Title:
Cyclic Responses of Axially Restrained Diagonally Reinforced Coupling Beams
Author(s):
Min-Yuan Cheng, Ren-Jie Tsai, Jui-Cheng Hung, and Richard S. Henry
Publication:
Structural Journal
Volume:
122
Issue:
3
Appears on pages(s):
105-117
Keywords:
axial restraint; coupling beams; deformation; diagonal; stiffness; strength
DOI:
10.14359/51744395
Date:
5/1/2025
Abstract:
This research aims to investigate cyclic responses of axially
restrained diagonally reinforced coupling beams, where the applied
axial force was proportional to the beam axial elongation. Six
diagonally reinforced concrete coupling beams with an aspect ratio
of 2.0 were tested under reversed cyclic displacements. The key
test parameters included the magnitude of axial restraint and shear
stress demand. The test results showed that the specimen deformations
were primarily attributed to the beam end rotation. Specimen
peak strength, which increased as the axial restraint was applied,
can be reasonably estimated using probable flexural strength at
the beam ends where the axial restraint force was considered. All
specimens exhibited a minimum of 6.0% chord rotation prior to
failure, and the failure mechanism was associated with the damage
at beam ends and reinforcement anchorage. The ultimate chord
rotation capacity, shear rigidity, and flexural rigidity of the specimens
were found to be insensitive to both shear stress demand
and the magnitude of axial restraint. Axially restrained specimens
showed significantly reduced axial elongation compared to those
without axial restraint. The axial elongation of specimens without
axial restraint can be adequately estimated using existing models.
Analysis indicated an average flexural and shear rigidity of
0.13EcIg and 0.41GcAg, respectively, for all tested specimens.
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