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Two basic types of singleplate connections are usedfor “simple framing” (whereconnection end restraint isignored for member design):

single plate shear connections and ex-tended single plate shear connections.The first type is used for beam-to-beamand beam-to-column-flange connec-tions, where the end of the supported

 beam frames close to the face of thesupporting member. The second typeis used for beam-to-beam and beam-to-column-web connections, where theend of the supported beam stops shortof either the flanges of the supporting

 beam or the flanges of the column.

SINGLE PLATE SHEAR

CONNECTIONS

Support Conditions

The behavior of single plate shearconnections is affected by the support

conditions, which are idealized as  being either flexible or rigid. If the beam is supported by an ideal flexiblesupport such as a beam, which is tor-sionally unrestrained, then the beamend rotation is entirely accommodated

 by rotation of the support. However ifthe beam is supported by a fully rigidsupport, such as the flange of a W-shape column, then the welded edge ofthe plate will remain vertical whenloaded by a gravity shear force and ro-tation is accommodated by deforma-

tion within the connection. In the idealflexible connection, the inflection pointis at the face of the supporting mem-

 ber; but in the ideal rigid connectionthe inflection point moves away fromthe inflection point. Since “real” sup-ports seldom behave exactly as flexibleor rigid connections, redundant designprocedures are necessary to provide asafe and efficient design.

New Tables and Concepts

New tables are provided to include

X-bolt capacities for ASD design. The

new ASD tables will also expand to in-clude 9 to 12 rows of bolts for the singlevertical column. These concepts are al-ready provided in the AISC LRFD 3rdEdition Manual.

Tables are presented for both ASDand LRFD single plate connection ca-pacities/strengths utilizing both ASTMA36 plate and A572 GR50 plate.

Design procedures with examplecalculations are presented for extendedsingle plate shear connections to gird-ers and column webs.

General Requirements for

Connecting Plates, Bolts, and

Welds

The connection can have one or twovertical columns of bolts, with two to12 horizontal bolt rows spaced at 3”-vertical pitch spacing. The horizontal

  bolt gage for the double-verticalcolumns of bolts may be 3” or 3 ½ ” as

required to satisfy AISC minimum bolt-spacing requirements for standardholes or horizontal short slotted holes.

The horizontal and vertical bolt-edge distances for the beam web (Lh &Lv) and the shear plate (Edh & Edv)shall be the greater of 1.5 times the boltdiameter or 1-½” in the as-built condi-tion. The horizontal beam-web end-edge distance (Lh) shall exceed thisdimension by ¼” as detailed on shopfabrication drawings.

The horizontal distance from the

face of the support to the first line of bolts shall be a minimum of 2½” to amaximum of 5¼”.

Bolts can have standard holes orshort slots, and can be snug-tight orpretensioned.

Material for the shear plate can beeither A36 or A572 GR50.

Welds for the shear plate to the sup-porting member must be double-filletwelds, equivalent-strength partial-pen-etration welds, or full-penetrationwelds using E70XX electrodes.

M. Thomas Ferrell is presi-dent of Ferrell Engineering,Inc., of Birmingham, AL. He isa member of the AISC Com-mittee on Manuals and Text-books, the AISC TC6Connections Committee, theASCE Committee on Designof Steel Buildings, and theASCE Connections Commit-tee.

Designing with

Single Plate Connections

M. Thomas Ferrell

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To provide for stability during erec-tion, it is recommended that the mini-mum plate length be at least one half ofthe T-dimension of the beam beingsupported. If the beam has no interme-diate lateral support such that it is un-supported laterally between the

connections at its ends, then the platelength shall be increased to at least ac-commodate one extra row of bolts be-yond the above-mentioned minimum.

The plate thickness must satisfyplate buckling criteria required in Part9 of the AISC Manual for local bucklingof beams coped at both the top and bot-tom flanges. For rotational ductility,the maximum plate thicknesses must

 be limited as required for either single-vertical column or double-vertical col-umn connections. When using bearing

 bolts with threads excluded from theshear plane, the minimum thickness is3/8” for 3/4”- and 7/8”-diameter bolts and1/2” for 1”- and 11/8”-diameter bolts.

Limit State Considerations

Bolt shear considering bolt eccentricity• Material bearing strength of the bolt

group for both the plate and the beam web

• Plate shear yielding• Plate shear fracture• Plate block shear• Plate flexural yielding due to bend-

ing using the plastic section modu-lus of the plate

• Plate flexural fracture due to bending• Weld strength for plate to support-

ing member• Block shear for coped beams• Flexural yielding of the coped sec-

tion of the beam• Rotational demand of connection

for rigid connections only

EXTENDED SINGLE PLATE

SHEAR CONNECTIONS

Types of Extended Single PlateShear Connections

These connections are used for“simple framing” similar to the singleplate shear connections. For the ex-tended connections, it is necessary toconsider the effects of the shear andmoment forces in design of the sup-porting member. This is not necessaryfor the single plate shear connections.The extended connections are com-monly used for simple beams framingto column webs when column stiffen-

ers are required due to moment beam

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connections to the column flange.They also can be used to simplify erec-tion procedures for beams framing tocolumn webs, even when column stiff-eners are not required for moment

  beams to the column flange. These

connections are sometimes used forframing to girder webs. This detaileliminates coping of the supported

 beams and simplifies the erection of themember. The coping of the beams cangreatly reduce the strength of the sup-ported beams when the girder flangesare wide.

Support Conditions

Since the shear and moment forcesaffect the design of the supportingmember, guidelines will be provided to

determine adequate column sizes forvarious beam end reactions.

Unstiffened Extended Single

Plate Connections

Use of unstiffened extended single

plate connections is discouraged exceptfor small shear forces. Tests have indi-cated that column-web distortions andtwist in the unstiffened plates limit thestrength of this type of connection.

General Requirements for

Connecting Plates, Bolts, and

Welds:

• Bolt bearing considering bolt eccen-tricity

• Material bearing strength of the boltgroup for both the extended plate

and the beam web

• Extended plate shear yielding• Extended plate shear fracture• Extended plate block shear• Extended plate flexural yielding

due to bending using the elastic sec-tion modulus of the plate

• Extended plate flexural fracture dueto bending

• Extended plate buckling• Weld strength for the extended plate

to the stiffener plates and the sup-porting member.

• Stiffener plate shear yielding• Stiffener plate flexural bending• Weld strength for the stiffener plates

to the column flanges.#

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