Title: Rectangular Spiral Binders Effect on Plastic Hinge Rotation Capacity in Reinforced Concrete Beams

Author(s): Edward G. Nawy, Rodolfo F. Danesi, and John J. Grosko-

Publication: Journal Proceedings

Volume: 65

Issue: 12

Appears on pages(s): 1001-1010

Keywords:

DOI: 10.14359/7532

Date: 12/1/1968

Abstract:
Limit design of concrete indeterminate structures is based on rotation compatibility of the plastic hinges. Improved rotation capacity of the hinges permits better redistribution of moments and higher reserve strength of structural systems. This investigation deals with the use of rectangular spiral binders for confining the concrete in beams to increase the rotation capacity of the plastic hinge. These spirals serve simultaneously as diagonal tension rein-forcement. Two series were tested: tension hinges in beams 84 in. (2.1 m) span subjected to transverse load only, and compression hinges in beams 80 in. (2.0 m) span subjected to both transverse and axial load. It is found that rectangular spirals are very effective in increasing the rotation capacity of tension and compression plastic hinges. A possible maximum effective percentage by volume of rectangular spirals for p'' seems to be about 3.0 percent for tension hinges and slightly more than 2.0 percent for compression hinges.