Title:
Behavior of Exterior Beam-Column Connections with Headed Bars under Non-Reversible Cyclic Loading (Prepublished)
Author(s):
Gustavo J. Parra-Montesinos and Jacob Zeuske
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
anchorage; bar groups; breakout strength; development length; shear; joints
DOI:
10.14359/51746793
Date:
4/25/2025
Abstract:
Two large-scale beam-column connections with beam longitudinal headed bars were tested to evaluate their susceptibility to breakout failures. The specimens were designed following the strength and transverse reinforcement detailing provisions in Chapter 15 of ACI 318-19. The variable investigated was the headed bar embedment length, which was determined based on either Chapter 25 of ACI 318-19 or recent research at the University of Kansas, the latter leading to a 22% shorter embedment length. Both specimens exhibited beam flexural yielding, but the specimen with shorter bar embedment length experienced significantly more connection damage followed by a concrete breakout failure. Based on the limited test results, it is recommended that nominal joint shear strength be calculated based on a joint effective depth equal to the headed bar embedment length and a shear stress of 1.0λ√(fc' ) (MPa) [12λ√(fc' ) (psi)]. A method for calculating headed bar group anchorage strength in exterior beam-column connections is proposed, which led to reasonable and conservative strength estimates in the test specimens.