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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 15, Issue 6 - Nov 2011
Volume 15, Issue 5 - Sep 2011
Volume 15, Issue 4 - Jul 2011
Volume 15, Issue 3 - May 2011
Volume 15, Issue 2 - Mar 2011
Volume 15, Issue 1 - Jan 2011
Selecting the target year
Performance Improvement of Overpass Bridge by Weight Reduction
Kim, Sung Bae ; Nam, Sang Hyeok ; Kim, Jang-Ho Jay ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 51~60
DOI : 10.11112/jksmi.2011.15.2.051
In this study, structural safety capacity analysis of the overpass railway bridge between Konkuk Univ. and Guui station railroad has been performed. The overpass is expected to have suffered durability reduction by deterioration. The weight reduction of the overpass has been implemented to prevent further durability reduction and to improve performance capacity. To reduce the weight, 3 procedures of replacing concrete soundproofing wall to light-weight soundproofing wall, replacing gravel ballast to concrete ballast, and reducing the weight of trough have been performed. The analysis of static/dynamic behaviors and improved capacity of the light-weighted overpass bridge has been performed. The structural safety verification of the improved structure has been implemented by using rating factors of load carrying capacity of PSC I girder. The results have shown that the deflection has been reduced by 2.6mm and tensile strength has been improved by 1.07MPa, which indicate that the structural capacity has effectively been improved. Also, the natural frequency has improved by approximately 30% where vibration reduction and dynamic behavior improvement have been achieved. Moreover, in the rating factor evaluation based on analysis and test results, an improvement from 1.82 to 1.93 has been observed. Therefore, weight reduction method for the overpass is effective considering overall results.
Experimental Study on the Flexural Performance of Steel Beams Reinforced by AFRP Sheets
Kim, Kang Seok ; Nah, Hwan Seon ; Kim, Kang Sik ; Lee, Hyeon Ju ; Lee, Kang Min ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 61~69
DOI : 10.11112/jksmi.2011.15.2.061
Fiber Reinforced Plastic (FRP) sheets have been widely used to retrofit and rehabilitate RC structures, while in case of retrofitting steel structures, there are no codes and researches. It stems from configuration of member and characteristics of bonding behavior. This study focused on the static behavior of steel beams reinforcement by AFRP sheets. The main objective of the experimental programme was the evaluation of the force transfer mechanism, the increment of the beam load carrying capacity and the bending stiffness. A bending test was conducted on a H-shaped steel beam, with aramid FRP sheets bonded to its flanges. The mid-span deflection and the strain from three points along AFRP sheets were recorded Test results exhibit that the increment of the load-carrying capacity with reference to a mid-span deflection level of 15 mm(1/125mm of the clear span) was equal to 9.4% and for the two layers case, an elastic stiffness increment is slightly higher than one layer case.
Application for a BWIM Algorithm Using Density Estimation Function and Average Modification Factor in The Field Test
Han, Ah Reum Sam ; Shin, Soobong ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 70~78
DOI : 10.11112/jksmi.2011.15.2.070
The paper aims at developing a more reliable and accurate BWIM(Bridge Weigh-In-Motion) algorithm using measured strain data and examining its efficiency with various tests on bridges. It proposes a BWIM algorithm using density estimation function and average modification factor for moment-strain relationship. Density estimation function has been proved to be reliably applied when multiple axle loads are estimated. An average modification factor is applied to minimize overall error that can be encountered between theoretically computed moments and measured strains at multiple locations in a bridge. The developed algorithm has been successfully examined through numerical simulations, laboratory tests, and also by field tests on a multi-girder composite bridge.
Effect of Initial Flexural Crack on Resistance to Chloride Penetration into Reinforced Concrete Members
Yang, Eun Ik ; Jin, Sang Ho ; Kim, Myung Yu ; Choi, Yoon Suk ; Han, Sang Hun ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 79~87
DOI : 10.11112/jksmi.2011.15.2.079
In this study, the chloride penetration tests were performed for the initially cracked reinforced concrete members. The chloride diffusion characteristics and the critical crack width are compared, and the properties of self-healing are investigated. According to the test results, the chloride penetration resistance was greatly reduced as the surface crack width increased. When the mineral admixtures are added, the chloride penetration resistance of uncracked specimens were effectively increased, however, in case of the blast furnace slag and fly ash, the cracked specimens showed the more reduced resistance than OPC case, inversely. Also, the critical width was
, on average, for immersion test. The crack width with
was restored by self-healing, The parts restored by self-healing were seemed to be visually restored, however, the chloride penetration resistance was not restored, perfectly.
Load Distribution Factors for Determinating Shear Force in Steel Box Girder Bridges
Song, Jea Ho ; Kim, Min Wook ; Kim, Il Su ; Oh, Jin Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 88~97
DOI : 10.11112/jksmi.2011.15.2.088
For Korean design provisions are not equipped for skewed steel box girder bridges, when American provisions are adopted, load distribution factors different from real behavior are determinated. Furthermore the possibility of over or under estimated bridge design involves. The aim of this study is to provide more rational load distribution factor formulas based on real behavior for shear at obtuse corner of skewed steel box girder bridges. In order to accomplish the aim finite element analysis for a variety of skewed steel box girder bridge structural models is carried out, and each parameters degree of influence on wheel load distribution factors of skewed steel box girder bridges are analyzed. Then multiple regression analysis is fulfilled in order to propose formulas for determinating shear force load distribution factor of skewed steel box girder bridges.
Evaluation of Static Behaviour of Orthotropic Steel Deck Considering the Loading Patterns
Kim, Seok Tae ; Huh, Young ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 98~106
DOI : 10.11112/jksmi.2011.15.2.098
The deck of steel box girder bridges is composed of deck plate, longitudinal rib, and transverse ribs. The orthotropic steel decks have high possibility to fatigue damage due to numbers of welded connection part, the heavy contact loadings, and the increase of repeated loadings. Generally, the local stress by the repeated loadings of heavy vehicles causes the orthotropic steel deck bridge to fatigue cracks. The increase of traffic volume and heavy vehicle loadings are promoted the possibility of fatigue cracks. Thus, it is important to exactly evaluate the structural behavior of bridge considering the contact loading area of heavy vehicles and real load patterns of heavy trucks which have effects on the bridge. This study estimated the effect of contact area of design loads and real traffic vehicles through the finite element analysis considering the real loading conditions. The finite element analysis carried out 4 cases of loading patterns in the orthotropic steel deck bridge. Also, analysis estimated the influence of contact area of real truck loadings by the existence of diaphragm plate. The result of finite element analysis indicated that single tire loadings of real trucks occurred higher local stress than one of design loadings, and especially the deck plate got the most influence by the single tire loading. It was found that the diaphragm attachment at joint part of longitudinal ribs and transverse ribs had no effects on the improvement of structural performance against fatigue resistance in elastic analysis.
Investigation of Maximum Strength and Effective Bonding Length at the Interface Between Structure and GFRP Material Under Freeze-thaw Cycles and Applied Different Bonding Materials
Choi, Hyun Kyu ; Jung, Woo Young ; Ahn, Mi Kyoung ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 107~115
DOI : 10.11112/jksmi.2011.15.2.107
This research studies the behavior of the FRP-concrete interface subjected to two environmental substances. Frist is to investigate the behavior by the application of different bonding materials at the interface between FRP and concrete, second is to understand a long-term performance at the interface by Freeze-thaw actions. The parameters considered in this research are the maximum bonding strength and the effective bonding length at the FRP-concrete interface. In the first experimental phase, three types of specimens are fabricated and tested considering the number of applied bonding materials and the Freeze-thaw tests are performed to evaluate the behavior of the interface in the cycle range of 0 to 300 cycles. Finally, it is known that there is a 5~7% difference of the effective bonding length between applied bonding materials and the values for the maximum stress and the effective length under Freeze-thaw action are varied randomly as the freeze-thaw cycle is increased even though initial reduction of their capacities are occurred.
An Experiment and Analysis of Precast Concrete Baseplate on Bimodal Tram Dedicated Bridge
Cheon, Ju Hyoun ; Joo, Young Jong ; Kim, Ryang Gyun ; Yoon, Hee Taek ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 116~124
DOI : 10.11112/jksmi.2011.15.2.116
To purpose of this study is to develop the new type of precast concrete baseplate which is only for bimodal tram. The experiments with real size specimens, which are hollowed precast baseplate, prove the efficacy of new designed baseplate by comparing with the result of RCAHEST. Through tests progressed according to different loading locations, the specimens show the stability by the safety factor of 8~9. Also the results of RCAHEST that is the nonlinear finite element method program, appropriately estimate the occuring crack on concrete, yielding reinforcement and ultimate behavior at failure.
Geomatrically Non-linear Analysis Method by Curvature Based Flexibility Matrix
Kim, Jin Sup ; Kwon, Min Ho ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 125~135
DOI : 10.11112/jksmi.2011.15.2.125
The latest study for formulation of finite element method and computation techniques has progressed widely. The classical method in the formulation of frame elements for geometrically nonlinear analysis derives the geometric stiffness directly from the governing differential equation for bending with axial force. From the computational viewpoint of this paper, the most common approach is the finite element method. Commonly, the formulation of frame elements for geometrically nonlinear structures is based on appropriate interpolation functions for the transverse and axial displacements of the member. The formulation of flexibility-based elements, on the other hand, is based on interpolation functions for the internal forces. In this paper, a new method is used to suppose that interpolation functions for the displacements from the curvatures is Lagrangian interpolation. This paper derives flexibility matrix from that displacement functions and is considered the application of it. Using the flexibility matrix, this paper apply the program considered geometrically nonlinear analysis to common problems.
Evaluation on the Behavior of Slip Critical Joints with TS High Strength Bolts Subjected to a Size of Bolt Holes
Lee, Hyeon Ju ; Kim, Kang Seok ; Nah, Hwan Seon ; Lee, Kang Min ; Kim, Hyun Chul ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 136~143
DOI : 10.11112/jksmi.2011.15.2.136
The oversized and slotted holes are frequently required for the built-up in construction sites. The foreign provisions specify the reduction of the slip load subjected to the size of bolt holes and the direction of load. There are no domestic building codes and researches on the bolt holes. Therefore, it is necessary to evaluate a change of joint strength quantitatively according to the bolt-hole size and surface condition by means of experiment. This study was conducted to evaluate the slip load subjected to the size of bolt holes, and measured on a change of clamping force of high strength bolts during 168 and 800 hours to analyze the trend of relaxation after fastening bolts. Torque shear bolts defined on KS B 2819 was used for the specimen. Test results exhibit that the variation on the slip load of the others was below 10% by contrast with the standard hole and the highest rate of relaxation was 2.66% of the initial clamping force at the case of the long-slotted hole of 2.5D.
An Experimental Study on Flexural Behavior in Framed Structure of P.S.T Method
Cui, Jie ; Yoon, Jong Nam ; Eum, Ki Young ; Hong, Sung Nam ; Park, Sun Kyu ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 144~152
DOI : 10.11112/jksmi.2011.15.2.144
The existing underground trenchless methods use reinforcing rod in steel tube to obtain structural stiffness. However, there are some problems such as inconvenience of work and expensive material fee which are resulted from limited working space and reinforcing work. To resolve these problems, a new trenchless method, namely P.S.T method (Prestressed Segment Tunnel Method), is developed which uses joint to connect the steel segment and form erection structure in underground construction. Further, installing strands for prestressing. In order to evaluate the flexural capacity of the P.S.T method structure, experiment was conducted. The parameters considered in the experiment are the span-to-depth ratio, diameter of steel tube at corner, prestressing force and welding of joint. Altogether examining the flexural behavior, the effect of deflection in structure according to different parameters has also been analysised.
Estimation of Design Wind Speed Compatible for Long-span Bridge in Western and Southern Sea
Kim, Han Soo ; Lee, Hyun Ho ; Cho, Doo Young ; Park, Sun Kyu ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 153~160
DOI : 10.11112/jksmi.2011.15.2.153
Recently there are many long span cable supported bridges like Cable Stayed Bridge and Suspension Bridge already constructed or planned. Reconsidering of proper design wind load of long span bridge is required since the meteorological value based on the data only from 1960s to 1995 has been used when we estimate the wind load for designing long span bridges. In this paper, the research area was confined to western and southern coasts where many long span bridges have constructed. The method of moment and the least-squares method were used to estimate the expected wind speeds of 100 year's return period for girder bridges and for 200 year's return period for long span bridges based on the Gumbel's distribution. As the return-period wind speed on the land face was revised because of recent high speed velocity, the revised return-period wind speed is increased by 17%. Compatibility of return-period wind speed was also evaluated using RMS (Root Mean Square) error method. Aa a result of this paper, the least-squares method is more compatible than the method of moment in the case of western and southern coasts in Korea.
Application of High-Performance Steels to Enhance the Punching Shear Capacity of Two-Way Slabs
Yang, Jun Mo ; Shin, Hyun Oh ; Lee, Joo Ha ; Yoon, Young Soo ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 161~169
DOI : 10.11112/jksmi.2011.15.2.161
Two-way slabs reinforced with high-performance steels, which have several practical advantages of a reduction of congestion in heavily reinforced members, savings in the cost of labor and repair, the higher corrosion resistance, and a reduction of construction time, were constructed and tested. The influences of the flexural reinforcement ratio, concentrating the reinforcement in the immediate column region, and using steel fiber-reinforced concrete (SFRC) in the slab on the punching shear resistance and post-cracking stiffness were investigated, and compared with the punching shear test results of the slabs reinforced with conventional steels and GFRP bars. In addition, the strain distribution of flexural reinforcements and crack control were investigated, and the effective width calculating method for the average flexural reinforcement ratio was estimated. The use of high-performance steel reinforcement increased the punching shear strength of slabs, and decreased the amount of flexural reinforcements. The concentrating the top mat of flexural reinforcement increased the post-cracking stiffness, and showed better strain distribution and crack control. In addition, the use of SFRC showed beneficial effects on the punching shear strength and crack control. It was suggest that the effective width should be changed to larger than 2 times the slab thickness from the column faces.
Development of Smart Wireless Measurement System for Monitoring of Bridges
Heo, Gwang Hee ; Lee, Woo Sang ; Lee, Chin Ok ; Jeon, Joon Ryong ; Sohn, Dong Jin ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 170~178
DOI : 10.11112/jksmi.2011.15.2.170
In this paper, a research was performed to develop a wireless measurement system for bridge monitoring using MEMS sensor and bluetooth wireless communication module. First, in order to prove the suitability of MEMS sensor for the bridge measurement, its ranges of measuring acceleration and of frequency response were experimented. Also, the quality of wireless communication was tested by an experiment on long-distance communication for the knowledge of maximum communication distance, and also by an experiment on the data transmit-receive capability both inside and outside of a steel box bridge. Later, placing the wireless acceleration sensor system that had been developed in our lab on a bridge in public service, we acquired vibration data from the bridge under traffic load and analyzed its dynamic characteristics in realtime. For the analysis of the data, NExT & ERA algorithm were employed. The result of analysis was compared to the FE analysis of the same bridge, and the comparison made it possible to evaluate the performance of wireless acceleration sensor system. As a result, it was proven that the wireless acceleration sensor system developed with the use of MEMS sensor and bluetooth wireless communication module could be effectively applied to the measurement of structure whose vibration feature was low frequency like a bridge.
Evaluation of Fatigue Crack Growth Rate on the Surface of Steel Members Using COD(Crack Opening Displacement) Measurement
Kim, Kwang Jin ; Kim, In Tae ;
Journal of the Korea institute for structural maintenance and inspection, volume 15, issue 2, 2011, Pages 179~188
DOI : 10.11112/jksmi.2011.15.2.179
Steel structures have been allowed to have fatigue damage tolerance in fact. If it would be assessed whether fatigue crack is growing or not and How fast fatigue crack is propagating, we should make a rational decision on methods and a period of reinforcement in the maintenance. In this study, fatigue crack growth tests on two kinds of through-thickness cracked steel plates and a out-of-plane gusset welded joint were conducted to evaluate fatigue crack growth rate using the COD(Crack Opening Displacement), and COD measurement using strain gauges was examined to offer a practical method. As a result, we proposed a reasonable assessing method for fatigue crack growth rate using the COD and it was experimentally proved practical to estimate the COD through measuring strains.