• Title/Summary/Keyword: transverse cracking

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A Study on Joint Position at Concrete Pavement with Box Culverts (박스 암거가 통과하는 콘크리트 포장의 줄눈 위치에 관한 연구)

  • Park, Joo-Young;Sohn, Dueck-Su;Lee, Jae-Hoon;Jeong, Jin-Hoon
    • International Journal of Highway Engineering
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    • v.14 no.2
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    • pp.45-53
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    • 2012
  • Hollows are easily made and bearing capacity is lowered near underground structures of concrete pavement because of poor compaction and long term settlement of the ground. Distresses occur and lifespan is shortened because of larger stress induced by external loadings expected than that in the design. In this paper, the distresses of the concrete pavement slab over box culverts were investigated at the Korea Expressway Corporation(KEC) test road. The transverse cracking of the slabs over the culverts was compared between up and down lines with different soil cover depth. The box culvert without soil cover and concrete pavement were modeled and analyzed by the finite element method(FEM) to verify the transverse cracking at the test road. Wheel loading was applied after self weight of the pavement and temperature gradient of the concrete slab at Yeojoo, Gyeonggi where the test road is located were considered. Positions of maximum tensile stress and corresponding positions of the wheel loading were found for each loading combination. Joint position minimizing the maximum tensile stress was found and optimal slab length over the culverts with diverse size were suggested.

THERMAL EFFECTS ON THE STRAIN ENERGY RELEASE RATE FOR EDGE DELAMINATION IN CRACKED LAMINATED COMPOSITES

  • Soutis, C.;Kashtalyan, M.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2001.04a
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    • pp.1-6
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    • 2001
  • In this paper, edge delaminations in cracked composite plates are analytically investigated. A theoretical model based upon a sub-laminate approach is used to determine the strain energy release rate, $G^{ed}$, in [$\pm$$\theta_m$/$90_n$]$_s$ carbon/epoxy laminates loaded in tension. The analysis provides closed-form expressions for the reduced stiffness due to edge delamination and matrix cracking and the total energy release rate. The parameters controlling the laminate behaviour are identified. It is shown that the available energy for edge delamination is increased notably due to transverse ply cracking. Also thermal stresses increase substantially the strain energy release rate and this effect is magnified by the presence of matrix cracking. Prediction for the edge delamination onset strain is presented and compared with experimental data. The analysis could be applied to ceramic matrix composite laminates where similar mechanisms develop, but further experimental evidence is required.

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Flexural Behavior of Continuous Composite Bridges with Precast Concrete Decks

  • Chung, Chul-Hun
    • Journal of the Korea Concrete Institute
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    • v.15 no.4
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    • pp.625-633
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    • 2003
  • For the construction of open-topped steel box girder bridges, prefabricated concrete slab could offer several advantages over cast-in-situ deck including good quality control, fast construction, and elimination of the formwork for concrete slab casting. However, precast decks without reinforcements at transverse joints between precast slabs should be designed to prevent the initiation of cracking at the joints, because the performance of the joint is especially crucial for the integrity of a structural system. Several prestressing methods are available to introduce proper compression at the joints, such as internal tendons, external tendons and support lowering after shear connection. In this paper, experimental results from a continuous composite bridge model with precast decks are presented. Internal tendons and external tendons were used to prevent cracking at the joints. Judging from the tests, precast decks in negative moment regions have the whole contribution to the flexural stiffness of composite section under service loads if appropriate prestressing is introduced. The validity of the calculation of a cracking load fur serviceability was presented by comparing an observed cracking load and the calculated value. Flexural behavior of the continuous composite beam with external prestressing before and after cracking was discussed by using the deflection and strain data.

A Study on Transverse Cracking and Fatigue Properties of 50mm Thick FACW Weld Metal ; Effects of Preheating and Interpass Temperature (FCAW 50t 후판용접에 있어 예열 및 층간온도 변화에 따른 횡크랙 발생과 피로특성에 관한 연구)

  • 이해우;강성원
    • Journal of Welding and Joining
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    • v.15 no.3
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    • pp.56-64
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    • 1997
  • Macrostructural characteristic of the transverse cracks and fatigue behavior were studied for EH 32 TMCP 50mm thick plate welded with FACW under the variation in preheat and interpass temperatures. Transverse cracks were detected in specimen welded with preheat and interpass temperature below $30^{\circ}C$, but cracks were not detected in the specimens welded with preheat and interpass temperatures at the range of $100~120^{\circ}C$.C. The location of crack formation was found to strongly depend upon the thickness of weld layers as regard to the plate thickness.

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Seismic performance of RC short columns with light transverse reinforcement

  • Tran, Cao Thanh Ngoc;Li, Bing
    • Structural Engineering and Mechanics
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    • v.67 no.1
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    • pp.93-104
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    • 2018
  • The seismic behavior of reinforced concrete (RC) short columns with limited transverse reinforcement is investigated in this paper through an experimental program. The experimental program consists of four small-scale RC columns with an aspect ratio of 1.7, which are tested to the axial failure stage. The cracking patterns, hysteretic responses, strains in reinforcing bars, displacement decomposition and cumulative energy dissipation of the tested specimens are reported in detail in the paper. The effects of column axial load are investigated to determine how this variable might influence the performance of the short columns with limited transverse reinforcement. Brittle shear failure was observed in all tested specimens. Beneficial and detrimental effects on the shear strength and drift ratio at axial failure of the test specimens due to the column axial load are found in the experimental program, respectively.

Experimental behavior and shear bearing capacity calculation of RC columns with a vertical splitting failure

  • Wang, Peng;Shi, Qing X.;Wang, Qiu W.;Tao, Yi
    • Earthquakes and Structures
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    • v.9 no.6
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    • pp.1233-1250
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    • 2015
  • The behavior of reinforced concrete (RC) columns made from high strength materials was investigated experimentally. Six high-strength concrete specimen columns (1:4 scale), which included three with high-strength transverse reinforcing bars and three with normal-strength transverse reinforcement, were tested under double curvature bending load. The effects of yielding strength and ratio of transverse reinforcement on the cracking patterns, hysteretic response, shear strength, ductility, strength reduction, energy dissipation and strain of reinforcement were studied. The test results indicated that all specimens failed in splitting failure, and specimens with high-strength transverse reinforcement exhibited better seismic performance than those with normal-strength transverse reinforcement. It also demonstrated that the strength of high-strength lateral reinforcing bars was fully utilized at the ultimate displacements. Shear strength formula of short concrete columns, which experienced a splitting failure, was proposed based on the Chinese concrete code. To enhance the applicability of the model, it was corroborated with 47 short concrete columns selected from the literature available. The results indicated that, the proposed method can give better predictions of shear strength for short columns that experienced a splitting failure than other shear strength models of ACI 318 and Chinese concrete codes.

Solidification Cracking Behavior in Austenitic Stainless Steel Laser Welds (Part 1) - Evaluation of Solidification Cracking Susceptibility by Laser Beam Welding Varestraint Test - (오스테나이트계 스테인리스강 레이저 용접부의 응고균열 거동 (Part 1) - 레이저 용접용 Varestraint 시험 시스템을 이용한 응고균열 민감도 평가 -)

  • Chun, Eun-Joon;Lee, Su-Jin;Suh, Jeong;Kang, Namhyun;Saida, Kazuyoshi
    • Journal of Welding and Joining
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    • v.34 no.5
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    • pp.54-60
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    • 2016
  • In order to quantitatively evaluate the solidification cracking susceptibility in laser welds of three types of austenitic stainless steels (type 310: A mode, type 316-A: AF mode, type 316-B: FA mode solidifications), the laser beam welding (LBW) transverse-Varestraint tests consisted of multi-mode fiber laser, welding robot and hydraulic pressure system were performed. As the welding speed increased from 1.67 to 40.0 mm/s, the solidification brittle temperature range (BTR) of laser welds for type 316 stainless steels enlarged (316-A: from 37 to 46 K, 316-B: from 14 to 40 K), while the BTR for type 310 stainless steel reduced from 146 to 120 K. In other words, it founds that solidification cracking susceptibility could not be simply mitigated through application of LBW process, and the BTR variation behavior is quite different upon solidification mode of austenitic stainless steels.

Layered finite element method in cracking and failure analysis of RC beams and beam-column-slab connections

  • Guan, Hong;Loo, Yew-Chaye
    • Structural Engineering and Mechanics
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    • v.5 no.5
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    • pp.645-662
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    • 1997
  • A nonlinear semi-three-dimensional layered finite element procedure is developed for cracking and failure analysis of reinforced concrete beams and the spandrel beam-column-slab connections of flat plates. The layered element approach takes the elasto-plastic failure behaviour and geometric nonlinearity into consideration. A strain-hardening plasticity concrete model and a smeared steel model are incorporated into the layered element formulation. Further, shear failure, transverse reinforcement, spandrel beams and columns are successfully modelled. The proposed method incorporating the nonlinear constitutive models for concrete and steel is implemented in a finite element program. Test specimens including a series of reinforced concrete beams and beam-column-slab connections of flat plates are analysed. Results confirm the effectiveness and accuracy of the layered procedure in predicting both flexural and shear cracking up to failure.

Experimental and analytical behavior of a prestressed U-shaped girder bridge

  • Wu, Xun;Li, Hui
    • Structural Engineering and Mechanics
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    • v.61 no.3
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    • pp.427-436
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    • 2017
  • This paper presents an experimental and analytical investigation on the behavior of a U-shaped girder subjected to operation, cracking and ultimate loads. A full-scale destructive test was conducted on a U-shaped girder to study the cracking process, load-carrying capacity, failure mechanism and load-deformation relationships. Accordingly, the tested U-shaped girder was modeled using ANSYS and a non-linear element analysis was conducted. The investigation shows that the U-shaped girder meets the specified requirements of vertical stiffness, cracking and ultimate load capacity. Unfavorable torsional effect is tolerable during operation. However, compared with box girders, the U-shaped girder has a more transverse mechanical effect and longitudinal cracks are apt to occur in the bottom slab.

Diagnosis of Crack Occurrence of Very-Early Strength Latex-Modified Concretes through Field Tests (현장실험을 통한 VES-LMC 균열발생 원인분석)

  • Choi, Pan-Gil;Lee, Bong-Hak
    • Journal of Industrial Technology
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    • v.26 no.A
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    • pp.139-146
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    • 2006
  • Many concrete bridge decks develop transverse cracking shortly after construction. These cracks accelerate corrosion of reinforcing steel and lead to concrete deterioration, damage to components beneath the deck, unsightly appearance. These cracks shorten the service life and increase maintenance costs of bridge structures. In this study, VES-LMC overlay, which provides the same benefits as a conventional overlay, is designed to cure very quickly. Although the materials for VES overlays are more expensive, the cost is more than offset by the savings on traffic control and work zone safety measures. Otherwise, reaction of hydration occurs very rapidly in beginning step(concrete placing). As a results, thermal cracking can be occur by thermal stress in accordance with hydration-heat The purpose of this study was to estimate diagnosis of crack occurrence of VES-LMC through field tests at early-age.

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