Designing a splice

ILX designs two kinds of splice:

• Beam shear splice. One or two plates join the webs of two beams at a point of contraflexure and carry the shear across the gap. Each side is bolted or welded.
• Compression splice. Flange plates on the outside of both flanges join two wide-flange members. Use it for a truss chord or strut, or for a column. The ends can be finished to bear or not.

Both editors work like the single-plate editor (see Designing a single-plate connection):

• the design reruns live;
• the status bar shows OK, NG or GEOMETRY NOT FEASIBLE;
• clicking a part in the drawing opens its fields;
• the Checks and Compliance tabs explain every result.

To start one, choose New connection and pick Beam shear splice or Compression splice (chord / column) in the first wizard step.

Beam shear splice #

Configuration #

Loads on the shear splice #

Enter the shear across the splice and, if there is one, the axial force (+ tension). You can enter it in any of these forms:

• service dead and live loads
• a required strength
• ASCE 7 combinations
• your own load cases

The splice is assumed to sit at a point of contraflexure, so the moment at the splice centerline is zero.

Each side #

A bolted side has:

• Bolt rows (shared by both sides), spacing s and the plate's vertical edge distance Lev;
• the number of bolt columns and their gage;
• Centerline to first bolt column. The beam-end edge distance is this value minus half the gap.
• Plate edge distance beyond the last column.

A welded side has:

• the lap of the plate on the web, measured from the beam end;
• the weld size;
• the weld shape: C-shape, vertical only, or top and bottom.

The welds start at the beam end.

Eccentricity #

The shear does not pass through either connection, so each side is designed for a moment V × e. Eccentricity carried by sets how that moment is shared:

The plate is checked for flexure with the largest of these moments, as both AISC examples do.

What the shear splice checks #

Copes #

Turn on a top and/or bottom cope and choose which beam ends are coped (Coped beams: both, A or B). The cope length is measured from the beam end.

The coped-beam moment is taken from the cope face to the line of action of the shear. That line of action is never taken closer to the beam than the splice centerline.

Geometry not feasible #

The design is marked NOT FEASIBLE when any of these hold:

• the beam ends touch;
• the plate runs into the flange fillets or a cope;
• a bolt lies off the plate or the web;
• holes overlap;
• a cope removes the whole web;
• a weld has no web to sit on.

The message names the fix.

Compression splice (column or chord) #

Splice type #

Loads on the compression splice #

Enter the axial force (+ tension) and the moment about the major axis at the splice, in one of these forms:

• service dead and live loads
• a required strength
• load cases

Each flange carries F = P/2 ± M/d, where d is the shallower member's depth.

For a column finished to bear:

• the plates are designed for the net flange tension from the load cases. A dead load that offsets the moment tension is taken into account.
• turn on Structural integrity and enter the nominal D + L tributary to the column below this splice to check AISC 360 B3.9(a). That check uses nominal strengths only.
• choose a Seismic column splice for a column of a seismic force-resisting system (AISC 341-22):
  • SFRS column: D2.5. Enter the loads of the overstrength seismic load where they govern (D2.5b(a)). With the distance to the beam flange connection ILX checks the 4 ft rule of D2.5a (a clear height under 8 ft puts the splice at half of it). With the story height H the report gives the D2.5c shear Mpc / (αs H) about both axes. The flange plates carry no shear: splice the web with plates on both sides (D2.5d).
  • Braced frame (SCBF, EBF, BRBF; F2.6d, F3.6d, F4.6d) adds a load case M = 0.5 Mp / αs of the smaller member with P = 0, and the shear Σ Mp / (αs Hc) with the clear height Hc.
  • Special moment frame (E3.6g.5, bolted splices) adds a load case M = Ry Fy Zx / αs of the smaller column (Ry from Table A3.2) and the web splice shear Σ Mpc / (αs Hc).
  • Every seismic splice checks the D2.2 bolted-joint rules: standard holes or short slots across the load, and pretensioned bolts with Class A (or better) faying surfaces.

For a chord finished to bear:

• enter the member length and the splice location;
• the flange plates are designed for the lesser of 50% of the compression as tension and the moment from a transverse load of 2% of the compression at the splice, with the member pinned (AISC 360 J1.4(b));
• the transverse shear is reported. Web splice plates are not designed.

Flange plates and bolts #

What the compression splice checks #

AISC Manual Table 14-3 gives standard column splice details. Use them as the minimum for ordinary gravity columns.

Verification of the splice examples #

Both splice types reproduce the AISC Design Examples end to end, in LRFD and ASD:

• II.A-20, the all-bolted shear splice;
• II.A-21, the bolted and welded shear splice;
• II.C-3, each member-to-plate joint of the heavy wide-flange compression connection.

The comparison tables and the documented differences are on the Verification page (see Verification).

• II.A-21 weld length: AISC measures the short welds from the splice centerline; ILX uses the weld that can actually be placed, measured from the beam end. This is conservative, and with AISC's idealization ILX reproduces every published value.
• II.C-3 gusset shear: the shear yielding and rupture of the gusset plates along the chord (l = 32 in., 5 holes) and along the vertical (l = 31¾ in., 7 holes) are reproduced with the gusset section inputs. For the vertical, ILX gives 514 kips where the example prints 515, because the example rounds the net area.