Influence of axial compression on the bearing behavior of high-strength reinforced concrete column and steel beam (New-RCS) joint
Journal
Engineering Structures
Journal Volume
345
Start Page
121447
ISSN
01410296
Date Issued
2025-12-15
Author(s)
Abstract
The study investigated the influence of axial compressive load on the bearing behavior of high-strength reinforced concrete column and steel beam (New-RCS) joint through experimental and analytical approaches. Two large-scale exterior beam-column joint specimens were tested to realistically capture joint mechanics under seismic loading. The specimens used high-strength SD690 reinforcement and 70 MPa concrete. The variable parameter was the normalized axial compression force in the column (10 % and 50 %). These values correspond approximately to the lower and upper bounds of practical gravity-load levels in columns of moment-frame buildings. The specimen under 50 % axial compression showed slightly higher joint bearing strength. An analytical model was developed to explicitly account for the influence of axial compression. The model indicated that joint bearing strength increases up to about 40 % normalized axial load, then decreases, consistent with experimental results. Both the proposed analytical model and the American Society for Civil Engineers (ASCE) pre-standard provisions offered reliable estimates of joint bearing strength within the axial load range (10–60 %) of practical interest. However, caution is needed at very low axial loads (<10 %), where ASCE provisions may be unconservative, as supported by past studies and the present model. Finally, the Taiwan New-RC draft’s minimum joint depth provisions effectively prevented rebar slippage. In contrast, the ASCE pre-standard may require impractically large joint depths because it does not fully account for bonding behavior in high-strength concrete.
Subjects
Beam-column joint
Bond behavior
Composite structures
High-strength reinforcement
Hybrid joint
Joint strength
Minimum joint depth requirement
Reinforced concrete column and steel beam system (RCS)
SDGs
Publisher
Elsevier Ltd
Type
journal article