Development length of prestressing strands cast in lightweight self-consolidating concrete

Abstract

Abstract This paper investigates the development length of 0.6 in. (15.2\xa0mm) diameter prestressing strands. Fifty flexural tests were conducted on twenty-five pretensioned concrete beam specimens, which had a cross-section of 6.75 in. by 12 in. (170\xa0mm by 305\xa0mm) and were 18 ft (5.5\xa0m) long. The specimens were cast with two normal weight and four lightweight self-consolidating concrete mixtures with compressive strengths of 4000 psi (27.6\xa0MPa) at prestress transfer and 6000 psi (41.4\xa0MPa) at 28-day of age or 6000 psi (41.4\xa0MPa) at prestress transfer and 7000 psi (48.3\xa0MPa) at 28-day of age. The measured development length was approximately half the value predicted using the ACI 318 and AASHTO equations. Shear cracking leading to shear and bond failures at short embedment lengths made determination of the true development length difficult for lightweight specimens, but embedment lengths resulting in pure flexural failure were similar for all specimen types.