Title:
Development of Large High-Strength Headed Reinforcing Bars (Prepublished)
Author(s):
Ali Banaeipour, David Darwin, Matt O’Reilly, and Andrés Lepage
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
anchorage; beam-column joint; bond, development length; headed bar; high-strength concrete; high-strength steel; large-scale testing
DOI:
10.14359/51744381
Date:
11/22/2024
Abstract:
The ACI 318-19 Building Code does not allow the use of headed bars larger than No. 11 (No. 36) due to insufficient experimental data. Thirty large-scale simulated beam-column joint specimens containing high-strength No. 11 (No. 36), No. 14 (No. 43), or No. 18 (No. 57) headed bars were tested to investigate the effects on anchorage strength of key factors, including bar stress at failure, bar size, bar spacing, embedment length, transverse reinforcement, concrete compressive strength, and loading condition. Specimens exhibited concrete breakout, side splitting, or a combination, with four exhibiting a shear-like failure. Anchorage of larger bars is noticeably influenced by joint shear demand and loading conditions. Descriptive equations developed based on 164 tests, accurately characterize anchorage strength for headed bars up to No. 18 (No. 57). They indicate that anchorage strength is proportional to concrete compressive strength to a power close to 0.2 and that the contribution of parallel ties for large headed bars is lower than that observed for smaller headed bars.