• Title/Summary/Keyword: rebar location

Search Result 22, Processing Time 0.023 seconds

Seismic Response Analysis of Lightly Reinforced Concrete Shear Walls

  • Rhee, In-Kyu
    • International Journal of Railway
    • /
    • v.3 no.2
    • /
    • pp.73-82
    • /
    • 2010
  • Global and local behaviors of a lightly RC shear walls are investigated in this paper. For the sake of cyclic behaviors, nominal ground accelerations of 0.15 g, 0.40 g and 0.55 g which associated with natural periods of the walls are applied as listed in French CAMUS-2000 shake table test. Modified Kent & Park model, Drucker-Prager model for concrete material and $Giufr\acute{e}$-Menegotto-Pinto model for rebar are used for time history analyses using fiber/solids elements respectively. Alternatively, Eulerian beam analysis are discussed by imposing inelastic hinges at the most possible plastic hinge location using modified Takeda's trilinear model with stiffness reduction. Relative displacements, base shears, bending moments of 5-story shear building with 36-tons of mass under bi-lateral seismic excitation are extracted and compared with EC-8, PS-92 and KBC-09 provisions. Multi-scaled degradation process; material damage, elemental fracture and structural failure in turn is discussed in the view of numerical accuracy, efficiency and limitation depending on three different model-based analyses.

  • PDF

Detection of the Cavity Behind the Tunnel Lining by Single Channel Seismic and GPR Method (GPR 및 단일채널 탄성파탐사에 의한 터널라이닝 배면공동 조사)

  • Shin, Sung-Ryul;Jo, Chul-Hyun;Shin, Chang-Soo;Yang, Seung-Jin;Jang, Won-Yil
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.2 no.4
    • /
    • pp.148-158
    • /
    • 1998
  • Determining the thickness if concrete lining and detecting of the cavity where is located behind tunnel lining plays an important role in the safety diagnosis of tunnel structure and the quality control. In this study, we made use of GPR and seismic method in order to find the cavity or flaw. Although GPR is very useful method in the concrete lining without rebar, it is difficult to detect the cavity in the reinforced concrete lining. We applied mini-seismic method to the reinforced concrete lining. The obtained seismic data was processed by means of seismic section in time domain and image section of power spectrum in frequency domain using Impact-Echo method as well. The proposed method can accurately show the location and depth of the cavity in the reinforced concrete lining.

  • PDF

Internal Object Detection Monitoring System in Reinforced Concrete Structure using UWB-RF (UWB-RF를 이용한 콘크리트 구조물의 내부 물체 검출 모니터링 시스템)

  • Park, Dae-Hyuck;Kang, Eui-Sun
    • Journal of Digital Contents Society
    • /
    • v.18 no.7
    • /
    • pp.1457-1464
    • /
    • 2017
  • This paper is to introduce the a system which monitors and detects the object position in reinforced the concrete structure using UWB-RF. This system is able to check any changes in the inside of the concrete structure using its penetration and reflection characteristics and it can also numerically measure the position of rebar in the concrete structure. For the verification of the performance of this system, we set up the internal compositions of concrete in 3 different types of test-bed. On the other hand, for the measuring of the location of rebar, which varies depending on the type of structure, the software which shows the distance in the structure were used. The result shows that the position in the concrete could be measured within the tolerance of ${\pm}1{\sim}4mm$ depending on the type of structure in the concrete.

Current Status and Analysis of Durability for Buildings Long Neglected after Construction Discontinuation in Jeju (제주지역 공사중단 건축물의 현황조사 및 내구성 분석)

  • Han, In-Deok;Kim, Doo-Seong;Jang, Myunghoun
    • Journal of the Korea Institute of Building Construction
    • /
    • v.23 no.4
    • /
    • pp.441-452
    • /
    • 2023
  • Buildings that have been long neglected can suffer severe durability reduction due to factors such as rebar rust and concrete quality deterioration resulting from exposure to outside air. Furthermore, the issues associated with these suspended buildings, including safety accidents, social crimes, and environmental pollution, are becoming increasingly serious. This study investigates the current status of these buildings in the Jeju area, identifies the problems, and examines the durability of the structure in a specific location to assess the possibility of future use. Aesthetic surveys(visual and slope inspections) as well as non-destructive tests(compressive strength tests, neutralization tests, and rebar detection tests) were conducted to assess durability. The analysis revealed that the structure maintained satisfactory durability and the building's condition was good in comparison to the years of neglect.

Influence of Bubble Sheet Applying Methods on Temperature of Exposed Joint Rebar at Wall Surface of Load-Bearing Wall Structure Building During Winter (동절기 벽식구조 건축물 벽부분의 버블시트 포설방법 변화가 이음부 노출철근의 온도에 미치는 영향)

  • Han, Cheon-Goo;Lee, Jea-Hyeon;Kim, Min-Sang
    • Journal of the Korea Institute of Building Construction
    • /
    • v.17 no.2
    • /
    • pp.149-155
    • /
    • 2017
  • In this research, the surface covered curing method using the double-layered bubble sheet was evaluated. This double-layered bubble sheet has outstanding insulating performance with its low heat conductivity and high economic feasibility with its high durability. However, in the case of wall-typed building construction, the area of exposed rebar is curious on curing performance with the double-layered bubble sheet in spite of the double-layered bubble sheet showed favorable performance for slab. Therefore, in this research, regarding the actually constructed wall-typed apartment building, the most efficient curing method was suggested based on the evaluation of curing performance depending on temperature distribution depending on various location of covered or exposed rebar. As a result, the D method was determined as the most efficient curing method without any concern of early-age frost damage. However, by considering easiness of construction, the B method of covering the pieced double-layered bubble sheet on gap between rebars can be another option of desired result.

An evaluation of compressive lap splice of the D22 rebar by concrete strengths (콘크리트 강도변화에 따른 D22mm 철근의 압축이음 성능 평가)

  • Lee, Sung-Ho;Chun, Sung-Chul;Oh, Bo-Hwan
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.04a
    • /
    • pp.1081-1084
    • /
    • 2008
  • Column specimens were constructed with main parameters significantly affecting the strength of the compression lap splice, such as lap length, spacing of lapped bars, amount and location of transverse reinforcements, and concrete strength. An experimental study has been conducted with column specimens in concrete strength of 40 to 60 MPa. Diameters of lapped reinforcing bars are 22 mm. An axial load was monotonically applied to the column specimens. All specimens failed in a brittle sudden manner and cover concrete was blasted out at maximum load. Compression lap splice strengths of specimens were evaluated from strains measured at the beginning of the lap length. Effects of the main parameters on the strengths of compression lap splice are assessed. Similarly to strengths of tension lap slice, the compression splice strength is found to be affected by lap length, spacing of lapped bars, transverse reinforcements.

  • PDF

An Experimental Study on the Bond Splitting Strength between Composite Concrete and Deformed rebar (복합콘크리트와 이형 철근간의 부착강도에 관한 실험적 연구)

  • Yoon, Seung-Joe;Ho, SeungWoung
    • Journal of the Regional Association of Architectural Institute of Korea
    • /
    • v.21 no.3
    • /
    • pp.87-92
    • /
    • 2019
  • To relieve noise between floors in Korea, recent domestic and overseas studies have been developing materials that have the properties of ceramic, which is an inorganic compound, and polymer, which is an organic compound, to introduce a new function to polymer. This study conducted a bending strength experiment between re-bar and new composite concrete mixing POSS (Polyhedral Oligomeric Silses-quioxanes) nano complex on the inside of concrete, and by assembling the inside of each concrete with 3 and 4 main re-bars as an experiment to supplement various problems that occur by the expression of this strength and the distribution of the reinforcement. The number of the main re-bars. and the direction of laying the concrete were applied as the principal variables of the experiment. Upon experiment, there were no differences in the bond strength based on the location of the main re-bar, and a 2 % increase in the bond strength was shown in the specimen laid in the same direction as the main re-bar in comparison to that of the specimen laid in a different direction from the main re-bar. The experiment results displayed that the composite concrete had uniform performance based on the rapid reaction speed of POSS nano complex.

Development of Remote Measurement Method for Reinforcement Information in Construction Field Using 360 Degrees Camera (360도 카메라 기반 건설현장 철근 배근 정보 원격 계측 기법 개발)

  • Lee, Myung-Hun;Woo, Ukyong;Choi, Hajin;Kang, Su-min;Choi, Kyoung-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.26 no.6
    • /
    • pp.157-166
    • /
    • 2022
  • Structural supervision on the construction site has been performed based on visual inspection, which is highly labor-intensive and subjective. In this study, the remote technique was developed to improve the efficiency of the measurements on rebar spacing using a 360° camera and reconstructed 3D models. The proposed method was verified by measuring the spacings in reinforced concrete structure, where the twelve locations in the construction site (265 m2) were scanned within 20 seconds per location and a total of 15 minutes was taken. SLAM, consisting of SIFT, RANSAC, and General framework graph optimization algorithms, produces RGB-based 3D and 3D point cloud models, respectively. The minimum resolution of the 3D point cloud was 0.1mm while that of the RGB-based 3D model was 10 mm. Based on the results from both 3D models, the measurement error was from 10.8% to 0.3% in the 3D point cloud and from 28.4% to 3.1% in the RGB-based 3D model. The results demonstrate that the proposed method has great potential for remote structural supervision with respect to its accuracy and objectivity.

Seismic Evaluation of the Existing RC Piers (기존 철근콘크리트 교각의 내진성평가)

  • 전귀현;이지훈
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.2 no.4
    • /
    • pp.155-168
    • /
    • 1998
  • In this paper, the structural properties of the existing reinforced concrete(RC) piers are surveyed and the major factors influencing the member strength and deformation capacity are identified. Also a seismic evaluation procedure of RC piers is presented. The factors controlling the member strength are the applied axial load, the reinforcement ratio and yield strength of longitudinal rebar for flexural strength, and the transverse reinforcement for shear strength. Member deformation capacity largely depends on transverse reinforcement ratio and anchor detail, and splice location of longitudinal reinforcement. The above structural detail should be investigated for the detail seismic evaluation of RC piers. The most of existing RC piers have inadequate transverse reinforcement anchor details and the splices of longitudinal reinforcement in the pier bottom where plastic hinges are formed after yielding. Therefore the deformation capacity is not enough for the ductile flexural behavior of the RC piers. The presented evaluation procedure can be used for the rational decisions as to seismic retrofitting of the existing RC piers.

  • PDF

Influence of Reinforcements on the Chloride Diffusion Analysis of Concrete Structures (철근의 영향을 고려한 콘크리트 구조물의 염소이온 확산해석)

  • 오병환;장봉석;이명규
    • Journal of the Korea Concrete Institute
    • /
    • v.14 no.6
    • /
    • pp.883-891
    • /
    • 2002
  • The chloride penetration in concrete structures is influenced by many factors such as types of cement and admixture proportion. Therefore, the effects of these factors on chloride diffusion must be correctly considered. The conventional diffusion analysis also neglected the existence of reinforcing bar in concrete structures. The purpose of the present paper is therefore to investigate the effect of reinforcing bar on the chloride diffusion in concrete structures. For this purpose, a comprehensive finite element analyses have been conducted to obtain chloride penetration profile. The results indicate that the chlorides are accumulated in front of a reinforcing bar and that the accumulation is much larger for the case of large diameter bars. The higher accumulation of chloride at bar location causes much faster corrosion of reinforcing steel. It can be concluded from the present study that the effects of reinforcing bars must be considered in chloride diffusion analysis for more realistic prediction of durable life of concrete structures.