A beam to beam connection in steel framing usually means a smaller beam framing into the web of a larger beam (the girder) with a bolted shear connection, such as a single plate shear tab or a pair of clip angles. To keep both top flanges at the same level, the smaller beam’s top flange is cut back, which is called a cope.
That one detail shows up on almost every steel floor and roof. This guide covers the connection types, why and how beams are coped, a worked example with real AISC dimensions, and what happens during erection.
Beam, Girder and Where They Meet
In a typical steel floor, girders run between columns and beams run between girders. The beams carry the deck and pass their reactions to the girders, which pass them to the columns. If the terms are fuzzy, our guide to girder vs beam vs joist sorts them out.
There are two basic ways for a beam to meet a girder:
- Framed (flush): the beam frames into the side of the girder web, and the tops of both are level so the deck sits flat. This is the common case and the subject of most of this article.
- Stacked: the beam sits on top of the girder’s top flange and is bolted down. No cope is needed, but the floor gets deeper and the beam needs to be braced against rolling over at the support.
Simple Shear vs Moment Connections
Most beam to girder connections are simple shear connections. They transfer the vertical reaction and let the beam end rotate a little as it bends, so the girder is not twisted by the beam. The beam is designed as simply supported.
When a beam has to be continuous over a girder, or resist lateral load as part of a frame, the flanges are connected too, and the joint becomes a moment connection. Those are less common at girders, because a girder web is a poor place to resist twisting from a flange force.
Common Types of Beam to Girder Shear Connection
The AISC Steel Construction Manual (Part 10) covers several standard simple shear connections. The ones you will meet most at girders:
| Connection | How it is made | Where it is used |
|---|---|---|
| Single plate (shear tab) | One plate shop-welded to the girder web; beam web bolted to it in the field | Very common; simple shop work and easy erection from one side |
| Double angle (clip angles) | Two angles on either side of the beam web, bolted or welded to the beam and bolted to the girder web | Heavier reactions; symmetrical load path |
| Single angle | One angle on one side of the beam web | Light beams and tight spaces |
| Shear end plate | Plate welded across the beam end, bolted to the girder web | Shop-heavy, needs accurate beam length |
| Seated | Beam rests on an angle seat on the girder, with a top or side angle for stability | Useful for erection, more common at column webs |
Shear tabs and clip angles are usually bolted with high-strength structural bolts. Our guide to bolt grades explains the markings and strength classes you will see on the drawings.
Why Beams Are Coped
When a beam frames into a girder with the tops level, the beam’s top flange runs straight into the girder’s top flange. The beam can only get close to the girder web if the end of its top flange, and a little of its web, is cut away. That notch is a cope.
Bo Dowswell’s paper Local Strength of Single-Coped Beams (AISC Engineering Journal, Fourth Quarter 2018, read October 2026) notes that in beam-to-beam connections the supported beam’s top flange is usually coped to clear the supporting beam’s flange. The paper also explains the cost: the coped part of the web carries bending and shear with no flange to stiffen it, so it can buckle locally. The 15th Edition AISC Manual revised its coped-beam procedure to reflect this, and the engineer has to check the coped section, not just the full beam.
Worked Example: W12x26 Into a W18x50
Here are the dimensions that drive the cope, from the AISC Shapes Database v16.0 (as published on our W12x26 page and W18x50 page, checked October 2026):
| Dimension | W12x26 (beam) | W18x50 (girder) |
|---|---|---|
| Depth, d | 12.2 in | 18.0 in |
| Flange width, bf | 6.49 in | 7.50 in |
| Flange thickness, tf | 0.380 in | 0.570 in |
| Web thickness, tw | 0.230 in | 0.355 in |
| k (design) | 0.680 in | 0.972 in |
Cope depth
With the tops level, the beam’s cope has to drop below the girder’s top flange and the curved fillet where that flange meets the web. That zone is the girder’s k distance, 0.972 in for a W18x50. The detailer rounds the cope depth up from there to a practical fabrication dimension.
Cope length
The cope has to run back past the tip of the girder flange. Half the girder flange, minus half its web, is (7.50 − 0.355) / 2 = 3.57 in from the face of the web to the flange tip. Add a clearance gap and the setback of the beam end from the web, and you have the cope length. The beam end itself stops short of the girder web by a small setback so it can be swung into place.
When both flanges are coped
If the beam is as deep as the girder, for example a W12x26 framing into another W12x26 (both 12.2 in deep), the bottom flanges collide as well. Both flanges are then coped, a double cope, which leaves only a short length of web at the connection. Double-coped beams lose more strength at the end and need their own checks, so engineers often avoid equal-depth framing where they can.
What the Engineer Checks
Sizing a beam to girder connection is a structural design task for a licensed structural engineer. The typical checks include:
- Bolts: shear strength and bearing on the beam web, the tab or angles and the girder web.
- Plates or angles: shear yielding, shear rupture and block shear.
- Welds: the shop weld from the tab or angles to the girder web.
- Coped beam: bending and local buckling of the coped web, plus block shear at the bolt group.
- Girder web: local strength where the reaction enters, especially with beams framing in from both sides.
On many projects the engineer of record lists the reactions and the connection type, and the fabricator’s engineer designs the actual connection. Either way, the reaction comes from the design, not from a rule of thumb, and you cannot read connection capacity from the size of the beam.
Erection: Bolting Up Safely
OSHA’s steel erection standard, 29 CFR 1926.756 Beams and columns (read October 2026), sets two rules that shape these connections:
- At least two bolts per connection before the crane lets go. Solid web members must be secured with at least two bolts per connection, of the size and strength on the erection drawings and drawn up wrench-tight, before the hoisting line is released.
- Double connections. Where two beams frame into opposite sides of a column web or a beam web over a column and share the same bolt holes, at least one bolt with its wrench-tight nut must stay on the first member while the second is fitted, unless a seat or equivalent device holds it.
That second rule is why connections where members share holes are often detailed with staggered bolts or an erection seat. Our guide to structural steel erection covers the rest of the sequence on site.
Common Problems on Site
- Cope too shallow: the beam will not swing into place past the girder flange or fillet.
- Beam too long: the setback was missed and the beam end hits the girder web.
- Holes out of line: field reaming or new holes need the engineer’s approval.
- Field cope added without approval: a cope cut on site changes the beam’s end strength and has to be checked.
- Rough cope corners: re-entrant corners of copes are cut to a radius rather than a sharp notch, because sharp notches start cracks.
Beam to Beam Connection FAQ
What is the most common beam to beam connection?
A simple shear connection with the beam framing into the girder web, usually a single plate shear tab or double clip angles, with the beam’s top flange coped so the tops are level.
What is a coped beam?
A beam with part of a flange and web cut away at the end so it can fit against another member. A single cope removes the top flange; a double cope removes both flanges.
Can I weld a beam directly to another beam?
Field-welded beam connections exist, but they need a designed weld, qualified welders and inspection, and they make erection slower. Shop-welded tabs or angles with field bolts are the usual approach. Do not add welds to an existing connection without an engineer.
Does coping weaken a beam?
It reduces the strength at the beam end, because the web near the cope has no flange to stiffen it. The engineer checks the coped section, and deep or long copes may need a heavier beam or a stiffener.
How many bolts does a beam connection need?
The final number comes from the design reaction. During erection, OSHA requires at least two bolts per connection before the hoisting line is released.
The Short Version
Most beam to beam connections are bolted shear connections into the girder web, with the beam’s top flange coped so both tops are level. The cope depth clears the girder flange and fillet, the cope length clears the flange tip, and equal-depth beams need a double cope. A licensed structural engineer sizes the connection, and erection follows OSHA’s two-bolt rule.
Reference information only, not engineering advice. Disclaimer.