Title:
High-Strength Headed Bars in Joints of Special Moment Frames under Cyclic Loading
Author(s):
H.-J. Lee, F.-C. Yu, K.-C. Lin, J.-C. Wang, B. L. Worsfold, and J. F. Silva
Publication:
Structural Journal
Volume:
121
Issue:
6
Appears on pages(s):
105-120
Keywords:
anchorage; beam-column joint; development length; headed bars; high-strength reinforcement; joint shear; reversed cyclic loading
DOI:
10.14359/51740866
Date:
11/1/2024
Abstract:
This paper presents cyclic test results of nine beam-column joints,
fabricated with Grades 60, 80, and 100 (Grades 420, 550, and
690) No. 11 (D36) headed bars in joints with matching concrete
strengths. With the exception of the joint shear determination, each
specimen was designed in accordance with ACI 318-14 provisions
for special moment frame joints. The headed bar embedment length
was determined using 1.0fy in accordance with ACI 318-14, rather
than the ACI 318-19 requirement to use 1.25fy to calculate the
development length. Test results demonstrate that the ACI 318-14
development length can be used for closely spaced high-strength
No. 11 (D36) headed bars in joints with Code-conforming transverse
reinforcement. This paper also aggregates the test data with
prior research and compares the data with descriptive equations
and breakout methodology for assessing the development length
and anchorage strength of headed bars. The results support several
design recommendations for the ACI 318 provisions.