• Title, Summary, Keyword: Slab joint

Search Result 198, Processing Time 0.15 seconds

Benefits of Puddling of Fiber Reinforced UHSC for Enhanced Transmission of Column Loads

  • Lee, Joo-Ha;Kim, Gyu-Dong;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.75-78
    • /
    • 2005
  • This study reports on the structural characteristics of slab-column connections using an ultra-high-strength-fiber-reinforced concrete. Compression tests were performed on two slab-column and four isolated column specimens. During the column load tests were performing on the slab-column specimens, the slab loads were also applied to consider actual confinement condition at the slab-column joint. The main parameter investigated was the ' puddling ' of ultra-high-strength-fiber-reinforced concrete. This paper also investigates the effects of some parameters on slab-column specimens and isolated column specimens without the surrounding slab for their ability to transmit axial loads from the ultra-high-strength concrete columns through slab-column connections. The beneficial effects of the ultra-high-strength-fiber-reinforced concrete puddling on the transmission of column loads through slab-column connections are demonstrated.

  • PDF

A Study on the Evaluation System of Jointed Concrete Pavement (콘크리트포장 줄눈부의 평가에 관한 기법연구)

  • Park, Je-Seon;Lee, Joo-Hyung;Hong, Chang-Woo;Lee, Jung-Ho
    • Journal of Industrial Technology
    • /
    • v.19
    • /
    • pp.245-251
    • /
    • 1999
  • The joint in the concrete pavement provides a control against transverse or longitudinal cracking at slab, which may be caused by temperature or moisture variation during or after hydration. Without control of cracking, random crack may cause more serious distresses and result in structural or functional failure of pavement system. Sometimes, joint itself, purposed to control crack, may cause a distresses in joint due to its inherent weakness in structural integrity. Thus, the load transfer capacity in joint is very important for serviceability and durability. The purpose of this dissertation was to develop an evaluation system at joints of jointed concrete pavement using finite element analysis was performed using ILLI-SLAB program with a selected variables which might affect fairly to on the performance of transverse joints. The most significant variables were selected from precise analysis. It was concluded that the variables which most significantly affect to pavement deflections are the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G), and limiting criteria on the performance of joints at JCP at 300pci, 500,000 lb/in. respectively.

  • PDF

The Experimental Study on Transverse Field Joint Method of Precast Road Deck Slab of Double Deck Tunnel in Great Depth (대심도 복층터널 프리캐스트 중간슬래브의 횡방향 현장이음방식에 대한 실험연구)

  • Lee, Doo-Sung;Kim, Bo-Yeon;Bae, Chul-Gi;Hur, Jae-Hun
    • Journal of the Korea Concrete Institute
    • /
    • v.29 no.1
    • /
    • pp.23-32
    • /
    • 2017
  • The joints between precast PSC slabs of the intermediate road slab in double deck tunnel are inevitably generated in the road traffic vehicle traveling direction. Therefore, it is important to make the behavior of parts on the joint in one piece. The imtermediate road slab system of double deck tunnel in great depth proposed in this study will be constructed with precast PSC slab in order to minimize the construction period. And the joint connection between the precast slab has been developed in two methods: the 'Transverse tendon reinforcement method' and 'High strength bolts connection method'. Also, the experiments were performed for the full scale model in order to evaluate the performance of the intermediate road deck slab with two type joints systems, the structural stability was verified through the F.E.M analsysis. The results of static loading test and F.E.M analysis investigated a very stable behavior of intermediate road deck slab in double deck tunnel applying the joint methods developed in this study, in the cracks and deflections to satisfy the design standards of Highway Roads Bridges (2011), it was determined that there is no problem even servicebility.

Behavior of Jointed Concrete Pavement by Box Culvert and Reinforced Slab (박스형 암거와 보강슬래브에 의한 줄눈 콘크리트 포장의 거동)

  • Park, Joo Young;Sohn, Dueck Su;Lee, Jae Hoon;Yan, Yu;Jeong, Jin Hoon
    • International Journal of Highway Engineering
    • /
    • v.14 no.6
    • /
    • pp.25-35
    • /
    • 2012
  • PURPOSES : Hollows are easily made, and bearing capacity can be lowered near underground structures because sublayers of pavement settle for a long time due to difficult compaction at the position. If loadings are applied in this condition, distresses may occur in pavement and, as the result, its lifespan can decrease due to the stress larger than that expected in design phase. Although reinforced slab is installed on side of box culvert to minimize the distresses, length of the reinforced slab is fixed as 6m in Korea without any theoretical consideration. The purpose of this paper is investigating the behavior of concrete pavement according to the cover depth of the box culvert ad the length of the reinforced slab. METHODS : The distresses of concrete pavement slabs were investigated and cover depth was surveyed at position where the box culverts were located in expressways. The concrete pavements including the box culverts were modeled by finite element method and their behaviors according to the soil cover depth were analyzed. Wheel loading was applied after considering self weight of the pavement and temperature gradient of the concrete pavement slab at Yeojoo, Gyeonggi where a test road was located. After installing pavement joint at various positions, behavior of the pavement was analyzed by changing the soil cover depth and length of the reinforced slab. RESULTS : As the result, the tensile stress developed in the pavement slab according to the joint position, cover depth, and reinforced slab length was figured out. CONCLUSIONS : More reasonable and economic design of the concrete pavement including the box culvert is expected by the research results.

Structural Performance of RC Slab-Wall Joints Reinforced by Welded Deformed Steel Bar Mats (철근격자망을 사용한 슬래브-벽체 접합부의 구조성능)

  • Park, Seong-Sik;Yoon, Young-Ho;Lee, Bum-Sik
    • LHI Journal of Land, Housing, and Urban Affairs
    • /
    • v.2 no.1
    • /
    • pp.61-68
    • /
    • 2011
  • In order to clarify the structural performances of Welded Deformed Steel Bar Mats (WDSBM), the research stated includes the tests for standard hook of top bars of slab in concrete slab-wall joints, the tests for embedment length of top bar of slab, and the development strength tests for standard hook. The test results are as follows; (1) For slab-wall joints using WDSBM as reinforcement in slab, if the top bars of WDSBM are spliced by ordinary bars with sufficient development length and size, it is enough for the strength and crack control. (2) When WDSBM of slab is spliced in joint, the strength is increased with the embedment of bars of this WDSBM into wall. Beyond peak strength, however, ductility is diminished to that as no splice due to pull-out failure. (3) For slab-wall system, ultimate strain of concrete for flexural compression zone in lower surface of slab seems much greater than that of normal concrete beam. The reason is that normal concrete beam has the joint with $180^{\circ}$, however slab-wall joint has the $90^{\circ}$ of which concrete can be confined.

Experimental Analysis of Stress Intensity Factors by Combination With Moire Method and Slab Analogy (모아레法 과 스라브相似 의 複合 에 의한 應力擴大係數 의 實驗的 解析法 -有限板크랙 의 $K_I$$K_II$-)

  • 최선호;권재도;김종주;채영석
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.6 no.4
    • /
    • pp.315-322
    • /
    • 1982
  • The slab analogy method was introduced in the 1920's for the first time as a new experimental stress analysis method. Notwithstanding its theoretical propriety, this method has not been recognized as efficient one because of its difficulty in practical measurement of the slab curvature. In this paper, aiming at experimental determination of two-dimensional stress intensity factors(S. I. F) of arbitrarily shaped cracks which had been regarded as almost impossible by conventional method, the slab analogy was reevaluated. Measuring of slab curvature was replaced by three simple measuring factors to overcome vital slab-analogy's shortcoming by joint use of the shadow-moire method. A determination formula was also derived from the theory of fracture mechanics. By this newly exploited method, it was found that the slab analogy still has its great advantage in determination of S.I.F. of arbitrarily shaped cracks with considerable accuracy compared with existent experimental methods.

Effect of temperature and moisture on curling of early age concrete slabs (재령 초기 콘크리트 슬래브의 컬링에 미치는 온도와 수분의 영향)

  • Sun, Ren-Juan;Nam, Young-Kug;Hong, Seung-Ho;Jeong, Jin-Hoon
    • International Journal of Highway Engineering
    • /
    • v.10 no.1
    • /
    • pp.105-115
    • /
    • 2008
  • It is known that the long-term behavior and performance of jointed concrete pavement due to slab curling are affected by the environmental factors such as temperature, moisture, and so on. However, any relationships between the curling and its factors have not been defined clearly yet because of insufficient detailed investigation. The temperature, relative humidity, strain, vertical displacement of a concrete slab, and horizontal movement of its transverse joints were investigated by various sensors and devices instrumented in the slab of a concrete pavement section constructed for this study. The constraint of the curling by joint stiffness was investigated in addition to effect of the temperature and moisture on the early aged concrete slab by analyzing the field data measured for approximately 4days from concrete placement. The curling of the concrete slab showed 24hour cycles mainly because of the temperature effect, and the upward curling gradually increased because of the long-term effect of drying shrinkage of the concrete. The magnitude and variation of the curling were significantly affected by the joint stiffness which is comprised of aggregate interlocking and other factors. The effect of the variation of the seasonal joint stiffness varying with the temperature and long-term drying shrinkage on the slab curling will be investigated as a further study.

  • PDF

Prediction of the Effective Concrete Strength for Column-Slab Connections

  • Lee, Joo-Ha;Lee, Seung-Hoon;Sohn, Yu-Shin;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.577-578
    • /
    • 2009
  • For cases where the column concrete strength exceeds 1.4 times the slab concrete strength, the KCI Code requires that either: puddled high-strength concrete(HSC) be used in the slab, or the use of vertical dowels and spirals through the joint, or the use of an effective concrete strength in the joint. This paper studies on the third strategy. A prediction model of the effective concrete strength for interior columns was proposed using an analogy of brick and mortar in brick masonry. The proposed prediction model is verified by comparison with experimental results and various design equations.

  • PDF

Behavior and Strength of Wall-Slab Connection in SC Structure (SC구조 벽-바닥 접합부의 내력 및 거동 특성)

  • Kim, Hyeong Gook;Kim, Woo Bum;Kim, Won Ki
    • Journal of Korean Society of Steel Construction
    • /
    • v.20 no.2
    • /
    • pp.347-354
    • /
    • 2008
  • Steel plate-concrete (SC) structure has recently been used in nuclear power structure because of its construction efficiency. In this study, experimental and analytical study to investigate the behavior of the SC structure's wall slab connection was carried out. Experiments were performed for typical SC and RC connections in order to examine the basic difference between each structure. Finite element analysis was performed and the result of the analysis was found to closely reflect the experimental result. By varying the thickness of the shear plate and friction coefficients and the distance of applied load from the wall, the influence of the parameters on the joint strength and failure modes were examined. Finally, it was confirmed that the joint strength formula proposed in th this research gives conservative results.

Tests of Slab-Column Connections with Partially Debonded Reinforcement under Cyclic Lateral Loading (부분적인 비 부착 철근을 갖는 슬래브-기둥 접합부의 반복 횡하중 실험)

  • Choi, Jung-Wook;Song, Jin-Kyu
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.13-16
    • /
    • 2006
  • This article summarizes tests conducted on two full-scale interior slab-column connections with and without partially debonded reinforcement subjected to cyclic loading. Each test specimen consisted of a 4.2m square slab with a 355mm square column protruding 1.5m above and below the slab. The slab thickness was 152mm. The specimen with partially debonded reinforcement exhibited more lateral drift capacity than did the specimen with fully bonded reinforcement. With partial debonding of the flexural reinforcement, cyclic load appeared to produce less damage to the connection in the vicinity of the slab-column joint region.

  • PDF