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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 13, Issue 6 - Nov 2009
Volume 13, Issue 5 - Sep 2009
Volume 13, Issue 4 - Jul 2009
Volume 13, Issue 3 - May 2009
Volume 13, Issue 2 - Mar 2009
Volume 13, Issue 1 - Jan 2009
Selecting the target year
Local Damage Detection Using Acceleration ARX Model
Shin, Soobong ; Park, Hye-Youn ; Kim, Jae-Cheon ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 115~121
The paper presents a signal-based damage detection algorithm of ARX model using dynamic acceleration data. An ARX model correlates acceleration data measured at two locations in a structure by considering those two sets of data as input and output signals. For detecting damage, the error between the measured data and the predicted response from the defined ARX model is computed in time and used for a statistical evaluation. A normal distribution function from the error in time is constructed and its statistical characteristic values are used for the evaluation of damage. By comparing the normal distribution functions before and after damage, three different types of damage indices are proposed. The efficiency and limitation of the proposed algorithm with the statistical evaluation of damage indices have been examined and discussed through laboratory experiments.
A Study on Constructability Improvement of LB-DECK Panel
Cho, Hyun-Chul ; Lho, Byeong-Cheol ; Cho, Gyu-Dae ; Choi, Kyu-Hyung ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 122~128
This study is to improve constructability of LB-DECK construction in site such as inconvenience of main and distribution bars in arrangements LB-DECK Panel which is work is applied to many bridges these days as a permanent formwork. So, the constructability is improved by changing the method of allocation of main reinforcing bar and distribution bar which is reviewed for improving efficiency of design and construction process among the suggested methods. The crack shapes, deflections, and strains under static load of the improvement of LB-DECK Panel are compared and analyzed to former LB-DECK Panel. As a result, 13% of strength compared to before the improvement of LB-DECK Panel, and 10% of strength is increased in the case of slab.
Determination of Optimal Locations for Measuring Displacements to Adjust Cable Tension Forces of Cable-Stayed Bridges
Shin, Soobong ; Lee, Jung-Yong ; Kim, Jae-Cheon ; Jung, Kil-Je ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 129~136
The paper presents an algorithm of selecting optimal locations for measuring displacements(OLD) to adjust cable tension forces during the construction of cable-stayed bridges. The rank for optimal locations can be determined from the effective independence distribution vectors(EIDV) that are computed from the Fisher Information Matrices(FIM) formulated with the displacement sensitivities. To examine the efficiency and reliability of the proposed algorithm for determining OLD, a simulation study on a cable-stayed bridge has been carried out. The results using FIM formulated with displacements are compared with those using FIM with displacement sensitivities through the simulation study. The effects of measurement noise and error in cable length on the adjustment of cable tension forces are evaluated statistically by applying the Monte Carlo scheme.
Evaluation of the Stiffness of Hi-Form Joint Using Damage Detection Method
Chang, Kug-Kwan ; Chun, Young-Soo ; Kang, Woo-Joo ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 137~144
This paper provides the results from evaluating the stiffness of Hi-Form joint by an experiment and the system identification method using the dynamic modal data, and the reasonable modeling method of Hi-Form joint which is proposed for improved stair construction recently. Based on the crack pattern and load-displacement relationship and the damage distribution, it can be judged that Hi-Form joint can't fully transfer the forces between the elements linked, and we propose that the joint is modeled as a element which have a stiffness with 50% decrease.
Stability of Analytical Fragility Curve of Bridge on Earthquake
Lee, Jong-Heon ; Lee, Soo-Choul ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 145~152
In performing a risk analysis on structure for earthquake, it is imperative to identify the vulnerability of structures associated with various stages of damage. And the earthquake resisting capability is needed for structures like bridge. So the damage analysis of bridges with or without isolator for earthquake effects is necessary. In this paper, the risk analysis of seismic isolated LRB bridges considering earthquake effects such as PGA, PGV, SA, SV, and SI is performed using fragility curves to assure the earthquake resisting capability of the structures. And, the stability of fragility curve is investigated with respect to input earthquake.
Strengthening Design Using Rating Factor Considering Increment of Tendon Force for Two-Span Steel-concrete Composite Bridges Strengthened by Straight External Tendons
Choi, Dong-Ho ; Yoo, Hoon ; Kim, Yong-Sik ; Kim, Sung-Won ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 153~164
In this paper, a method of increasing in load-carrying capacity is shown in two-span steel-concrete composite bridges strengthened by external tendons. An analytic expression for the increment of tendon force under external loads is derived using virtual work method for straight external tendons and a new rating factor equation is proposed. Considering the initial tendon force and its increment under external loads, an analytic procedure has been developed to calculate the number of tendons and the initial tendon force from the proposed rating factor equation. This method is used to verify a validity and rationality for an existing two-span composite steel-concrete bridge.
A Design and Performance Evaluation of Semi-active MR Damper for the Smart Control of Construction Structures
Heo, Gwang-Hee ; Jeon, Joon-Ryong ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 165~171
This research developed two semi-active MR dampers whose gaps in the orifice area were different from each other, and evaluated their damping performance by loading tests. The Damping performance of MR dampers characteristically depends on various factors like their material and mechanical ones, but most importantly on the size of gap in the orifice area. For this research, we designed the orifice gaps of two dampers as each 1.0mm and 2.0mm, both with the 80mm outer diameter of the orifice. We also designed two loading test sets with different input currents, and acquired different control ability from them. The acquired test results were analyzed and evaluated with their maximum and minimum damping force and also their dynamic range from the force-displacement hysteresis loops and the force-input current relationship curve. This research clearly proved how the damping performance of control devices depends on the gap effect, and also presented a possibility that the two dampers developed in this research could be used for the smart control of construction structures by effectively adapting the input current and the number of coil turns.
Dynamic Modeling of Semi-active Squeeze Mode MR Damper for Structural Vibration Control
Heo, Gwang-Hee ; Jeon, Joon-Ryong ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 172~180
Normally in order to build a semi-active control system equipped with MR damper, the dynamic modeling of the damper is required to numerically predict its dynamic damping force and also its behavioral characteristics. For the dynamic modeling of the MR damper, this paper attempts to predict and evaluate its dynamic behavior by applying specifically both a power model and a Bingham model. Dynamic loading tests were performed on the squeeze type of damper specially designed for this research, and force-displacement hysteresis loops confirmed the effectiveness of the damper as a semi-active control device. In the meantime, in order to evaluate the effectiveness of each model applied, the model parameter for each model was identified. On the basis of the parameter, we derived the error ratio of the force-velocity relationship curve and the dynamic damping force, which was contrasted and compared with the experimental results of the squeeze type of damper. Finally, the squeeze type of MR damper developed in this research was proved to be valid as a semi-active control device, and also the evaluation of the two dynamic models showed they were working fine so that they were likely to be easily utilized to numerically predict the dynamic characteristics of any dampers with MR fluid as well as the squeeze type of MR damper.
A Study on Temperature Properties Analysis for Tension Measurement of Steel Cables Using Magnetic Sensor
Park, Hae-won ; Ahn, Bong-young ; Lee, Seung-seok ; Park, Jeong-hak ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 181~188
Measuring the tensile strength of steel cables used to support bridges is a critical inspection item in terms of the safety of a bridge. Today, cable tension is measured with the vibration method and loadcell. Recently, some advanced countries have conducted studies on measuring tension with magnetic method and are suggesting prospective results. Since there were no such studies ongoing in Korea, we began a study on measuring tension with magnetic method as we are undergoing researches to improve the precision of measurements. It is necessary to consider the influence for the magnetic field and the temperature of steel cables in tension measurement of magnetic method. In this paper, we tested an output characteristic of tension sensor according to temperature and deduced temperature compensation coefficient in the given magnetic field and applied the compensation coefficient to the tension measurement system in the lab. We analyzed and evaluated testing results for the output voltages of the tension sensor according to cable tensions.
Evaluation of Structural Performance of Self-anchored Suspension Bridge Using Bridge Health Monitoring System
Kim, Jeong-Hoon ; Song, Jae-Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 189~198
In this paper, the performance of bridge health monitoring system(BHMS) installed in suspension bridge was tested and the field loading tests have been done by using BHMS to get quantitative results on the response of bridge. Before the field tests, globally structural analysis was performed to verify and estimate the test results and the static and dynamic field loading tests were carried out. Depending on comparison with results of field tests and structural analysis, field tests results were evaluated as 30%~50% less than structural analysis results, so it was confirmed that the bridge has excellent structural performance. Therefore field test results were measured within an acceptable error range, so it is verified that the BHMS in the bridge has been reliable and efficient.
Influence of Cracks in Precast Concrete Deck on the Flexural Strength of Composite Half PC Slab
Seo, Tae-Seok ; Lee, Moon-Sung ; Choi, Chang-Sik ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 199~205
Recently, as the concern for the development of a construction method for an environmental protection and for tall building is increasing, the use of the half precast concrete(PC) slab that has the solution of environmental problems and the advantage such as reduction of construction period is being demanded. However, there is shortcoming that the crack can occur easily while constructing, and these cracks can have a bad influence upon the structural performance of PC composite slab. However, there is little studies on the influence of these cracks on the structural performance of composite PC slab. In this study, the specimen caused the crack before pouring topping concrete in the half PC slab and the PC composite slab without the cracks were produced to investigate the structural performance of PC composite slab with crack.
Evaluation of Behavior and Ductility of Reinforced Concrete Beams Strengthened With AFRP
Kim, Jun-Won ; Kim, Tae-Wan ; Hong, Sung-Nam ; Park, Sun-Kyu ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 206~214
Due to its outstanding feature, FRP is used widely for the material of strengthening in USA and Japan recently, and there have been active researches in korea as well. This study evaluates the behavior and ductility of each structure experiment using EBR and NSMR strengthening method with different AFRP types and strengthening area. There was the biggest increase in the load when the strengthening area is expanded showing a brittle aspect, and eventually the immature failure occurred. With regard to the methods, it is found that the NSMR method is more effective to strengthen the structure, and the uneven surface causes ductile failure.
Measuring and Correcting The Compressive Axial Strain of Concrete Cylinders Retrofitted by External Jackets
Choi, Eun-soo ; Lee, Young-Geun ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 215~222
In this study, steel and FRP jackets are used to confine concrete cylinders. The FRP jacket behaviors compositely with concrete since there is bonding between them. However, the used steel jacket in this study do not behavior compositely with concrete since there is not an adhesive between them. The steel jackets are attached by external forces and the welding. This study suggests the measuring method of the axial strain for the confined concrete cylinders showing noncomposite behavior with the jackets and the correcting method of the measured strain for the composite-behavior jackets. For the noncomposite-behavior steel jacket, the axial strain of the steel surface does not represent the axial strain of the concrete inside. Also, a compressormeter can not be used. Thus, the two rigid plates at the top and bottom of a cylinder are placed and the distance of the two plates are measured and used for estimating the axial strain of the concrete. For the composite-behavior FRP jacket, the vertical strain measured on the FRP surface can be used for estimating the axial strain of the concrete. However, the vertical strain on the FRP surface contains the tensile strain due to the bulge of the concrete and, thus, the tensile strain should be corrected from the vertical strain. The corrected verticals strains compared with the measured strain or a existing constitute model; the result is satisfactory. The uncorrected stress-strain curves have the potential to under estimate the ductile behavior and the energy-dissipation-capacity of the composite-behavior FRP jackets.
Bending Performance Evaluation of Concrete Filled Tubular Structures With Various Diameter-thickness Ratios and Concrete Strengths
Lee, Sang-Youl ; Park, Dae-Yong ; Lee, Sang-Bum ; Lee, Rae-Chul ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 223~230
In this study we deal with bending behaviors of a concrete filled tubular(CFT) with various diameter-thickness ratios and concrete strengths. In finite element analysis using a commercial package(LUSAS), the bonding effect between concrete and steel in CFT structures is modeled by applying a joint element for the bonding surface. In order to consider the nonlinearity of concrete and steel tubes, stress-strain curves of the concrete and steel are used for the increased stresses in a plastic domain. The numerical results obtained from the proposed method show good agreement with the experimental data from load-displacement curves of a steel tube under distributed loads. Several parametric studies are focused on structural characteristics of CFT under bending effects for different diameter-thickness ratios and concrete strengths.
Understanding the Asymptotic Convergence of Domain of Attraction in Extreme Value Distribution for Establishing Baseline Distribution in Statistical Damage Assessment of a Structure
Kang, Joo-Sung ; Park, Hyun-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 13, issue 2, 2009, Pages 231~242
The baseline distribution of a structure represents the statistical distribution of dynamic response feature from the healthy state of the structure. Generally, damage-sensitive dynamic response feature of a structure manifest themselves near the tail of a baseline statistical distribution. In this regard, some researchers have paid attention to extreme value distribution for modeling the tail of a baseline distribution. However, few researches have been conducted to theoretically understand the extreme value distribution from a perspective of statistical damage assessment. This study investigates the asymptotic convergence of domain of attraction in extreme value distribution through parameter estimation, which is needed for reliable statistical damage assessment. In particular, the asymptotic convergence of a domain of attraction is quantified with respect to the sample size out of which each extreme value is extracted. The effect of the sample size on false positive alarms in statistical damage assessment is quantitatively investigated as well. The validity of the proposed method is demonstrated through numerically simulated acceleration data on a two span continuous truss bridge.