according to the Korea Standard. The test results was compared with previously equations suggested by other researcher. From the test, these traditional nondestructive methods are simple, quick, has proven to be reliable and useful method for predicting the concrete strength. The test results were compared with the previous equations and then newly proposed own equations based on the test results. The proposed equations have the suitable precision and accuracy for applying the high strength concrete structures.
Evaluation of Load Capacity Reduction in RC Beam with Corroded FRP Hybrid Bar and Steel
Oh, Kyung-Suk ; Moon, Jin-Man ; Park, Ki-Tae ; Kwon, Seung-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 10~17
DOI : 10.11112/jksmi.2016.20.2.010
Steel corrosion is a very significant problem both to durability and structural safety since reinforcement has to support loads in tensile region in RC(Reinforced Concrete) member. In the paper, newly invented FRP Hybrid Bar and normal steel are embedded in RC beam member, and ICM (Impressed Current Method) is adopted for corrosion acceleration. Utilizing the previous theory of Faraday's Law, corrosion amount is calculated and flexural tests are performed for RC beam with FRP Hybrid Bar and steel, respectively. Corrosion amount level of 4.9~7.8% is measured in normal RC member and the related reduction of flexural capacity is measured to be -25.4~-50.8%, however there are no significant reduction of flexural capacity and corrosion initiation in RC samples with FRP Hybrid Bar due to high resistance of epoxy-coated steel to corrosion initiation. In the accelerated corrosion test, excellent performance of anti-corrosion and bonding with concrete are evaluated but durability evaluation through long-term submerged test is required for actual utilization.
Analysis of Bascule Bridge Behavior Based on Measurement Data
Kong, Byung-Seung ; Noh, Dong-Oh ; Kyung, Kab-Soo ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 18~25
DOI : 10.11112/jksmi.2016.20.2.018
Bascule bridge, with its use to help vessels ply, has a several examples overseas of being serviced for more than decades years by careful maintenance, admitted its significance as landmarks for its rareness. Yeongdo Bridge, the sole bascule bridge in Korea was reconstructed in 2013 after being demolished because of its corrosion and aging, and now operates once in a day. Recently, safety inspections are executed thanks to demands getting higher for maintenance and safety of bridges, but measurement and analysis about bascule bridges are scarce. This study includes the analysis of the bascule bridge's behavior such as stress, vibration and reaction in normal condition and while it lifts up, based on measurement. We expect that this study will be used as an initial data to compare and confirm bridge's changes as service year and the number of operation increase.
Strength and Pore Characteristics of Alkali-activated Slag-Red Mud Cement Mortar used Polymer According to Red Mud Content
Kwon, Seung-Jun ; Kang, Suk-Pyo ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 26~33
DOI : 10.11112/jksmi.2016.20.2.026
The alkali-slag-red mud(ASRC) cement belongs to clinker free cementitious material, which is made from alkali activator, blast-furnace slag(BFS) and red mud in designed proportion. This study is to investigate strength and pore characteristics of alkali-activated slag cement(NC), clinker free cementitious material, and ordinary portland cement(C) mortars using polymer according to red mud content. The results showed that the hardened alkali-activated slag-red mud cement paste was mostly consisted of C-S-H gel, being very fine in size and extremely irregular in its shape. So the hardened ASRC cement paste has lower total porosity, less portion of larger pore and more portion of smaller pore, as compared with those of hardened portland cement paste, and has higher strength within containing 10 wt.(%) of alkali-activated slag cement(NC) substituted by red mud.
A Long-Term Friction Test of Bridge Bearings Considering Running Speed of Next Generation Train
Oh, Soon-Taek ; Lee, Dong-Jun ; Jun, Sung-Min ; Jeong, Shin-Hyo ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 34~39
DOI : 10.11112/jksmi.2016.20.2.034
Structural behaviour of PSC box bridge, on which KTX train runs, is analysed up to 500 km/h speed considering 12 stages track irregularity and interaction between bridge and vehicle. To evaluate wheel forces and rotations of vehicle, lateral wheel forces, derail factor and offload factor calculated on the track combining the bridge and 170 m normal track are compared with existing allowed limits. Maximum longitudinal displacement and accumulated sliding distance of the brige bearings for simply supported and 2 span continuous PSC bridges are presented by each running speeds. Long-term friction tests based on EN-1337-2 are conducted between PTFE and DP-mate plates. Finally, the long-term friction tests are proposed to consider the increasing speed of next generation high-speed train.
Safety Evaluation on Interaction between Track and Bridge in Continuous Welded Railway Bridge Considering Seismic Load
Shim, Yoon-Bo ; Kim, Yun-Tae ; Kim, Sang-Chel ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 40~48
DOI : 10.11112/jksmi.2016.20.2.040
To observe the rail-slab interaction in continuous welded railway(CWR) bridge when earthquake occurs, additional axial rail stresses and relative longitudinal displacements between rail and bridge deck were calculated with input of various load combinations and 3 different types of seismic loads to an analytical model. As results of analysis, it can be found that standard response spectrum proposed by Korea Rail(KR) network authority for earthquake design showed less additional axial rail stresses than allowable levels, but greater relative longitudinal displacement between rail and bridge deck, which means that adjustment of relative longitudinal displacement within a standard level is much more difficult than axial train stress. Additionally, if a large-scaled earthquake as occurred at Kobe, Japan comes up, then both of additional axial rail stress and relative displacement in rail-bridge deck may exceed allowable levels, which indicates to make proper design guides against sudden earthquake occurrence.
Mechanical Properties and Predictions of Strength of Concrete Containing Recycled Coarse Aggregates
Yang, In-Hwan ; Kim, Kyoung-Chul ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 49~59
DOI : 10.11112/jksmi.2016.20.2.049
According to KS and Standard Specifications for Concrete, the compressive strength of concrete containing recycled aggregate is limited to 27 MPa and thereafter there are little research on concrete containing recycled aggregate of its compressive strength of greater than 27 MPa. Therefore, to expand the applicability of concrete recycled coarse aggregate(RCA), this paper concerns the mechanical properties of concrete containing RCA with compressive strength ranging from 30 to 60 MPa. The experimental parameters were water-cement ratio and replacement ratio of RCA. Water-cement ratio(w/c) was 0.36, 0.46 and 0.53, and replacement ratio of RCA was 30, 50, 70 and 100%. The experimental results were discussed about compressive strength, elastic modulus, split tensile strength and modulus of rupture. Test results of elastic modulus were compared to the design code predictions. Experimental elastic modulus for concrete with w/c=0.53 decreased by greater than 10% compared with that for concrete with w/c=0.36. The design code predictions for elastic modulus overestimated the experimental results. Whereas, the design code predictions for modulus of rupture underestimated the measured values.
Studies on the Water Resistance Properties of the Polyurethane Foam Silicone Foal Control Agent according to the Type of Silicone Foam Stabilizer
Kim, Keun-Hur ; Kim, Hyun-Min ; Kim, Sung-Rae ; Kim, Young-Geun ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 60~66
DOI : 10.11112/jksmi.2016.20.2.060
Polyurethane foam index a of the cell structure and the absorption change by using the foam stabilizer of six to investigate the polyurethane foam index producing the agent to the siloxane analyzed with silicon foam stabilizer with FE-SEM in accordance with the characteristics of the silicon-based foam stabilizer cell structure of the primary DC-193 on the chain ends is PO n dog bond, DC-2585, DC-5125, DC-198 has been confirmed as a close cell, silicone surfactant is combined EO n dog to a siloxane main chain terminus DC-5043 and DC-5598 that appeared to open cell structure. In addition, most absorption of the DC-5043 appeared was the size of the open cell greatest formed by the absorption of the cell structure change this absorption of the size of the close cell most detailed and uniform DC-193 appeared small household water-resistant best many showed. The performance test of the water was found to be excellent.
Mechanical Property of Fiber Reinforced Concrete according to the Change of Curing Method
Kim, Chun-Ho ; Kim, Nam-Wook ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 67~73
DOI : 10.11112/jksmi.2016.20.2.067
When assessing crack initiation of fiber reinforced concrete, usually tensile strength or flexural strength is becomes indicator, but also depend on the curing effect take place during the production of specimen. In general, after conducting concrete specimen is cured by water at temperature
in laboratory, and accomplished the assessment of strength, but most of concrete structure is kept in drying condition after moist curing through the prescribed period. However, unlike these trends that technological advances have been made, influence of the difference of curing method on crack strength is not yet clear. Therefore, in this study, it is examined on the effect of curing methods affecting the mechanical property of fiber reinforced concrete, especially crack strength.
Influence of Analytical Models on the Seismic Response of Modular Structures
Choi, Kyung-Suk ; Lee, Ho-Chan ; Kim, Hyung-Joon ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 74~85
DOI : 10.11112/jksmi.2016.20.2.074
Seismic design of modular structures is usually carried out under the assumption that their load-carrying mechanism is similar to that of traditional steel moment-resisting frames(SMRFs). However, the load carry mechanism of modular structures would be different with that of traditional SMRFs because of their overlapped structural elements and complicated details of connections for the assembly of the unit-modules. In this study, nonlinear static analyses of 3 and 5-story prototype modular structures have been carried out with four different analytical models, which are established in consideration for the effects of overlapped elements and the hysteretic behavior of connections. Prototype structures present different lateral stiffness and strength depending on the modeling of overlapped elements and the rotational behavior of connections. For modular structures designed under assumption that overlapped structural elements are fully composite each other and connections between unit-modules are fixed, their lateral strength and stiffness can be over-estimated. Furthermore, it is known from the analysis results that modular structures with more than 3-stories would possess relatively low overstrength compared to traditional SMRFs.
Cavity Detection of Chamber by GPR
Lee, Hyun-Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 86~93
DOI : 10.11112/jksmi.2016.20.2.086
To find the buried pipes and cavities, GPR detection were proceed by the type and depth of underground pipes and cavities buried in the Chamber. In the case of asphalt pavement and non-pavement, the exploration of buried pipe were easy than the concrete and reinforced concrete pavement. In the case of air cavity, the buried depth of 1 m was evaluated as the detection was possible.
Sulfate Resistance of Alkali-Activated Materials Mortar
Park, Kwang-Min ; Cho, Young-Keun ; Lee, Bong-Chun ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 94~101
DOI : 10.11112/jksmi.2016.20.2.094
This paper presents an investigation into the durability alkali-activated materials(AAM) mortar and paste samples manufactured using fly-ash(FA) and ground granulated blast furnace slag(GGBFS) exposed to a sulfate environment with different GGBFS replace ratios(0, 30, 50 and 100%), sodium silicate modules(
1.0, 1.5 and 2.0) and initial curing temperatures(
). The tests involved immersions for a period of 6 months into 10% solutions of sodium sulfate and magnesium sulfate. The evolution of compressive strength, weight, length expansion and microstructural observation such as x-ray diffraction were studied. As a results, as higher GGBFS replace ratio or Ms shown higher compressive strengths on 28 days. In case of immersed in 10% sodium sulfate solution, the samples shows increase in long-term strength. However, for samples immersed in magnesium sulfate solutions, the general observation was that the compressive strength decreased after immersion. The most drastic reduction of compressive strength and expansion of weight and length occurred when GGBFS or Ms ratios were higher. Also, the XRD analysis of samples immersed in magnesium sulfate indicated that expansion of AAM caused by gypsum(
); the gypsum increased up to 6 months continuously.
Chloride Diffusivity of Concrete using Recycled Aggregate by Strength Levels
Lee, Jun ; Lee, Bong-Chun ; Cho, Young-Keun ; Jung, Sang-Hwa ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 102~109
DOI : 10.11112/jksmi.2016.20.2.102
This paper presents mechanical properties and chloride diffusivity of the recycled aggregate concretes(RAC) in which natural coarse aggregate was replaced by recycled coarse aggregate(RCA) by compressive strength levels(20, 35, 50 MPa). A total of 9 RAC were produced and classified into three series, each of which included three mixes designed with three compressive strength levels of 20 MPa, 35 MPa and 50 MPa and three RCA replacement ratios of 0, 50 and 100%. Engineering properties of RAC were tested for slump test, air content, compressive strength, chloride penetration depth and chloride diffusion coefficient. The test results indicated that the workability of RAC could be improved or same by RCA replacement ratios, when compared with that containing no RCA. This is probably because of the RCA shape improving the workability of RAC. Also, the test results showed that the compressive strength was decreased by 9~10% as the RCA replacement ratios increase. Furthermore, the result indicated that the measured chloride diffusion coefficient increases by 144% with the increase of the RCA replacement. In the case of the concrete having low level compressive strength, the increase of chloride diffusion coefficient tends to be higher when using the RCA. However, the trend of chloride diffusion coefficient in high level compressive strength concrete is similar to that obtained in general concrete. This is because that the effect of the RCA replacement could be a decrease with increase of compressive strength. Therefore, an advance on the admixture application and mix ratio control are required to improve the chloride resistivity when using the recycled aggregate in large scale.
Analysis of Life Cycle Costs of Railway Track : A Case Study for Ballasted and Concrete Track for High-Speed Railway
Jang, Seung Yup ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 110~121
DOI : 10.11112/jksmi.2016.20.2.110
In the decision-making, such as selection of structure, construction method, or time and scheme of maintenance, the evaluation of life-cycle cost(LCC) is of great importance. The maintenance cost occupy a large portion of the LCC of the railway track as well as the initial construction cost. Futhermore, the proportion of the maintenance cost is much higher in the ballasted track. Thus, the importance of the LCC evaluation is higher than in any other engineering structures. In this study, a LCC model that can consider various design parameters such as the type of track structure, annual traffic volume, axle load, train speed, and proportion of curve sections and engineering structures has been developed. Fundamental data for calculating costs also have been presented. Based on the model and data proposed, the trends in the variation of LCC according to the design parameters were examined and the most important design parameters in the LCC analysis of railway track were investigated. The results show that the proportion of renewal and operational costs is much higher in the ballasted track than in the concrete track, and the annual traffic volume and ballast taming period are most significant factors on the LCC of the ballasted track. On the contrary, it is revealed that the proportion of the initial construction costs in the concrete track is much higher, and the LCC of the concrete track is less sensitive to the traffic volume, train speed, and axle load.
Evaluation of Hydraulic Stability Using Real Scale Experimental on Porous Concrete Revetment Block
Kim, Bong-Kyun ; Seo, Dae-Seuk ; Park, Jun-Seok ; Kim, Yun-Yung ;
Journal of the Korea institute for structural maintenance and inspection, volume 20, issue 2, 2016, Pages 122~130
DOI : 10.11112/jksmi.2016.20.2.122
The past few decades of industrialization enabled human-centered stream developments, which in turn resulted in constructing straight or covered streams, which are used only for sewage disposal purpose. However, these types of streams have become the cause of flood damages such as localized heavy rain. In response, various construction methods have been implemented to prevent stream and embankment damages. However, regulations regarding these measures only lay out minimum standards such as the height of slopes and the minimum angle of inclination. Moreover, examination of tractive force, the most crucial factor in preventing flood damage, is nonexistent. Therefore, this study evaluates various tractive forces by implementing a porous concrete tetrapod at a full scale artificial stream for experiment, controlling the rate of inflow, and measuring the velocity and depth of the stream under different experiment conditions. The test results of the compressive strength, and porosity and density of rock of the porous concrete tetrapod was between 16.6 and 23.2 MPa, and the actual measurement of air void was 10.1%, thus satisfying domestic standard. The result of tractive force experiment showed a limiting tractive force of
, not satisfying the tractive force scope of
the stream design working expertise proposes. However, there was neither damage nor loss of blocks and hardpan. Based on previous researches, it can be expected that there will be resistance against a stronger tractive force. Therefore, it is necessary to conduct another experiment on practical limiting tractive force by adjusting some experimental conditions.