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http://dx.doi.org/10.11112/jksmi.2018.22.5.082

Effects of Transverse Reinforcement on Headed Bars with Large Diameter at Cut-off Points  

Jung, Hyung-Suk (Department of Architectural Engineering, Catholic Kwandong University)
Publication Information
Journal of the Korea institute for structural maintenance and inspection / v.22, no.5, 2018 , pp. 82-90 More about this Journal
Abstract
The nuclear structures are composed of large diameter bars over No.36. If the hooked bars are used for anchorage of large diameter bars, too long length of the tail extension of the hook plus bend create congestion and make an element difficult to construct. To address those problems, headed bars were developed. Provisions of ACI 318-08 specify the development length of headed bars and ignore the effect of transverse reinforcement based on the background researches. However, if headed bars are used at the cut-off or lap splice, longitudinal reinforcements, which are deformed in flexural members, induce tensile stress in cover concrete and increase the tensile force in the transverse reinforcement. The object of this research is to evaluate the effects of transverse reinforcement on the anchorage capacity of headed bar so anchorage test with variable of transverse rebar spacing was conducted. Specimens, which can consider the behavior at the cut-off, were tested. Test results show that failure of specimen without transverse reinforcement was sudden and brittle with concrete cover lifted and developed stress of headed bars was less than half of yield strength of headed bars. On the other hand, in the specimen with transverse reinforcement, transverse rebar directly resist the load of free-end so capacity of specimens highly increased.
Keywords
Cut-off; Headed bar; Large diameter; Transverse reinforcement;
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  • Reference
1 Federation Internationale du Beton (2000), Bond of reinforcement in concrete : state-of-art-report, Bulletin 10. Lausanne: federation internationale du Beton(fib), pp. 104
2 Ferguson, P. M., and Thompson, J. N. (1965), Development Length of Large High Strength Reinforcing Bars, ACI Journal, V. 62, No. 1, Jan, pp. 71-94
3 ASTM A970/A970M-09 (2009), Standard Specification for Headed Steel Bars for Concrete Reinforcement, West Conshohocken, PA., pp. 8
4 ASTM E8/E8M-11 (2011), Standard Test Methods for Tension Testing of Metallic Materials, American Society of Testing and Materials, pp. 15
5 ACI Committee 349 (2006), Code Requirements for Nuclear Safety-Related Concrete Structures (ACI 349-06), ACI, Farmington Hills, Mich., USA, 465 pp.
6 ASME (2010), ASME Boiler and Pressure Vessel Code, Section III, Division 2, American Society of Mechanical Engineers, New York, USA, 156 pp.
7 ACI Committee 318 (2008), Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary, ACI, Farmington Hills, Mich., USA, 216 pp.
8 DeVries, R. A. (1996), Anchorage of Headed Reinforcement in Concrete, PhD dissertation, The University of Texas at Austin, Austin, 294 pp.
9 Thompson, M. K., Ziehl, M. J., Jirsa, J. O., and Breen, J. E.(2005), CCT Nodes Anchored by Headed Bars-Part 1: Behavior of Nodes, ACI Structural Journal, V. 102, No. 6, Nov.-Dec., pp. 808-815
10 Thompson, M. K., Ledesma, A., Jirsa, J. O., and Breen, J. E.(2006), Lap Splices Anchored by Headed Bars, ACI Structural Journal, V. 103, No. 2, Mar.-Apr., pp. 271-279
11 Lee, Y.T, (2008), An Experimental Study on the Lap Splice Performance of Headed Steel Reinforcements with Confinement Details, Journal of the Architectural Institute of Korea, Structural Section, V. 24, No. 5, May., pp. 59-66