• Journal of the Korean Geotechnical Society
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• v.35 no.7
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• pp.5-14
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• 2019

In this study, a prototype abutment was constructed to establish a safety assessment technique of pier and a series of non-destructive tests using impact load. The surcharge load was loaded from 0 tonf to 2.5 tonf on the prototype abutment, and maximum surcharge load was up to 25 tonf. To analyze the behavior of the piers according to the direction of impact, a total of three types of analysis were performed: the direction of the pier, the direction perpendicular to the pier, and the outer direction of the pier. The height of the impact was also tested at each top and bottom. The measuring instrument used an accelerometer to measure the acceleration response when impacted. Based on the series of experimental results, specific values were calculated according to the direction of an impact and the surcharge load using the Fast Fourier Transform (FFT). In addition, the phase difference was used to analyze the pier from the primary 1st mode to the 4th mode.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.143-153
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• 2021

The corroded pier that has corrosion of the tranverse steel, main steel and lapsplice directly affects the seismic performance. The corrosion of the tranvese and main steel directly reduce the shear strength and bendig strength. If steel corrosion occurs in lap splice, the flexural strength and flexibility of existing corroded pier that are not seismic design are significantly reduced. In addition, as the axial force acting on the pier increase the shear strength. Considering these effects. In this stuydy, we cosidered steel corrosion, lap splice and axial force, for a reasonable evaluation of seismic-performance. It is confirmed that flexular failure occurs at pies where shear failure is expected to occur due to corrosion of reinforcement. These failure modes and their reason are analyzed, and necessary considerations are presented for seismic reinforcement.

• Geomechanics and Engineering
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• v.24 no.4
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• pp.389-397
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• 2021

Pile foundation is a typical form of bridge foundation and viaduct, and large-diameter rock-socketed piles are typically adopted in bridges with long span or high piers. To investigate the effect of a mountain slope with a deep overburden layer on the bearing characteristics of large-diameter rock-socketed piles, four centrifuge model tests of single piles on different slopes (0°, 15°, 30° and 45°) were carried out to investigate the effect of slope on the bearing characteristics of piles. In addition, three pile group tests with different slope (0°, 30° and 45°) were also performed to explore the effect of slope on the bearing characteristics of the pile group. The results of the single pile tests indicate that the slope with a deep overburden layer not only accelerates the drag force of the pile with the increasing slope, but also causes the bending moment to move down owing to the increase in the unsymmetrical pressure around the pile. As the slope increases from 0° to 45°, the drag force of the pile is significantly enlarged and the axial force of the pile reduces to beyond 12%. The position of the maximum bending moment of the pile shifts downward, while the magnitude becomes larger. Meanwhile, the slope results in the reduction in the shaft resistance of the pile, and the maximum value at the front side of the pile is 3.98% less than at its rear side at a 45° slope. The load-sharing ratio of the tip resistance of the pile is increased from 5.49% to 12.02%. The results of the pile group tests show that the increase in the slope enhances the uneven distribution of the pile top reaction and yields a larger bending moment and different settlements on the pile cap, which might cause safety issues to bridge structures.

• International Journal of High-Rise Buildings
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• v.11 no.1
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• pp.1-14
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• 2022

Debates on what is the first skyscraper have been ongoing from time to time since the construction of the Home Insurance Building in Chicago in 1885, which is generally recognized as the first built skyscraper. This paper attempts to verify this assertion through a detailed investigation after identifying the criteria that characterize a skyscraper. By considering and examining several competing buildings for the title of "first skyscraper" in terms of their levels of satisfying these criteria, the paper reconfirms that the Home Insurance Building in Chicago indeed qualifies as the first skyscraper and is the harbinger of future skyscrapers. By introducing technological and associated architectural innovations in this pioneering building, its designer William Le Baron Jenney paved the way for the construction of future skyscrapers. In traditional construction, heavy masonry walls especially at lower levels did not allow large window openings in exterior walls that would permit ample daylight. For the Home Insurance Building, originally built with 10 stories, Jenney created a metal-framed skeletal structure that carried the building's loads, making the building lighter and allowed for large windows permitting ample natural light to the building's interior. The exterior iron columns were encased in relatively small masonry piers mainly for fireproofing, weather-protection and façade aesthetics. Relying on the structural framing on the building's perimeter, the exterior masonry thus turned into a rudimentary "curtain wall" system, heralding the use of curtain wall construction in future skyscrapers. This building's innovative structural system led to what is known as the "Chicago Skeleton," and eventually produced remarkable skyscrapers all over the world.

• Journal of Korean Port Research
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• v.10 no.1
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• pp.1-14
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• 1996

Rapid change in the technological environment of marine transportation and the development of the ocean shipping industry have fostered a revolution in the port system. This in turn has caused major changes in the function and use of port in Korea. Aside from this, Mokpo Port, however continues to decline, because the existing port facilities and related subsystem are already obsolete with no chance of regaining operational effectiveness and treatment for proper implementation. Although a few studies have been done on the Mokpo Port, has not been found, any reseach for the analytical approach to the transportation system of it. This paper aims to make an extensive analysis of the physical distribution system in Mokpo Port focusing on the coordination of subsystems such as navigational aids system. The base of introduced simulation tool here is the queueing theory. The overall findings are as follows: 1. Among those vessels called at Mokpo Port in 1994, 556 ships(2,736,669 G/T) are oceangoing while 8155 ships(2,587,217 G/T) are domestic. The average size of oceangoing vessels is 4,922,1 G/T, and the domestic is 317,8 G/T. The average arrival interval and service time of the domestic vessels are 6.0 hours and 24.1 hours respectively marking the berth occupation rate over 100%. Those for oceangoing vessels are 34.5 hours, 120.0 hours and 37.2%. In order to maintainin the berth occupation rate to 70% the capacity considering the 1994 of domestic piers must be extended to 145% and oceangoing vessels must be increased to 165%. 2. The capacity of approaching channel is enough to handle the total traffic volume of 3. Tugs are sufficiently being provided to handle all ships requiring their services 4. The capacity of storage and inland transportation systems are sufficient to handle the throughput and the yard stroage utilization rate of No.1 - No.5 is 4.5% and No.6 is 30% of 1993's. 5. The utilization rate of LLC(Level Looping Crane) and PNT(PNeumaTic) are 2.7% and 18.8%, respectively.

• Journal of Korean Port Research
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• v.4 no.1
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• pp.3-20
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• 1990

The Port of Pusan, the largest port in Korea, handled 23% of total sea borne cargo movement, 14% of imported cargo, 58% of exported cargo and 95% of container cargo in 1989. Also the port of Pusan has been played a key role in handing container cargo throughout the last 10 years. The paper is aimed to survey the effect of sea borne cargo movement to urban transportation, that is, to find traffic volume arising by general/bulk cargoes through the port and to estimate vehicle rated of container tractor tailer on the roads between terminal including conventional piers and ODCY, and finally the following results are obtained. (1) AADV of truck to transport general/bulk cargoes are 6,322 units in 1989,and routes penetrate into the center of city and pass through the most of urban arterials. (2) In the container transport, if HVEF is adopted to 3 of tractor trailer, AVR in each transport freeway 13.7%. (3) IF HVEF is adopted to 6 of tractor trailer. AVR are as follows: BooDoo-Ro 44.1%, WooAm-Ro 39.3%, SooYoung-Ro 17.8%, Urban freeway 20.3%. Based upon these results, the following suggestions were drawn : o ODCY scattered around the city should be unified in a few groups to raise port productivity. o Rail service for inland container transportation should be escalated to relieve urban traffic congestion. o Coastal feeder service between terminal and hinterland should be studied to restrict the penetration of container tractor trailer into the central parts in the urban areas. o Exclusive freeway system for effective container transportation should be implemented to reduce urban traffic delay.

• Composites Research
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• v.21 no.3
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• pp.24-30
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• 2008

Durability problems may arise in the concrete, which is one of the major construction materials, used in the construction field. Bridge piers and foundation piles are usually made with concrete and they are exposed to the moisture and hence the durability of the concrete reduced significantly due to oxidization of re-bar and icing of concrete. To mitigate such problems, FRP tube has been developed and the concrete filled FRP tube (CFFT) has been investigated to find the confinement effect which is provided additionally. It was reported that if the concrete is wrapped with FRP, strength and chemical resistance are improved significantly. In order to apply such a member in the construction field, structural behavior and applicable design guideline or design criteria must be thoroughly investigated. In the experimental investigation, the results are compared with the previous research results and the relationship which can predict the ultimate strength and strain is suggested. In addition, some comments found at the compression tests are given briefly.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.473-484
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• 2006

The capacity spectrum method (CSM) can be used to simply estimate the maximum displacement response of the nonlinear structures. To evaluate seismic performance of multi-span bridges using the CSM, the representative response for structural system should be derived from the multi-degree-of-freedom (MDOF) responses by using the equivalent single-degree-of-freedom (ESDOF) method. The ESDOF method is used to calculate the capacity curve of the structural system from the pushover curves of all piers or structural members estimated by the pushover analysis. In order to evaluate an accuracy of ESDOF methods used in the CSM, the maximum displacements estimated by the CSM incorporating the several ESDOF methods are compared to those by the inelastic time-history analysis for several artificial earthquakes corresponding to the design spectrum.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.955-963
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• 2006

As the geometrical characteristic of the curved bridge, the seismic response of curved bridges are different from straight bridges. This study analyzed the seismic response of the curved bridges considering diverse factors such as radius of curvature, direction of seismic load and support condition. The improved simple modeling of the curved bridge for seismic analysis is proposed, and it is compared with the detail modeling in order to verify the simple modeling. Three simply supported curved bridges and six 3-span continuous bridges are selected for seismic analysis. The behavior of curved bridges are evaluated in terms of the displacement and the force at supports and piers under seismic load applied in various directions. The results of this study show that upward reaction force may appear in simply supported curved bridge under seismic load. And continuous curved bridges are affected by the direction of the seismic load.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.131-143
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• 2009

Under transverse earthquake shaking, arching action of bridge structures develops along the deck between the abutments thus providing the so-called deck resistance. The magnitude of the arching action for bridge structures is dependent on the number of spans, connection condition between deck and abutment or piers, and stiffness ratio between superstructure and substructure. In order to investigate the arching action effects for inelastic seismic responses of PSC Box bridges, seismic responses evaluated by pushover analysis, capacity spectrum analysis and nonlinear time-history analysis are compared for 18 example bridge structures with two types of span numbers (short bridge, SB and long bridge, LB), three types of pier height arrangement (regular, semi-regular and irregular) and three types of connection condition between superstructure and substructure (Type A, B, C). The arching action effects (reducing inelastic displacement and increasing resistance capacity) for short bridge (SB) is more significant than those for long bridge (LB). Semi-regular and irregular bridge structures have more significant arching action than regular bridges.