TY - JOUR
T1 - Serviceability check of pretensioned concrete members reinforced with 2,400 Mpa high strength prestressing strnads
AU - Joo, Hyo Eun
AU - Han, Sun Jin
AU - Ju, Hyunjin
AU - Choi, Seung Ho
AU - Park, Min Kook
AU - Kim, Kang Su
N1 - Publisher Copyright:
© 2018 by Korea Concrete Institute.
PY - 2018
Y1 - 2018
N2 - In recent years, high strength 7-wire strands that have a 2,400 MPa tensile strength were developed, for which the serviceability check specified in ACI318-14 and KCI 2012 need to be reviewed. The current design codes (KCI 2012 or ACI318-14) permitted that the tensile stress of reinforcing bars at service loads can be assumed as two-thirds of their yield strengths. However, they restricted the net tensile stress of the prestressing strands in Class C prestressed concrete (PSC) members at service loads (∆fps) to be less than 250 MPa regardless of the tensile strengths of prestressing strands. Therefore, in this study, a parametric analysis was conducted on the PSC members reinforced with 2,400 MPa high strength prestressing strands considering the key influential factors on the ∆fps, such as shape and size of section, partial prestressing ratio (PPR), reinforcing index (w), and magnitude of effective prestress (fse). The analysis results showed that the ∆fps is not affected by section size, and decreases in accordance with increasing fse, PPR, and cracking moment to service moment ratio (Mcr/Mservice). Based on the analysis results, a simple design table was suggested to check if the ∆fps satisfies its limitation at the design stages, which does not require any complex iterative calculations for checking ∆fps.
AB - In recent years, high strength 7-wire strands that have a 2,400 MPa tensile strength were developed, for which the serviceability check specified in ACI318-14 and KCI 2012 need to be reviewed. The current design codes (KCI 2012 or ACI318-14) permitted that the tensile stress of reinforcing bars at service loads can be assumed as two-thirds of their yield strengths. However, they restricted the net tensile stress of the prestressing strands in Class C prestressed concrete (PSC) members at service loads (∆fps) to be less than 250 MPa regardless of the tensile strengths of prestressing strands. Therefore, in this study, a parametric analysis was conducted on the PSC members reinforced with 2,400 MPa high strength prestressing strands considering the key influential factors on the ∆fps, such as shape and size of section, partial prestressing ratio (PPR), reinforcing index (w), and magnitude of effective prestress (fse). The analysis results showed that the ∆fps is not affected by section size, and decreases in accordance with increasing fse, PPR, and cracking moment to service moment ratio (Mcr/Mservice). Based on the analysis results, a simple design table was suggested to check if the ∆fps satisfies its limitation at the design stages, which does not require any complex iterative calculations for checking ∆fps.
KW - 2,400 MPa strands
KW - Non-linear analysis
KW - Prestresssed concrete
KW - Serviceability
KW - Tensile stress
UR - http://www.scopus.com/inward/record.url?scp=85052223958&partnerID=8YFLogxK
U2 - 10.4334/JKCI.2018.30.1.075
DO - 10.4334/JKCI.2018.30.1.075
M3 - Article
AN - SCOPUS:85052223958
SN - 1229-5515
VL - 30
SP - 75
EP - 82
JO - Journal of the Korea Concrete Institute
JF - Journal of the Korea Concrete Institute
IS - 1
ER -