• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.114-122
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• 2014

Currently, global warming has become a serious problem arising from the usage of fossil fuels such as coal and petroleum. Moreover, due to the global warming, heat wave, heavy snow, heavy rain, super typhoon are frequently occurring all over the world. Due to these serious natural disasters, concrete structures and infrastructures are seriously damaged or collapsed. In order to handle these problems, climate change oriented construction technology and codes are necessary at this time. Therefore, in this study, the validity of the present concrete mixture proportions are evaluated considering temperature and humidity change. The specimens cured at various temperature and humidity conditions were tested to obtain their compressive and split tensile strengths at various curing ages. Moreover, performance based evaluation (PBE) method was used to analyze the satisfaction percentage of the concrete cured at various condition. From the probabilistic method of performance evaluation of concrete performance, feasibility and usability can be determined for future concrete mix design.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.439-445
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• 2020

In this paper, the seismic performance evaluation was performed on 100 existing open-cut power cable tunnels, including ones that did not consider seismic design, in order to verify that the government's demand level (seismic special grade, 0.22 g). The results of the seismic performance evaluation show that most of the tunnels have seismic performance of 0.3 to 1 g, satisfying the level of the seismic special grade and securing the seismic safety. Meanwhile, the earthquake response analysis and structural test were performed to verify the validity of the method and the results of the seismic performance evaluation of the tunnels by the response displacement method, and to verify their seismic safety. As a result, the relative displacement due to the response displacement method under the 0.22 g earthquake was conservative than the results of the earthquake response analysis, and the results of load-displacement curves and response modification coefficient calculation by real scale structural tests showed the safety of the tunnels.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.259-266
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• 2022

In this study, we developed a deep learning and vision sensor-based assembly performance evaluation method isfor prefabricated steel structures. The assembly parts were segmented using a modified version of the receptive field block convolution module inspired by the eccentric function of the human visual system. The quality of the assembly was evaluated by detecting the bolt holes in the segmented assembly part and calculating the bolt hole positions. To validate the performance of the evaluation, models of standard and defective assembly parts were produced using a 3D printer. The assembly part segmentation network was trained based on the 3D model images captured from a vision sensor. The sbolt hole positions in the segmented assembly image were calculated using image processing techniques, and the assembly performance evaluation using the k-nearest neighbor algorithm was verified. The experimental results show that the assembly parts were segmented with high precision, and the assembly performance based on the positions of the bolt holes in the detected assembly part was evaluated with a classification error of less than 5%.

• Smart Structures and Systems
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• v.11 no.6
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• pp.637-662
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• 2013

The Jiangyin Bridge is a suspension bridge with a main span of 1385 m over the Yangtze River in Jiangsu Province, China. Being the first bridge with a main span exceeding 1 km in Chinese mainland, it had been instrumented with a structural health monitoring (SHM) system when completed in 1999. After operation for several years, it was found with malfunction in sensors and data acquisition units, and insufficient sensors to provide necessary information for structural health evaluation. This study reports the SHM system upgrade project on the Jiangyin Bridge. Although implementations of SHM system have been reported worldwide, few studies are available on the upgrade of SHM system so far. Recognizing this, the upgrade of original SHM system for the bridge is first discussed in detail. Especially, lessons learned from the original SHM system are applied to the design of upgraded SHM system right away. Then, performance assessment of the bridge, including: (i) characterization of temperature profiles and effects; (ii) recognition of wind characteristics and effects; and (iii) identification of modal properties, is carried out by making use of the long-term monitoring data obtained from the upgraded SHM system. Emphasis is placed on the verification of design assumptions and prediction of bridge behavior or extreme responses. The results may provide the baseline for structural health evaluation.

• Land and Housing Review
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• v.15 no.3
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• pp.153-164
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• 2024

Structural health monitoring involves performance evaluation based on measurements for maintenance purposes. By back-calculating measured Frequency Response Function (FRF) data, the concept of effective mass was introduced and applied to the performance evaluation of structural members. An identification method was proposed that uses participation factors to estimate the dynamic parameters and the strength of concrete of structural members. The appropriateness of these methods for identifying dynamic parameters and concrete strength of structural members was validated through experimental results, proving their utility in non-destructive testing for concrete strength.

• Journal of Korean Association for Spatial Structures
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• v.9 no.4
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• pp.73-80
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• 2009

It is very important that predict the inelastic seismic behavior exactly for seismic performance evaluation of a building in the performance based seismic design. But, it is difficulty that predict the building behavior of actual and exact in simplified load-deformation relation of structural material and members. In this study, system ductility and story ductility capacity of building structure used to the Backbone hinge Model are estimated and compared considering the characteristics of load-deformation relation of structural material and members. Analyses results, bilinear hinge model has lower system ductility and story ductility demands than those of backbone hinge model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.289-296
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• 2003

The evaluation on performance of gel type penetrative water-repellent for durability progress of concrete structure has carried out in this study. And liquid type waterproof agents have been estimated with same method. Also normal concrete that was not applied water-repellent and waterproof agents have been estimated. As results, the penetrative depth of gel type water-repellent were deeper than that of liquid type waterproof agents and those were superior to these in physical and durable performance.

• Structural Engineering and Mechanics
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• v.50 no.4
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• pp.419-439
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• 2014

In this study, the structural performance of a seven span masonry arch bridge was evaluated. Investigations were performed on Aspendos (Belkis) Masonry Arch Bridge which was located on road of Aspendos Acropolis City in Antalya, Turkey. The old bridge was constructed in the early of fourth century AD, but it was exposed to the earthquakes in this region and the overloading by the river water. The old bridge was severely damaged and collapsed by probably an earthquake many years ago and a new bridge was then reconstructed on the remains of this old bridge by Seljuk in the 13th century. The bridge has also been affected from overflowing especially in the spring of each year, so some protective measures should be taken for this monumental bridge. Therefore, the structural performance under these loading has to be known. For this purpose, an initial finite element model was developed for the bridge and it was calibrated according to ambient vibration test results. After that, it was analyzed for different load cases such as dead, live, earthquake and overflow. Three load combinations were taken into account by deriving from these load cases. The displacements and the stresses for these combination cases were attained and compared with each other. The structural performance of Aspendos Masonry Arch Bridge was determined by considering the demand-capacity ratio for the tensile stress of the mortar used in Aspendos Masonry Arch Bridge. After these investigations, some concluding remarks and offers were presented at the end of this study.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.1
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• pp.33-39
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• 2013

Structural insulated panels, structurally performed panels consisting of a plastic insulation bonded between two structural panel facings, are one of emerging products with a viewpoint of its energy and construction efficiencies. These components are applicable to fabricated wood structures. In Korea, there are few technical documents regulated structural performance and engineering criteria in domestic market. This study was conducted to identify fundamental performance of both monotonic load and quasi static cyclic load for SIPs in shear wall application. Static test results showed that maximum load was 44.3kN, allowable shear load was 6.1kN/m, shear stiffness was 1.23 M N/m, and ductility ratio was 3.6. Cyclic test was conducted by two kinds of specimens : single panel and double panels. Cyclic test results, which were equivalent to static test results, showed that maximum load was 45.42kN, allowable shear load was 6.3kN/m. Furthermore the accumulated energy dissipation capability for double panels was as 2.3 times as that for single panel. From performance of structural tests, it was recommended that the allowable shear load for panels was at least 6.1kN/m.

• Fire Science and Engineering
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• v.29 no.5
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• pp.23-28
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• 2015

Recently, structural materials have been developed to have high performance, and SM 520 has been developed and used for high-rise buildings. However, fires frequently occur in buildings, and the number of victims and amount of damage increase year by year. However, the evaluation of fire resistance performance for structural beams made of SM 520 is done with specimens made of ordinary structural steels with boundary conditions of a fixed beam, and the results are allowed for use in steel-framed buildings. This study analyzed the fire resistance performance of statistically indeterminate beams built with SM 520. The analysis used a fire engineering technique that includes mechanical and thermal data of SM 520 and heat transfer theory, and heat stress analysis was also conducted. The results from the analysis were compared with those from a statistically determinate beam made of ordinary structural steels.