TY - JOUR
T1 - Pretensioned prestress friction losses considering contact imperfection at deviators in prestressed concrete girders
AU - Yan, Meng
AU - Yang, Yongqing
AU - Li, Xiaobin
AU - Bao, Yi
AU - Sun, Jingfei
AU - Sun, Baolin
N1 - Publisher Copyright:
© 2020 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2021
Y1 - 2021
N2 - Pretensioned prestressed concrete (PC) girders are prefabricated in series to reduce cost and facilitate fabrication efficiency. However, a consensus of the calculation of prestress friction losses at deviators is not achieved yet. The existing calculation methods assume a perfect contact between prestressing tendon and deviator, which is inconsistent with observed imperfect contact in real-life practices. This research considers imperfect contact in the investigation of the friction loss through theoretical analysis and experimentation. Three representative types of deviators are investigated and compared in terms of the magnitude of the friction loss. Modified equations for calculating the friction are proposed through the theoretical study, validated against experiment, and applied to investigate the distribution and effects of friction loss in series girders. The results show that the friction loss due to contact imperfection accounts for a significant percentage (61%) of the total friction loss. The equations without considering contact imperfection underestimated friction loss by up to 54 MPa, overestimated the elongation of tendons by up to 77 mm, and overestimated the camber and crack resistance of series girders by up to 6.6%. This study provides new insights into pretensioned prestress friction loss, and the modified equations are useful to improve the design, fabrication, and evaluation of PC girders.
AB - Pretensioned prestressed concrete (PC) girders are prefabricated in series to reduce cost and facilitate fabrication efficiency. However, a consensus of the calculation of prestress friction losses at deviators is not achieved yet. The existing calculation methods assume a perfect contact between prestressing tendon and deviator, which is inconsistent with observed imperfect contact in real-life practices. This research considers imperfect contact in the investigation of the friction loss through theoretical analysis and experimentation. Three representative types of deviators are investigated and compared in terms of the magnitude of the friction loss. Modified equations for calculating the friction are proposed through the theoretical study, validated against experiment, and applied to investigate the distribution and effects of friction loss in series girders. The results show that the friction loss due to contact imperfection accounts for a significant percentage (61%) of the total friction loss. The equations without considering contact imperfection underestimated friction loss by up to 54 MPa, overestimated the elongation of tendons by up to 77 mm, and overestimated the camber and crack resistance of series girders by up to 6.6%. This study provides new insights into pretensioned prestress friction loss, and the modified equations are useful to improve the design, fabrication, and evaluation of PC girders.
KW - Contact imperfection
KW - deviator
KW - hardness difference
KW - prestressed concrete girders
KW - pretensioned prestress friction loss
KW - tendons
UR - http://www.scopus.com/inward/record.url?scp=85091132741&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85091132741&partnerID=8YFLogxK
U2 - 10.1080/15732479.2020.1821719
DO - 10.1080/15732479.2020.1821719
M3 - Article
AN - SCOPUS:85091132741
SN - 1573-2479
VL - 17
SP - 1639
EP - 1650
JO - Structure and Infrastructure Engineering
JF - Structure and Infrastructure Engineering
IS - 12
ER -