What a beam cope is, and why the drawing calls for one

A cope is a notch cut into the end of a steel beam, removing part or all of the top flange, the bottom flange, or both, so the beam can slide past the flange of whatever it frames into. A beam that connects to the web of a girder, rather than sitting on top of it, has to bring its own flanges into the space the girder's flanges already occupy, and without a cope those flanges would collide with the girder before the beam's web ever reached the connection. The cope cuts away exactly what is in the way and nothing more.

Why the flange is the problem in the first place

A beam framing flush into the side of a girder, same top-of-steel elevation, has to fit its web against the girder's web, usually through a shear tab or a pair of angles. The girder's own flanges, top and bottom, project out from its web and sit in the path the beam's flanges would otherwise occupy. On a W16x26 beam meeting a W21x44 girder with tops flush, for instance, the girder's 6.5-inch top flange stands out about 3 inches on each side of its web, right where the beam's top flange would land. The W16x26 is 15.7 inches deep, shallower than the roughly 18 3/8 inches of flat web between the W21x44's flange fillets, so its bottom flange clears and only the top needs a cope. The cope removes the beam's flange, and the web material directly behind it, for a short length back from the end, clearing the girder's flange so the connection can go together.

What a cope detail actually specifies

A cope callout on a shop drawing gives a length, a depth, and a corner radius: how far back from the end the cut runs, how deep it cuts down from the top (or up from the bottom) of the flange, and the radius left at the inside corner where the cut turns. All three numbers answer to something real. The length has to clear the supporting member's flange plus whatever erection tolerance the job allows. The depth is set by the supporting member's flange thickness and the fillet where that flange meets its web, plus a little clearance, since cutting away more web than necessary weakens the end of the beam for no reason. The radius exists because a square inside corner concentrates stress at exactly the point a coped beam is already working hardest, and a tight or absent radius there is a known starting point for a crack.

A cope is not a bevel, and it is not a notch for a weld

It is worth separating a cope from two things it resembles on a drawing but is not. A bevel, cut along the edge of a plate for a groove weld, opens an angle so a weld can penetrate to the root; it removes a sliver of material along one face, not a rectangular block at a beam end. A weld access hole, sometimes called a rat hole, is a small cutout near a beam's flange-to-web junction that lets a weld electrode or backing bar reach a joint it could not otherwise reach; it serves a welding procedure, not a clearance problem between two framing members. A cope solves neither of those problems. It exists because two pieces of steel, both the width the engineer specified, would otherwise occupy the same physical space.

Who decides a beam needs one

The cope itself is a detailing decision, drawn by the fabricator's detailer from the connection the engineer of record designed, not something a crew improvises at the saw. The engineer sets the framing, the member sizes, and the connection type; the detailer works out that a W16x26 into a W21x44 at this elevation needs a cope of this length and depth to physically go together, and that detail goes back through the shop drawing review before anything gets cut. A beam that shows up on the erection drawings flush with the top of a girder, with no cope noted and no clearance shown, is either framed to bear on top rather than into the side, or it is a drawing that needs an RFI before the saw runs.

What this note does not cover

This note explains what a cope is and why a beam end gets one, as a definition, not a procedure. It does not cover how the cope gets cut, checked, or signed off at the bench, where the length, depth, and radius get verified against the detail with a tape, a square, and a radius gauge before the piece ships; that bench check is its own note on this site. It does not cover the connection design itself, the angles, bolts, or shear tab that actually transfer the load once the cope lets the pieces meet, which remains the engineer of record's work. It does not cover a cope's effect on a beam's shear capacity at the coped section, a strength check, block shear among others, that belongs to the engineer's design, not the shop floor.

What to do with this on your own job

If a set of erection drawings shows a beam framing into the side of a girder or column with no cope detail anywhere on the sheet, that is worth an RFI before the beam gets cut, not an assumption that the shop will figure it out. A cope missing from the drawings is a beam that does not fit the day it arrives on site.