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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
Structural Optimization of Planar Truss using Quantum-inspired Evolution Algorithm
Shon, Su-Deok ; Lee, Seung-Jae ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 1~9
DOI : 10.11112/jksmi.2014.18.4.001
With the development of quantum computer, the development of the quantum-inspired search method applying the features of quantum mechanics and its application to engineering problems have emerged as one of the most interesting research topics. This algorithm stores information by using quantum-bit superposed basically by zero and one and approaches optional values through the quantum-gate operation. In this process, it can easily keep the balance between the two features of exploration and exploitation, and continually accumulates evolutionary information. This makes it differentiated from the existing search methods and estimated as a new algorithm as well. Thus, this study is to suggest a new minimum weight design technique by applying quantum-inspired search method into structural optimization of planar truss. In its mathematical model for optimum design, cost function is minimum weight and constraint function consists of the displacement and stress. To trace the accumulative process and gathering process of evolutionary information, the examples of 10-bar planar truss and 17-bar planar truss are chosen as the numerical examples, and their results are analyzed. The result of the structural optimized design in the numerical examples shows it has better result in minimum weight design, compared to those of the other existing search methods. It is also observed that more accurate optional values can be acquired as the result by accumulating evolutionary information. Besides, terminal condition is easily caught by representing Quantum-bit in probability.
Experimental Study on the Load Transfer Behavior of Steel Grid Composite Deck Joint
Shin, Hyun-Seop ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 10~21
DOI : 10.11112/jksmi.2014.18.4.010
The joint of prefabricated steel grid composite deck is composed of concrete shear key and high-tension bolts. The flexural and shear strength of the joint were experimentally evaluated only by the bending and push-out test of the joint element. In this study the lateral load transfer behavior of the joint in deck structure system is experimentally evaluated. Several decks connected by the joint are prefabricated and loaded centrically and eccentrically. In the case of centrically loaded specimens, the analysis results show that for the same loading step the rotation angle of the joint with 4 high-tension bolts is larger than the case of the joint with 9 high-tension bolts. Consequently, flexural stiffness of deck and lateral load transfer decrease in the case of specimen with 4 high-tension bolts. But, in the case of eccentrically loaded specimens, it is found that there are no significant differences in the load transfer behavior. The further analysis results about the structural behavior of the joint show that lateral load transfer can be restricted by the load bearing capacity of the joint as well as punching shear strength of the slab. Furthermore, considering that high-tension bolts in the joint didn`t reach to the yielding condition until the punching shear failure, increase in the number of high-tension bolts from 4 to 9 has a greater effect on the flexural stiffness of the joint and deck system than the strength of them.
Analytical Study on Structural Behavior of Surface Damaged Concrete Member by Calcium Leaching Degradation
Choi, Yoon-Suk ; Jang, Yong-Hwan ; Choi, So-Yeong ; Kim, Il-Sun ; Yang, Eun-Ik ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 22~32
DOI : 10.11112/jksmi.2014.18.4.022
Durability is one of the most important and attractive subjects in concrete research field because not only durability of concrete is reduced by various degradation factors but also its reduction adversely influences the structural performance and service life of concrete structure. For this reason, a considerable amount of papers associated with concrete durability have been published and those researches were mainly focused on the changes of intrinsic properties of concrete due to chemicophysical degradations. However, the relationship between durability of concrete and structural behavior of concrete member has not been well established yet. In this study, calcium leaching degradation, a cause of concrete strength reduction, was dealt with. The experiments of compressive and flexural behavior of degraded concrete member were performed to evaluate the characteristics of structural behavior according to degradation level. Finally, the results from the experiments were compared with those obtained from nonlinear FEM analysis. The results from this study clearly showed that leaching degradation leads to decrease in compressive strength and compressive behavior evolves from brittle to ductile failure pattern during the degradation process. Load capacity and flexible rigidity of the degraded RC member decreased when the degradation level increased, in compressive zone. Additionally, it was found that the values from nonlinear FEM analysis, CDP model in ABAQUS, coincided well with the experimental results.
Nonlinear Analysis Model Considering Failure Mode of Unreinforced Masonry Wall
Baek, Eun-Lim ; Kim, Jung-Hyun ; Lee, Sang-Ho ; Oh, Sang-Hoon ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 33~40
DOI : 10.11112/jksmi.2014.18.4.033
The final purpose of this study is to evaluate the seismic performance of unreinforced masonry (URM) building more accurately. For that, shear strength and hysteresis model considering failure mode of the URM wall were discussed. The shear strength of URM wall without openings could be calculated by determining on the minimum value between the rocking strength suggested by domestic research and the sliding strength suggested by FEMA. The wall having openings could be predicted properly by the FEMA method. And the nonlinear hysteresis models for flexural and shear behaviors considering failure mode were proposed. As the result of the nonlinear cyclic analysis that carried out using suggested models, these analysis models were proper to represent the seismic behavior of URM walls.
Evaluation of Structural Performance of Reinforced Concrete Beams using Hybrid Retrofitting with Groove and Embedding FRP Rod and CFRP Sheet
Ha, Gee-Joo ; Ha, Young-Joo ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 41~49
DOI : 10.11112/jksmi.2014.18.4.041
In this study, experimental research was carried out to evaluate the structural performance of the reinforced concrete beam using hybrid retrofitting with two materials (groove and embedding FRP rod, CFRP sheet) in existing reinforced concrete buildings. Seven reinforced concrete beams, retrofitted groove and embedding FRP rod (NER series) and groove and embedding FRP rod with CFRP sheet (NERL series), and standard specimen (NBS) were constructed and tested under monotonic loading. Design parameters of test specimens are the amount of groove and embedding FRP rod and lapping CFRP sheet. Test results showed that the maximum load carrying capacity of specimens with groove and embedding FRP rod and groove and embedding FRP rod with CFRP sheet (NERL series) were increased the by 12~46% and 22~77% respectively in comparison with the standard specimen NBS. Test specimens NER series were failed with the adhesion slip and concrete cover separation. And test specimens NERL series were failed with the adhesion slip due to the confining effect of lapping CFRP sheet.
Experimental Performance Evaluation of Steel Mesh as Maintenance and Reinforcement Materials
Kim, Yeon-Sang ; Choi, Seung-Jai ; Kim, Jang-Ho Jay ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 50~58
DOI : 10.11112/jksmi.2014.18.4.050
Due to the cost burden of new construction, the necessity of repair and retrofitting of aged structures is sharply increasing as the domain of repair and retrofitting construction is expanding. Because of the necessity, new technologies for repair and retrofitting are continuously studied in Korea and foreign countries. Steel adhesive method, fiber reinforced plastic (FRP) surface adhesive method, and external prestressing method are used to perform the repair and retrofitting works in Korea. In order to consider a repair method using steel mesh reinforced cement mortar (SMCM), 3-point flexural member test was conducted considering repair area and layer number of SMCM. Five types of specimens including ordinary reinforced concrete (RC) specimen with dimensions of
(mm) were cast for testing the deflection measurement, a LVDT was installed at the top center of the specimens. Also, a steel strain gauge and a concrete strain gauge were placed at the center of the specimens. A steel strain gauge was also installed on the shear reinforcement. The 3 point flexural member test results showed that the maximum load of SMCM reinforced specimen was higher than that of basic RC specimen in all of the load-displacement curves. Also, the results showed that, when the whole lower part of the basic RC specimen was reinforced, the maximum load and strain were 1.18 and 1.37 times higher than that of the basic RC specimen, respectively. Each specimen showed a slightly different failure behavior where the difference of the results was caused by the difference in the adhesive level between SMCM and RC. Particularly, in SM-B1 specimen, SMCM spalled off during the experiment. This failure behavior showed that the adhesive performance for RC must be improved in order to utilize SMCM as repair and retrofitting material.
Thermal Insulation Performance of Composite Waterproofing Method of Thermal Supplement Type
Choi, Sung-Min ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 59~66
DOI : 10.11112/jksmi.2014.18.4.059
Insulation of rooftop is one of the major performance to energy-saving construction. Further, waterproofing performance is also important. For such a reason, it is need to develop waterproofing method containing thermal insulation property. This study was wanted to evaluate thermal insulation performance about the composite waterproofing method of thermal supplement type that is developed recently. As a result of waterproofing performance test, every test item was showed over the performance standards of KS (Korean (Industrial) Standards). And the result of thermal insulation performance test, the highest temperature in the styrofoam box was
, the bubble sheet box was
, the insulation sheet box was
and the waterproofing sheet box of thermal supplement type was
. In observations of thermal bridges of sheet`s joint, thermal bridges was not identified at the sheet`s joint. As a result, composite waterproofing method of thermal supplement type is interpreted to have thermal insulation performance.
Analytical Study for Design of Shape and Arrangement Spacing of Studs in Steel Plate Concrete(SC) Wall subjected to Shear and Axial Forces
Cho, Sung-Gook ; Lim, Jin-Sun ; Jeong, Young-Do ; Yi, Seong-Tae ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 67~76
DOI : 10.11112/jksmi.2014.18.4.067
In this study, the behavior of Steel Plate Concrete (SC) walls subjected to shear and axial forces to investigate the effects of shape and arrangement spacing of studs on the design of SC walls was analytically reviewed. For this purpose, 9 cases of finite element analyses considering the different shape and spacing of studs in SC wall were performed. The results showed that the steel plate was yielded at the lower load than the second yielding shear force of the design skeleton curve when the spacing of stud is excessively far from each other. It is also found that the shape of the stud did not affect the shear behavior of SC wall but, the spacing influenced to its composite action. In this study, it was also proven that the inclined shaped stud resists more effectively to the bucking load than the general shaped stud in SC wall.
Reduction of Prestress Loss in PSC (Prestressed Concrete) Continuous Girder by Employing Block-out Method
Shin, Kyung-Joon ; Kim, Yun-Yong ; Kim, Seung-Jin ; Choo, Tae-Heon ; Lee, Hwan-Woo ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 77~83
DOI : 10.11112/jksmi.2014.18.4.077
Prestressed concrete girder bridge has been one of the most widely used bridges in the world because of its excellent construction feasibility, economic efficiency, serviceability, and safety. In certain situations, the prestressing tendon is supposed to be bent by the construction error and the radius of curvature at the continuous joint of PSC girders, and this leads to the loss of prestressing force. However, this kind of prestress loss is not considered in the design and construction processes. This study proves that the prestress loss occurs at the continuous joint due to the local bending of tendon by the construction error or the radius of curvature. Also, a method that can reduce this type of prestress loss is proposed, and proved by the experiment. The result shows that maximum 10% of prestress loss occurs at the continuous joint and the proposed block-out method can reduce the prestress loss ratio by maximum 5%, approximately. This means that the block-out method can enhance the prestressing efficiency of continuous PSC girder bridges.
Estimation on the Durability of Metakaolin Concrete According to the W/B Ratio
Kim, Chun-Ho ; Kim, Nam-Wook ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 84~91
DOI : 10.11112/jksmi.2014.18.4.084
In this study, in order to find the improvement effect of metakaolin for using improvement of strength in concrete structures, it is investigated the diffusion coefficient of chloride ions and adiabatic temperature rise test. As a result, due to the mixing of metakaolin, it has been confirmed reducing diffusion coefficient of chloride ions and could prevent down of slump for use of adding fly ash. Therefore, ensuring resistance to chloride ion penetration into concrete, it is possible to enlarge the W/B ratio and reduce the adiabatic temperature rise by mixing of metakaolin. So, it is confirmed that the durability of concrete structures is increased.
Applicability Evaluation and Development of High Strength Spacer with Plastic Fiber and Slag Cement
Kwon, Seung-Jun ; Jo, Hong-Jun ; Park, Sang-Soon ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 92~98
DOI : 10.11112/jksmi.2014.18.4.092
Spacer is a construction material for maintaining cover depth and steel installation, however several problems like staining, leakage, and cracking are currently issued due to performance degradation and unsatisfactory dimensional stability of spacer. Plastic composite is widely used for prevention of brittle failure in cement based material, which yields improvement of crack resistance and ductile failure. This study is for development and applicability evaluation of high strength spacer with slag cement for environmental load reduction and plastic composite like polypropylene fiber, nylon fiber, and glass fiber. For this work, unit weight of 4 different plastic fibers are evaluated through preliminary tests. Physical tests including compressive, flexural, and tensile strength and durability tests including absorption, permeability, length change, crack resistance, carbonation, and freezing and thawing are performed. Through various tests, optimum plastic fiber is selected and manufacturing system for high strength spacer with the selected fiber is developed. Dimensional stability of the developed spacer is evaluated through field applicability evaluation.
An Experimental Study on the Temperature Difference between the Top and Bottom Flange in Steel Girder without Concrete Slab
Shin, Dong-Wook ; Kim, Kyoung-Nam ; Jung, Kyoung-Sup ; Lee, Seong-Haeng ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 99~106
DOI : 10.11112/jksmi.2014.18.4.099
In order to study the reasonable design thermal loads, the steel box girder bridge specimen which have no concrete slab was manufactured with the real size dimension. The temperature data were measured for 5 month at the 18 thermo gauges which were attached according to height. The temperature differences between the top and bottom flange in steel box girder specimen were calculated and the temperature gradient models were proposed by the probabilistic method. This proposed model showed a correlation of approximately 97% when compared with the similar model of Euro Code. Thus, the temperature gradient models which were suggested in this study may be used as the basis data in calculating the design load temperature.
Statistical Homogeneity Tests and Multiple Comparison Analysis for Response Characteristics between Treatments of Bridge Groups
Hwang, Jin-Ha ; Kim, Ju-Han ; An, Seoung-Su ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 107~117
DOI : 10.11112/jksmi.2014.18.4.107
This study tests homogeneity and performs multiple comparison analysis among treatment levels of each factor group through t-test by materials and analysis of variance by structural type and service period. For that descriptive statistical analysis is performed for static and dynamic response characteristics and their ratios of calculated versus measured values based on a good many safety assessment reports for bridges. Homogeneity and post hoc test based on descriptive statistical analysis provide the measures for homogeneity identification among comparison groups in addition to the statistical reference values such as central tendency, variation and shape. This study is expected to be valuable for structural integrity assessment and design by comparing the measured and calculated values with the reference values for the homogeneous group identified, which can help the engineers review the adequacy of the values and put the group database to practical use.
Compressive Strength Estimation Technique of Underwater Concrete Structures using Both Rebound Hardness and Ultrasonic Pulse Velocity Values
Shin, Eun-Seok ; Lee, Ji-Sung ; Park, Seung-Hee ; Han, Sang-Hun ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 118~125
DOI : 10.11112/jksmi.2014.18.4.118
As the earth`s current global warming has caused elevation of sea water temperature, size of storms is foreseen to increase and consequently large damages on port facilities are to be expected. In addition, due to the improved processing efficiency of port cargo volume and increasing necessity for construction of eco-friendly port, demands for various forms of port facilities are anticipated. In this study, two kinds of nondestructive evaluation (NDE) techniques (rebound hardness and ultrasonic pulse velocity methods) are investigated for the effective maintenance of smart green harbor system. A new methodology to estimate the underwater concrete strengths is proposed and its feasibility is verified throughout a series of experimental works.
A Study Scope of Optimal Heating and Drying Process of Timber Heated by Microwave
Shin, Ki-Hoon ; Park, Cheul-Woo ; Son, Dong-Won ; Lim, Nam-Gi ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 126~137
DOI : 10.11112/jksmi.2014.18.4.126
Characteristics of heating and drying of Canadian-imported Douglas-fir timber using microwave in order to secure convenience and quality of drying timber and to get basic data for secondary conservation treatment are as follows: As the results of analysis of change curves of internal temperature of the timber after irradiating it, round timber and board timber showed stable heat distribution, heat consumption and surface water-content in heating with 30kW for 30 minutes and 120 minutes and with 40kW for 3 minutes and 9 minutes, respectively. Especially, surface water-content distribution according to heating by microwave showed very even leveling and water-content decrease rate was also more 30% compared to its weight showing excellent dry efficiency. And in case of soaking timbers into liquid chemicals for secondary conservation according to the analysis results of heat consumption, it is expected that large amount of preservative will be permeated. Therefore, timber heated by microwave is remarkably available for using industrial materials and developing secondary utilized products with its fast water-content decrease and dryness and higher heat consumption.
Development and Performance Evaluation of Under Cut Anchor Stone Curtain Wall Construction Method
Chang, Kug-Kwan ; Park, Nam-Wook ;
Journal of the Korea institute for structural maintenance and inspection, volume 18, issue 4, 2014, Pages 138~146
DOI : 10.11112/jksmi.2014.18.4.138
Structural safety as well as variety and aesthetics of building facade are currently gathering more attention in building construction and stone curtain wall is widely used in exterior wall. However, two main problems are existed in curtain wall construction method. One is an uniformity of construction quality and the other is a repair work of stone panels. Also, the noise and vibration occurring in construction may be cause of civil complaint. Therefore, a new method is needed to overcome these problems. This paper presents a new stone curtain wall system using under cut anchor and secondary holes that was developed in this study. Additionally, structural performance evaluation was conducted to verify the constructability and structural safety for wind pressure and seismic load. Through the evaluation of this method, improved constructability and economic efficiency were verified.