TY - GEN
T1 - VALIDATION OF THE HONG KONG (HKBD) AND JAPANESE (JSCE) CODE CONCRETE CREEP PREDICTION MODELS
AU - Fanourakis, George C.
N1 - Publisher Copyright:
© Fédération Internationale du Béton – International Federation for Structural Concrete.
PY - 2022
Y1 - 2022
N2 - Creep strain, a requirement of the concrete design process, is a complex phenomenon that has proven difficult to model. Although laboratory tests may be undertaken to quantify creep magnitude, these are generally expensive and not a practical option. Hence, empirical code-type prediction models are used to predict creep strain. This paper considers the accuracy of the Hong Kong Code of Practice Model (HKBD, 2020 [1]) and the Japan Society of Civil Engineers Standard Specification for Concrete Structures (JSCE, 2010 [2]). In the case of the JSCE, two models were considered, one applicable to normal strength concretes (referred to as JSCE) and the subsequently introduced model which is applicable to high strength concretes (> 55 MPa), referred to as JSCE HS. The models were evaluated, when compared with the actual creep strains measured, 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 HKBD and JSCE models generally over-predicted specific creep at all ages. Furthermore, the JSCE HS generally slightly over-predicted specific creep for the first 28 days and then under-predicted thereafter. The HKBD model was found to be the least accurate with an overall coefficient of variation (ωall) of 56.2%. The relatively simple JSCE HS, which was applied to all six of the mixes, of which only one mix classified as high strength, was the most accurate model with a ωall of 21.8%. The JSCE model was less accurate than the JSCE HS, yielding a ωall of 30.2%. When comparing the accuracy of the three models investigated to the accuracy of 17 other international code-type models that were previously investigated by the author, the JSCE HS was the second most accurate and the HKBD was ranked 17th in terms of accuracy (of the 20 models considered), respectively.
AB - Creep strain, a requirement of the concrete design process, is a complex phenomenon that has proven difficult to model. Although laboratory tests may be undertaken to quantify creep magnitude, these are generally expensive and not a practical option. Hence, empirical code-type prediction models are used to predict creep strain. This paper considers the accuracy of the Hong Kong Code of Practice Model (HKBD, 2020 [1]) and the Japan Society of Civil Engineers Standard Specification for Concrete Structures (JSCE, 2010 [2]). In the case of the JSCE, two models were considered, one applicable to normal strength concretes (referred to as JSCE) and the subsequently introduced model which is applicable to high strength concretes (> 55 MPa), referred to as JSCE HS. The models were evaluated, when compared with the actual creep strains measured, 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 HKBD and JSCE models generally over-predicted specific creep at all ages. Furthermore, the JSCE HS generally slightly over-predicted specific creep for the first 28 days and then under-predicted thereafter. The HKBD model was found to be the least accurate with an overall coefficient of variation (ωall) of 56.2%. The relatively simple JSCE HS, which was applied to all six of the mixes, of which only one mix classified as high strength, was the most accurate model with a ωall of 21.8%. The JSCE model was less accurate than the JSCE HS, yielding a ωall of 30.2%. When comparing the accuracy of the three models investigated to the accuracy of 17 other international code-type models that were previously investigated by the author, the JSCE HS was the second most accurate and the HKBD was ranked 17th in terms of accuracy (of the 20 models considered), respectively.
KW - Codes
KW - Concrete
KW - Creep
KW - MEASURED HKBD JSCE JSCE HS
KW - Models
KW - Structural design
UR - http://www.scopus.com/inward/record.url?scp=85143916350&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85143916350
SN - 9782940643158
T3 - fib Symposium
SP - 1621
EP - 1630
BT - Proceedings for the 6th fib International Congress, 2022- Concrete Innovation for Sustainability
A2 - Stokkeland, Stine
A2 - Braarud, Henny Cathrine
PB - fib. The International Federation for Structural Concrete
T2 - 6th fib International Congress on Concrete Innovation for Sustainability, 2022
Y2 - 12 June 2022 through 16 June 2022
ER -