• Title, Summary, Keyword: Approach slab

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Strut-Tie Model Approach Associated with 3-Dimensional Grid Elements for Design of Structural Concrete - (II) Validity Evaluation (3차원 격자요소를 활용한 콘크리트 구조부재의 스트럿-타이 모델 설계 방법 - (II) 타당성 평가)

  • Kim, Byung Hun;Yun, Young Mook
    • Journal of The Korean Society of Civil Engineers
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    • v.34 no.2
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    • pp.437-446
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    • 2014
  • In this study, the ultimate strengths of 13 slab-column joints and 51 torsional beams were evaluated to verify the validity of the strut-tie model approach presented in the companion paper. In addition, the design of the bridge pier subjected to multiple load combinations with longitudinal and lateral loads was conducted. The analysis results were compared with those by the provisions of BS 8110, ACI 318, and AASHTO-LRFD. The design results of the bridge pier were also compared with those by the provisions of ACI 318's sectional design method and AASHTO-LRFD's strut-tie model method.

An Experimental Study on Overlap Control at Plate Rolling (후판압연에서의 오버랩 제어에 대한 실험적 연구)

  • 천명식;한석영;이준정;김종근
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.376-385
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    • 1991
  • For manufacturing trimming-free plates which have rectangular shaped edges and straight edges in as-rolled state, it is necessary to investigate rolling characteristics of overlap, bulge and width deviation etc. in a standardized plate rolling process. The present wok is for preventing edge overlap as the first approach to develop trimming-free plate rolling technique. An experimental study on overlap control was done with plasticine material in order to examine influence factors and find a control method by use of a laboratory mill scaled down to one tenth of actual production mill. It was found that edge overlapping was increased with the increase of slab thickness and of broadside rolling ratio, but decreased with the increase of chamfered amount on slab edges. In the simulated rolling experiment with edge chamfered slabs of various chamfered angles, the chamfered angle of 60.deg. was the most effective one for reducing overlapping irrespective of slab thickness and of broadside rolling ratio.

Simplified slab design approach for parking garages with equivalent vehicle load factors

  • Kwak, Hyo-Gyoung;Song, Jong-Young
    • Structural Engineering and Mechanics
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    • v.9 no.3
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    • pp.305-321
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    • 2000
  • This paper develops a simplified, but effective, algorithm in obtaining critical slab design moments for parking garages. Maintaining the uniformly distributed load concept generally adopted in the design of building structures, this paper also introduces the equivalent vehicle load factors, which can simulate the vehicle load effects without taking additional sophisticated numerical analyses. After choosing a standard design vehicle of 2.4 tons through the investigation of small to medium vehicles made in Korea, finite element analyses for concentrated wheel loads were conducted by referring to the influence surfaces. Based on the obtained member forces, we determined the equivalent vehicle load factors for slabs, which represent the ratios for forces under vehicle loads to these under uniformly distributed loads. In addition, the relationships between the equivalent vehicle load factors and sectional dimensions were also established by regression, and then used to obtain the proper design moments by vehicle loads. The member forces calculated by the proposed method are compared with the results of four different approaches mentioned in current design codes, with the objective to establish the relative efficiencies of the proposed method.

An Evaluation for Progressive Collapse Resisting Capacity of a 80F RC Flat Plate for Sustainable Super Tall Building (지속가능한 초고층 건물을 위한 80층 RC 플랫 플레이트 건물의 연쇄붕괴 저항성능 평가)

  • Seo, Dae-Won;Kim, Hae-Jin;Shin, Sung Woo
    • KIEAE Journal
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    • v.10 no.5
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    • pp.151-157
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    • 2010
  • This study is connected with evaluation of the progressive collapse resisting capacity for sustainable RC super tall building design. As the progressive collapse is not considered in current design codes in Korea, differences between linear static and dynamic analysis based on the GSA guidelines was analyzed for better evaluation, and the analysis model of flat plate system was determined. Finally, the progressive collapse resisting capacity was evaluated for structural system of super tall building. According to this study, the results by linear dynamic analysis were underestimated than the results by linear static analysis. Thus, the dynamic coefficient value of 2 provides conservative approach. The Effective Beam Width's model, currently used in field, is useful for the analysis about lateral force, but this model does not consider the effect of load redistribution by the slab. Hence, finite element analysis considering slab element will be needed for progressive collapse resisting capacity of the flat plate system. Finally, analysis model of 80-story building designed based on KBC(Korea Building Code) shows the weakness against progressive collapse because the DCR value is over 2. Thus, the countermeasure for alternative loading path such as installment of spandrel beam and reinforcements around slab is required to prevent the progressive collapse.

An Experimental Approach to Investigate the Heat Transferring Effect of Carbon Nanotube on the Concrete Slab (실내실험을 통한 Carbon Nanotube의 콘크리트슬래브 열전달 효과)

  • Kim, Heesu;Ban, Hoki
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.12
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    • pp.59-63
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    • 2017
  • In the cold region, road surface is frequently frozen, resulting in property/facility damage as well as people's death. In order to prevent the road surface from being frozen, conventional deicing methods such as salt, geothermal, and electric wires have been widely used. However, theses methods have some problems such as anti-environment, high-construction and -maintenance cost and so on. To improve the drawbacks of aforementioned methods, carbon nanotube (CNT) was used as an heating material in the laboratory test. Through the test, heat transferring effect of CNT on the concrete slab was investigated and maximum interval of CNT installation was determined.

A Study on the Section Design of FRP-Concrete Composite Slabs Considering Failure Behaviors (파괴 거동을 고려한 FRP-콘크리트 합성 바닥판의 단면 설계에 관한 연구)

  • 조근희;김병석;이영호
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.641-646
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    • 2002
  • FRP-concrete composite slab is consisted of brittle materials and then shows brittle failure mechanism. This study suggests a new design approach that FRP-concrete composite slab leads to ductile failure, and investigates their failure behaviors for two types of section by numerical analysis. Box-type section is higher than I-type section in load capacity to required FRP quantity. Each section was designed so that the strain of FRP plate is 50% to its ultimate strain on initiation of concrete crushing, and it is verified that displacement ductility is more than two. Ductility capacity can be improved by reducing the strain of FRP on initiation of concrete crushing, but as the strain of FRP is reduced load capacity to required FRP quantity is also reduced. Therefore section optimization study is needed considering safety and economical efficiency.

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Long term earth pressure behavior behind stub abutment (난쟁이 교대배면의 장기 토압거동)

  • 박영호;정경자;김낙영;황영철
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.779-786
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    • 2002
  • To find a long term horizontal movement of superstructure caused by seasonal thermal change, several types of gages are installed such as soil earth pressuremeter behind stub abutment and jointmeter between approach slab and relief slab. As results, maximum passive earth pressure behind integral bridge abutments centerline with lateral movement of superstructure is about 1/6 of classic Rankine's earth pressure. And its distribution is not triangular but rectangular shape due to shape behind integral bridge abutments.

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Ultimate Strength of Composite Beams with Unreinforced Web Opening (유공 합성보의 극한강도식의 제안)

  • 김창호;박종원;김희구
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.369-374
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    • 1999
  • A practical approach of calculating the ultimate strength of composite beams with unreinforced web opening is proposed. In this method, the slab shear contribution at the opening is calculated as the smaller of the shear strength of the slab and the pullout capacity of the shear connectors at the high moment end. A simple interaction equation is used to predict the ultimate strength under simultaneous bending moment and shear force. Strength prediction by the proposed method is compared with previous test results and the predictions by other analytical method. The comparison shows that the proposed method predicts the ultimate capacity with resonable accuracy.

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Stiffness Reduction Factor for Flat-Plate Structures under Combined Load (조합하중을 받는 무량판 구조의 강성 감소 계수에 관한 고찰)

  • 송진규;최정욱;윤정배
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.302-310
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    • 2003
  • Cracking of slabs will be caused by applied load and volume changes during the life of a structure and thus it reduces flexural stiffness of slabs. The effect of slab cracking must be considered for appropriate modeling of the flexural stiffness for frame members used in structural analysis. Analytical and experimental study was undertaken to estimate the stiffness reduction of slabs. In the analytical approach, the trend of slab stiffness reduction related to gravity and lateral loads is found and the stiffness reduction factor ranged from a half to a quarter in ACI building code is reasonable when defining range. Analyzing results of the test by Hwang and Moehle for 0.5% drift show that the differences of rotational stiffness on the connection types is found and good results of lateral stiffness using the value of one-third is obtained.

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Design of Dang-San Steel Railway Bridge (당산철교의 설계)

  • 유동호;김선일
    • Computational Structural Engineering
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    • v.12 no.4
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    • pp.69-69
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    • 1999
  • Design of Dangsan Steel Railway Bridge(a part of Seoul Subway Line NO. 2), which is supposed to be replaced after its 15years survice, was done, and the reconstruction has begun in Dec. 1997. The design include new superstruc-ture and bridge piers, retrofitting of the foun-dation, rail system, electric and signal, etc. In this paper, design of the structure is mainly summarized. The main span superstructure, across Han river, is composite section which is com-posed of steel box and reinforced concrete deck slab with 9 span continuous. The superstructure for the approaches is bottom througth type 2-cell steel box girder with steel floor system and concrete deck slab with 3 or 4 span continuous. The bridge piers was planned to be reconstructed based upon the result from the various investi-gations, while the foundation(cassion and pile foundation) was planned to be retrofitted. For superstructure erection, the method of combination of barge bent and heavy lifting and the launching truss method was investigated for the main span and approach spans, respectively.

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