Title:
Redistribution of Internal Forces in Reinforced Concrete Beams Subjected to Combined Load
Author(s):
Jung-Yoon Lee, Na-Yeong Kim, DongIk Shin, Kil-Hee Kim, and Muhammad Haroon
Publication:
Structural Journal
Volume:
120
Issue:
6
Appears on pages(s):
151-165
Keywords:
bending moment; combined load; force redistribution; torsional strength
DOI:
10.14359/51739093
Date:
11/1/2023
Abstract:
In an actual structure, torsion seldom acts alone; rather, a complex
load combination acts together. Members subjected to a complex
loading condition—that is, shear, bending, torsion, and so on—
show lower strength compared to the members under torsion only.
However, when structural members exhibit ductile behavior, the
force-deformation correlation of shear force, bending, and torsional
moment may change due to the redistribution of internal forces. In
this study, the interaction of bending and torsional moments was
evaluated by analyzing the test results of 123 reinforced concrete
(RC) members subjected to combined loading. Additionally, 13 RC
beams subjected to combined actions of bending and torsional
moments were tested to investigate the effect of force redistribution.
The results indicate that the post-yielding behavior of actual
members subjected to combined loading significantly differs from
the theoretically predicted one. This is because the theoretically
induced bending and torsional moment interaction curves are
based on strengths corresponding to the yield point of reinforcement. However, the experimental results show that the force redistribution mechanism develops after the first reinforcement yielding. Consequently, the torsional strength does not decrease as sharply as theoretically assumed, even when the bending moment increases.