Introduction to Bolts as Shear Connectors in Concrete-Filled Steel Columns
Overview
In concrete-filled steel tube (CFST) columns, shear connectors are crucial for ensuring composite action between the steel tube and the enclosed concrete core. Bolts are increasingly used as shear connectors due to their ease of installation, adjustability, and effectiveness in transferring shear forces
Role of Shear Connectors
Shear connectors prevent slip and separation between the steel tube and concrete under axial, bending, and shear loads. They enhance
Load transfer (shear and longitudinal forces)
Ductility and stiffness of the composite column
Bond strength (supplementing natural adhesion/friction)
In this example, the bolts, concrete, and steel column are modeled as three-dimensional solid parts. You can see a figure of the assembled parts below
Bolts as Shear Connectors
Types of Bolts Used
Head studs (welded or bolt-on)
High-strength bolts
Blind bolts (for hollow sections where only one side is accessible)
Post-installed adhesive bolts (for retrofitting)
Advantages Over Other Connectors
Ease of installation (no welding required in many cases)
Adjustable positioning (can be placed post-concrete pouring in some designs)
Better fatigue resistance compared to welded studs
Suitable for thick-walled tubes where welding is difficult
Design Considerations
Shear capacity: Depends on bolt material, diameter, and embedment depth
Spacing & arrangement: Typically staggered or in rows to prevent concrete cracking
Concrete confinement: Bolt heads/anchors enhance mechanical interlock
Failure modes: Bolt shear, concrete crushing, or pull-out failure must be checked
Applications
Bridge piers
High-rise building columns
Seismic-resistant structures (bolts improve energy dissipation)
Bolts offer a practical and efficient solution for shear connection in CFST columns, particularly where welding is impractical. Proper design ensures optimal composite behavior, enhancing the column’s strength and durability
After the simulation, all results are available. You can see some figures for the results below