Title:
Effect of High Axial Load on Cyclic Response of Exterior Beam-Column Joints with High-Strength Reinforcement
Author(s):
Hung-Jen Lee, Fu-Chi Yu, and Ker-Chun Lin
Publication:
Structural Journal
Volume:
122
Issue:
3
Appears on pages(s):
161-172
Keywords:
axial load; beam-column joint; confinement; high-strength reinforcement; joint shear; reversed cyclic loading
DOI:
10.14359/51745667
Date:
5/1/2025
Abstract:
This paper investigates the seismic performance of exterior beamcolumn
joints in special moment frames (SMFs) with varying axial
load ratios. Cyclic testing of four additional specimens with an
axial load ratio of 0.45 is compared with four companion specimens
at 0.10. Each specimen was designed and constructed with
Grades 60, 80, or 100 (No. 420, 550, or 690) reinforcement in
accordance with ACI 318-19 provisions for special moment frame
joints, except for the provisions of joint shear and confinement.
While ACI 318-19 tightens confinement requirements for SMF
columns and joints, especially under high axial loads, this study
reveals that increasing the axial load ratio benefits joint behavior.
The study also demonstrates the feasibility of using high-strength
reinforcement in exterior beam-column joints of SMFs, provided
that appropriate modifications are made. The findings in this study
have influenced modifications from ACI 318-19 to the Building
Code Requirements for Concrete Structures in Taiwan.