Authors: Fayez Moutassem; Mohammad I. Hossain
Addresses: Department of Civil and Infrastructure Engineering, American University of Ras Al Khaimah, Ras Al Khaimah, P.O. Box 10021, United Arab Emirates ' Department of Civil Engineering and Construction, Bradley University, 1501 W Bradley Ave, Peoria, Illinois 61625, USA
Abstract: High strength concrete (HSC) is regularly used in precast prestressed concrete structures. The allowable tensile stresses in various codes do not account for high early strength HSC exceeding 10,000 psi (69 MPa). In this study, design equations are developed for the tensile stress limits at the time of initial prestress and at service. An experimental program is developed and it involved the use of mineral admixtures and subjecting fresh concrete to 24 hours of accelerated heat curing to mimic actual field conditions. Comparison between various design codes (ACI 318, AASHTO, and LRFD) has revealed that all the code equations significantly underestimated the allowable tensile stresses at service and are therefore too conservative. The proposed tensile stress limits would ensure a more economical design of high strength prestressed concrete members.
Keywords: concrete; high-strength; prestressed; precast; compression; flexure; allowable stresses; heat-curing; tensile limits.
International Journal of Structural Engineering, 2022 Vol.12 No.1, pp.31 - 43
Accepted: 09 Jan 2021
Published online: 30 Nov 2021 *