International Concrete Abstracts Portal

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:

Issue:

Appears on pages(s):

Keywords: axial restraint; coupling beams; deformation; diagonal; stiffness; strength

DOI: 10.14359/51744395

Date: 12/6/2024

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 reverse 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 0.13E_cI_g and 0.41G_cA_g, respectively, for all tested specimens.