Box Column to H-Beam Rigid Connections: The Joint That Makes Frames Rigid

Rigid beam-column connections make steel frames act as one rigid system, transferring moment between beams and columns. Below is data from an actual box column to H-beam moment connection.

Basic Specs

Column Schedule

How It Works

The rigid joint transfers moment three ways:

• Beam flange welded: beam top and bottom flanges groove-welded to column face
• Web bolted: beam web bolted to shear tab on column
• Column stiffener inside: horizontal through stiffener matches beam flange
• Cover plates: thickened plates at beam flanges for moment transfer

Advantages

1. Rigid frame action — moment connection makes frame sway-resistant
2. No bracing needed — rigid frames don't need diagonal bracing
3. Box column strong — rectangular tube column resists biaxial bending
4. Shop-welded, site-bolted — flange welded in shop, web bolted on site
5. Stiffener aligned — internal stiffener matches beam flange, no local deformation

Disadvantages / Limitations

1. Weld inspection critical — flange groove welds must pass ultrasonic test
2. Field bolted only web — web bolts carry shear, not moment
3. Box column fabrication — internal stiffeners need welding access inside box
4. Precise alignment needed — beam must align exactly with stiffener
5. More steel weight — stiffeners and cover plates add weight

Typical Applications

1. Steel frame buildings — office and commercial steel frames
2. High-rise steel structures — moment-resisting frames for tall buildings
3. Seismic zones — rigid frames for earthquake resistance
4. Industrial plants — heavy crane buildings with moment frames
5. Parking garages — moment-resisting steel parking structures

Fabrication Notes

• Box columns shop-welded, internal stiffeners inserted during fabrication
• Beam flanges groove-welded to column in shop, web bolted on site
• Cover plates welded at beam flanges for moment transfer
• All welds Grade 2 or better, ultrasonic tested

Box column to H-beam rigid connection — box columns 300×300 to 500×400, Q355B, beam flanges welded with cover plates, web bolted, internal through stiffener, moment-resisting joint for steel frame buildings.

**WhatsApp**: +86‑13889862778, +86‑18242444407
**Email**: eddie@zdsteels.com, wells@zdsteels.com