TY - GEN
T1 - Evaluation of the creep coefficients of the hkbd and jsce code concrete creep prediction models
AU - Fanourakis, George
N1 - Publisher Copyright:
© fédération internationale du béton (fib).
PY - 2020
Y1 - 2020
N2 - Creep of concrete is an important design consideration. National design codes therefore provide empirical based models for the estimation of creep deformation. Such models generally estimate a creep coefficient (ι) and an elastic modulus (E) of the concrete, both of which are used to predict the creep strain at any age. The creep coefficient (ι) is the ratio of the creep strain (ιc) to the elastic strain (ιe). Extensive research, by the author, on the accuracy of 14 international code-type creep prediction models concluded that the creep coefficient component (ι) of prediction models correlated highly significantly with the predicted creep and, on that basis, justifies further investigation of its accuracy. This paper assesses the accuracy of the creep coefficients (ι) predicted by the Hong Kong Code of Practice for Structural Use of Concrete (HKBD, 2013) and the Japan Society of Civil Engineers Standard Specification for Concrete Structures (JSCE, 2007). In the case of the JSCE, two models were considered, the one applicable to normal strength concretes (referred to as JSCE) and the other applicable to high strength concretes (> 55 MPa), referred to as JSCE HS. The accuracy of the models was evaluated by comparing the predicted with the actual (measured) creep coefficients (ι), over a period of approximately six months, on a range of concretes under laboratory-controlled conditions, for six mixes (comprising three aggregate types and two water-cement ratios). The JSCE HS Model, which considered the least factors of the models investigated, was the most accurate model, yielding an overall coefficient of variation (ωall) of 30.6 %. The HKBD Model was the least accurate with a ωall of 45.2 %, being only slightly less accurate than the JSCE Model (which yielded a ωall of 43.1 %). The results of this investigation were compared to those of 16 other models.
AB - Creep of concrete is an important design consideration. National design codes therefore provide empirical based models for the estimation of creep deformation. Such models generally estimate a creep coefficient (ι) and an elastic modulus (E) of the concrete, both of which are used to predict the creep strain at any age. The creep coefficient (ι) is the ratio of the creep strain (ιc) to the elastic strain (ιe). Extensive research, by the author, on the accuracy of 14 international code-type creep prediction models concluded that the creep coefficient component (ι) of prediction models correlated highly significantly with the predicted creep and, on that basis, justifies further investigation of its accuracy. This paper assesses the accuracy of the creep coefficients (ι) predicted by the Hong Kong Code of Practice for Structural Use of Concrete (HKBD, 2013) and the Japan Society of Civil Engineers Standard Specification for Concrete Structures (JSCE, 2007). In the case of the JSCE, two models were considered, the one applicable to normal strength concretes (referred to as JSCE) and the other applicable to high strength concretes (> 55 MPa), referred to as JSCE HS. The accuracy of the models was evaluated by comparing the predicted with the actual (measured) creep coefficients (ι), over a period of approximately six months, on a range of concretes under laboratory-controlled conditions, for six mixes (comprising three aggregate types and two water-cement ratios). The JSCE HS Model, which considered the least factors of the models investigated, was the most accurate model, yielding an overall coefficient of variation (ωall) of 30.6 %. The HKBD Model was the least accurate with a ωall of 45.2 %, being only slightly less accurate than the JSCE Model (which yielded a ωall of 43.1 %). The results of this investigation were compared to those of 16 other models.
KW - Codes
KW - Coefficients
KW - Concrete
KW - Creep
KW - Models
UR - http://www.scopus.com/inward/record.url?scp=85134840188&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85134840188
SN - 9782940643042
T3 - fib Symposium
SP - 1163
EP - 1170
BT - Concrete structures for resilient society - Proceedings of the fib Symposium, 2020
A2 - Zhao, Bin
A2 - Lu, Xilin
PB - fib. The International Federation for Structural Concrete
T2 - International fib Symposium on Concrete structures for resilient society, 2020
Y2 - 22 November 2020 through 24 November 2020
ER -