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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Korean Society of Civil Engeneers
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Volume & Issues
Volume 30, Issue 6D - Dec 2010
Volume 30, Issue 6C - Dec 2010
Volume 30, Issue 6B - Dec 2010
Volume 30, Issue 6A - Dec 2010
Volume 30, Issue 5D - Oct 2010
Volume 30, Issue 5C - Oct 2010
Volume 30, Issue 5B - Oct 2010
Volume 30, Issue 5A - Oct 2010
Volume 30, Issue 4D - Aug 2010
Volume 30, Issue 4C - Aug 2010
Volume 30, Issue 4B - Aug 2010
Volume 30, Issue 4A - Aug 2010
Volume 30, Issue 3D - Jun 2010
Volume 30, Issue 3C - Jun 2010
Volume 30, Issue 3B - Jun 2010
Volume 30, Issue 3A - Jun 2010
Volume 30, Issue 2D - Apr 2010
Volume 30, Issue 2C - Apr 2010
Volume 30, Issue 2B - Apr 2010
Volume 30, Issue 2A - Apr 2010
Volume 30, Issue 1D - Feb 2010
Volume 30, Issue 1C - Feb 2010
Volume 30, Issue 1B - Feb 2010
Volume 30, Issue 1A - Feb 2010
Selecting the target year
System Reliability-Based Design Optimization Using Performance Measure Approach
Kang, Soo-Chang ; Koh, Hyun-Moo ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 193~200
Structural design requires simultaneously to ensure safety by considering quantitatively uncertainties in the applied loadings, material properties and fabrication error and to maximize economical efficiency. As a solution, system reliability-based design optimization (SRBDO), which takes into consideration both uncertainties and economical efficiency, has been extensively researched and numerous attempts have been done to apply it to structural design. Contrary to conventional deterministic optimization, SRBDO involves the evaluation of component and system probabilistic constraints. However, because of the complicated algorithm for calculating component reliability indices and system reliability, excessive computational time is required when the large-scale finite element analysis is involved in evaluating the probabilistic constraints. Accordingly, an algorithm for SRBDO exhibiting improved stability and efficiency needs to be developed for the large-scale problems. In this study, a more stable and efficient SRBDO based on the performance measure approach (PMA) is developed. PMA shows good performance when it is applied to reliability-based design optimization (RBDO) which has only component probabilistic constraints. However, PMA could not be applied to SRBDO because PMA only calculates the probabilistic performance measure for limit state functions and does not evaluate the reliability indices. In order to overcome these difficulties, the decoupled algorithm is proposed where RBDO based on PMA is sequentially performed with updated target component reliability indices until the calculated system reliability index approaches the target system reliability index. Through a mathematical problem and ten-bar truss problem, the proposed method shows better convergence and efficiency than other approaches.
Behavior of Hollow Box Girder Using Unbonded Compressive Pre-stressing
Kim, Sung Bae ; Kim, Jang-Ho Jay ; Kim, Tae Kyun ; Eoh, Cheol Soo ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 201~209
Generally, PSC girder bridge uses total gross cross section to resist applied loads unlike reinforced concrete member. Also, it is used as short and middle span (less than 30 m) bridges due to advantages such as ease of design and construction, reduction of cost, and convenience of maintenance. But, due to recent increased public interests for environmental friendly and appearance appealing bridges all over the world, the demands for longer span bridges have been continuously increasing. This trend is shown not only in ordinary long span bridge types such as cable supported bridges but also in PSC girder bridges. In order to meet the increasing demands for new type of long span bridges, PSC hollow box girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m. The developed PSC girder applies compressive prestressing at H-type compression reinforcements using unbonded PS tendon. The purpose of compressive prestressing is to recover plastic displacement of PSC girder after long term service by releasing the prestressing. The static test composed of 4 different stages in 3-point bending test is performed to verify safety of the bridge. First stage loading is applied until tensile cracks form. Then in second stage, the load is removed and the girder is unloaded. In third stage, after removal of loading, recovery of remaining plastic deformation is verified as the compressive prestressing is removed at H-type reinforcements. Then, in fourth stage, loading is continued until the girder fails. The experimental results showed that the first crack occurs at 1,615 kN with a corresponding displacement of 187.0 mm. The introduction of the additional compressive stress in the lower part of the girder from the removal of unbonded compressive prestressing of the H-type steel showed a capacity improvement of about 60% (7.7 mm) recovery of the residual deformation (18.7 mm) that occurred from load increase. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation of PSC girders are relatively easy, and the cost of maintenance is expected to decrease.
A Study on Dynamic Capacity Assessment of PSC Box Girder High Speed Railway Bridges Using Time Series Load
Han, Sung Ho ; Bang, Myung Seok ; Lee, Woo Sang ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 211~219
The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.
A Study for Creep Effect of the Interfacial Adhesive Layer on the Behavior of Concrete with CFRP
Park, Yong Deuk ; Shin, Seung Kyo ; Kang, Suk Hwa ; Lim, Yun Mook ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 221~228
External bonding of carbon fiber reinforced polymer (CFRP) sheets has been widely accepted as a popular method for strengthening of deteriorated RC structures. The long-term behavior of CFRP-strengthened RC structure is often affected by that of the interface between CFRP sheets and concrete. This study aims at applying a viscoelastic model to describe the creep behaviour of the adhesive layer bonding CFRP sheet to concrete, the CFRP-concrete interface. Reviews of available models on concrete creep behavior have been first carried out and then new FE analysis model is proposed. The proposed FE analysis model based on the maxwell model has been verified by previous experimental results. It is shown that the creep effect of interfacial adhesive layer is very important on the long-term behavior of concrete structures strengthened with CFRP.
Estimation of Shear Strength of RC Shear Connection for the Steel-Concrete Composite Girder
Shin, Hyun Seop ; You, Young Jun ; Jeong, Youn Ju ; Eom, In Su ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 229~239
For the purpose of improvement of the load carrying capacity and constructibility of the conventional steel-concrete composite girder through a effective appliance of the construction materials and optimization of the girder section, a new type section of composite girder and RC shear connection were proposed. In this study shear strength of the RC shear connection is estimated, and the characteristics of shear load-slip behaviour is analyzed. Push-out tests on shear specimens and FEM analysis with various design parameters are carried out, and results are analyzed. The results of test and FEM analysis showed that shear strength of RC shear connection is underestimated by the design provisions of the current design code. By regression analysis a empirical equation for the estimation of shear strength of RC shear connection is proposed.
Development of Slender Aerodynamic Girder for Suspension Bridges
Kwon, Soon-Duck ; Lee, Myeong-Jae ; Cho, Eukyung ; Lee, Seung-Ho ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 241~256
This study intends to develop an aerodynamic girder for suspension bridge with width corresponding to 1/70 of the main span length. In the first step of present study, parametric study for the effects of major structural properties on aerodynamic stability of bridges was performed. The span length and natural frequency of bridges were found to be free from girder width, girder height, and aspect ratio of width to height. The empirical equation according to confidence interval was proposed to estimate the natural frequencies of bridges from span length. From the sensitivity analysis, it was revealed that the torsional frequency was dominant parameter among various structural properties that affected flutter velocity mostly. The final aerodynamic bridge section which satisfied the flutter criteria was found from section wind tunnel tests for 30 cross sectional models. The aerodynamic stability of the developed cross section was verified by multimode flutter analysis. The present economical cross section can be used for long span suspension bridge.
Applications of Displacement Response Estimation Algorithm Using Mode Decomposition Technique to Existing Bridges
Chang, Sung-Jin ; Kim, Nam-Sik ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 257~264
Generally, estimations on the displacement as an important factor in evaluating the safety of large structures could be a barometer assessing whether the condition of the structure is deteriorating. Practically, it is not easy how to measure the displacement response to large structures like suspension bridges. In this study, as a method for estimation displacement response from strain signals, mode decomposition technique is proposed. Total displacement response is estimated by superposing quasistatic displacement response and modal displacement responses in dominant modes with larger contributions after estimating the modal displacement responses. If foiled strain gauges are used to measure strain signals, there would likely to generate electric noise, what's more, the more measuring points there are the more economic burden it could be. In order to solve such problems, fiber optic bragg-grating(FBG) sensors were used, which have multi-point measurements with no effect on electric noises. Therefore, the experiment was performed through dynamic load test of suspension bridge and plate-girder bridge to review the possibility for using mode decomposition technique.
Proposal of Stress-Strain Relations Considering Confined Effects for Various Composite Columns
Park, Kuk Dong ; Hwang, Won Sub ; Yoon, Hee Taek ; Sun, Woo Hyun ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 265~275
Concrete filled steel tube and concrete encased steel tube columns are expected to have confined effects of concrete by steel and reinforced effects of local buckling by concrete. On the basis of confined state concrete models of previous researches, stress-strain and load-displacement relations of RC, CFT and CET columns are analyzed by steel ratio. After comparing analysis results with experimental results, Modified stress-strain relations are derived through evaluation the influence upon confined effects of concrete in each cases. Also, the modified stress-strain models are carried out to be compared with specified strength of various countries.
Construction Stage Analysis of Hybrid Composite Cable-Stayed Girder Bridge Using Eccentrically Loaded Derrick Crane
Park, Taekwun ; Kim, Moon Kyum ; Won, Jong Hwa ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 277~286
Derrick or caterpillar crane is generally used for the long-span/cable-stayed bridge construction by pre-cast segment lifting from over-land or water transportation. The heavy weight of them, however, could make defects on unstable under-construction structure and, furthermore a method of conventional segment transportation is also able to occur additional time and cost. In this study, in order to improve conventional construction method, the newly developed derrick crane is mainly considered. It could be not only eccentrically loadable on constructing girder but having rotatable boom for segment transportation from back-side. A series of construction stage using developed derrick crane is defined and also its numerical analysis is conducted. To reflect load characteristics of developed derrick crane on construction stage analysis, on/out of service load is separately calculated by considering vertical/lateral rotation range of boom and it is loaded on 4 fixed positions of crane. The derrick crane on this study could be time and cost saving solution for cable-stayed bridge construction and also make contributions to construction load reduction in its process.
Experimental Study on Static Behavior of Laterally Strengthened Spliced Prestressed Concrete Girder using Bending Moment Connector
Kim, Jae Heung ; Kim, Jang-Ho Jay ; Kim, Sung Bae ; Yi, Na Hyun ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 287~295
The main purpose of this study is to investigate the static behavior of spliced prestressed concrete girder with bending moment connector and lateral prestressing. Four (4) spliced girders and one (1) monolithic girder had been fabricated and tested to compare their static behaviors. Same geometry and materials are used to fabricate these spliced and monolithic girders. A monolithic girder and one (1) spliced girder without lateral bending connector are used as control specimens to estimate the performance of three (3) spliced girders with lateral bending connector. Deflections at the middle of girders have been measured for evaluation. Also, strains of the concrete at the middle of span and connection points have been measured. It was found from the result that laterally strengthened spliced girders showed improved ultimate strength but less stiffness compared to the monolithic girder at the ultimate state. Laterally strengthened spliced girder also showed improved strength as well as improved stiffness compared to the spliced girder without lateral strengthening.
Verification of Multi-point Displacement Response Measurement Algorithm Using Image Processing Technique
Kim, Sung-Wan ; Kim, Nam-Sik ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 297~307
Recently, maintenance engineering and technology for civil and building structures have begun to draw big attention and actually the number of structures that need to be evaluate on structural safety due to deterioration and performance degradation of structures are rapidly increasing. When stiffness is decreased because of deterioration of structures and member cracks, dynamic characteristics of structures would be changed. And it is important that the damaged areas and extent of the damage are correctly evaluated by analyzing dynamic characteristics from the actual behavior of a structure. In general, typical measurement instruments used for structure monitoring are dynamic instruments. Existing dynamic instruments are not easy to obtain reliable data when the cable connecting measurement sensors and device is long, and have uneconomical for 1 to 1 connection process between each sensor and instrument. Therefore, a method without attaching sensors to measure vibration at a long range is required. The representative applicable non-contact methods to measure the vibration of structures are laser doppler effect, a method using GPS, and image processing technique. The method using laser doppler effect shows relatively high accuracy but uneconomical while the method using GPS requires expensive equipment, and has its signal's own error and limited speed of sampling rate. But the method using image signal is simple and economical, and is proper to get vibration of inaccessible structures and dynamic characteristics. Image signals of camera instead of sensors had been recently used by many researchers. But the existing method, which records a point of a target attached on a structure and then measures vibration using image processing technique, could have relatively the limited objects of measurement. Therefore, this study conducted shaking table test and field load test to verify the validity of the method that can measure multi-point displacement responses of structures using image processing technique.
Application of Nonlocal Anisotropic Damage Model for the Reinforced Concrete Structures
Woo, Sang Kyun ; Kwon, Yong Gil ; Han, Sang Hoon ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 309~316
This paper proposed a nonlocal anisotropic damage model to simulate the behavior of plain and reinforced concrete structures that are predominantly tensile and compressive load. This model based on continuum damage mechanics, used a symmetric second-order tensor as the damage variable. For quasi-brittle materials, such as concrete, the damage patterns were different in tension and in compression. These two damage states were modeled by damage evolution laws ensuring a damage tensor rate proportional to the total strain tensor in terms of principal components. To investigate the effectiveness of proposed model, the double edge notched specimen experimented by nooru-mohamed and reinforced concrete bending beam were analyzed using the implementation of the proposed model. As the results for the simulation, the nonlocal anisotropic damage model with an adequate control of rupture correctly represented the crack propagation for mixed mode fracture. In the structural failure of reinforced concrete bending beam, the proposed model can be showed up to a very high damage level and yielding of the reinforcements.
Prediction of Flexural Capacity of Steel Fiber-Reinforced Ultra High Strength Concrete Beams
Yang, In Hwan ; Joh, Changbin ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 317~328
The method to evaluate the flexural capacity of steel fiber-reinforced ultra high strength concrete beams was proposed in this study. An experimental program was set up and fourteen beams have been tested. Test results were compared with predictions by design code and by the proposed method, respectively. It was found that predictions by using ACI 544 Committee recommendations considerably underestimate the flexural capacity. Underestimation of flexural capacity resulted from that of tensile stress block. Three-point bending test data of notched prism specimens and their inverse analysis results were incorporated into modeling of tension stress block. The ratio of the predicted to the experimental flexural capacity was in the range of 0.98 to 1.14. The present study represents that the proposed method allows more realistic prediction of flexural capacity of steel fiber-reinforced ultra high strength concrete beams.
Evaluation of Bursting Behavior in Anchorage Zone of PSC I Girders
Choi, Kyu Chon ; Park, Young Ha ; Paik, In Yeol ;
Journal of The Korean Society of Civil Engineers, volume 30, issue 3A, 2010, Pages 329~336
An experimental study to evaluate bursting behavior in anchorage zone of the standard PSC I girders (span length : 30 m) has been carried out. The arrangement of bursting reinforcement in anchorage zone of the standard PSC I girders is considered to be designed without accurately reflecting the stress flows in the end zone of the PSC I girders caused by presstressing forces of the tendons. Also, due to excessive arrangement of the bursting bars, the workability of the girder is decreased greatly. In this study, three specimens with the same dimensions as the end zone of the standard PSC I girder are prepared and the experiment is carried out by applying PS forces. The bursting reinforcement of each specimen consists of 100 mm, 200 mm, and 300mm spacings, respectively. The experimental results show that the range of the PS forces to cause crack in the anchorage zone of the specimen are more than 1.6 times of the design PS forces. The bursting cracks occur in the vertical direction on the inside of all specimens. After applying 2.7 times of the design PS force, some of the transverse bursting reinforcements only in the specimen reinforced by 300 mm spacing yielded. The experimental results show that the anchorage zone of the standard PSC I girders arranged by 300 mm spacing of the bursting reinforcements which is the maximum spacing allowed in the road bridge design specifications, can be considered safe enough.