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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
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Journal DOI :
Korea Institute for Structural Maintenance Inspection
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Volume & Issues
Volume 17, Issue 6 - Nov 2013
Volume 17, Issue 5 - Sep 2013
Volume 17, Issue 4 - Jul 2013
Volume 17, Issue 3 - May 2013
Volume 17, Issue 2 - Mar 2013
Volume 17, Issue 1 - Jan 2013
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Augmented Reality (AR)-Based Sensor Location Recognition and Data Visualization Technique for Structural Health Monitoring
Park, Woong Ki ; Lee, Chang Gil ; Park, Seung Hee ; You, Young Jun ; Park, Ki Tae ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 1~9
DOI : 10.11112/jksmi.2013.17.2.001
In recent years, numerous mega-size and complex civil infrastructures have been constructed worldwide. For the more precise construction and maintenance process management of these civil infrastructures, the application of a variety of smart sensor-based structural health monitoring (SHM) systems is required. The efficient management of both sensors and collected databases is also very important. Recently, several kinds of database access technologies using Quick Response (QR) code and Augmented Reality (AR) applications have been developed. These technologies provide software tools incorporated with mobile devices, such as smart phone, tablet PC and smart pad systems, so that databases can be accessed very quickly and easily. In this paper, an AR-based structural health monitoring technique is suggested for sensor management and the efficient access of databases collected from sensor networks that are distributed at target structures. The global positioning system (GPS) in mobile devices simultaneously recognizes the user location and sensor location, and calculates the distance between the two locations. In addition, the processed health monitoring results are sent from a main server to the user's mobile device, via the RSS (really simple syndication) feed format. It can be confirmed that the AR-based structural health monitoring technique is very useful for the real-time construction process management of numerous mega-size and complex civil infrastructures.
A Regression-Based Estimation of Strain Distribution for Safety Monitoring of the Steel Girder Subjected to Uncertain Loads
Lee, Ji Hoon ; Choi, Se Woon ; Park, Hyo Seon ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 10~20
DOI : 10.11112/jksmi.2013.17.2.010
To evaluate the safety of a beam structure, strains are measured as an indicator of structural states. However, unless strain sensors are installed exactly on where maximum or other representative strains occur, the techniques by which rational assessment through measured strains is accomplished are required. Thus, this study suggests a process to estimate strain distribution on the steel beam from discrete strains measured by sensors. In the presented technique, the targeted beam is regarded to be subjected to unknown loads so that applicability is enhanced. Final strain distribution is given as form of a function after regression analysis. To verify the performance of estimation, a bending test for steel beam on which distributed and concentrated loads simultaneously act is conducted. From the comparison between estimated and directly measured strains in the test, the curve of strain distribution and the strain at arbitrary location could be predicted within maximum relative error 3.32% and maximum absolute error of
, respectively. Thus reliable and practical monitoring is expected to apply effectively for the steel beam structure.
Real-time Feedback Vibration Control of Structures Using Wireless Acceleration Sensor System - System Design and Basic Performance Evaluation -
Jeon, Joon Ryong ; Park, Ki Tae ; Lee, Chin Ok ; Heo, Gwang Hee ; Lee, Woo Sang ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 21~32
DOI : 10.11112/jksmi.2013.17.2.021
This is a preliminary study for the real-time feedback vibration control of building structures. The study developed a wireless acceleration sensor system based on authentic technology capacities, to integrate with the Prototype AMD system and ultimately construct the feedback vibration control system. These systems were used to evaluate the basic performance levels of the control systems within model building structures. For this purpose, the study first developed a wireless acceleration sensor unit that integrates an MEMS sensor device and bluetooth communication module. Also, the study developed an operating program that enables control output based on real-time acceleration response measurement and control law. Furthermore, the Prototype AMD and motor driver system were constructed to be maneuvered by the AC servo-motor. Eventually, all these compositions were used to evaluate the real-time feedback vibration control system of a 2-story model building, and qualitatively measure the extent of vibrational reduction of the target structure within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within 1st and 2nd resonance frequency as well as the random frequency of the model building structure. Ultimately, this study confirmed the potential of its wireless acceleration sensor system and AMD system as an effective tool that can be applied to the active vibration control of other structures.
Local Behavior of Structural Details for Orthotropic Steel Deck Bridge with Longitudinal Rib of Open Section and Retrofitting Method of Fatigue Cracks
Lee, Sung Jin ; Kyung, Kab Soo ; Lee, Hee Hyun ; Jeon, Jun Chang ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 33~44
DOI : 10.11112/jksmi.2013.17.2.033
Although many studies have been performed for the structural details of orthotropic steel deck, most of them were focused on the trough rib of standard type, but not for orthotropic steel deck with longitudinal rib of open section used at beginning of the deck. In order to investigate the cause of fatigue crack for orthotropic steel deck bridge serviced 31 years with longitudinal rib of open section, in this study, the behavior characteristics of target structural details were analyzed based on measurement data under real traffic condition. Also the typical loading truck passing the target bridges was estimated with the structural analysis detailed, and the stresses and deformation patterns of target structural details were analyzed by performing the detailed structural analysis. Based upon the analysis, retrofitting methods of the fatigue crack were suggested and its validation was examined. From this study, it was clarified that fatigue crack of longitudinal rib with open section were affected with the stress increment by shear deformation in the rib and the occurrence of alternative stress due to moving vehicle. In addition, it was known that it is important to perform fatigue design reflected the local behavior of the structural details.
Study on Rib's Structural Details of Double Baseplate Connection Through Numerical Analysis
Hwang, Won Sup ; Kim, Hee Ju ; Ham, Jun Su ; Hwang, Seung Hyun ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 45~53
DOI : 10.11112/jksmi.2013.17.2.045
In this study, steel-pier's structural behavior by design variables of ribs were analyzed in order to improve structural details of ribs supporting double base plates. A numerical analysis was conducted using commercial FE analysis program. Anchor bolts and reinforced bars were made of BEAM element, and coefficient of friction was applied to contact surfaces. After that, the analytical result was compared with experiment of previous study to verify analysis methods. Steel-pier's load-displacement relation was analyzed according to various rib's design variables (rib's central angle, height, thickness) by using proven analysis methods, and proper rib's design ranges were proposed.
Vibration Reduction Effects of Stay Cable Due to Friction Damper
Kim, Hyung Ku ; Yhim, Sung Soon ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 54~61
DOI : 10.11112/jksmi.2013.17.2.054
Stay cable has a strong axial rigidity due to large initial tension and, on the other hand, it has a weak laterally flexural rigidity. Wind loads or traffic loads cause the cables to vibrate significantly and affect the mechanical properties and the performance of cables of cable-stayed bridge (CSB). Therefore, the development of vibration reduction design is an urgent task to control the vibration vulnerable long-span bridges. As Friction damper (FD) shows to reduce the amplitude and duration time of vibration of cable of CSB from measured date in field test, friction damper can be considered that it is effective device significantly to reduce the amplitude and duration time in vibration of cable of CSB under traffic load, wind load and so on. Vibration characteristics of cable can change according to manufacturing method and type of established form. Nevertheless, analysis method in this study can present the design of friction damper for vibration reduction of cable of cable-stayed bridge from now on.
Displacement and Velocity Dependence of Clamped Shape Metallic Dampers
Lee, Hyun Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 62~70
DOI : 10.11112/jksmi.2013.17.2.062
The purpose of this study is the displacement and velocity dependence evaluation of clamped shape metallic damper, which were evaluated superior in energy dissipation capacity than straight type slit damper. For this purpose, 6 metallic damper specimens are prepared and dependence test are performed. Test variables are displacement dependence and velocity dependence. 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 shows 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 slow target velocity (40mm/sec). Therefore the hysteresis dependence of metallic damper were evaluated as close relation to the loading displacement and velocity conditions.
Displacement Ductility of Circular RC Column According to the Spacing of Spirals
Ko, Seong Hyun ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 71~82
DOI : 10.11112/jksmi.2013.17.2.071
Eight small scale circular reinforced concrete columns (4.5 aspect ratio) were tested under cyclic lateral load with constant axial load. The selected test variables are longitudinal steel ratio (2.017%, 3.161%), transverse steel ratio, and axial load ratio (0, 0.07, 0.15). Volumetric ratio of spirals of all the columns is 0.335~0.894% in the plastic hinge region. It corresponds to 39.7~122.3% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The final objectives of this study are to provide quantitative reference data and tendency for performance or damage assessment based on the performance levels such as cracking, yielding, steel fracture, etc. In this paper, describes mainly failure behavior, strength degradation behaviour, displacement ductility of circular reinforced concrete bridge columns with respect to test variables.
Structural Restoration for the Electric Power Transmission Tower Damaged by Foundation Settlements
Lee, Ho Beom ; Park, Jong Kwon ; Kim, Il Soo ; Jang, Il Young ; Song, Jae Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 83~93
DOI : 10.11112/jksmi.2013.17.2.083
Generally the capacities of electric power transmission tower's members are improved by increasing their stiffness nature through injection of grout or attachment of other structural stiffeners. Those are for upgrading their axial strength by fulfillment of proper materials into pipe members, increment of member dimension by addition of section, or a combination of the two. However the use of innovative and unusual procedures would be positively recommended for getting more stable state. It is that buckled members are replaced with lengthened and strengthened members. In providing the structural restoration procedures for the existing electric power transform tower whose main members have been damaged due to unequal foundation settlement, structural damage inspection works and numerical analyses for the damaged one and the restored one were done in detail at first. secondarily member-exchanging works using a newly-generated jacking system and strengthened members were achieved. This figures are to point clearly to inherent advantages attending the management of the towers.
A Study on the Highest Exposure Temperatures of Exposed Reinforced Concrete Structures at Fire
Kim, Seong Soo ; Lee, Jeong Bae ; Kim, Il Kon ; Song, Jong Jin ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 94~100
DOI : 10.11112/jksmi.2013.17.2.094
In this paper, Machinery analysis was conducted, in order to predict highest exposure temperatures and the analyze fire damage in the case of fire on reinforced concrete structure. After analyzing differential thermal of reference materials in accordance with temperature of concrete reference core specimen, it turned out that powerful endothermic peak came resulting from evaporation of capillary water and get water untill
, another endothermic peak came resulting from decomposition of calcium hydroxide at
, and then mass of reference materials remarkably decreased due to endothermic reaction. Another powerful endothermic reaction came after decomposition of calcite at
. After analyzing X-ray diffraction of reference materials in accordance with temperature of concrete reference core specimen, it turned out that calcium hydroxide existed until the temperature of
, but CH almost disappeared and CaO appeared from
. The production increased in proportion to the temperature. This is because that calcium hydroxide and calcite are decomposed and CaO is produced when the temperature of concrete increases with fire. It is estimated that calcium hydroxide and calcite are utterly decomposed and peak disappears, and peak of CaO is remarkably formed instead, at the temperature of
Study on the Thermal Characteristics of Concrete Using Micro Form Admixture
Park, Young Shin ; Kim, Jung Ho ; Jeon, Hyun Kyu ; Seo, Chee Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 101~109
DOI : 10.11112/jksmi.2013.17.2.101
Recently, it is certain that the increase of heating and cooling energy consumption by radical change in climate condition has caused serious problems related to environmental and energy concerns associated with increase of fossil fuel usage and carbon dioxide production as well as global warming. So, various actions to reduce greenhouse gas exhaustion and energy consumption have been prepared by world developed countries. Our government has also been trying to seek energy control methods for houses and buildings by proclaiming political polices on low-carbon green growth and construction and performance standards for environment-friendly housing. The energy consumption by buildings approximately reaches 25% of total korea energy consumption, and the increasing rate of energy consumption by buildings is stiffer than the rate by the other industries. The greatest part in the buildings of the energy consumption is building facade. While lots of research projects for reducing energy consumption of the facade have been conducted, but a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research presents here a study to improve the insulation property of structural concrete formed by micro form admixture (MFA) with experimentally reviewing the physical, mechanical and thermal characteristics of the concrete. As the results of this experiment, in the case of concrete mixed with MFA, slump loss has been improved. As the mixing ratio of MFA increases, the compressive strength is decreased and thermal conductivity is increased. Also it was found that water-cement ratio increases, the compressive strength is decreased and thermal conductivity is increased. but, there was not big influence by the change of fine aggregate ratio.
A Study on the Eco-Friendly Durable Pre-Painting for Concrete Structure
Jo, Byung Wan ; Choi, Ji Sun ; Lee, Seong Won ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 110~116
DOI : 10.11112/jksmi.2013.17.2.110
A concrete structure has become bigger and higher because of development of construction technology and a change in construction environment. Also it tends to focus on repairing, reinforcement and exterior in harmony with environment for structure maintenance and performance improvement. The research is about eco friendly durable painting applicable to concrete structure using civil and architecture. it purpose to improve external beauties and durable problems due to flexibility by variation of temperature, adhesion of exterior wall, crack and delamination in existing organic and mineral painting. For those problems, we made a eco friendly pre-paint that is made with preliminary treatment mixture as a highly enriched waterproof agent and adhesive increasing agent in preprocessing mixture. Then we performed an experiment on durability of prevention neutralization of concrete, durability abrasion, hiding power, adhesion, temperature resistance and resistance to chemical attack. The result of an experiment shows that hiding power is over 0.96 in standard test, durability abrasion test got higher value 1mg than water paint 75mg and tensile strength is 6 times higher than standard waterproof specification.
Effect of Freezing and Thawing on Adhesion of Cement Concrete with Coarse-sand Coated FRP
Lee, Gyu Phil ; Park, Kwang Phil ; Hwang, Jae Hong ; Kim, Dong Gyou ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 117~123
DOI : 10.11112/jksmi.2013.17.2.117
As fiber reinforced polymer (FRP) material is appled for a curved structure such as tunnel, FRP material must has a curved shape. Until now, the curved FRP material has been producted by hand-lay-up or filament winding work. It is impossible for mass production of the curved FRP material by these methods. Also, the quality of product by these methods is lower than that by pultrusion method. New pultrusion method and equipment had been developed for production of FRP material with steady curvature. The objective of this study is to evaluate the effect of freezing and thawing on adhesion of cement concrete with coarse-sand coated FRP in repair and reinforcement of cement-concrete structure using curved FRP material.
Adhesive Properties of High Flowable SBR-modified Mortar for Concrete Patching Material Dependent on Surface Water Ratio of Concrete Substrate
Do, Jeong Yun ; Kim, Doo Kie ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 124~134
DOI : 10.11112/jksmi.2013.17.2.124
This study investigated the effect of surface water on concrete substrate on adhesive strength in tension of very high flowable SBR-modified cement mortar. The specimens were prepared with proportionally mixing SBR latex, ordinary portland cement, silica sand, superplasticizer and viscosity enhancing agent. Polymer cement ratio (P/C) were 10, 20, 30, 50 and 75% and the weight ratio of fine aggregate to cement were 1:1 and 1:3. The specimens obtained with different P/C and C:F were characterized by unit weight, flow test, crack resistance and adhesion test. After basic tests, two mixtures of P/C=20% and 30% in case of C:F=1:1, and one mixture of P/C=50% in case of C:F=1:3 were selected, respectively. These three selected specimens were studied about the effect of surface water evenly sprayed on concrete substrate by a amount of 0, 0.006, 0.012, 0.017, 0.024g per unit area (
) of concrete substrate surface The results show that surface water on concrete substrate increases the adhesive strength in tension of high flowable SBR-modified cement mortar and improve the flowability compared to the non-sprayed case.
A Study on the Improvement of Early-age Compressive Strength of Smart BFS Powder Added Cement Mortar
Yi, Seong Tae ; Noh, Jae Ho ; Kim, Jin Hyung ; Lee, Kang Jin ;
Journal of the Korea institute for structural maintenance and inspection, volume 17, issue 2, 2013, Pages 135~141
DOI : 10.11112/jksmi.2013.17.2.135
In this study, to improve the early-age compressive strength of mortar, the compressive strength tests of mortar mixed smart BFS powder added powder of rapid setting additives milled by processing, using functional grinding aid, the power-typed rapid setting cement clinker developed by sintering industrial waste and by-products with much CaO-
to cement were performed. From the tests, the followings are found that (1) for BFS early-age strength improvement test (Series I): early-age strength improvement of BFS mixed rapid setting additive milled after adding functional grinding aid, when the clinker is milled, is superior and (2) for OPC early-age strength improvement test (Series II): case of additive mixed rapid setting powder typed activator milled after adding functional grinding aid to Clinker-C showed the higher compressive strength.