• Title/Summary/Keyword: concrete stress block

Search Result 94, Processing Time 0.03 seconds

Analysis of the Reinforced I section UHPCC (Ulrea High Performance Cementitous Composites) beam without stirrup (전단철근이 없는 I형 휨보강 UHPCC 보의 거동해석)

  • Kim Sung Wook;Han Sang Muk;Kang Su Tae;Kong Jeong Shick;Kang Jun Hyung;Jun Sang Eun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2004.11a
    • /
    • pp.409-412
    • /
    • 2004
  • Over last decade extensive researches have been undertaken on the strength behaviour of Fiber Reinforced Concrete(FRC) structures. But the use of Ultra-High Strength Steel Fiber Cementitious Concrete Composites is in its infancy and there is a few experiments, analysis method and design criteria on the structural elements constructed with this new generation material which compressive strength is over 150 MPa and characteristic behaviour on the failure status is ductile. The objective of this paper is to investigate and analyze the behaviour of reinforced rectangular structural members constructed with ultra high performance cementitious composites (UHPCC). This material is known as reactive powder concrete (RPC) mixed with domestic materials and its compressive strength is over 150MP. The variables of test specimens were shear span ratio, reinforcement ratio and fiber quantity. Even if there were no shear stirrups in test specimens, most influential variable to determine the failure mode between shear and flexural action was proved to be shear span ratio. The characteristics of ultra high-strength concrete is basically brittle, but due to the steel fiber reinforcement behaviour of this structure member became ductile after the peak load. As a result of the test, the stress block of compressive zone could be defined. The proposed analytical calculation of internal force capacity based by plastic analysis gave a good prediction for the shear and flexural strength of specimens. The numerical verification of the finite element model which constitutive law developed for Mode I fracture of fiber reinforced concrete correctly captured the overall behaviour of the specimens tested.

  • PDF

Effects of Transverse Reinforcement on Flexural Strength and Ductility of High-Strength Concrete Columns (횡보강근에 따른 고강도 콘크리트 기둥의 휨강도와 연성)

  • 황선경;윤현도;정수영
    • Journal of the Korea Concrete Institute
    • /
    • v.14 no.3
    • /
    • pp.365-372
    • /
    • 2002
  • This experimental investigation was conducted to examine the behavior of eight a third scale columns made of high-strength concrete(HSC). The columns were subjected to constant axial load corresponding to target value of 30 percent of the column axial load capacity and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement(Ps=1.58, 2.25 %), tie configuration(hoop-type, cross-type, diagonal-type) and tie yield strength(fy=5,600, 7,950 kgf/$\textrm{cm}^2$). Test results indicated that the flexural strength of all the columns did not exceed calculated flexural capacities based on the equivalent concrete stress block used in current design code. Columns with 42 percent higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-99 were shown ductile behavior. With axial load of 30 percent of the axial load capacity, the use of high-strength steel as transverse reinforcement may lead to equal or higher ductility than would be achieved with low-strength steel.

Bearing Reinforcing Effect of Concrete Block with a Round End according to the Application of Aluminum Stiffener (알루미늄 보강재 적용에 따른 원형 단부 콘크리트 블록의 지압 보강 효과)

  • Seok Hyeon Jeon;Tae-Yun Kwon;Jin-Hee Ahn
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.27 no.3
    • /
    • pp.38-46
    • /
    • 2023
  • In this study, a bearing test was performed and analytically evaluated to evaluate the bearing performance according to the application of the aluminum stiffener in round-end concrete. In the bearing strength test, the change in bearing performance due to the aluminum stiffener using the aluminum form for manufacturing concrete with round-end, and the steel anchor bolts for member movement and assembly was confirmed. The FE analysis model was identically configured to the experimental conditions, and the result was compared with the experiment. Also, the crack patterns and stress behavior were confirmed. In addition, the effect of strength change of the aluminum stiffener on the round-end concrete was also evaluated analytically. The bearing strength of the round-end concrete increased by about 20% due to the aluminum stiffener, and it was confirmed that the steel anchor bolt did not affect the bearing strength. The maximum load and crack patterns shown as a result of FE analysis were similar to those of the experiment. As a result of FE analysis according to the strength change of the aluminum stiffener, the maximum load change according to the increase and decrease of the strength of the aluminum stiffener by 10% and 20% was evaluated to have no significant effect at a maximum of about 4% compared to before the strength change.

A Study on Reinforcement Method of Concrete Block for Direct Fixation Tracks on Serviced Light Rail Transit (공용중인 경전철 직결 궤도 콘크리트 도상블록의 보강 방안 연구)

  • Jung-Youl Choi;You-Song Kang;Dae-Hee Ahn;Jae-Min Han;Jee-Seung Chung
    • The Journal of the Convergence on Culture Technology
    • /
    • v.9 no.3
    • /
    • pp.633-640
    • /
    • 2023
  • In this study, numerical analysis was performed based on field investigation to derive an appropriate reinforcement method by analyzing the displacement behavior characteristics of concrete blocks generated in the direct fixation track on the bridges of the serviced light rail transit. The track of this study was a direct fixation track on a sharp curved track, and the problem of movement of the concrete blocks installed on the bridge deck in the longitudinal and lateral directions occurred. In this study, based on the finite element model using 3D solid elements, the behavior of the direct fixation track that could be occurred under operating load conditions was analyzed. In addition, the reinforcement effect of various reinforcement methods was analyzed. As a result of analyzing the lateral displacement before and after reinforcement, it was analyzed that the maximum lateral displacement after reinforcement under the extreme lateral wheel loads significantly decreased to about 3% (about 0.1mm) compared to before reinforcement. In addition, as a result of examining the generated stress of the filling mortar, bridge decks, and reinforcing bar, it was analyzed that all of them secured a sufficient safety factor of 2.6 or higher, and the optimal conditions for the reinforcement method were derived. Therefore, it is judged that the number of anchoring reinforcements and symmetrical anchor placement reviewed in this study will be effective in controlling the occurrence of lateral displacement of concrete blocks and securing the structural integrity of bridges and concrete blocks.

Ultimate Strength of Anchorage Zone according to Geometric Parameters of Post-Tensioning Anchorage using a Finite Element Method (유한요소해석을 통한 포스트텐션 정착구 형상 변수의 정착부 극한강도 영향 분석)

  • Kwon, Yangsu;Kim, Jin-Kook;Kwak, Hyo-Gyoung
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.28 no.3
    • /
    • pp.317-324
    • /
    • 2015
  • The design of anchorage zone in a post-tensioned member has been started from the evaluation of the ultimate resisting capacity as well as the maximum bursting stress developed, and a lot of design codes including AASHTO and PTI describe their design equations to determine the bearing strength of concrete at the anchorage zone. However, these equations usually give conservative results because their derivation is based on the simple anchorage with a wide bearing plate in the surface without any additional consideration for the load transfer mechanism through transverse ribs on the anchorage. To assess the influence of geometric parameters related to the transverse ribs on the resisting capacity of anchorage block, experiments and analysis are conducted. After verifying the validity of numerical model conducted through correlation studies between experimental and analytical results, parametric studies with changes in the transverse ribs are followed and design recommendations for the anchorage block are suggested from the numerical results obtained.

Bond Capacity of Near-Surface-Mounted FRP in Concrete Corresponding to Fire-Protection Method (콘크리트에 표면매립보강된 FRP의 내화단열방법에 따른 부착성능)

  • Lim, Jong-wook;Kim, Tae-hwan;Seo, Soo-yeon
    • Journal of the Architectural Institute of Korea Structure & Construction
    • /
    • v.35 no.1
    • /
    • pp.3-10
    • /
    • 2019
  • The purpose of this paper is to find the fire-protection method for keeping on the bond capacity of Near-Surface-Mounted (NSM) FRP under high temperature. Experiments have been carried out to evaluate the bond capacity of NSM FRP by using CFRP-plates and to confirm the heat transfer to the concrete block when the refractory insulation is attached to the surface of NSM FRP. Bond test of NSM FRP under room temperature was conducted to obtain the maximum bond strength. And then a heating tests were carried out with keeping the bond stress of 30% of the maximum bond strength. As a result, the bond capacity of NSM FRP was disappeared when the temperature at epoxy reached to its glass transition temperature (GTT). In order to secure the bond capacity of the NSM FRP, it is necessary to protect the front as well as side by using insulation materials.

An Experimental Study on the Analysis of Behavior Characteristics of the NDB Soil Nailing System (NDB 쏘일네일링 시스템의 거동특성 평가에 관한 실험적 고찰)

  • 김홍택;정성필;박시삼;전경식
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2003.03a
    • /
    • pp.521-528
    • /
    • 2003
  • In this study, a newly modified soil nailing technology called as the NDB(New Down and Board) soil nailing system is introduced. To improve the trafficability, workability, and economical efficiency, SMC(Sheet Molding Compound) board is adopted instead of using the concrete block facing. The SMC board has a distinct advantage of showing a fine view by directly coating with any kind of environmental photos. Composite material properties of the SMC board and cement grout are distinguished features of the NDB soil nailing system. In the present study, both laboratory tests(bending and punching failure tests) and field pull-out tests are carried out to analyze the behavior characteristics of the NDB soil nailing system, including the stress and strain distribution.

  • PDF

FE Analysis of Forged Parts of Suspension Bridge : cases of Strand Shoe and Hanger Socket (입체요소를 이용한 현수교 주단강품의 유한요소해석 : 스트랜드슈와 행어소켓)

  • 최창근;이태열;노혁천;김재철
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1998.04a
    • /
    • pp.149-156
    • /
    • 1998
  • In suspension bridges, the axial farces in the wires are transferred by side pressure on the semicircular face, and further from the strand shoe through rods to a base plate fixed to the massive concrete part of the anchor block. For prefabricated strands the most common way of anchoring is by socketing the ends of the strands. In this study, strand shoe and hanger socket are analyzed far various load conditions using Finite Element Method. The finite element models are built using MSC/PATRAN and analysis is carried out using MSC/NASTRAN. Results are again completely processed using MSC/PATRAN. From the results of the analysis, trends of deformation and stress distribution are reviewed and important factors to consider in the design of strand shoe and hanger socket are discussed.

  • PDF

Flexural Capacity and Non-Linear Characteristic Evaluation of Circular Column Confined by Carbon Sheet Tube (카본시트튜브로 구속된 원형기둥의 휨내력 및 비선형 특성에 대한 연구)

  • Lee, Kyoung Hun;Yoo, Youn Jong;Kim, Hee Cheul;Hong, Won Kee;Lee, Young Hak
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.11 no.3
    • /
    • pp.143-150
    • /
    • 2007
  • Six full scale column specimens have been tested under the constant axial and cyclic lateral load. An equivalent stress block parameter was used to estimate flexural capacity of columns confined by carbon sheet tube. Through the non-linear regression analysis, behaviors of CFCST(Concrete Filled Carbon Sheet Tube) columns under the cyclic lateral load were estimated and compared with test results.

Evaluation of Hydraulic Stability Using Real Scale Experimental on Porous Concrete Revetment Block (다공성콘크리트 호안블록의 실규모 실험을 통한 수리안정성 평가)

  • Kim, Bong-Kyun;Seo, Dae-Seuk;Park, Jun-Seok;Kim, Yun-Yung
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.20 no.2
    • /
    • pp.122-130
    • /
    • 2016
  • The past few decades of industrialization enabled human-centered stream developments, which in turn resulted in constructing straight or covered streams, which are used only for sewage disposal purpose. However, these types of streams have become the cause of flood damages such as localized heavy rain. In response, various construction methods have been implemented to prevent stream and embankment damages. However, regulations regarding these measures only lay out minimum standards such as the height of slopes and the minimum angle of inclination. Moreover, examination of tractive force, the most crucial factor in preventing flood damage, is nonexistent. Therefore, this study evaluates various tractive forces by implementing a porous concrete tetrapod at a full scale artificial stream for experiment, controlling the rate of inflow, and measuring the velocity and depth of the stream under different experiment conditions. The test results of the compressive strength, and porosity and density of rock of the porous concrete tetrapod was between 16.6 and 23.2 MPa, and the actual measurement of air void was 10.1%, thus satisfying domestic standard. The result of tractive force experiment showed a limiting tractive force of $47.202N/m^2$, not satisfying the tractive force scope of $67N/m^2$ the stream design working expertise proposes. However, there was neither damage nor loss of blocks and hardpan. Based on previous researches, it can be expected that there will be resistance against a stronger tractive force. Therefore, it is necessary to conduct another experiment on practical limiting tractive force by adjusting some experimental conditions.