• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.10
• /
• pp.104-110
• /
• 2005

In this paper, unmanned vehicle system and VFF algorithm development with vehicle dynamics is the main topic as a part of Intelligent Transportation System. Unmanned vehicle system is classified by vehicle system and control system. Authors used RC servo motor for longitudinal control via throttle angle, shift lever control, and brake control. For lateral control, authors used step motor, equipped with reduction gear. Unmanned vehicle has nine ultrasonic sensors in front of the unmanned vehicle. After the microcontroller computes the distance between unmanned vehicle and obstacle, the control computer calculates the steering angle enough to avoid the obstacle.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.609-614
• /
• 2001

This paper is to explain reasonable shear behavior that can apply usually to reinforced concrete beams on the basic concepts of existent analysis and experimental research information. This study is succession $paper^{2) 3) 4) 5)}$ of treatise announced in existing and main control variable of reinforced concrete beams with stirrups used internal force state factor($\alpha$). Shear failure of reinforced concrete beams with stirrups is Influenced greatly because of the actual geometrical shape(a/d) of the concrete and flexural reinforcement steel ratio, stirrup reinforcement ratio and concrete compression strength, size effect etc. Therefore, shear behavior of reinforced concrete beams with stirrups that flexural crack is happened can be explained easily through proper extent proposal of internal force state factor($\alpha$) that express internal force state flowing. Use existent variable truss model by analysis model to explain arch action. Also, wish to compose each failure factors and correlation with internal force state factor by function, and when diagonal cracks happens, internal force state factor($\alpha$) study whether shear stress and some effect are.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.579-584
• /
• 2001

The reinforced concrete(RC) beam is developed cracks because the compression strength of concrete is strong but the tensile strength is weak. The structural strength and stiffness is decreased by reduction of tension resistance capacity of concrete due to the developed cracks. Using the fiber reinforced concrete that is increased the flexural strength and tensile strength at tensile part can enhance the strength and stiffness of concrete structure and decrease the tensile flexural cracks and deflection. Therefore, The reinforced concrete used the fiber reinforced concrete at tensile part ensure the safety and serviceability of the concrete structures. In this study, analytical model of a dual concrete beam that is composed of the normal strength concrete at compression part and the high tensile strength concrete at tensile part is developed by using the equilibrium condition of forces and compatibility condition of strains and is parted into elastic analytical model and ultimate analytical model. Three group of test beam that is formed of one reinforced concrete beam and two dual concrete beams for each steel reinforcement ratio is tested to examine the flexural behavior of dual concrete beams. The comparative study of total nine test beams is shown that the ultimate load of a dual concrete beams relative to the reinforced concrete beams have an increase in approximately 30%. In addition, the initial flexural rigidity, as used here, refer to the slope of load-deflection curves in elastic state is increased and the deflection is decreased.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.493-498
• /
• 2002

An experimental investigation was conducted to study the behavior of high-strength RC wide beam-column joints with slab subjected to reversed cyclic loads under constant axial load. Six half scale interior wide beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including three specimens without slab and three specimens with slab. The primary variables were compressive strength of concrete( $f_{ck}$ =240, 500kgf/c $m^2$), the ratio of the column-to-beam flexural capacity( $M_{r}$=2$\Sigma$ $M_{c}$$\Sigma$ $M_{b}$ ; 0.77-2.26), extended length of the column concrete($\ell$$_{d}$ ; 0, 9.6, 30cm), ratio of the column-to-beam width(b/H ; 1.54, 1.67). Test results are shown that (1) the behavior of specimen using high-strength concrete satisfied the required minimum ductile capacity according to increase the compressive strength, (2). In the design of the wide beam-column joints, one should be consider the effects of slab stiffness which is ignored in the current design code and practice.ice.e.e.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.1
• /
• pp.93-102
• /
• 2002

Steel fiber and polymer are used widely for reinforcement material of RC structures because of its excellences of the durability, serviceability as well as mechanical properties. The purpose of this study is to investigate the shear behavior of polymer cement high strength concrete beams mixed with steel fiber. The compressive strength of concrete was based on the 100$\times$200 mm cylinder specimens. The compressive strength of concrete are 320$kgf/cm^2$, 436 $kgf/cm^2$ and 520 $kgf/cm^2$ in the 28 days. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns and fracture modes. Also, load-strain and load-deflection examined. During the test cracks were sketched against the load values according to the growth of crack. result are as follows; (1) The failure modes of the specimens are increased in rigidity and durability with mixing steel fiber and polymer. (2) The load of initial crack was similar a theory of shear-crack strength. (3) The deflection and strain at failure load of Polymer-steel fiber high strength concrete beams were increased, improving the brittleness of the high strength concrete.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.36 no.4
• /
• pp.39-47
• /
• 1994

This research focuses on producing a cheap polymer, and also experiments for marking with the high strength polymer concrete structures. At present only a few tests on shear behavior in polymer reinforced concrete beams(PRC) have been reported. In the current experiments, the reinforced concrete beams with polymer fraction are investigated. The beams in this study are supported by conventional stirrups at appropriate intervals and they are designed to take static loads. The strength of beams are measured and the behavior of beams under each loading are oh served in order to determine some advantages of adding polymer to reinforced concrete beams. The static testing data consist of load, displacement, and strain at specified reinforcement locations, and the support displacement In the static tests, it has been observed that the beams fail in the same way as RC. However, it is observed to he rather weak in impact, hut it can he said that its increase of strength and excellency of repairing are verified. Consequently this work strongly suggests that the steam-curing or the air-curing or the air-curing must be performed to increase the strength.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.130-133
• /
• 2006

Owing to Higher story tendency and ceiling hight restriction of recent times, even though the depth of Coupling Beam decreases the demand efficiency is coming to be high rather so it is the difficult to satisfy a demand efficiency with the actual existing RC/Steel condition. It has been researched a lot of methods as an alternative plan about these but designer cannot apply them for the reason ; the structure standard and theory background are not taking a triangular position. As accomplishing the test research about the beams-wall connections department of steel-plate composite coupling beams from the research in the study it examines closely the beams-wall connections conduct quality and tries to provide the fundamental data for reasonable and optimum connection department designs. It knows that connection fixation degree and composite conduct degree of member part together become the important variable showing an energy dissipation ability in Test result.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.601-608
• /
• 2000

Steel fiber and Polymer are used widely for the reinforcement material of RC structures because of its excellence of durability, serviceability as well as mechanical properties. Polymer-Steel fibrous high strength concrete beam's input ratio are 1.0%. The shear span-to-depth ratio are 1.5, 2.8 and 3.6, compressive strength of specimens 320kg/㎠, 436kgf/㎠ and 520kgf/㎠ in 28 days. The static test was carried out to measure the ultimate load, the initial load of flexural crack and of diagonal crack, from which crack patte군 and fracture modes are earned. Also, stress-strain, load-strain and load-deflection are examined during the test cracks(shear crack, flexural crack, and diagonal tension crack), when the load values are sketched according to the growth of crack. Result are as follows; (1) The failure modes of the specimens increase in rigidity and durability in accordance with the increase of mixing steel fiber and polymer. (2) The load of initial crack was the same as the theory of shear-crack strength (3) Polymer-Steel fibrous high strength concrete beams have increased the deflection and strain at failure load, improving the brittleness of the high strength concrete. (4) In this result of study, an additional study need to make a need formular because the study is different from ACI formular and Zsutty formular.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1995.10a
• /
• pp.246-251
• /
• 1995

To reduce the size of structural members high strength concrete has recently been utilized for structrue such as ultra-high-rise buildings and prestressed concrete bridges in North America. and its compressive strength has gone up to 1300kgf/$\textrm{cm}^2$. In Japan, research on high-strength concrete has been undertaken on a large scale by the national enterprise so-called New RC Project, and this project purposed to develop the design compressive sstength of 1200kgf/$\textrm{cm}^2$. Considering these circumstance. the aim of this aim of this experimental study is to develop ultra-high-strength concrete with compressive stength over 2300kgf/$\textrm{cm}^2$ with domestic current materials. There are so many factors which influence on manufacturing of ultrahigh-strength concrete. The experimental factors selected in this study are mixing methods, curing methods, water-binder ratio, maximum size of coarse aggregate, and the replacement proportion of cement by silica fume. The results of this expermental study show that it is possible to develop the ultra-high-strength concrete with compressive strength over 2300kgf/$\textrm{cm}^2$.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1995.10a
• /
• pp.252-255
• /
• 1995

To reduce the size of structural members, high strength concrete has recently been utilized for structure such as ultra-high-rise buildings and prestressed concrete bridges in North America. And its compressive strength has gone up to 1300kgf/$\textrm{cm}^2$. In Japan. research on high-strength concrete has been undertaken on a large scale by the national enterprise so-called New RC Project, and this Project purposed to develop the design compressive strength of 1200kgf/$\textrm{cm}^2$. Considering these circumstance. the aim of this experimental study is to develop ultra-high-strength concrete with compressive strenght over 2300kgf/$\textrm{cm}^2$ with domestic current materials. There are so many factors which influence the manufacturing of ultra-high-strength concrete. The experimental factors selected in this study are mixing methods. curing methods. water-binder ratio, maximum size of coarse aggregate, and the replacement proportion of cement by silica fume. The results of this expermental study show that it is possible to develop the ultra-high-stength concrete with compressive strength over 2300kgf/$\textrm{cm}^2$.