Title:
Torsion Experiment and Cracking-Torque Formulas of Prestressed Concrete Beams
Author(s):
Chyuan-Hwan Jeng and Min Chao
Publication:
Structural Journal
Volume:
115
Issue:
5
Appears on pages(s):
1267-1278
Keywords:
angle of twist; beam; cracking; formula; prestressed concrete; small deformation measurement; softened membrane model; torsion
DOI:
10.14359/51702373
Date:
9/1/2018
Abstract:
Previous torsion experiments on prestressed concrete (PC) beams have various limitations. A new experimental project was therefore conducted to test seven PC beam specimens under pure torsion. This new torsion test of PC beams achieved accurate measurement of small twists before and around cracking, and improved other aspects, including precise measurement of prestressing forces and prestress transfer. The test also enabled assessment of relatively large specimens with medium to high prestress levels and high concrete strengths. Experimental results from seven specimens are presented in this paper. The experimental values of cracking torque Tcr for the seven specimens, and for another 12 specimens from a previous experiment, are compared with the Tcr values calculated using a recently developed rational formula for reinforced concrete. Using these comparisons, a new Tcr formula for PC beams with concentrated or distributed tendons is proposed, which accurately predicts the cracking torques of the 19 specimens.