Clip Angle vs End Plate Connections

A clip angle connection uses one or two angles (usually a pair — the "double angle" connection) bolted or welded between the beam web and the supporting member. An end plate connection uses a flat plate shop-welded across the end of the beam, then field-bolted to the support. Both are simple shear connections doing the same structural job; the practical difference for a fabricator is that clip angles are mostly bolting labor with more pieces and more bolts, while end plates trade bolts for shop welding and demand tighter beam-length tolerance.

If you price connections as a flat percentage of tonnage, the difference barely registers. If you price them per connection — which you should on anything connection-heavy — a double angle typically runs $5–15 more in material and hardware than a comparable shear end plate, but the end plate carries more shop weld time. Which one wins depends on your shop's bolt-vs-weld economics.

How each connection appears on structural drawings

You will rarely see the words "clip angle" or "end plate" called out on a framing plan. Both hide in the typical details and the general notes, which is exactly why they get missed in takeoffs.

Clip angles (double angles) show up as:

A typical detail showing two angles back-to-back on either side of a beam web, called out like 2L4X3-1/2X3/8 X 0'-8 1/2" or 2-L4X3X5/16
Schedule tables titled "TYPICAL BEAM CONNECTION SCHEDULE" listing angle size and bolt rows by beam depth
Section cuts at beam-to-column and beam-to-girder joints where you can see the angle legs straddling the web
On older drawings, the note "std. double angle conn. per AISC" with no size at all — the detailer picks it

End plates show up as:

A plate callout across the beam end in section: PL 3/8 X 6 X 0'-11 1/2" with a weld symbol (usually fillet welds both sides of the web)
The phrase "shear end plate" or "flexible end plate" (the UK/EN term) in typical details
Bolt gauge and pitch dimensions on the plate face rather than through the beam web — with an end plate, no bolts pass through the beam itself

One trap: a full-depth extended end plate with bolts above and below the flanges is a moment connection, not a shear connection, and it prices completely differently — thicker plate, more bolts, often stiffeners. If the plate extends past the flanges, stop and check. The steel connection types guide covers how to sort shear from moment connections quickly.

Also don't confuse the end plate with a single shear plate (shear tab), which is welded to the support and bolted through the beam web. Similar-looking detail, opposite welding location, different erection sequence — the shear tab guide walks through that one.

Typical clip angle sizes and end plate thicknesses

Clip angles cluster in a narrow band of the angle catalog. A 4" leg gives you room for a standard bolt gauge on the outstanding leg; 5/16" and 3/8" thicknesses cover most beam reactions in ordinary framing. These are the AISC sizes you will see over and over, with catalog weights:

| Angle (AISC) | Weight (lb/ft) | Weight per pair, 8 1/2" long (lb) | Typical use | |---|---|---|---| | L3X3X1/4 | 4.9 | 6.9 | Light infill beams, W8–W10 | | L3X3X5/16 | 6.1 | 8.6 | W10–W12, low reactions | | L4X3X5/16 | 7.2 | 10.2 | W12–W14 standard | | L4X3X3/8 | 8.5 | 12.0 | W14–W16 | | L4X3-1/2X3/8 | 9.1 | 12.9 | W16–W18, the workhorse | | L4X4X3/8 | 9.8 | 13.9 | Heavier reactions, wider gauge | | L5X3-1/2X3/8 | 10.4 | 14.7 | Deep beams, 4+ bolt rows (longer than 8 1/2") |

Angle length follows bolt rows: figure roughly 3" per row plus edge distances, so a 2-row angle is about 5 1/2"–6", 3-row about 8 1/2"–9", 4-row about 11 1/2"–12". On metric jobs the same connection shows up as paired EN angles — L 80x80x8 (9.6 kg/m), L 90x90x8 (10.9 kg/m), and L 100x100x10 (15.0 kg/m) are the common picks, and BS 4-part designations map to the same sizes. A fuller size reference is in the steel angle sizes chart.

Shear end plates are simpler to summarize:

| Beam depth | Typical plate | Approx. plate weight (lb) | |---|---|---| | W8–W12 | PL 1/4 X 5 X 0'-6" to 0'-9" | 2–3 | | W12–W16 | PL 5/16 X 6 X 0'-9" to 0'-12" | 5–8 | | W16–W21 | PL 3/8 X 6 X 0'-12" to 0'-15" | 8–12 | | W21–W27 | PL 3/8–1/2 X 7 X 0'-15" to 0'-21" | 12–22 |

The plate is partial-depth for shear connections — usually about 55–75% of the beam depth. Full-depth or extended means look again (see the moment-connection trap above).

Cost comparison: material, bolts, and welding labor

Here is a worked example for one beam end on a W16X26 with a 3-row connection, using typical 2026 hardware pricing (A325 3/4" bolt assemblies at $2.50–2.85 each depending on length):

| Cost item | Double angle (all-bolted) | Shear end plate | |---|---|---| | Steel | 2L4X3-1/2X3/8 X 8 1/2" = 12.9 lb ≈ $9.00 | PL 3/8 X 6 X 12" = 7.7 lb ≈ $5.40 | | Bolts | 3 through web + 6 to support = 9 × $2.65 ≈ $23.85 | 6 to support = 6 × $2.65 ≈ $15.90 | | Shop labor | Punch/drill 4 pieces, bolt angles to beam: ~0.4–0.6 hr | Fit + fillet weld both sides of web (~24" of 1/4" fillet): ~0.5–0.8 hr | | Field labor | 6 field bolts | 6 field bolts | | Direct cost @ $85/hr shop | ~$67–84 | ~$64–89 |

Per connection, it is close to a wash on direct cost — which surprises people who assume "more bolts = more expensive." The real differences show up at scale:

Bolt count. The all-bolted double angle uses 50% more bolts. On a 400-connection job that is 1,200 extra bolt assemblies, roughly $3,200 in hardware plus the shop and field time to install them. Shops that shop-weld the angles to the web instead of bolting claw most of that back.
Weld exposure. The end plate puts every connection through the weld shop. If your welding is the bottleneck (or your weld rate is $95/hr while your fitting rate is $75/hr), double angles pencil out better. If you run an efficient weld line, end plates do.
Tolerance risk. An end plate beam must be cut to length within about 2 mm (1/16")— the plate is flush against the support, and there is no slack. Double angles forgive a short beam because the angles can shim and slot. Reject-and-recut costs on end plate jobs are a real line item; experienced shops add margin for it.
Erection. Double angles on a beam-to-girder joint can be knifed in and hung on one bolt fast. End plates need the beam swung in square. Erectors generally price them similarly, but tight multi-beam joints favor angles.

For where connection costs sit in the context of a full bid — including moment connections and braced-frame gussets that dwarf both of these — see how much steel connections cost.

When engineers choose each — and what it means for your bid

Double angles dominate US practice for beam-to-girder connections and heavier shear reactions. They carry more load than a shear tab of the same depth, handle coped beams well, and every US detailer has the AISC tables memorized. Expect them on: industrial platforms, mezzanines, older-vintage details, and anywhere the EOR wrote "double angle per AISC Manual."

End plates dominate UK, European, and Australian practice — the "flexible end plate" is the default simple connection in BS/EN detailing culture. In the US you see them on: metal building frames (bolted end plate splices and knees are the PEB standard), beams framing to HSS columns (you cannot reach inside a tube to bolt an angle, so you weld a plate and bolt from outside), and jobs detailed offshore by teams with EN habits.

For your bid, the flag to watch is who detailed it and where the columns are hollow. A US drawing set full of HSS columns will quietly shift dozens of connections from angles to end plates or through-plates, moving cost from your bolt budget to your weld budget. Price the weld hours, not just the piece count.

Takeoff tips: counting angles and plates accurately

Connection material is where manual takeoffs bleed. The members are on the plan; the angles and plates are in details, schedules, and general notes, multiplied by a per-end count nobody wrote down. A repeatable process:

Count beam ends, not connections. Every beam has two ends; each end gets one connection. 60 infill beams = 120 connection sets. Work from the framing plan and let the count drive quantities.
Multiply angles by two. A "double angle" callout is two physical angles. 2L4X3X3/8 X 0'-8 1/2" per end, 120 ends = 240 angles, ~1,450 lb of material that appears nowhere in the member schedule.
Pull bolt counts from the connection schedule, not intuition. 3 rows on a double angle is 9 bolts per end if field-bolted both sides, 6 if shop-welded to the web. That assumption alone swings hardware cost 50%.
Take off weld inches for end plates. Two fillet passes down the web depth per plate. 120 ends × 24" = 240 ft of 1/4" fillet — that is real shop hours, not a rounding error.
Read the general notes last. "All connections not otherwise detailed shall be double angle connections per AISC Table 10-1" is a sentence that adds thousands of dollars of material to a job with zero connection details drawn.

This is also a place where software has caught up. SteelFlo detects connection callouts — angle designations, plate callouts, bolt patterns — directly from the drawing set alongside the members, with 95–99% accuracy when paired with your review, so the 2L4X3X3/8 buried in a typical detail lands in your BOM instead of your contingency.

Run your next connection-heavy job through a free takeoff

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