Uniform Elongation of Steel Reinforcing Bars manufactured to Korean Standards

Eun-Ho Lee; Se-Rim Pyo; Hyeon-Woo Lee; Tae-Won Oh; Jae-Hoon Lee

doi:10.22725/JSRP.2025.3.2.37

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2025 Vol.3, Issue 2 Next Page

Research Article

Uniform Elongation of Steel Reinforcing Bars manufactured to Korean Standards 한국 표준에 따라 생산된 철근의 균일연신율

31 December 2025. pp. 37-48

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Abstract

Tensile tests were conducted on 149 reinforcing bar specimens manufactured in Korea in accordance with KS D 3504. The test results were analyzed with respect to steel grades and compared with the minimum requirements of Eurocode 2 and ACI 318-19 Code. Specimen diameters ranged from 9.53 mm (D10) to 57.3 mm (D57), with yield strengths of 426–816 MPa and tensile strengths of 571–962 MPa. It was found that uniform elongation tends to decrease as yield and tensile strength increase. For general-purpose reinforcing bars with specified yield strengths of 600 MPa or less, all specimens showed uniform elongations greater than 5 %, thus satisfying Eurocode 2. All SD400S seismic bars exhibited greater than 10 % uniform elongations, meeting both Eurocode 2 (7.5 %) and ACI 318-19 Code (9 % for Grade 420 MPa steel). However, 4 of 10 SD500S and 7 of 13 SD600S specimens fell below 7.5 %, failing to satisfy Eurocode 2, and 3 of 10 SD500S and 4 of 13 SD600S specimens did not meet the ACI 318-19 Code minimum requirement of 7 % for Grade 550 MPa steel. Based on these results, revision proposals for KS D 3504 and the Korean Concrete Bridge Design Code(Limit State Design Method) were suggested.

Keywords

steel reinforcing bars

uniform elongation

Korean Standard

Eurocode 2

ACI 318-19 code

한국의 철근표준 KS D 3504에 따라 한국에서 생산된 철근을 대상으로 인장시험을 실시하여 총 149개의 균일연신율 실측값을 얻었고, 강종에 따른 경향을 분석하였으며 Eurocode 2와 ACI 318-19 Code의 최소 균일연신율 조건과 비교하였다. 시험편의 지름은 9.53 mm (D10)에서 57.3 mm (D57)까지의 범위로, 인장시험 결과 항복강도는 426~816 MPa의 범위를 보였으며 인장강도는 571~962 MPa의 범위를 보였다. 측정된 균일연신율 값은 철근의 항복강도와 인장강도가 증가할수록 감소하는 경향을 보였다. 설계기준항복강도가 600 MPa 이하로 건설현장에서 사용되고 있는 일반구조용 철근은 모두 5 %를 초과하는 균일연신율로 Eurocode 2의 최소 균일연신율 조건을 만족하였다. 내진용 SD400S 철근 시험편은 10개 모두 10 %를 초과하는 균일연신율로 Eurocode 2의 최소 균일연신율 조건인 7.5 %를 만족하였고, 설계기준항복강도 420 MPa에 대한 ACI 318-19 Code의 최소 조건 9 % 또한 만족하였다. 그러나 내진용 SD500S 철근 시험편은 10개 중 4개, SD600S 철근 시험편은 13개 중 7개가 7.5 % 미만으로 Eurocode 2의 최소 균일연신율 조건을 만족하지 못하였다. 또 SD500S 철근 시험편 10개 중 3개, SD600S 철근 시험편은 13개 중 4개가 설계기준항복강도 550 MPa에 대한 ACI 318-19 Code의 최소 조건 7 %를 만족하지 못하였다. 이 결과를 바탕으로 KS D 3504와 한국 콘크리트교 설계기준(한계상태설계법)의 개정안을 제안하였다.

키워드

철근

균일연신율

KS 한국표준

Eurocode 2

ACI 318-19 Code

References

ACI Committee 318 (2019) Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary. Farmington Hills, MI; American Concrete Institute (ACI).

ASTM (2022a) Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement (ASTM A615/A615M), USA, American Society for Testing and Materials (ASTM)

ASTM (2022b) Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement (ASTM A706/A706M), USA, American Society for Testing and Materials (ASTM)

BS 4449 (2005) Steel for the Reinforcement of Concrete-Weldable Reinforcing Steel-Bar, Coil and Decoiled Product Specification, British Standards.

CEN (2023) Eurocode 2: Design of Concrete Structures – Part 1-1: General rules and rules for buildings, bridges and civil engineering structures (BS EN 1992-1 : 2023), London, UK; European Committee for Standardization (CEN), British Standards Institute (BSI).

ISO (1998) Metallic materials-Tensile testing at ambient temperature (ISO 6892), International Organization for Standardization, 1998.

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KIBSE (Korean Institute of Bridge and Structural Engineers) (2021) Concrete Bridge Design (Limit State Design Method) (KDS 24 14 21) Design Code and Commentary. Seoul, Korea: KIBSE. (In Korean)

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Information

Publisher :Korean Institute of Bridge and Structural Engineers
Publisher(Ko) :한국교량및구조공학회
Journal Title :Journal of Structure Research and Practice
Journal Title(Ko) :한국교량및구조공학회 논문집
Volume : 3
No :2
Pages :37-48
Received Date : 2025-11-03
Accepted Date : 2025-11-08
DOI :https://doi.org/10.22725/JSRP.2025.3.2.37

Journal of Structure Research and Practice ISSN:3022-4241(Print) 3022-7267(Online) 한국교량및구조공학회 논문집

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