• Journal of the Korea Institute of Building Construction
• /
• v.4 no.1
• /
• pp.141-146
• /
• 2004

1) As a result of compressive strength experiment, rupture compressive strength showed more increases in specimens of 15% and 20% of Cockle shells in those of non-mixture. Comparing compressive strength between no-mixed Specimens and Specimens of containing Cockle shells, Specimens containing Cockle shells showed higher strength in 60 days and 90 days of age, and as ark Cockle is contained and age is elapsed, compressive strength is also increased In addition, estimation of compressive strength by reactive hardness in concrete using Cockle shells as aggregate shows low reliability. 2) As a result of experimenting compressive strength after heating, Specimens containing Cockle shells and non-mixed Specimens showed similar strength at $200^{\circ}C$, but compressive strength was lowered as content of Cockle shells increased at over $400^{\circ}C$ and heating temperature was higher. It is because Cockle shells was fired by heat and then its adhesion and bonding capacity were lost. 3) To sum up the above experimental results, it is found that using splitted Cockle shells as aggregate for concrete by 10%~20% showed the same or higher compressive strength and shear strength as concretes using general aggregate and it can be used as substitute aggregate of concrete. It is considered that for future use of splitted Cockle shells as substitute concrete aggregate, continuous researches of its durability, applicability and economy are needed.

• International Journal of High-Rise Buildings
• /
• v.6 no.3
• /
• pp.227-235
• /
• 2017

This paper describes some of the challenges for structural design of a mid-story seismic isolated high-rise building, which is located near Tokyo station, completed in 2015. The building is a mixed-use complex and encompasses three volumes: one substructure including basement and lower floors, and a pair of seismic isolated superstructures on the substructure. One is a 136.5m high Main Tower (office use), and the other is a 98.5 m high South Tower (hotel use). The seismic isolation systems are arranged in the $3^{rd}$ floor of the Main Tower and $5^{th}$ floor of the South Tower, so that we call this isolation system as the mid-story seismic isolation. The primary goal of the structural design of this building was to secure high seismic safety against the largest earthquake expected in Tokyo. We adopted optimal seismic isolation equipment simulated by dynamic analysis to minimize building damage. On the other hand, wind-induced vibration of a seismic isolated high-rise building tends to be excited. To reduce the vibration, the following strategies were adopted respectively. In the Main Tower with a large wind receiving area, we adopted a mechanism that locks oil dampers at the isolation level during strong wind. In the South Tower, two tuned mass dampers (TMDs) are installed at the top of the building to control the vibration. In addition, our paper will also report the building performance evaluated for wind and seismic observation after completion of the building. In 2016, an earthquake of seismic intensity 3 (JMA scale) occurred twice in Tokyo. The acceleration reduction rate of the seismic isolation level due to these earthquakes was approximately 30 to 60%. These are also verified by dynamic analysis using observed acceleration data. Also, in April 2016, a strong wind exceeding the speed of 25m/s occurred in Tokyo. On the basis of the record at the strong wind, we confirmed that the locking mechanism of oil damper worked as designed.

• Journal of the Korea Institute of Building Construction
• /
• v.17 no.1
• /
• pp.47-54
• /
• 2017

Cement industry is typical carbon-emission industry. If the industrial by-products(granulated blast-furnace slag (GGBFS), fly ash, etc.) are used a large amount, it might be able to reduce cement consumption and mitigate carbon emissions. In this case, however, decrease of early strength is relatively large. Therefore, there is a limitation in increase of the amount of substitute. Considering these circumstances, it would be a good solution to reduce carbon emissions in cement industry to improve the performances of mixed cement through proper alkali-activation in Portland blended cement using GGBFS or fly ash. Therefore, this study prepared concrete in ready-mixed concrete manufacturing facilities with an addition of a binder which used 2.0% modified alkali sulfate activator after mixing Portland cement, GGBFS and fly ash in the ratio of 4:4:2 and assessed its basic properties. The results found the followings: The use of modified alkali-sulfate activator slightly reduced slump and shortened setting time. As a result, bleeding capacity decreased while early strength improved. In addition, there is no big difference in carbonation resistance. It appears that there should be continued experiments and analyses on the related long-term aged specimens.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.12 no.4
• /
• pp.21-28
• /
• 2012

Hoe beak village (Donggu manseokdong, Akasaki Village) is the oldest slums in Incheon. Recently, 'Mixed residential environment improvement project' is being promoted as Aboriginal entire resettlement goals in place of 'new building reconstruction and redevelopment projects' knock down everything this hoe beak village existed already. Resident representatives meeting configuration goes, but still do business magazine in the right direction. Therefore, in this study, the proposed architectural solutions to meet the demand of residents on the research problems, performed in a manner that the local improved hoe Buri village residential environment improvement projects and analyze the current situation and characteristics. In this study, the following improvements are presented. Prepare guidelines and maintain design guidelines for maintaining the identity of the village, Improve continuous landscape of the village, Construction of mixed-use sanitation facilities, Using a mini-lot and Vacant for Ssamzie Park Development, Units of housing types for Shared housing and co-operation are proposed.

• ETRI Journal
• /
• v.30 no.4
• /
• pp.535-545
• /
• 2008

This paper introduces a systematic top-down and bottom-up design methodology to assist the designer in the implementation of continuous-time (CT) cascade sigma-delta (${\Sigma}{\Delta}$) modulators. The salient features of this methodology are (a) flexible behavioral modeling for optimum accuracy-efficiency trade-offs at different stages of the top-down synthesis process, (b) direct synthesis in the continuous-time domain for minimum circuit complexity and sensitivity, (c) mixed knowledge-based and optimization-based architectural exploration and specification transmission for enhanced circuit performance, and (d) use of Pareto-optimal fronts of building blocks to reduce re-design iterations. The applicability of this methodology will be illustrated via the design of a 12-bit 20 MHz CT ${\Sigma}{\Delta}$ modulator in a 1.2 V 130 nm CMOS technology.

• ETRI Journal
• /
• v.30 no.4
• /
• pp.546-554
• /
• 2008

Phase-locked loops (PLLs) are among the most important mixed-signal building blocks of modern communication and control circuits, where they are used for frequency and phase synchronization, modulation, and demodulation as well as frequency synthesis. The growing popularity of PLLs has increased the need to test these devices during prototyping and production. The problem of distinguishing and classifying the responses of analog integrated circuits containing catastrophic faults has aroused recent interest. This is because most analog and mixed signal circuits are tested by their functionality, which is both time consuming and expensive. The problem is made more difficult when parametric variations are taken into account. Hence, statistical methods and techniques can be employed to automate fault classification. As a possible solution, we use the back propagation neural network (BPNN) to classify the faults in the designed charge-pump PLL. In order to classify the faults, the BPNN was trained with various training algorithms and their performance for the test structure was analyzed. The proposed method of fault classification gave fault coverage of 99.58%.

• Journal of the Korean housing association
• /
• v.23 no.3
• /
• pp.53-61
• /
• 2012

Openness to outside is one of the most critical advantages for high-rise buildings. However, the effect of openness can be decreased if it is blocked by other high-rise buildings, especially built within the building complex of commercial district. The purpose of this study is to identify the horizontal openness of high-rise residential buildings by comparing 3 different cases of building arrangement type. A new method of evaluation has been introduced on the basis of distance to measure the openness including the matter of securing privacy. As a result of this study, comparative analysis was possible and relatively plentiful results of analysis could be drawn out. Through the process of analysis, this study set the evaluation indicators suitable to the analysis of openness of unit households. Thereby, the results of this study are expected to be used as useful basic data in planning high-rise mixed-use buildings.

• Journal of the Korea Institute of Building Construction
• /
• v.1 no.1
• /
• pp.160-168
• /
• 2001

This study aims at the development of computer program for the deformation analysis of soft ground, and using this computer program, study the constraint effect of deformation heaving, lateral displacement of the soft ground reinforced with improvement of soft ground up to hard strata, under intact state(natural). The following results are obtained. 1. Improvement of soft ground to the hard strata works well against the settlement of neighboring ground. 2. the larger the rigidity or width of improvement of layer to hard strata is, the less settlement occurs. 3. Improvement of soft ground to the hard strata is of no use.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.11a
• /
• pp.95-96
• /
• 2012

This study makes with the environment-friendly artificial stone which doesn't use the cement and natural aggregate and increases the blast furnace slag that is the eco-friendly material that is the industrial byproduct, fly ash, and availability of the red mud and applies the coares aggregate substitute material as the cleistothecium. The experimental plan according to it indicated the compressive strength and flexural strength which is the most excellent in the mixied ratio 40% of the result degree of closeness magnetism of experimenting with the optimal mix obtained through the preceding stude.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2005.05a
• /
• pp.81-84
• /
• 2005

Due to increased demands for durable and high-performance concrete structures, the use of admixtures has become essential. In this paper, material properties, and durability of concrete mixed with natural inorganic minerals(R-1) are obtained from test results. Through the comparisons with OPC(Ordinary Portland Cement) concrete, the R-1 concrete shows improved compressive strength and durability.