A New Smoothing Technique for Transfer-Length Determination

ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

  


Title: A New Smoothing Technique for Transfer-Length Determination

Author(s): A. T. Ramirez-Garcia, C. N. Dang, R. A. Deschenes Jr., W. M. Hale, and J. R. Martí-Vargas

Publication: Structural Journal

Volume: 115

Issue: 6

Appears on pages(s): 1551-1561

Keywords: prestressing strand; pretensioned concrete; smoothing technique; transfer length

Date: 11/1/2018

Abstract:
Transfer length is a significant parameter in the design of pretensioned concrete members. This study reports the measured transfer length of 15.2 mm (0.6 in.) prestressing strands. Twenty-four pretensioned concrete beams were cast using conventional concrete. The compressive strength at release ranged from 27 to 65 MPa (4000 to 9500 psi). Transfer lengths were determined by measuring concrete surface strains and using the average maximum strain (AMS) method. A new technique was developed to smooth the measured concrete surface strains. The measured transfer lengths were compared to the predicted transfer lengths using ACI 318-14 and AASHTO-LRFD equations. The results indicate that the proposed smoothing technique provides better results than the current three point moving average technique. The current code equations are conservative to predict transfer length for pretensioned concrete members having concrete compressive strength at release greater than 27 MPa (4000 psi).