Title:
Normal and High Strength Continuously Wound Ties
Author(s):
Malory R. Gooding, Elizabeth A. Mosier, Bahram M. Shahrooz
Publication:
CRC
Volume:
Issue:
Appears on pages(s):
82
Keywords:
DOI:
Date:
1/1/2022
Abstract:
Advancements in steel reinforcement bending machines have allowed for the fabrication of continuously wound ties (CWTs), which are constructed from a single piece of reinforcement. CWTs are being used in place of conventional transverse reinforcement in concrete compression members to reduce waste and speed the construction process. CWTs are also expected to enhance the performance of special seismic compression members (a) due to anticipated improved confinement of the compressed concrete core and (b) because most legs of CWTs do not rely on hooks for development. Special boundary elements (SBEs) of structural walls are an example of a member that can benefit from the use of CWTs. A total of twenty reduced scale SBEs were fabricated and subjected to uniaxial, monotonically increasing axial compression to evaluate the performance of members reinforced with CWTs. All the specimens reached and exceeded axial compressive strength capacity calculated using the measured material properties and ignoring the reduction factor of 0.80 that accounts for unintended eccentricity. The specimens confined with CWTs exhibited improved post-peak ductility in comparison to those employing conventional ties. However, all the current ACI requirements for transverse reinforcement must be satisfied to take full advantage of enhanced post-peak ductility offered by CWTs. Post-peak ductility was found to be further enhanced by utilizing Gr. 80 CWTs in conjunction with 10 ksi concrete.