• Earthquakes and Structures
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• v.10 no.2
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• pp.409-428
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• 2016

To realise the full benefits of a self-centering seismic resilient system, the designer must ensure that the entire structure does indeed re-center following an earthquake. The idealised flag-shaped hysteresis response that is often used to define the cyclic behaviour of self-centering concrete systems seldom exists and the residual drift of a building subjected to an earthquake is dependent on the realistic cyclic hysteresis response as well as the dynamic loading history. Current methods that are used to ensure that re-centering is achieved during the design of self-centering concrete systems are presented, and a series of cyclic analyses are used to demonstrate the flaws in these current procedures, even when idealised hysteresis models were used. Furthermore, results are presented for 350 time-history analyses that were performed to investigate the expected residual drift of an example self-centering concrete wall system during an earthquake. Based upon the results of these time-history analyses it was concluded that due to dynamic shake-down the residual drifts at the conclusion of the ground motion were significantly less than the maximum possible residual drifts that were observed from the cyclic hysteresis response, and were below acceptable residual drift performance limits established for seismic resilient structures. To estimate the effect of the dynamic shakedown, a residual drift ratio was defined that can be implemented during the design process to ensure that residual drift performance targets are achieved for self-centering concrete wall systems.

• International Journal of High-Rise Buildings
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• v.8 no.3
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• pp.201-209
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• 2019

This paper presents a structural design of the "(Tentative Name) Toranomon Hills Residential Tower" which is currently under construction in Tokyo. The building is a reinforced concrete high-rise residential complex building with 54 stories above ground, 4 basement levels, and a building height of about 220 m. It is a requirement to provide the highest grade of residence in Japan, and in terms of the structural design, it is required to provide wide and comfortable spaces with high seismic performance. These requirements are satisfied by providing a total of 774 vibration control walls of two types. Also, to further improve the structural performance, steel fibers at the rate of 1.0vol% are provided in the ultra-high strength concrete used in the column members.

• Earthquakes and Structures
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• v.25 no.2
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• pp.89-97
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• 2023

In order to obtain the impact of socket connection interface forms and socket gap sizes on the seismic performance of reinforced concrete (RC) socket prefabricated bridge piers, quasi-static tests for three socket prefabricated piers with different column-foundation connection interface forms and reserved socket gap sizes, as well as to the corresponding cast-in-situ reinforced concrete piers, were carried out. The influence of socket connection structure on various seismic performance indexes of socket prefabricated piers was studied by comparing and analyzing the hysteresis curve and skeleton curve obtained through the experiment. Results showed that the ultimate failure mode of the socket prefabricated pier with circumferential corrugated treatment at the connection interface was the closest to that of the monolithic pier, the maximum bearing capacity was slightly less than that of the cast-in-situ pier but larger than that of the socket pier with roughened connection interface, and the displacement ductility and accumulated energy consumption capacity were smaller than those of socket piers with roughened connection interface. The connection interface treatment form had less influence on the residual deformation of socket prefabricated bridge piers. With the increase in the reserved socket gap size between the precast pier column and the precast foundation, the bearing capacity of the prefabricated socket bridge pier component, as well as the ductility and residual displacement of the component, would be reduced and had unfavorable effect on the energy dissipation property of the bridge pier component.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.501-509
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• 2019

The construction of foundation piles for buildings and bridges is changing from pile driving to an injected precast pile method. The goal is to minimize environmental damage, noise pollution, and complaints from neighboring residents. However, it is necessary to develop economic piles that are optimized for precasting by a centrifugal method in terms of both the material and structural system. A reinforced joint method is proposed for reinforced concrete piles (RC piles) manufactured by centrifugal casting. A previous study concluded that the structural performance of the current joint system for RC piles could be improved by using a reinforced joint composed of extended circular band plates and studs. In this study, the structural performance of such a joint was validated experimentally by bending and shear strength measurements. The proposed joint reinforcement method showed adequate structural performance in terms of bending and shear strength. The overall load-deflection behavior is close to that of a structure without joints, so it is expected that the behavior and performance of the design can be reliably reflected in site structures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.362-370
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• 2019

The internal pressure capacity of a modular containment structure requires analysis to prevent the release of radioactive material in the case of an accident. To analyze the capacity, FEM models were prepared while considering the tendon arrangements and the contact surfaces between precast concrete modules, and then static analyses were carried out. The changing characteristics in the displacement and stress under step-wise loading were analyzed, along with the effects of selected parameters. For comparison, the capacity of a monolithic containment structure was also analyzed. Parametric analyses were done to suggest ranges of parameters such as the tendon force, tendon spacing, tendon location in concrete thickness direction, friction coefficient, and concrete thickness. The tendon force and frictional force provide a combined effect between contact surfaces of modules. The same level of internal pressure capacity can be secured even in the modular containment structure as in the monolithic containment structure by increasing the tendon force with additional tendons.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.363-375
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• 2019

Since the double-deck tunnel is deeply constructed in the city, it is necessary to secure the installation space of air supply and exhaust, escape passage stairs, elevator, distribution facilities and connection tunnels in the vertical shaft for the double-deck tunnel. Also, in order to minimize the effect of construction on adjacent area, it is necessary to construct the concrete structures at high speed in vertical shaft after tunnel excavation. Therefore, the slabs and the stairs in vertical shaft are needed to be constructed using precast concrete, and the rapid construction techniques of bracket for supporting the inner precast structure are needed. The bracket installation methods include cast-in-place concrete, precast concrete and steel. In this study, the improvement of the steel brackets with good economical efficiency and good workability was carried out in consideration of the improvement of the construction speed. We have developed a new bracket that is optimized through bracket shape improvement, anchor bolt position adjustment and quantity optimization. As a result of the structural performance test, it was confirmed that the required load supporting capacity was secured. As a result of structural performance test for bar type anchor bolt and bent anchor anchor bolt, it was confirmed that the required load carrying capacity was secured and that the load bearing capacity of bent anchor bolt was large.

• Journal of the Korean Society of Safety
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• v.28 no.2
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• pp.55-59
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• 2013

The analytical model was constituted to evaluate the flexural strength of UHPFRC(ultra high performance fiber reinforced concrete) member. The analytical approach was attemped to study the effect of the joint and the result compared with the experimental study to verify the analytical model. The calculated value tends to underestimate about 23%~25% in comparison with the experimental result of the jointed test member because the bond stress between precast UHPFRC and cast-in-place UHPFRC surface is not considered in the analytical model. But in the case of the continuous test member, the analytical model provides reasonable results for the flexural strength of UHPFRC member.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.4
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• pp.87-95
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• 2012

Autoclaved lightweight concrete (ALC), also known as autoclaved aerated concrete (AAC), is a lightweight, precast building material that simultaneously provides structure, insulation. ALC is a unique building material. Because of its cellular nature, it is lightweight, self-insulating, as well as sound and fireproof. ALC products include blocks, wall panels, floor and roof panels, and lintels. Recently, the use of ALC has became increasingly popular. However, ALC have high water absorption, low compressive strength and popout the origin of the low surface strength in its properties. Thus, this study is to improve the fundamental strength by controls of increasing of admixtures and chemical reactants. Admixtures make use of meta kaolin and silica fume, chemical reactants make use of sodium silicate and sodium hydroxide. From the test result, the ALC using admixtures and chemical reactants have a good fundamental properties compared with plain ALC. These good fundamental properties is caused by the admixtures and chemical reactants of ALC by the reason of the micro filling effect and chemical binding of C-S-H gel, tobermolite and quartz.

• Structural Engineering and Mechanics
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• v.84 no.2
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• pp.225-238
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• 2022

In order to improve the cracking resistance of reinforced concrete and give full play to the advantages of prefabricated assembly structure in construction, prestressed reinforced concrete composite beam (PRCC) is proposed. Through the bending static test of seven I-shaped beam specimens, the bending failure modes and bearing capacity of PRCC and reinforced concrete composite beam are compared and analyzed, and the effects of prestress size, prestressed reinforcement layout and prestress application sequence on the flexural behavior of PRCC beams are studied. The results show that the cracking load and ultimate load of PRCC beams significantly increased after prestressing, and prestressed tendons can effectively control the crack development. With the increase of prestressing degree, the deformation resistance and bending stiffness of PRCC beams are increased. The application sequence of prestress has little influence on the mechanical properties of PRCC beams. The crack width, stiffness and normal section bearing capacity of PRCC beam are analyzed, and the calculated results are in good agreement with the experimental results.

• Journal of the Korean Institute of Rural Architecture
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• v.2 no.2
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• pp.115-126
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• 2000

Retaining walls are used to prevent excessive movement of retained soils. Typical retaining walls include gravity, reinforced concrete, reinforced earth and tie-back. However, from a practical viewpoint there are still drawbacks among these often constructed retaining walls. New types of retaining walls constructed with precast concrete blocks are proposed. This type of retaining wall is incorporates each blocks interconnected with adjacent block by connecting unit to build up a flexible retaining-wall system. This paper focus to behavior characteristics includes deformation and distribution of lateral earth pressure by loading tests and FEM analysis. For model tests, a 1/10 scale reduce models are manufactured include unevenness part, drainage hole and connecting unit and steel wire used to connect each blocks with adjacent block. To simulate the real retaining walls closely, uneven parts are interconnected each other and the construction type of blocks and wall front inclination are varied to investigate the relative displacement of individual block and the location of maximum deformation of wall as increasing surcharging. Additionally, PENTAGON3D, which solve the geotechnical and other problem, used for verifying and comparing with model tests.