• Title/Summary/Keyword: service load state behavior

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A Study on the Service Load State Behavior of Reinforced Concrete Plate Member

  • Bhang, Jee-Hwan;Kang, Won-Ho
    • KCI Concrete Journal
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    • v.12 no.2
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    • pp.55-72
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    • 2000
  • This paper proposes a mechanical model to describe the load-deformation responses of the reinforced concrete plate members under service load state. An Analytical method is introduced on the basis of the rotating crack model which considers equilibrium, compatibility conditions, load-strain relationship of cracked member, and constitutive law for materials. The tension stiffening effect in reinforced concrete structures is taken into account by the average tensile stress-strain relationship from the load-strain relationship for the cracked member and the constitutive law for material. The strain compatibility is used to find out the crack direction because the crack direction is an unknown variable in the equilibrium and compatibility conditions. The proposed theory is verified by the numerous experimental data such as the crack direction, moment-steel strain relationship, moment-crack width relationship. The present paper can provide some basis for the provision of the definition of serviceability for plate structures of which reinforcements are deviated from the principal stresses, because the present code defines the serviceability by the deflection, crack control, vibration and fatigue basically for the skeletal members. The proposed theory is applicable to predict the service load state behavior of a variety of reinforced concrete plate structures such as skew slab bridges, the deck of skew girder bridges.

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The Service State Behavior of Reinforced Concrete Membrane Elements using Rotating Crack Model

  • Bhang, Jee-Hwan;Kang, Won-Ho
    • KCI Concrete Journal
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    • v.11 no.3
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    • pp.53-64
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    • 1999
  • A theory is proposed to predict the response of the load-deformation relationship of the reinforced concrete structures under the service state after cracking. The crack direction and concrete strains through the loading history before failure can be estimated by this theory based on the rotating crack model, which considers equilibrium, compatibility conditions, and average stress-strain relationship. The proposed crack direction and deformation show good agreement with test results under service state. The behavior of a variety of concrete structures, such as shear walls, deep beams and the web of box girders, can be predicted by this proposed theory under service state.

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Experimental Study on Flexural Behavior of PSC I Girder and the Effect of External Prestressing (PSC I합성 거더의 휨 거동 및 외부 강선 보강효과에 관한 실험 연구)

  • Lee, Byeong-Ju;Park, Jae-Guen;Kim, Moon-Young;Shin, Hyun-Mock;Park, Chang-Ho
    • Journal of the Korea Concrete Institute
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    • v.19 no.6
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    • pp.755-762
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    • 2007
  • For the evaluation of the load carrying capacity of the deteriorated PSC I girder bridge in service load state and the verification of the grade to the reinforcement effect of actual bridge strengthened by external prestressing tendons, the field test using vehicles is applied widely. Because this teat was executed in elastic range, the investigation of the characteristics of behavior caused by live load is only available. And it is impossible to estimate load carrying capacity in limit state and nonlinear behavior after that a crack is appeared. In this study, the 27-year-old prestressed concrete girder bridge is used and various load tests are performed, so we evaluate the behavior characteristics of the bridge in service load state and ultimate load state, and estimate the load carrying capacity of bridge. In addition, the artificial damages are induced from cutting internal tendons, and external tendons is added to strengthen it as much as vanished internal tendons. Next we compare the damage state with the strengthening state. In case of the application of external prestressing method to PSC I girder bridge, the present experiment result may decide more exactly the load carrying capacity of actual bridge, the amount for reinforcement, and the standard of quality control etc. at reinforcement work.

Repair Performance of Engineered Cementitious Composites(ECC) Treated with Wet-Mix Spraying Process

  • Kim, Yun-Yong
    • International Journal of Concrete Structures and Materials
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    • v.18 no.3E
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    • pp.207-211
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    • 2006
  • This paper presents an experimental study on the repair performance of sprayed engineered cementitious composites(ECC) serving as a repair material. Sprayable ECC, which exhibit tensile strain-hardening behavior in the hardened state and maintain sprayable properties in the fresh state, have been developed by using a parallel control of micromechanical design and rheological process design. The effectiveness of sprayable ECC in providing durable repaired structures was assessed by spraying the ECC and testing them for the assessment. The experimental results revealed that, when sprayed ECC were used as a repair material, both load carrying capacity and ductility represented by the deformation capacity at peak load of the repaired flexural beams were obviously increased compared to those of commercial prepackaged mortar(PM) repaired beams. The significant enhancement in the energy absorption capacity and tight crack width control of the ECC repair system treated with wet-mix spraying process suggests that sprayed ECC can be effective in extending the service life of rehabilitated infrastructures.

Flexural behavior of concrete beams reinforced with CFRP prestressed prisms

  • Liang, J.F.;Yu, Deng;Yu, Bai
    • Computers and Concrete
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    • v.17 no.3
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    • pp.295-304
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    • 2016
  • An experimental investigation on the behaviour of concrete beams reinforced with various reinforcement, including ordinary steel bars, CFRP bars and CFRP prestressed concrete prisms(PCP). The main variable in the test program was the level of prestress and the cross section of PCP.The modes of failure and the crack width were observed. The results of load-deflection and load-crack width characteristics were discussed. The results showed that the CFRP prestressed concrete prisms as flexural reinforcement of concrete beams could limit deflection and crack width under service load and PCP can overcome the serviceability problems associated with the low elastic modulus/strength ratio of CFRP.

A Study of Statistic Behavior of Segmental U-shaped Prestressed Concrete Girder Applied with Integrated Tensioning Systems (복합긴장방식이 적용된 세그멘탈 U형 거더 정적 거동 연구)

  • Hyunock Jang;Ilyoung Jang
    • Journal of the Society of Disaster Information
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    • v.20 no.2
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    • pp.329-338
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    • 2024
  • Purpose: This study verified the safety of the improved box-type girder behavior by comparing and evaluating the bending behavior results of a full-scale specimen based on the analytical behavior of the splice element PSC U-shaped girder with integrated tensioning systems. Method: Based on the results of the service and strength limit state design using the bridge design standard(limit state design method), the applied load of a 40m full-scale specimen was calculated and a static loading experiment using the four-point loading method was performed. Result: When the design load, crack load, and ultimate load were applied, the specimen deflection occurred at 97.1%, 98.5%, and 79.0% of the analytical deflection value. When the design load, crack load, and ultimate load were applied, the crack gauge was measured at 0.009~0.035mm, 0.014~0.050mm, and 6.383~5.522mm at each connection. Conclusion: The specimen behaved linear-elastically until the crack load was applied, and after cracks occurred, it showed strainhardening up to the ultimate load, and it was confirmed that the resistance of bending behavior was clearly displayed against the applied load. The cracks in the dry joints were less than 25% of grade B based on the evaluation of facility condition standard. The final residual deformation after removing the ultimate load was 0.114mm, confirming the stable behavior of the segment connection.

Tests on the Flexural and Shear Behavior of Partially Prestressed Concrete Beams(I) -About the Ultimate State Behavior and Prestressing Indicies (부분(部分) 프리스트레스트 콘크리트 부재(部材)의 휨 및 전단(剪斷) 실험(實驗)(I) -극한상태(極限狀態)의 거동(擧動)과 프리스트레싱 지표(指標)에 대(對)하여)

  • Chang, Sung Pil;Kang, Won Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.9 no.4
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    • pp.27-39
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    • 1989
  • The partially prestressed concrete members have intermediate degree of prestressing between the reinforced and fully prestressed concrete members. Partially prestressed concrete members take advantages of both the merits of fully prestressed concrete members under the service load state and those of reinforced concrete members under the ultimate load state. Total 12 partially prestressed concrete T-beams were m4de and tested to find the effects of prestressing ratio, stirrup arrangement and shape of cross section on the flexural and shear behavior of the partially prestressed concrete beams. In this paper, the test procedure and the ultimate behavior of test beams are described. The validity of prestressing indices is checked by analyzing test results.

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A Study on the Explicit Multicast Network for Guaranteeing Quality of Service (QoS) (서비스 품질 (QoS) 보장형 명시적 멀티캐스트망의 연구)

  • 오승훈;고성원;김영한
    • Proceedings of the IEEK Conference
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    • 2002.06a
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    • pp.53-56
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    • 2002
  • In this paper, we study the network structure that can guarantee the end-to-end quality of service in the Explicit multicast network. In order to guarantee the end-to-end quality of service, we adopt the end-to-end measurement based admission control (EMBAC) scheme. For the effective measurement of the network state and minimum influence on the current data traffic, the queue structure, which the drop precedence in assured forwarding (AF) Per hop behavior (PHB) of the differentiated service (Diffserv) is applied to, is proposed. Through a simulation, we show that EMBAC can make tile controlled load service in tile AF PHB applied Xcast network, and the qualify of the admitted traffic is guaranteed. In addition, the performance of the EMBAC is changing according to the selling parameter of AF PHB.

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Shear Deformation based on the Biaxial Tension-Compression Theory in Prestressed Concrete Members applied by Axial Loading (이축인장압축장이론에 기반한 PSC보의 전단변형)

  • Jeong, Jae-Pyong;Kim, Dae-Joong;Mo, Gui-Suk;Kim, Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.281-284
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    • 2006
  • ASCE-ACI Committee 426 and 445, on Shear and Torsion, well noted in their report that recent research work regarding shear and torsion had been devoted primarily to members. But it was not logical approach of PSC members applied by axial force based on the shear deformation in web element. And it was not included that the effect of axial is to shift the shear strain(or crack width) in the web element versus the applied shear curve up or down by the amount by which the biaxial tension-compression state varies. The shear strength also increases or decreases, so that the change in shear strain at service load due to the presence of axial load is to some extent changed. Generally, in corresponding beams the shear strain at service load is less in the beam subject to axial compression and greater in the beam subject to axial tension, than in the beam without axial load. In particular, however, no research were available on the shear deformation in shear of PSC members with web reinforcement, subject to axial force in addition to shear and bending. Therefore, this study was basically performed to develop the program for the calculation of the shear deformation based on the shear effect of axial force in prestressed concrete members.

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Ultimate strength behavior of steel plate-concrete composite slabs: An experimental and theoretical study

  • Wu, Lili;Wang, Hui;Lin, Zhibin
    • Steel and Composite Structures
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    • v.37 no.6
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    • pp.741-759
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    • 2020
  • Steel plate-concrete composite slabs provide attractive features, such as more effective loading transfer, and more cost-effective stay-in-place forms, thereby enabling engineers to design more high-performance light structures. Although significant studies in the literatures have been directed toward designing and implementing the steel plate-concrete composite beams, there are limited data available for understanding of the composite slabs. To fill this gap, nine the composite slabs with different variables in this study were tested to unveil the impacts of the critical factors on the ultimate strength behavior. The key information of the findings included sample failure modes, crack pattern, and ultimate strength behavior of the composite slabs under either four-point or three-point loading. Test results showed that the failure modes varied from delamination to shear failures under different design factors. Particularly, the shear stud spacing and thicknesses of the concrete slabs significantly affected their ultimate load-carrying capacities. Moreover, an analytical model of the composite slabs was derived for determining their ultimate load-carrying capacity and was well verified by the experimental data. Further extensive parametric study using the proposed analytical methods was conducted for a more comprehensive investigation of those critical factors in their performance. These findings are expected to help engineers to better understand the structural behavior of the steel plate-concrete composite slabs and to ensure reliability of design and performance throughout their service life.