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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
Flexural Behavior of High Strength Reinforced Concrete Beams by Replacement Ratios of Recycled Coarse Aggregate
Lee, Yong-Taeg ; Hong, Seung-Uk ; Kim, Seung-Hun ; Baek, Sang-Ki ; Cho, Young-Sang ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 1~9
DOI : 10.11112/jksmi.2014.18.1.001
Recently, natural aggregate was adequate to supply the demand due to increase of building construction. National pollution induced by construction waste caused by the reconstruction and redevelopment was cited as the major social issues in Korea. Therefore, government are required by law to use the recycled aggregate. In order to consider safety, KS F 2573 recommend that recycled aggregate with below design strength 27MPa and replacement ratio of 30%. This study on flexural behaviors of reinforced concrete beam was conducted and the specimens employed in test were planed with high strength concrete (40, 50 and 60MPa) and recycled aggregate replacement ratio (0, 30, 50, 100%). Although the flexural strength of reinforced concrete beam has trendy to decrease with increase of replacement ratio, it is meet to KCI 2007. The comparison results show that reinforced concrete beam using recycled aggregate can apply as flexural member in building construction.
Structural Integrity Evaluation of Mechanically Fastened FRP Beams Under the Effects of Sustained Loads and Environments
Lee, Jae-Ha ; Kim, Woo-Seok ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 10~18
DOI : 10.11112/jksmi.2014.18.1.010
Mechanically fastening FRP (MF-FRP) strips using nails and anchors, has been shown to provide a more ductile behavior to the strengthened structural element than using bonded FRP. To further advance the state of the knowledge on this strengthening method, the current study examined environmental effects for six months on MF-FRP beams. Reinforced concrete beams strengthened with mechanically fastened FRP strips and subjected to sustained loads for six months were exposed to outdoor weather and constant high temperatures (
). For comparison, the behavior of RC beam with and without sustained loads was evaluated. Results from flexural tests did not show any significant degradation or change of failure mode as a result of sustained load and of environmental effects such as high temperatures and outdoor weather over a period of six months. Failure of the beams was governed by FRP delamination followed by concrete crushing as not much load applied to the nail and anchors because of slip effects.
A Study on the Improvement of the Steel Pylon Base Design Using Nonlinear FEM Analysis
Jung, Soo-Hyung ; Park, Sung-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 19~30
DOI : 10.11112/jksmi.2014.18.1.019
In this study nonlinear FEM analysis for steel pylon base of a cable supported bridge is performed in order to compare the results of Akashi-Kaikyo bridge`s design specification established in 1970. Due to convenience of its application, the Akashi grand bridge`s design specification has been applied to the base design of cable stayed bridges. It has been using linear spring in order to model prestressed high tensioned bars between steel pylon bottom plates and the base concrete. However, the results of nonlinear FEM analysis revealed that the Akashi-Kaikyo bridge`s design specification has various problems in the analysis of the steel pylon base. And the steel pylon base has various complex members connecting with each other, and it is main member to resist against the wind load or the earthquake load. Therefore, the nonlinear FEM analysis has to be conducted in order to predict the behavior of steel pylon base exactly. Also, the nonlinear FEM analysis is more reasonable for the load and resistant factor design.
Design of Rigid Joints Using Strut-Tie Model
Won, Dae-Yon ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 31~39
DOI : 10.11112/jksmi.2014.18.1.031
In order to design rigid zone area of frame structures, it is important to predict the direction change of internal stresses according to the bending moment acting on the joint region. In this study, it was examined whether current highway bridge design standards are useful to design different types of rigid joints having a various haunch shapes. In addition, stress distributions of inside of various rigid joints were inspected using the linear elastic finite element analysis. Based on the results of finite element analysis, the strut-tie models to design rigid joints are proposed. Suggested by this study, the strut-tie models have a same level of accuracy to a linear elastic finite element analysis. The proposed strut-tie models will be useful to design reinforcement details of rigid joints having a various haunch types.
An Experimental Study on the Pullout Failure Behavior of Post-installed Concrete Set Anchor
Suth, Ratha ; Yoo, Seung-Woon ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 40~47
DOI : 10.11112/jksmi.2014.18.1.040
Recently the use of concrete post-installed set anchors has been increasing because this constructing method is flexible and easy to attach or fix structural members when we repair, reinforce, or remodel structures. Accordingly, designers and builders of Korea depend on foreign design codes since there are no exact domestic anchor design codes that they could credit. The anchor in plain concrete loaded in tensile exhibits various failure modes such as concrete breakout, splitting, steel failure, pull-out and side-face blowout, that depending on the tensile strength of the steel, the strength of concrete, embedment depth, interval, the edge distance and the presence of adjacent anchor. The objective is to investigate the effects of the variations like anchor embedment depth, interval and edge distance on pull-out fracture behavior of post-installed concrete set anchor embedded in plain concrete.
Study on Reinforcement Effect of Circular RC Columns by Helical Bar Under Cyclic Lateral Load
Kim, Seong-Kyum ; Park, Jong-Kwon ; Han, Sang-Hee ; Kim, Byung-Cheol ; Jang, Il-Young ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 48~58
DOI : 10.11112/jksmi.2014.18.1.048
In this study, quasi-static according to the displacement-controlled (strain control) method tests on RC columns for seismic reinforcement performance in accordance with the provisions of the seismic design and construction before 1992 design code for highway bridges in korea. Used reinforcement that improves the performance of Inorganic Helical Bar, a kind of alloy steel, circular columns were tested outside the seismic reinforcing. In the experiment, fracture behavior, lateral load-displacement relation, ductility and energy assessment evaluation was performed through tests. The variables in experimental are section force of reinforcement, spiral reinforcement spacing, reinforcement method. Improved seismic performance and effect were confirmed through quasi-static test experiments. The results of study confirmed determination the appropriate size of reinforcement, reinforcement forces, spacing and selection of the type required, furthermore, not only mechanical reinforcement but also substitution of high-strength concrete reinforced with concrete cover improved seismic performance.
A Dynamic Analysis of Rotations at the center of Vehicle Running High Speed KTX Train on the PSC Box Bridges
Oh, Soon-Tack ; Lee, Dong-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 59~67
DOI : 10.11112/jksmi.2014.18.1.059
A dynamic analysis is carried out to provide an evaluation method of running safety for a PSC box bridge located on the Gyung-Bu high speed railway. The numerical models of bridge and train vehicle are developed in detail with corresponding interaction system. Three dimensional skeleton element model of PSC box bridge and 38-degree-of-freedom of vehicle are adopted from the existing properties of KTX bridge and train vehicle. Analysed three direction rotations of vehicle on the bridge and ground tracks are compared for running speeds up to 500 km/h with 10 km/h constant increments. The comparison of the rotations will be an improved evaluation method of Running Safety in stead of the existing standard method.
Characteristics of Bond Strength as Types of Primer for the Facilities of Anti-corrosion Waterproofing Materials by the Reversed Pressure and Concrete Surface Condition
Oh, Sang-Keun ; Heo, Neung-Hoe ; Shin, Hong-Chul ; Choi, Sung-Min ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 68~74
DOI : 10.11112/jksmi.2014.18.1.068
Recently, concrete facility as advanced water treatment facilities is extending in the water treatment facilities according to raise awareness of pure drinking water and delicious water. For this reason, it is increased to the necessity need to make the standard and the development of waterproofing and anti-corrosion materials for concrete structures applied water treatment tank. So, related research has become active recently. However, as the limit of research focused on durability improvement of top coating material, it is insufficient to study on the adhesion strength between the concrete surface and primer. Therefore, there is to confirm the adhesion of between concrete surface and the three primers used as anti-corrosion waterproofing materials, and to investigate the properties of adhesion strength according to the condition such as dry condition, wet condition, and water pressure condition of the concrete surface in this study.
Evaluation of Mechanical Properties and Crack Resistant Performance in Concrete with Steel Fiber Reinforcement and CSA Expansive Admixture
Choi, Se-Jin ; Park, Ki-Tae ; Kwon, Seung-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 75~83
DOI : 10.11112/jksmi.2014.18.1.075
In order to prevent brittle failure of concrete, steel fiber reinforcement is effective composite material. However ductility of steel fiber reinforced concrete may be limited due to shrinkage caused by large content of cement binder. Chemical prestressing for steel fiber reinforcement in cement matrix can be induced through expansive admixture and this can increase reinforcing effect of steel fiber. In this study, mechanical performances in concrete with CSA (Calcium sulfoaluminate) expansive admixture and steel fiber reinforcement are evaluated. For this work, steel fiber reinforcement of 1 and 2% of volume ratio and CSA expansive admixture of 10% weight ratio of cement are added in concrete. Mechanical and fracture properties are evaluated in concrete with steel fiber reinforcement and CSA expansive admixture. CSA concrete with steel fiber reinforcement shows increase in tensile strength, initial cracking load, and ductility performance like enlarged fracture energy after cracking. With appropriate using expansive admixture and optimum ratio of steel fiber reinforcement, their interactive action can effectively improve brittle behavior in concrete.
Experimental Study on the Early Strength Development Mechanism of Cement Paste Using Hardening Accelerator and High-Early-Strength Cement
Min, Tae-Beom ; Cho, In-Sung ; Lee, Han-Seung ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 84~92
DOI : 10.11112/jksmi.2014.18.1.084
The purpose of study is to analyze mechanism with early high portland cement and hardening accelerator. As the result, it was concluded that hardening accelerator makes accelerates appearance of
through experiment using TG-DTA when it hydrates with cement. On the result of compressive strength, as increasing the amount of hardening accelerator used, early compressive strength was improved. Also, as a result of hydration heat, hardening accelerator accelerates hydration of
that is cement`s component. On the result of XRD`s analyzation, hydration product for each age could be check and it was shown that as increasing the amount of hardening accelerator used, peak point of hydration product was recorded high. As the result of SEM, appearance of C-S-H was shown as the amount of
`s appearance and each age according to additive contents of hardening accelerator. Therefore hardening accelerator used on this study is effective on getting early compressive strength.
A Study of Accelerated Corrosion Test and Chloride Penetration Analysis with Artificial Seawater Immersion Condition
Park, Sang-Soon ; Jeong, Ji-Won ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 93~100
DOI : 10.11112/jksmi.2014.18.1.093
Steel reinforcement buried in concrete structure in submerged zone does not easily become corroded due to lack of dissolved oxygen. For that reason, accelerated corrosion test in submerged state is performed with an electrochemical method, which is not suitable for actual corrosion mechanism and makes it difficult to find relevance with long-term behavior. In this study, accelerated corrosion test was performed with the temperature and chloride concentration as main variables in order to establish a method for accelerated corrosion test in submerged zone. Corrosion was determined by the result of reinforcement corrosion monitoring based on galvanic potential measurement and half-cell potential method. The accelerated corrosion test result showed that temperature had the most dominant influence. To determine the chloride content, chloride concentration by depth in the test sample was measured. With the same conditions, chloride penetration interpretation was performed by DuCOM, a FEM durability interpretation program. Also, a test was performed to measure dissolved oxygen according to soaking conditions of artificial seawater, which was used for verifying the validity of the accelerated corrosion test result.
Experimental Study on Tension-Hardening and Softening Characteristics in Reinforced Mortar with CSA Expansion Agent
Choi, Se-Jin ; Ahn, Jung-Kil ; Park, Ki-Tae ; Kwon, Seung-Jun ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 101~110
DOI : 10.11112/jksmi.2014.18.1.101
Expansion agent is a very effective admixture for prevention of cracking due to autogenous/drying shrinkage and this can induce internal chemical prestress to embedded reinforcement. In this paper, tension-softening and hardening in cement mortar with steel and CSA expansion agent are experimentally evaluated. Cement mortar with steel reinforcement is prepared and tensile strength test is performed for evaluation of cracking and tensile behavior. In spite of slightly reduced strength and elasticity in CSA mortar, significantly increased tension-hardening behavior is evaluated in CSA mortar with induced chemical prestress. Furthermore previous tension softening models are compared with the test results and improvement are proposed.
Leaching Capacity and Rate of Alkali Ions from Hardened Cement Paste
Shim, Hyun-Bo ; Hwang, Jun-Pil ; Ann, Ki-Yong ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 111~118
DOI : 10.11112/jksmi.2014.18.1.111
The present study concerns the leachability of alkali ions from hardened cement paste in terms of an increase in the pH together with the rate of alkali leaching. To evaluate the influence of mix design on the leaching capacity and rate of alkali, different water-cement ratios (W/C) and binders were used to manufacture paste specimens. The cement paste was made in the form of rectangular bucket where deionised water was subsequently supplied as solvent media. Then the specimen was wrapped in polythene film to avoid contact to atmospheric conditions, which may affect the water chemistry in the bucket. The pH of media was monitored until no further change in the pH value was observed, of which value then used to calculate the leaching capacity and rate. The influence of binder on the pH of solvent is more dominant than that of water to cement ratio: OPC paste produced the highest level of alkali leaching, whilst 30% PFA and 60% GGBS pastes imposed lower level of alkali leaching. After the monitoring of the pH, the inner bucket was ground with an increment of 1.0 mm to measure the leaching influence using the suspension consisting of paste powder and deionised water. It was found that the impact zone for OPC was about 7-8 mm, whilst 30% PFA and 60% GGBS had deeper impact depth of the alkali leaching.
Engineering Properties of Semi-rigid Pavement Material Produced with Sulfur Polymer Emulsion and Reinforcing Fibers
Lee, Byung-Jae ; Seo, Ji-Seok ; Noh, Jae-Ho ; Kim, Yun-Yong ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 119~127
DOI : 10.11112/jksmi.2014.18.1.119
The application of sulfur polymer emulsion (SPE) as an acrylate substitute for semi-rigid pavement grout was evaluated, and the performance improvement by employing PVA fibers were also evaluated. The result indicated that the filling ratio of semi-rigid pavement material decreased as the fiber content increased, but it was measured to be 92~94% in every mixing condition, which satisfies the target performance, 90%. The maximum Marshall stability value of semi-rigid pavement material was measured to be 25.4 kN, which is about 4.7 times higher than the Korean Standard required for semi-rigid pavement material, 5.0 kN. The dynamic stability evaluation of semi-rigid pavement material indicated that the resistance to deformation from the wheel tracking test was improved by an SPE substitution, and in every mixing condition, the deformation converged to a constant value after 45 minutes with the same dynamic stability of 31,500 times/mm. The strain at the flexural failure was about 0.53%, which shows superior rigidity to asphalt pavements. The examination of abrasion resistance and impact resistance showed that the loss ratio was 9.8~6.0% in every mixing condition, which indicates a good abrasion resistance. Also, when fiber content ratio was 0.3%, the impact resistance was 2.82 times higher compared to plain (i.e., when fibers were not added). In the limited range of this study, an SPE substitution ratio of 30% was found to be an optimal level considering the mechanical and durability performance. In addition, it is thought that semi-rigid pavement material with superior performance could be manufactured if fiber content ratio up to 0.3% is applied depending on the purpose of use.
The Experimental Study on the Suggestion for Bond Strength Standard of Sprayed Fire Resistive Materials Used at the Substation Steel Structures
Park, Dong-Su ; Joung, Won-Seoup ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 128~137
DOI : 10.11112/jksmi.2014.18.1.128
Sprayed fire resistive materials are mainly used at steel structures to satisfy fireproof construction standard. However, the regulations on bond strength have been not considered with the exception of structures in the nuclear power plants, although it is an important factor showing material properties. Therefore, this paper suggested guidelines for bond strength of sprayed fire resistive materials used in the substation, by measuring bond strength according to aging of structures and impact loading considering environment of substations. It is judged that the bond strength suggested in this paper is the minimum value because it was measured from specimens widely used.
Estimation Method of Strain Distribution for Safety Monitoring of Multi-span Steel Beam Using FBG Sensor
Oh, Byung-Kwan ; Lee, Ji-Hoon ; Choi, Se-Woon ; Park, Hyo-Seon ; Kim, You-Sok ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 138~149
DOI : 10.11112/jksmi.2014.18.1.138
This study proposes an estimation method of strain distribution for multi-span steel beam structure under unspecific loading conditions. The estimation method in this paper employs the curve fitting using the least square method from measured strain data, not analytical method. To verify the proposed estimation method, a static loading test for multi-span steel beam on which distributed and concentrated loads act was conducted. The strain data for verification was measured by FBG sensors that have multiplexing technology. The analysis of the accuracy of strain estimation for distributed and concentrated loads and the errors by considering the number of measured points used in the estimation were conducted. In the maximum strain points, the strains could be estimated with the errors of 5.89% (loading step 1) and 6.26% (loading step 2). In case of decreasing the number of sensors, it was also confirmed that the errors increased (0.26~0.37%). Through the curve fitting method, it is possible to estimate the strain distribution (maximum strains and their locations) of multi-span beam for unspecific loads and go over the limit of the analytical estimation method which is suitable for specific distributed loads.
Equation for Estimating Natural Frequencies of Initially Stressed Rectangular Plates
Park, Sung-Jin ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 150~159
DOI : 10.11112/jksmi.2014.18.1.150
A simplified method for the calculation of buckling and vibrational characteristics of initially stressed rectangular plate and antisymmetric angle-ply laminated plates is presented in this paper using the natural frequencies under unloading state. The equation of motion of rectangular plate with two opposite edges simply supported is investigated on the basis of Rayleigh-Ritz method and Mindlin plate theory with effect of the curvature term. The relationships of the non-dimensional natural frequencies with initial stresses the coeffcients of critical buckling and the boundaries of the dynamic principal instability region can be characterized by the non-dimensional natureal frequencies under unloading state. Numerical examples are presented to verify the simplified equations and to illustrate potential applications of the analysis.
Efficiency Test for Low Electric Power Type and MEMS Based 3-axis Accelerometer
Lee, Byeung-Leul ; Lee, Seung-Jae ; Moon, Dae-Joong ; Jung, Jin-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 160~165
DOI : 10.11112/jksmi.2014.18.1.160
In this study, an efficiency test was performed by fabricating MEMS (Micro Electro Mechanical Systems) based 3-axis acceleration sensor modules and an earthquake monitoring system was composed. Data acquisition device (NI-9239) with a 24bit ADC (Analog to Digital Converter) was used for improving the performance of 3-axis acceleration sensor modules and filtered data (100Hz Low Pass Filter) was used for reducing noises. Also this paper focused on detecting meaningful vibration in the building by developing the earthquake monitoring software. If vector sum of 3-axis acceleration is greater than the preset value, the value will be recorded and saved to the file.
Nondestructive Diagnosis of NPP Piping System Using Ultrasonic Wave Imaging Technique Based on a Pulsed Laser Scanning System
Kim, Hyun-Uk ; Lee, Chang-Gil ; Park, Seung-Hee ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 166~173
DOI : 10.11112/jksmi.2014.18.1.166
A noncontact nondestructive testing (NDT) method is proposed to detect the damage of pipeline structures and to identify the location of the damage. To achieve this goal, a scanning laser source actuation technique is utilized to generate a guided wave and scans a specific area to find damage location more precisely. The ND: YAG pulsed laser is used to generate Lamb wave and a piezoelectric sensor is installed to measure the structural responses. The measured responses are analyzed using three dimensional Fourier transformation (3DFT). The damage-sensitive features are extracted by wavenumber filtering based on the 3D FT. Then, flaw imaging techniques of a pipeline structures is conducted using the damage-sensitive features. Finally, the pipes with notches are investigated to verify the effectiveness and the robustness of the proposed NDT approach.
Verification on the Application of Monitoring for Frame Structures Using the VRS-RTK Method through the Free Vibration Test
Choi, Se-Woon ; Park, Hyo-Seon ; Kim, Bub-Ryur ; Lee, Hong-Min ; Kim, You-Sok ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 1, 2014, Pages 174~182
DOI : 10.11112/jksmi.2014.18.1.174
To monitor the wind-induced responses of buildings, conventional real-time kinematic (RTK) methods based on two global positioning system (GPS) receivers (e.g., a reference and a rover) are widely applied. However, these methods can encounter problems such as difficulty in securing and maintaining a space for a reference station. With the recently developed virtual reference station (VRS)-RTK approach, the position of a structure can be measured using only a rover receiver. In this study, to evaluate the applicability of VRS-RTK methods in monitoring the lateral structural responses of frame structures, we performed free vibration tests on a one-story frame model (the first natural frequency of 1 Hz) and a three-story frame model (the first natural frequency of 0.85 Hz). To assess the reliability of the displacement and acceleration responses measured by the GPS, we performed a concurrent measurement using laser displacement sensors and an accelerometer. The accelerometer results were consistent with the GPS measurements in terms of the time history and frequency content. Furthermore, to derive an appropriate sampling rate for the continuous monitoring of buildings, the errors in the displacement responses were evaluated at different GPS sampling rates (5, 10, 20 Hz). The results indicate that as the sampling rate increased, the errors in the displacement responses decreased. In addition, in the three-story model, all modal components (first, second, and third modes) could be recorded at a sampling rate of 20 Hz.