• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.519-526
• /
• 2010

The construction site for $\bigcirc\bigcirc$ transformer substation was located at a mountain valley. In order to prepare the site, the valley was first filled with crushed rock debris up to 63m. Since the main concern of this project is to minimize differential settlement of the foundation of transformer facilities, dynamic compaction was performed every 7m followed by reinforcement with EMP(Ez-Mud Piling). The EMP is one of bored piling methods, in which a hole is bored by means of air percussion and maintain by injecting Ez-Mud. Then a PHC pile (Pretensioned spun High strength Concrete pile) is embedded and finalized with a hammer. In this study, bearing capacities and long term behavior of a pile installed by EMP were investigated. To achieve these objectives, a series of tests such as static and dynamic load tests were conducted. In addition, a construction quality control standard was proposed based on the test results.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.4
• /
• pp.37-48
• /
• 2010

The seismic control effect of reinforced concrete structures with low energy dissipating capacity due to stiffness degradation is investigated through nonlinear time history analysis. The primary structure is idealized as a SDOF system of modified Takeda hysteresis rule and an elasto-perfectly-plastic nonlinear spring is added to represent a hysteretic damping device. Based on statistics of the numerical analysis, equivalent linearization techniques are evaluated, and empirical equations for response prediction are proposed. As a result, estimation of the ductility demand with proposed empirical equations is more desirable than the equivalent linearization techniques. The optimal yield strengths based on empirical equations are significantly different from the optimal yield strength of elasto-perfectly-plastic systems. Also, the results indicate that the reduction effect of the ductility demand is more remarkable for smaller natural periods.

• Journal of the Korean Geosynthetics Society
• /
• v.10 no.3
• /
• pp.43-51
• /
• 2011

This paper describes the results of pullout tests in the laboratory, which are conducted to assess the pullout performance of recently developed geosynthetic strip reinforcement with rounded band anchor. The geosynthetic strip can be used as reinforcements in reinforced soil wall with concrete block facing. The pullout resistance of the geosynthetic strip with rounded band anchor is mobilized by the combination of the interface friction between soil-reinforcement surface and the passive soil resistance caused by the rounded band anchor. Therefore, both the friction resistance and the passive resistance have to be considered in design. From the pullout test results, when the rounded band anchor are formed in the end part of the geosynthetic strip, pullout strength increases about from 10% to 65%. The passive resistance can be evaluated based on the pullout test results.

• Culinary science and hospitality research
• /
• v.5 no.1
• /
• pp.175-204
• /
• 1999

Today, the hotel industry in a whole are facing serious problems with a number of reasons. To overcome this situation, Customer-Oriented Marketing is considered to be a solution for the hotel F & B management, due to the potential of F & B department. The main purpose of this study was to present the Food and Beverage Marketing Mix Strategies suitable for the market characteristics. To achieve the purpose of this study, theoretical and empirical approaches were used. In review of theoritical background, basic concepts and characteristics of hotel F & B, hotel F & B marketing environment, and hotel F & B marketing mix were studied. Based on the theoritical studies and previous studies, F & B marketing mix sub-components were chosen. In this research, F & B 5P's and 1I marketing mix are discussed, they are Product, Price, Promotion, People, Physical evidence and Image. Through the survey, a number of important segment markets are emerged, which lead to essential segment markets ; business, conference and leisure market. F & B marketing mix strategies as follows. First, for the physical evidence mix, to build up the position as deluxe hotels, it is necessary to matte an investment in technical and decorative components. Second, for the people mix, to assure the service quality, the education and training programs for employee are required. Third, for the image mix, to ensure the image of hotel brand strength, the consideration for public area layout, restaurant and bar ambience, and green policy are required. Fourth, for the product and price mix, to differentiate the F & B, it is necessary to offer thorned and ethnic cuisine, and signature restaurants. Fifth, for the promotion mix, to attract more cumstomers, creative and various promotion activities, and long-term investment in customer-oriented marketing are required. There were some limitations in this study. That is, most of hotels don't operate the concrete and effective F & B marketing, have difficulty in getting data base for F & B customer. Despite their limitations, this study add some values to hotel F & B management in that it introduce the service marketing mix strategies to hotel F & B marketing.

• Journal of the Korean Society for Railway
• /
• v.12 no.3
• /
• pp.388-395
• /
• 2009

To investigate the flexural behavior of RC beams strengthened with glass fiber sheets, 1 control beam and 8 strengthened beams (4 NU-beams without U-shaped band and 4 U-beams with U-shaped band) are tested. The variables of experiment are composed of the number of glass fiber sheets and the existence of U-shaped band, etc. The maximum load was increased by 48% and 34%, and the flexural rigidity by 920% and 880% for NU-beam and U-beam, respectively, compared with those of the control beam. The ductility ratios were 1.43$\sim$2.60 for NU-beam and U-beam. The experimental results showed that the strengthening system with U-shaped band controls the premature debonding and provides a more ductile failure mode than the strengthening system without U-shaped band. It can be found from the load-deflection curves that as the number of fiber sheets is increased, the maximum strength and the flexural rigidity is increased. The experimental results are compared with the analytical results of nonlinear flexural behaviors for strengthened RC beam. The experimental and analytical results were well agreed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.3
• /
• pp.132-142
• /
• 2007

In this study, a structural performance of R/C columns controlled by shear, strengthened with Sprayed FRP, was investigated. For this purpose, six 2/3-scaled column specimens were designed and tested by the pseudo-static reversed cyclic load under a constant axial load, which is 10% of the nominal axial strength of the column. Four specimens were strengthened by Sprayed FRP with different combinations of short fibers (carbon or glass) and resins (epoxy or vinyl ester). For comparison purpose, tests of a specimen strengthened with carbon fiber sheet (CFS) and a control specimen without strengthening were carried out, respectively. The result reveals that shear strengths and ductility capacities of columns strengthened with Sprayed FRP improved remarkably, compared to those of the control column, and the Sprayed FRP technique developed in this study is able to use the strengthening scheme of existing R/C columns.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.2 no.1
• /
• pp.128-135
• /
• 2006

Steel slag (divided into electric arc furnace slag and convener slag) is being produced by millions of tons per every year in many industrial countries. About 6.5 million tonnes of steel slag is produced yearly as an industrial by-product in Korea. Generally natural aggregate is relatively stable and does not enter into complex chemical reactions with water. Unfortunately, however. steel slag aggregate contains a small amount of free lime. The hydration of free lime makes steel slag aggregate unstable and liable to expand. In this paper, firstly, several aging methods are used in order to decrease the volume expansion of electric arc furnace slag, that is stabilization. The volume expansion of electric arc furnace slag is formulated from the experiment. From the formula, the residual expansibility is predicted with immersion expansion. Compressive strength of concrete with electric arc furnace slag has relation with the residual expansibility in slag aggregate.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.12 no.3
• /
• pp.223-237
• /
• 2010

The initial heating rate is well known as one of the most influencing factors on the occurrence of spalling and the loss of strength in concrete after fire initiation. In this study, a series of fire tests were carried out at different initial heating rates to find out its effects on the deterioration of tunnel structural members. Heat transfer analyses combined with an element elimination model were also carried out to verify its applicability in the same conditions as the fire tests. Moreover, the convection heat transfer coefficients compatible with fire test results were derived from parametric studies. In this course, their time-dependent variations were also analyzed at different initial heating rates. Finally, a numerical formula to estimate the heat transfer coefficients at the various initial heating rates was proposed by the interpolation of the results of numerical analyses.

• Steel and Composite Structures
• /
• v.50 no.6
• /
• pp.659-674
• /
• 2024

Casting Ultra High-Performance Concrete (UHPC) on an orthotropic steel deck and forming a composite action by connectors could improve the steel deck fatigue performance. This study presents the mechanical performance of a proposed post-combination connection between UHPC and steel, which had a low constraint effect on UHPC shrinkage. A total of 10 push-out tests were conducted for static and fatigue performance investigations. And the test results were compared with evaluation methods in codes to verify the latter's applicability. Meanwhile, nonlinear simulation and parametric works with material damage plasticity models were also conducted for the static and fatigue failure mechanism understanding. The static and fatigue test results both showed that fractures at stud roots and surrounding local UHPC crushes were the main failure appearances. Compared with normally arranged studs, group arrangement could result in reductions of static stud shear stiffness, strength, and fatigue lives, which were about 18%, 12%, and 27%, respectively. Compared with the test results, stud shear capacity and fatigue lives evaluations based on the codes of AASHTO, Eurocode 4, JSCE and JTG D64 could be applicable in general while the safety redundancies tended to be smaller or even insufficient for group studs. The analysis results showed that arranging studs in groups caused obviously uneven strain distributions. The severer stress concentration and larger strain ranges caused the static and fatigue performance degradations of group studs. The research outcome provides a very important basis for establishing a design method of connections in the novel post-combination steel-UHPC composite deck.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.4 s.26
• /
• pp.172-180
• /
• 2005

The purpose of this study is to suggest a new SRC(Steel Ready mixed Concrete) lining board. The research method of this study includes problem analysis of existing lining boards a constant load test and a fatigue test. The results of this study are as follow : 1) the suggested new lining board improves the function and reduce slipperiness than existing lining boards. 2) the strength of the new SRC lining board is analyzed as superior than existing lining boards from the results of constant load test and fatigue test.