CONNECTION DESIGN STANDARDDOC NO: CDS-1 CONNECTION DESIGN STANDARDS DOCUMENT NO: CDS-1 SECOND EDITION DATE: DECEMBER 9, 2005 CONNECTION DESIGN STANDARD DOC NO: CDS-1 TABLE OF CONTENTS Section 1 2 3 4 Description Connection Components Allowable Loads Connection Types Shear Connections Double Clip-Angle Connections Single-Plate Connections Seated Beam Connections Beam Copes and Cope Reinforcement Figures 4.1 thru 4.27 Moment Connections Directly welded flanges Flange plate connection Figures 5.1 thru 5.6 Truss and Vertical Bracing Connection Single Brace Connections Double Brace Connections Chevron Bracing Connections Brace connection at column base X-brace connection Figures 6.1 thru 6.26 Horizontal Bracing Connection Shear-tab Connections Clip-Angle Connections Figures 7.1 thru 7.6 Splices Connection Capacity Tables Calculation Summary Table Templates Design Software and Worksheets Page No 1-1 thru 1-3 2-1 thru 2-8 3-1 thru 3-2 4-1 thru 4-50 Release Date 5 5-1 thru 5-7 8/12/05 6-1 thru 6-27 6 7 7-1 thru 7-7 8 Appendix A Appendix B Appendix C 8-1 thru 8-5 A-1 thru A-7 B-1 thru B-36 C-1 thru C-33 12/9/05 Page i CONNECTION DESIGN STANDARD DOC NO: CDS-1 REFERENCES AISC Manual of Steel Construction, Allowable Stress Design, 9th Edition, Vol I AISC Manual of Steel Construction, Allowable Stress Design, 9th Edition, Vol II Connections Steel Structures, Design and Behavior, by Charles G. Salmon and John E. Johnson. Design of Welded Structures, A Publication of The James F. Lincoln Arc Welding Foundation, June 1996 5. Hollow Structural Sections, Connections Manual, 1st Edition, 1997 1. 2. 3. 4. Page ii CONNECTION DESIGN STANDARD 1.0 Connection Components DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Members are connected by means of welding or bolting. Structural framing members of a building are usually connected using high strength bolts. The different components of a connection are as follows. A connection can have some or all of the components listed below. 1. Beam/Column Web 2. Beam/Column Flange 3. Bracing Member 4. Bolts, Nuts and Washers 5. Welds 6. Clip Angle (Used for connecting beam webs to column or other beams) 7. Gusset Plate (Typically the plates at the ends of bracing members) 8. Seat Plate 9. Seat Angle 10. Stiffener Plate – Used to stiffen another plate against yielding, crippling, buckling, bending etc. Typically these are provided at column or beam webs, seat plate, etc. 11. Web Doubler Plate 12. Bearing Plate 13. Cap Plate Each of the components of the connection is checked for their limit states or failure modes. In addition to checking these components of the connection, local checks of the beam and column have to be done. The local checks include the beam copes, beam web, column web and column flange. The limit states for the connection components are as follows. 1. 2. 3. 4. 5. 6. 7. 8. Bolt failure due to shear or tension Weld failure Shear yielding (of beam web, of clip angle, etc) on gross area Shear rupture (of beam web, of clip angle, etc) on net area Tension yielding on gross area Tension rupture on effective net area Block shear (failure by shear and tension) of a block of material Bolt bearing (failure caused by excessive deformation at bolt holes or limited by proximity to a loaded edge) 9. Flexural yielding 10. Web yielding 11. Web crippling 12. Web buckling 13. Flange local bending 14. Prying action (causes additional tension in bolts based on the flexural stiffness of the connecting elements) 15. Whitmore section yielding or buckling of gusset plate at the ends of the bracing members When bolts are tensioned. The calibrated wrench method uses a manual or power wrench that stalls at a specified torque. a plate washer at least 5/16” thick with a standard hole could be used. the protrusions are flattened. The TC bolts are covered by ASTM F1852. which are torqued until the tip snaps off the threaded portion of the bolt indicating that the desired tension has been obtained. nuts shall be per ASTM A563 grade DH or A194 grade 2H. For structures that are not part of the main or critical load carrying system of a building. nuts shall be per ASTM A563. the turn-of-the-nut method and direct tension indicator method. grades C. Welding Material Common weld electrode used for joing carbon steel elements is the E70 weld electrode having a tensile strength of 70 ksi. DH or DH3 or A194 grade 2H. while A490 bolts are heat treated and are of alloy steel. When long slotted holes are used in an outer ply. Nuts for A490 bolts shall be A563 grade DH or DH3 or A194 grade 2H. A307 carbonsteel bolts that are not heat-treated may be specified. For galvanized bolts. Nuts: For ASTM A325 bolts. These washers shall be sized to cover the slot after installation. For A490 bolts a hardened washer 5/16” thick minimum shall be used. generally one hardened washer is provided under the turned element. Washers: Shall be per ASTM F436. Specification Section J3. hardened washer under the bolt head and the nut is provided. The turn-of-the-nut method is more reliable than calibrated wrench method.. For A325 bolts. The pre-tension loads are given in Table J3. A325 bolts are heat treated.7 of AISC Manual. The specified torque is calculated to obtain the desired tension in the bolt. . which are the calibrated wrench method.1 Material Requirement Bolts: The two common types of high-strength bolts are A325 and A490. D. High-strength bolts are pre-tensioned using one of the three methods. The “Specification for Structural Joints Using ASTM A325 or A490 Bolts” provided in the AISC Manual discusses these methods in detail.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 1. For A490 bolts. The amount of gap remaining will indicate the amount of tension in the bolt. Recent development is the tension control (TC) bolts. The turn-of-the-nut method develops the pretension in the bolt by turning the nut through a specified rotation past the snug condition. The direct tension indicator method uses a hardened washer with protrusions on one face. C3. E60 may also be specified but is not used extensively. High-strength bolts are installed with a pre-tension. 1-7 Pg. Grade B A500 Grade B A325 A325 A490 F1852 (TC bolts) F1852 (TC bolts) A307 A36 A572 Grade 50 A36 Min Yield Strength 50 ksi 36 ksi 46 ksi 50 ksi 36 ksi 36 ksi 50 ksi 36 ksi 35 ksi 46 ksi 92 ksi 81 ksi 92 ksi 81 ksi 36 ksi Min Tensile Strength 65 ksi 58 ksi 58 ksi 65 ksi 58 ksi 58 ksi 65 ksi 58 ksi 60 ksi 58 ksi 120 ksi 105 ksi 150 ksi 120 ksi 105 ksi 60 ksi 58 ksi AISC Manual Ref Page Pg. 1-92 Pg. 1-7 Note 1: For additional material properties not covered in the table. 4-4 Pg. 1-92 Pg. see the AISC Manual Reference pages. 1-7 Pg. 1-7 Pg. 4-4 High-Strength Bolts Common Bolts Gusset/Stiffener/B earing/Seat/Web Doubler/Cap Plates Clip/Seat/Claw Angles Pg. . 1-7 Angle 36 ksi 58 ksi Pg. 1-7 Pg. 1-92 Pg.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Table –1-1: Material Properties Connection Components (Commonly Specified) (Note 1) Component Beam/Column Members Brace/Truss Members Shapes/Plates/Misc Wide Flange Wide Flange Square or Rectangular HSS Wide Flange Wide Flange Angle Tee (Cut from W Shapes) Round HSS Square or Rectangular HSS ½” to 1” dia 1 1/8” to 1 ½” dia ½” to 1 ½” dia ½” to 1” dia 1 1/8” dia Plate ASTM Designation A992 A36 A500 Grade B A992 A36 A36 A992 A36 A53 Type E. pgs. the Class C friction coefficient can be used. When slipcritical bolts are used in a connection. The load obtained by elastic method is about 10% less than what is obtained by the ultimate load method. When the eccentric shear load is at an angle to the vertical. 4-59 thru 4-61 in the AISC Manual. In bearing-type connection. In lieu of this alternate method. bolts and welds shall be considered to share the load. The Allowable Loads for bolts in bearing on different material thicknesses is given in Table I-E of AISC Manual. The friction coefficient for various class of surface is provided in Specification for Structural Joints Using ASTM A325 or A490 Bolts. the design is based on a Class A surface. AISC Manual provides a procedure for using the instantaneous center of rotation method. the elastic method can always be used. Bolt allowables shall be reduced when using oversized or slotted holes. . The allowable shear given in Table I-D is based on a Class A surface. However.0 Allowable Loads for Bolts and Welds DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 2. The resistance is calculated as the clamping force times a coefficient of friction. Bolt and weld group subjected to shear load with an eccentricity can be designed using either elastic method or the ultimate strength method. Vol I. When steel is galvanized. The coefficient of friction varies depending on the type of surface preparation and the coating specified for the steel. However. in slip-critical connections. the resistance to slip is provided by the clamping force across the faying surface. also called the instantaneous center of rotation method. the elastic method shall be used. See Alternate Method 2.1 Bolts The Allowable Loads for bolts in tension is given in Table I-A of AISC Manual. However. Generally. Vol I. Long slotted holes are generally provided in only one ply of the connection.CONNECTION DESIGN STANDARD 2. These allowable can be revised (increased) if the faying surface is Class B or Class C. The Allowable Loads for bolts in shear is given in Table I-D of AISC Manual. the bolts shall not be considered to share the load with the weld. AISC Manual provides coefficients for both bolt and weld groups based on the instantaneous center of rotation method. Vol I. when bolt groups do not conform to the pattern given in the AISC Tables XI through XVIII. it is preferable to avoid such situations. Short slotted holes can be used in any or all plies of the connection. These Tables are conservative for slip-critical bolts and when used for ASTM A490 bolts. a Elastic Method of Bolt Analysis for bolts subjected to loads in the plane of the connection Let the assumed plane of the connection be X and Y Loads: Px. 2 Determine Polar Moment of Inertia Ip = Ix + Iy Let distance of the farthest bolt along X-Axis = Cx Let distance of the farthest bolt along Y-Axis = Cy Bolt Stress (X-Dir) = fx = ( Px ÷ n) + Mz * Cy ÷ Ip Bolt Stress (Y-Dir) = fy = ( Py ÷ n) + Mz * Cx ÷ Ip Resultant Bolt stress = fr = fx 2 + fy 2 should be less than allowable bolt shear.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 2. Py and Mz Where Px = Load along X-direction Py = Load along Y-direction Mz = Torsional moment caused due to eccentricity of Px and Py load about the centroid of bolt group Number of bolts = n Determine the Moment of Inertia Ix and Iy Determine the Moment of Inertia Ix = ∑y Where y is the distance of each bolt in the y-direction from the neutral axis. 2 x Determine the Moment of Inertia Iy = ∑ Where x is the distance of each bolt in the y-direction from the neutral axis.1. b Elastic Method of Bolt Analysis for bolts subjected to shear and tension due to bending Let the assumed plane of the connection be X and Y Loads: Py and Mx Where Py = Load along Y-direction Mx = Moment caused due to eccentricity of Py load about the X-axis Number of bolts = n Let distance of the farthest bolt along Y-Axis = Cy .1. 2. Prying action is discussed at the end of this section.3 for A325 and A490 bolts depending on whether threads are included in the shear plane or not. Hence. When a moment is applied across a faying surface that causes some portion to go into tension and some into compression. . For Slip-Critical Bolts The interaction of tension and shear is done only if there is a net direct tension on the joint. split-beam tee moment connection where the flanges of the tee deform and dig into the column causing extra tensile force in bolts or hanger type connections where the bending of the outstanding leg of angles or flanges of Tee cause prying forces. Therefore. although some bolts in the joint may experience tension and others do not. the bolts under tension need not be evaluated for the tension load since there is no net tension on the joint.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Bolt shear Stress (y-dir) = Bolt tensile Stress (z-dir) = fy = ( Py ÷ n) fz = ( Mx ÷ Ix ) × Cy See Section 2. the allowable tension stress is altered based on the equations provided in Table J3. c Bolts subjected to Tension and Shear When bolts are subjected to both tension and shear. 2. when there is a net direct tension on the joint. for example the clip angle of a shear connection subjected to tension or transfer loads. the interaction of tension and shear stresses has to be performed. For bearing type connections.1.7 of the AISC Specification For Bearing Type Bolts For bearing type bolts. the interaction of tension and shear is done. whether the tension is caused through direct tension or through a moment.c for checking bolts subjected to tension and shear simultaneously. As discussed earlier. Prying Action Prying action is the deformation of the connected part. In calculating the applied tension. the applied tension shall be the sum of the external load and any tension resulting from prying action produced by deformation of connected parts. the slip-critical joints obtain their resistance through the clamping force across the faying surface. The allowable bolt shear shall be reduced by the factor (1 − ft × Ab ÷Tb ) Where ft is the average tensile stress on a bolt caused by direct tension load And Ab is the nominal tensile area of the bolt given in Table I-A and Tb is the bolt pretension as given in Table J3. there is no change in the net clamping force across the joint.1. Welds shall be designed per the requirements of AWS D1. 1. These processes are covered under the general term ‘Arc Welding’. which acts as the shield for the weld. the thickness of the flange or angle leg required to develop the full tensile capacity without additional prying loads. Part 4 provides the Analysis and Design Methodology to determine the prying force. Most welding involves ferrous-based metals such as steel and stainless steel. 4. Weld joints are usually stronger or as strong as the base metals being joined. Most of the commonly used welding techniques employ an electric arc to generate the heat necessary for welding. In this process the stud itself acts as the electrode.2 Welds Welding is a process for joining similar metals. 2. Shielded Metal Arc Welding (SMAW) Submerged Arc Welding (SAW) Gas Metal Arc Welding (GMAW) Flux Cored Arc Welding (FCAW) Another unique arc welding technique is Stud Welding. The molten metal is contained within a ceramic ferrule.Structural Welding Code – Steel For Carbon steels used in the design. Allowable Stress for E70XX electrode and effective throat of welds shall be as provided in Table 2-1. Welding is done using localized heat input. This has similar or greater mechanical properties than the connected materials. ASD Manual.1 . 2. the E70XX electrode is the matching electrode commonly used. . the thickness of the angle or flange required to develop the moment due to prying. Note that shear connections subjected to axial loads usually require much thicker angles to resist the moment developed in the connection angle.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Hence prying action involves not only the bolts but also the flange or angle thickness. The gun is placed in position and an electric arc is created to melt the end of the stud. The stud is then driven into the molten metal by the gun creating a full penetration weld across the shank along with a small fillet around the stud. The stud is placed in a stud gun that contains a ceramic ferrule. Hence. Welding joins metals by melting and/or fusing the base metals being joined with or without a filler metal. 3. The different arc welding techniques are the following. bolt pitch and gage. shear connections subjected to axial loads shall be evaluated on a case by case basis. AISC. 3 x 70 ksi from root of joint to area the face of the weld. Tension or Same as base Typically equal to Compression parallel metal 0. 5/16 R where R Tension/compression Same as base = 2t.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Table 2-1: Effective Throat of Weld and Allowable Stress of E70XX Weld Weld Type Effective Throat Stress Type Allowable Stress Fillet Weld Shortest distance Shear on effective 0.707 x weld size to axis of weld Complete1) Thickness of the Tension/compression Same as base Penetration thinner part joined normal to effective metal Groove Weld 2) For Flare groove area weld.3 x 70 ksi rounded corner area PartialPenetration Groove Weld 1) Depth of chamfer (for J or U joint or for bevel >= 60 deg) 2) For bevel < 60 deg and >=45 deg it is depth of chamfer – 1/8 Shear parallel to axis of weld Tension normal to effective area Compression to effective area Tension/compression parallel to axis of the weld 0.3 x 70 ksi 0. t being the parallel to axis of the metal thickness of the weld material with the Shear on effective 0.3 x 70 ksi Same as base metal Same as base metal . the elastic method shall be used. pgs. In lieu of this alternate method. When the eccentric shear load is at an angle to the vertical. torsion and bending moment loads. 4-73 thru 4-74 in the AISC Manual. However. My and Mz Where Px and Py = Shear Loads Pz = tension Load Mx = Moment about the X-axis My = Moment about the Y-axis Mz Torsional Moment . Establish a coordinate system and determine the centroid of weld group. the following steps shall be taken.2. Properties of most commonly used weld groups are provided in Table 2-2. torsion and moment Welds can be subjected to a combination of shear. when bolt groups do not conform to the pattern given in the AISC Tables XI through XVIII. the elastic method can always be used. Mx. To investigate the weld. 1. Py. Determine the forces on the weld group.b Elastic Method of Weld Analysis for welds subjected to shear. 2.a Weld Analysis and Design Weld group subjected to shear load with an eccentricity can be designed using either elastic method or the ultimate strength method. Tables XIX through XXVI provide coefficients for weld groups based on the instantaneous center of rotation method.2. Loads: Px. See Alternate Method 2. Assume a unit thickness of weld and draw the effective cross-section of the weld group. 2. Pz. AISC Manual provides a procedure for using the instantaneous center of rotation method. AISC Manual. also called the instantaneous center of rotation method.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 2. Calculate the properties of weld treated as lines. The load obtained by elastic method is about 5% less than what is obtained by the ultimate load method. For example: Let the assumed plane of the connection be X and Y Properties required are Centroid Length Moment of Inertia Ix Moment of Inertia Iy Polar Moment of Inertia Ip Distance of the extreme weld point to the weld centroid along x-axis (cx) Distance of the extreme weld point to the weld centroid along y-axis (cy) 3. Specifications. Weld stress along x-axis due to Px = fx1 = Px / L Weld stress along y-axis due to Py = fy1 = Py / L Weld stress along z-axis due to Pz = fz1 = Pz / L Weld stress along x-axis due to Mz = Weld stress along y-axis due to Mz = Weld stress along z-axis due to Mx = Weld stress along z-axis due to My = fx 2 = ( Mz ÷ Ip ) × cy fxy 2 = ( Mz ÷ Ip ) × cx fz 2 = ( Mx ÷ Ix ) × cy fz 3 = ( My ÷ Iy ) × cx Total weld stress in x-direction: fxtot = fx1 + fx 2 Total weld stress in y-direction: fytot = fy1 + fy 2 Total weld stress in z-direction: fztot = fz1 + fz 2 + fz 3 5. Determine the weld size required for the computed weld stress.4. 8. Section J2. Combine the stresses vectorially. Resultant Weld stress shall be less than the weld allowable. Resultant Weld Stress: fr _ weld = fxtot 2 + fytot 2 + fztot 2 in kips/inch 6. Weld sizes shall also meet the AISC minimum weld size provided in Tables J2. moment and torsion.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4. Determine the individual weld stresses (in each principal axis) due to shear. . Check to ensure that the weld size does not exceed the maximum allowed per AISC Manual.3 and J2. Weld Allowable = Effective Throat Thickness x Allowable Weld Stress in kips/inch 7. [4]) .CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Table 2-2: Properties of Welds Treated as Lines (Courtesy Ref. Moment connections using WT or angles. WF beam to HSS column shear connections b. e.CONNECTION DESIGN STANDARD Connection Types DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Structural steel connections can be classified into the following broad categories. Vertical Bracing Connections a. all welded or a combination) a. g. End-Plate Connection (end plate is welded to the beam and field bolted to the column flange). End Plate Connection d. Brace connections at column base b. 1. Truss Connections (all bolted. Moment Connections a. Angle diagonal and strut to WT chord . h. WF beam to HSS column moment connections c. c. Directly welded flange type to column web (flanges are field welded to extension plates welded to the column flange and web and the beam web is field bolted to an extended shear plate). Framed Beam Connections (Double-Clip Angle Connections) b. HSS to HSS shear connections d. Horizontal Bracing Connections 4. Shear Connections a. K-Brace connection e. i. Seated Connections c. d. bottom flange plate is shop welded to the column flange and beam is field welded to the flange plates). Shop Welded-Field Bolted Flange Plate Connection (flange plates are shop welded to the column web and flange flange and the beam web is field bolted to an extended shear plate). b. Hanger and Post Connections 7. Other variations of the above listed moment connections 3. Chevron Brace connection (Inverted-V brace connection) c. X-Brace connection 5. Directly welded flange type to column flange (flanges are field welded to the column flange and the beam web is field bolted to a shear plate). Welded Flange Plate Connection (top flange plate is field welded to the column flange. f. HSS to WF beam moment connection 6. HSS Connections a. Angle diagonal and strut to WF chord b. Shop Welded-Field Bolted Flange Plate Connection (flange plates are shop welded to the column flange and the beam web is field bolted to a shear plate). Single and Double brace connections at beam/column intersection d. Beam to Beam moment connections (directly welded or using flange plates). Single-Plate Connection 2. reduced number of bolts. the framed beam connection for skew beams will have to be designed using bent plates instead of clip angles. these are variations of the basic connection types listed above. For example. However. such as fit up. Similarly. connections of sloping beams and connections to sloping beams will require additional considerations in design. WF diagonal and strut to WF chord d.CONNECTION DESIGN STANDARD c. K and N type) DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Several variations of the above mentioned connection types are typically encountered in the real world. larger than usual copes. Also. . etc. HSS to HSS truss connections (T. parameters such as bolt eccentricity will change depending on the amount of skew and such information shall be considered in the design. Single angle connections would require the consideration of eccentricity of the load with respect to the bolt line on the outstanding leg.1 thru 4. 4. shear plate and extended shear plates. 4-83 is useful. pg. this detail can be used as a “Knifed” connection (where the beam is lowered into position between the clip angles). For details of various typical shear connections see Figures 4. Other framed beam connections involve using bent plates for skew connections.1 Double Clip-Angle Connections These are the standard clip angle connections. This is accommodated by providing slotted holes on the outstanding leg of the clip angles that bolt to the supporting column flange.CONNECTION DESIGN STANDARD Shear Connections DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Framed Beam connections are generally made with a pair of clip angles. For a knifed connection. Four variants using bolts and/or welds can be formulated. allowance must be made for erection clearance between the clip angles. When supported on column flange. the procedure given in AISC Manual Part 4.24. For evaluation of this eccentricity effect. Single angle connections can also be used for lightly loaded members and where the beam is not subjected to loads that could cause twisting on it. . 3 x lv + 0.a Shop Bolted / Field Bolted Connection (Detail DCA-BB) DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Formulation for developing load capacity table for Double Bolted Clip Angle Connection using SlipCritical Bolts Step 1: Establish the Design Inputs: Bolt Type. Clip-Angle Yield Strength (Fy_angle) Clip-Angle Tensile Strength (Fu_angle) Beam Yield Strength (Fy). Bolt Diameter (d). AISC Manual Part 4 (or) Allowable Bolt Shear = n x (double shear capacity of bolt from Table I-D) Step 3: Determine Net Shear on the Angle: Use Table II-C.CONNECTION DESIGN STANDARD 4. of Bolts (n). Bolt Hole Dia (dh) No. II.1. AISC Manual Part 4 Block Shear = (C1 + C2) x Fu x tw (or) Block Shear = {(0. Beam web thickness (tw) Vertical Edge Distance for the top bolt (for coped beams) (lv) Distance from center of bolt hole to beam end (lh) Spacing of bolts (s) Cope depth (dc) Reduced beam depth (ho) Cope length (c) Reduced Section Modulus of the coped beam section (Sn) Supporting member web or flange thickness (t_supt) Step 2: Determine Allowable Bolt Shear in Kips: Use Table II-A. Vol.2 x Fu x d x tw x n Step 5: Determine Beam Block Shear (if beam is coped on top): Determine Coefficients C1 and C2 from Table I-G. Clip-Angle thickness (t). Clip-Angle Length (L).5 x lh) + 0. Manual of Steel Construction. AISC Manual Part 4 (or) Allowable Net Shear = 2 x [L-n(dh)] x t x 0.3 x Fu_angle Step 4: Determine Beam Web Bearing: Allowable Beam Web bearing load = 1. Beam Tensile Strength (Fu). Appendix B.3 [(n-1)(s-dh)-dh/2] –dh/4} x Fu x tw Step 6: Check cope based on AISC. . The ideal engineer is a composite . Excel worksheet no. load Allowable supporting member (web or flange) bearing load = 1..a. .2 x Fu x d x t_supt x n x 2 For Two-Sided Connection: Conservatively take 50% of the one-sided conn. but he may use the knowledge and techniques of any or all of these disciplines in solving engineering problems.. c. If the governing allowable is due to beam cope : Reinforce the cope with web doubler plates or horizontal stiffeners f. he is not a mathematician. If the governing allowable is due to net shear on the angle. he is not a sociologist or a writer. DCA-1 is applicable for evaluating this connection. If Actual Reaction exceeds the Allowable. If only a bottom cope is present conservatively assume it as top cope for design.3. If the governing allowable is due to bolt shear : Either increase number of bolts or increase bolt diameter b.a.2 for bearing type and slip-critical type connections.2. Step 7: Determine Supporting member (web or flange) bearing: For One-Sided Connection: Allowable supporting member (web or flange) bearing load = 1.3. If the governing allowable is due to block shear : Either increase number of bolts or add web doubler plates e. If the governing allowable is due to beam web bearing : Either increase number of bolts or increase bolt diameter or add web doubler plates d.1 and 5. If the governing allowable is due to supporting member web or flange thickness: Increase the connection depth. Capacity of this connection type for various beam sections is provided in Table CDS 4. or reinforce the support member.2 x Fu x d x t_supt x n Conclusion: Maximum Allowable Beam End Reaction = Minimum of Loads obtained from Steps 2 through 7. He is not a scientist. then the following can be done: a.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG For checking the beam copes and obtaining the allowable reaction see the procedure outlined in Section 5. increase angle thickness.1 and Table CDS 4. 4 x Fy x (L + a) x tw + 0. AISC Manual Part 4 (or) Allowable Net Shear = 2 x [L-n(dh)] x t x 0. Clip-Angle In-Standing Leg dimension (ISL) Clip-Angle Yield Strength (Fy_angle) Clip-Angle Tensile Strength (Fu_angle) Beam Yield Strength (Fy). Clip-Angle thickness (t). Weld A Capacity Based on angle length and weld size (limited by the beam web size) obtain Weld Capacity.1. Clip-Angle Length (L).b Shop Welded / Field Bolted Connection (Detail DCA-WB) Formulation for developing load capacity table for Double Clip Angle Connection (shop welded to beam web and field bolted to column or beam) using Slip-Critical Bolts Step 1: Establish the Design Inputs: Bolt Type. Bolt Diameter (d). Vol. Beam Tensile Strength (Fu). of Bolts (n). then Revised Allowable = tw x Weld Allowable per Table / Min.3 x Fu_angle Step 4: Determine Weld Capacity: Use Table III. AISC Manual Part 4. Appendix B. Manual of Steel Construction. II. web thickness per Table Step 5: Determine Beam Block Shear (if beam is coped on top): Block Shear = 0. . Fu = 70 ksi Distance from top of clip angle to edge of beam cope (a) Supporting member web or flange thickness (t_supt) Step 2: Determine Allowable Bolt Shear in Kips: Use Table II-A. Beam web thickness (tw) Cope depth (dc) Reduced beam depth (ho) Cope length (c) Reduced Section Modulus of the coped beam section (Sn) Weld Electrode E70XX. If the actual web thickness is less than the minimum required web thickness provided in the Table. Bolt Hole Dia (dh) No.5 x Fu x (ISL – setback) x tw Step 6: Check cope based on AISC. AISC Manual Part 4 (or) Allowable Bolt Shear = 2 x n x (single shear capacity of bolt from Table I-D) Step 3: Determine Net Shear on the Angle: Use Table II-C.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4. 2 x Fu x d x t_supt x n Conclusion: Maximum Allowable Beam End Reaction = Minimum of Loads obtained from Steps 2 through 7. c. d. Excel worksheet no. If Actual Reaction exceeds the Allowable. then the following can be done: a.2.2 x Fu x d x t_supt x n x 2 For Two-Sided Connection: Conservatively take 50% of the one-sided conn. . If the governing allowable is due to beam cope : Reinforce the cope with web doubler plates or horizontal stiffeners. If the governing allowable is due to net shear on the angle. f. If the governing allowable is due to supporting member web or flange thickness: Increase the connection depth. If the governing allowable is due to bolt shear : Either increase number of bolts or increase bolt diameter b. If the governing allowable is due to Weld capacity : Either increase weld size or increase weld length by increasing clip angle length.a. If only a bottom cope is present conservatively assume it as top cope for design.a.3.1 and 5. load Allowable supporting member (web or flange) bearing load = 1.3 through Table CDS 4.6 for bearing type and slip-critical type connections. DCA-2 is applicable for evaluating this connection. Step 7: Determine Supporting member (web or flange) bearing: For One-Sided Connection: Allowable supporting member (web or flange) bearing load = 1.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG For checking the beam copes and obtaining the allowable reaction see the procedure outlined in Section 5.3. or reinforce the support member. if possible. increase angle thickness. Capacity of this connection type for various beam sections is provided in Table CDS 4. If the governing allowable is due to block shear : Add web doubler plates e. Clip-Angle Length (L).5 x lh) + 0. AISC Manual Part 4 (or) Allowable Net Shear = 2 x [L-n(dh)] x t x 0. Clip-Angle Yield Strength (Fy_angle) Clip-Angle Tensile Strength (Fu_angle) Beam Yield Strength (Fy). Step 2: Determine Allowable Bolt Shear in Kips: Use Table II-A. Bolt Diameter (d). Beam web thickness (tw) Vertical Edge Distance for the top bolt (for coped beams) (lv) Distance from center of bolt hole to beam end (lh) Spacing of bolts (s) Cope depth (dc) Reduced beam depth (ho) Cope length (c) Reduced Section Modulus of the coped beam section (Sn) Weld Electrode E70XX. of Bolts (n). Clip-Angle thickness (t).1. Bolt Hole Dia (dh) No. AISC Manual Part 4 (or) Allowable Bolt Shear = n x (double shear capacity of bolt from Table I-D) Step 3: Determine Net Shear on the Angle: Use Table II-C.c Shop Bolted / Field Welded Connection (Detail DCA-BW) Formulation for developing load capacity table for Double Clip Angle Connection (Shop Bolted / Field Welded Connection) using Slip-Critical Bolts Step 1: Establish the Design Inputs: Bolt Type.3 x lv + 0.3 x Fu_angle Step 4: Determine Beam Web Bearing: Allowable Beam Web bearing load = 1.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4. Fu = 70 ksi Supporting member web or flange thickness (t_supt) Supporting Member Yield Strength (Fy_Supt).2 x Fu x d x tw x n Step 5: Determine Beam Block Shear (if beam is coped on top): Determine Coefficients C1 and C2 from Table I-G. Beam Tensile Strength (Fu). AISC Manual Part 4 Block Shear = (C1 + C2) x Fu x tw (or) Block Shear = {(0.3 [(n-1)(s-dh)-dh/2] –dh/4} x Fu x tw . Hence check the following: For One-Sided Connection: For Fy_Supt = 36 ksi. weld size shall be <= support member web x 0. If the governing allowable is due to weld on the outstanding leg: Increase the weld size (if possible). or increase weld length by increasing the length of the clip angle (if possible) or reinforce the supporting member web or flange to allow a bigger weld.a. Conclusion: Maximum Allowable Beam End Reaction = Minimum of Loads obtained from Steps 2 through 7. weld size shall be <= (support member web or flange thickness) x 1. Step 7: Check Weld on the Outstanding leg of the clip angle: Use Table III.3. then the following can be done: a.5 For Fy_Supt = 50 ksi. II. If the governing allowable is due to block shear : Either increase number of bolts or add web doubler plates e.1 and 5. increase angle thickness. For checking the beam copes and obtaining the allowable reaction see the procedure outlined in Section 5.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Step 6: Check cope based on AISC. Note: Connection capacity may be limited by the shear capacity of the supporting member. If Actual Reaction exceeds the Allowable. DCA-3 is applicable for evaluating this connection. Vol. If only a bottom cope is present conservatively assume it as top cope for design.67 Note: This approach may or may not be conservative depending on the weld size of the opposing connection. Weld B Capacity Based on angle length and Required weld capacity obtain the weld size. AISC Manual Part 4. weld size shall be <= support member web x 0.35 For Two-Sided Connection: (see note) For Fy_Supt = 36 ksi. If the governing allowable is due to beam cope : Reinforce the cope with web doubler plates or horizontal stiffeners f. c. Excel worksheet no. This assumes that the weld size of the connections on either side of the web is the same. If the governing allowable is due to bolt shear : Either increase number of bolts or increase bolt diameter b. If the governing allowable is due to net shear on the angle. Appendix B. weld size shall be <= support member web or flange thickness For Fy_Supt = 50 ksi. If the governing allowable is due to beam web bearing : Either increase number of bolts or increase bolt diameter or add web doubler plates d.3.2. .a. Manual of Steel Construction. Clip-Angle In-Standing Leg dimension (ISL) Clip-Angle Yield Strength (Fy_angle) Clip-Angle Tensile Strength (Fu_angle) Beam Yield Strength (Fy). Hence check the following: For One-Sided Connection: For Fy_Supt = 36 ksi.1. Clip-Angle thickness (t). Note: Connection capacity may be limited by the shear capacity of the supporting member. . Step 2: Check Weld on the Outstanding leg of the clip angle: Use Table III. Step 3: Determine Shear on the Angle: Allowable Net Shear = 2 x L x t x 0.35 For Two-Sided Connection: (see note) For Fy_Supt = 36 ksi. AISC Manual Part 4. weld size shall be <= support member web x 0.4 x Fy_angle Step 4: Determine Weld Capacity on the beam web: Use Table III. This assumes that the weld size of the connections on either side of the web is the same.67 Note: This approach may or may not be conservative depending on the weld size of the opposing connection. weld size shall be <= support member web x 0.d Shop Welded / Field Welded Connection (Detail DCA-WW) DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Formulation for developing load capacity table for Double Clip Angle Connection (shop welded to beam web and field welded to column or beam) Step 1: Establish the Design Inputs: Clip-Angle Length (L).CONNECTION DESIGN STANDARD 4. weld size shall be <= (support member web or flange thickness) x 1. Beam Tensile Strength (Fu). Weld B Capacity Based on angle length and Required weld capacity obtain the weld size. Beam web thickness (tw) Cope depth (dc) Reduced beam depth (ho) Cope length (c) Reduced Section Modulus of the coped beam section (Sn) Weld Electrode E70XX. weld size shall be <= support member web or flange thickness For Fy_Supt = 50 ksi. Fu = 70 ksi Distance from top of clip angle to edge of beam cope (a) Supporting member web or flange thickness (t_supt) Supporting Member Yield Strength (Fy_Supt).5 For Fy_Supt = 50 ksi. AISC Manual Part 4. Conclusion: Maximum Allowable Beam End Reaction = Minimum of Loads obtained from Steps 2 through 6.4 x Fy x (L + a) x tw + 0. or increase weld length by increasing the length of the clip angle (if possible). For checking the beam copes and obtaining the allowable reaction see the procedure outlined in Section 5. then Revised Allowable = tw x Weld Allowable per Table / Min. Manual of Steel Construction.5 x Fu x (ISL – setback) x tw Step 6: Check cope based on AISC. If the governing allowable is due to block shear : Add web doubler plates e. II.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Weld A Capacity Based on angle length and weld size (limited by the beam web size) obtain Weld Capacity If the actual web thickness is less than the minimum required web thickness provided in the Table. b.3. or reinforce the supporting member web or flange to allow a bigger weld. Vol. web thickness per Table Step 5: Determine Beam Block Shear (if beam is coped on top): Block Shear = 0. If Actual Reaction exceeds the Allowable.1 and 5. c.a.3. then the following can be done: a. d. Appendix B. . DCA-4 is applicable for evaluating this connection. If the governing allowable is due to beam cope : Reinforce the cope with web doubler plates or horizontal stiffeners Excel worksheet no. if possible.a. increase angle thickness. If the governing allowable is due to shear on the angle. If the governing allowable is due to Weld capacity on the beam web : Either increase weld size or increase weld length by increasing clip angle length.2. If only a bottom cope is present conservatively assume it as top cope for design. If the governing allowable is due to weld on the outstanding leg : Increase the weld size (if possible). by Abolhassan Astaneh 2. One is the normal single-plate shear connection and the other is the extended shear plate connection. Sherman Formulation for design of single plate connection Step 1: Establish the Design Inputs: Bolt Type.e. Plate Yield Strength (Fy_plate) Plate Tensile Strength (Fu_plate) Beam Yield Strength (Fy). by Al Ghorbanpoor and Donald R. Plate Length (L). of Bolts (n). when a beam frames into another beam from one side only or when a heavy girder frames into a light column) with standard holes. Thomas Ferrell 3. Designing with Single Plate Connections.2 Single Plate Connections DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Two types of single plate connections are possible. The single plate is welded to the support member and bolted to the beam. Plate thickness (tp). Design Procedures for Extended Shear Tabs. Beam web thickness (tw) Cope depth (dc) Reduced beam depth (ho) Cope length (c) Reduced Section Modulus of the coped beam section (Sn) Weld Electrode E70XX. The eccentricity depends on the support type and the type of holes used in the plate. eccentricity shall be taken as . Bolt Diameter (d). References to Technical Papers: 1. Beam Tensile Strength (Fu).CONNECTION DESIGN STANDARD 4. For flexible support (i. Bolt Hole Dia (dh) No. Behavior and Design of Single Plate Shear Connections. by M. The bolts have to be designed for the shear and moment due to the eccentricity. Fu = 70 ksi Vertical Edge Distance for the top bolt (for coped beams) (lv) Distance from center of bolt hole to beam end (lh) Vertical Edge Distance for the top bolt from plate edge (lvp) Distance from center of bolt hole to plate end (lhp) Distance of bolt line from the weld (a) Supporting member web or flange thickness (t_supt) Supporting Member Yield Strength (Fy_Supt). c. when a beam frames into another beam from one side only or when a heavy girder frames into a light column) with slotted holes. e. when a beam frames into a heavy column flange) with slotted holes. For any combination of support condition and hole type.e. d. Ideally the support is somewhere between flexible and rigid. eccentricity shall be taken as eb = |2n/3-a| When two beams frame on either side of a beam/girder: Use eb = a Step 2: Design parameters shall be based on the following rules: a. l = eb and knowing n. b. For use of Tables in AISC manual this shall not exceed 3”.e.2 x Fu_plate x tp x d x n .e. Minimum plate length shall be one-half of the T-dimension of beam to be supported. when a beam frames into a heavy column flange) with standard holes.CONNECTION DESIGN STANDARD eb = |(n-1)| -a| >= a DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG For flexible support (i.4 x Fy_plate x L x tp Step 3 Determine Bolt Group Capacity: Using Table XI or XII. determine Coefficient C Bolt Group Capacity = Rb = C x rv Where rv = Single shear bolt capacity from Table I-D Step 4: Determine Plate bearing Capacity: Allowable Plate bearing load = 1. eccentricity shall be taken as eb = |(n-1)| -a| For rigid support (i. Weld to be designed for maximum of Actual Reaction or 0. Distance of bolt line from the weld (a) shall be preferably 2½” and a maximum of 3½”. the larger value of eb shall be taken. the E70 electrode maximum weld size need not exceed ¾ of the plate thickness for A36 plate material. Hence. eccentricity shall be taken as eb = |2n/3-a| >= a For rigid support (i. The minimum plate thickness should be such that tpmin >= L/64 >= ¼” f. The maximum plate thickness should be d/2 + 1/16 in > = tpmin g. 3 x lv + 0.a.a. weld size shall be <= (support member web or flange thickness) x 1. Step 11: Determine Weld Capacity: For Rigid Connection and when beams frame on two sides of a girder: Eccentricity to be used for design of weld = ew = a + eb For Flexible Connection : Eccentricity to be used for design of weld = 0” Using Table XIX.CONNECTION DESIGN STANDARD Step 5: Check Shear Yielding Capacity of Plate: 0. Hence check the following: For One-Sided Connection: For Fy_Supt = 36 ksi. II.2 x Fu x d x tw x n Step 9: Determine Beam Block Shear (if beam is coped on top): Determine Coefficients C1 and C2 from Table I-G. AISC Manual Part 4 Block Shear = (C1 + C2) x Fu x tw (or) Block Shear = {(0.5 x lh) + 0.3 [(n-1)(s-dh)-dh/2] –dh/4}x Fu_plate x tp Step 8: Determine Beam Web Bearing: Allowable Beam Web bearing load = 1. Manual of Steel Construction.3. weld size shall be <= support member web or flange thickness For Fy_Supt = 50 ksi.857 for E60 Electrode C is obtained from the Table XIX for a = ew/L Note: Connection capacity may be limited by the shear capacity of the supporting member.35 .3 [(n-1)(s-dh)-dh/2] –dh/4} x Fu x tw Step 10: Check cope based on AISC.3 x Fu_plate x [ L – n(dh)] x tp DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Step 7: Check Plate Block Shear: Determine Coefficients C1 and C2 from Table I-G.2.0 for E70 Electrode And 0. AISC Manual Allowable weld capacity Pw = C x C1 x D x L Where D = Number of sixteenth of an inch in fillet weld size C1 = 1.1 and 5.5 x lhp) +0. For checking the beam copes and obtaining the allowable reaction see the procedure outlined in Section 5.3. Vol. If only a bottom cope is present conservatively assume it as top cope for design.4 x Fy_plate x L x tp Step 6: Check Shear rupture of plate: 0.3 x lvp + 0. Appendix B. AISC Manual Part 4 Block Shear_plate = (C1 + C2) x Fu_plate x tp (or) Block Shear_plate ={(0. or increase weld length by increasing the length of the plate. If Actual Reaction exceeds the Allowable. weld size shall be <= support member web x 0. Conclusion: Maximum Allowable Beam End Reaction = Minimum of Loads obtained from Steps 3 through 11. If the governing allowable is due to plate shear rupture : Either increase plate length or plate thickness. then the following can be done: a. SSPC-1 is applicable for evaluating this connection. This assumes that the weld size of the connections on either side of the web is the same. . If the governing allowable is due to beam web bearing : Either increase number of bolts or increase bolt diameter or add web doubler plates g. weld size shall be <= support member web x 0. If the governing allowable is due to plate block shear : Either increase number of bolts or increase plate thickness f. e. d.67 Note: This approach may or may not be conservative depending on the weld size of the opposing connection. Excel worksheet no. b. If the governing allowable is due to weld: Increase the weld size. if possible.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG For Two-Sided Connection: (see note) For Fy_Supt = 36 ksi. If the governing allowable is due to beam web block shear : Either increase number of bolts or add web doubler plates h. If the governing allowable is due to plate shear yielding : Either increase plate length or plate thickness. If the governing allowable is due to plate bearing : Either increase number of bolts or plate thickness or bolt diameter c. If the governing allowable is due to beam cope : Reinforce the cope with web doubler plates or horizontal stiffeners i.5 For Fy_Supt = 50 ksi. If the governing allowable is due to bolt shear : Either increase number of bolts or increase bolt diameter. CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4.2. if the horizontal web stiffener cannot be provided in the column web. The bolts and the plate shall be checked for the moment equal to the reaction times the eccentricity of the bolt line from the weld line. The eccentricity of the reaction force with respect to bolt line shall also be recalculated. Additional checks required when extended shear tab cannot be stiffened (this situation shall be avoided) If the distance ‘a’ exceeds 3” due to fit-up and constructability constraints. the column web has to be checked for yielding. 1. Sherman. the following shall be done to avoid the situation of an unstiffened extended shear tab. If the beam is framing into the column web. additional check for plate thickness has to be done to check for stability.a Additional considerations for Extended Shear Plate Connection Unstiffened extended shear plate connections should be avoided as much as possible. The point at weld is considered to be a pin-support subjected to shear only. For these additional checks and eccentricity calculation refer to the “Design Procedures for Extended Shear Tabs” by Al Ghorbanpoor and Donald R. a pair of horizontal stiffeners shall be provided and welded to the column flange and webs. When a beam framing into the column web has to stop short of the column flange or when a beam framing into the web of a girder has to stop short of the flange of the supporting girder. . The distance of the bolt line from the end of the horizontal column web stiffener shall not exceed 3”. 2. the shear plate shall be welded to the top and bottom flange and the distance of the bolt line from the edge of the flange shall not exceed 3”. If the beam is framing into another beam. Also. The shear plate shall be welded to the top and bottom horizontal stiffeners. Fu = 70 ksi Beam End Reaction: R Step 2: Using Table V-A (for Fy = 36 ksi) or Table V-B (Fy = 50 ksi) and for the given beam web thickness (tw) and reaction R. pick the connection type and bolt diameter that satisfies the required beam end reaction. provide a stiffened seated connection. . Chapter K. The design of unstiffened seat (bolted or welded) requires the following steps. determine the seat angle thickness required. As an alternate.4. For Welded Connection: Using Table VI-C. Beam web thickness (tw) Weld Electrode E70XX. B and C are good for Column Flanges only. Bolt Diameter (d). beam web stiffeners shall be provided as specified in AISC Manual. Note that Connection Types A. where N is the bearing length on the OSL (taken as length of OSL). Section K1. of Bolts (n). If the Actual Reaction exceeds the Allowable as obtained from the Tables. The unstiffened seat is designed to carry the entire reaction. which provides lateral support to the compression flange.3. while Connection Types A thru F can be used on column or beam webs. Outstanding Leg (OSL) of seat angle = 4” Length of Seat Angle Seat Angle Yield Strength (Fy_angle) Beam Yield Strength (Fy). Step 4: Check for Beam Web Crippling: Determine values ‘R3’ and ‘R4’ from the Allowable Uniform Load Tables. Note that for welded seated angle. use Tables VI-A and VI-B in lieu of Tables V-A and V-B. No. the top angle could also be placed on one side of the beam web at the top.CONNECTION DESIGN STANDARD 4. Note: Always provide a top angle. Step 1: Establish the Design Inputs: Bolt Type. Allowable Load due to Beam Web crippling is (R3 + NxR4). Conclusion: If the Beam Web Crippling limits the allowable reaction. pick the seat angle size.a Unstiffened Seated Beam Connections DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG The beam is supported on a seat that is not stiffened.3 Seated Beam Connections 4. thickness and weld size that satisfies the required beam end reaction. Step 3: For Bolted Connection: Using Table V-C and knowing the bolt type. Chapter K. Step 4: Using Table VII-B and knowing the bolt type. R2.3.b. Step 3: Using Table VII-A (for Fy_angle = 36 ksi or 50 ksi) and for the assumed outstanding leg as determined in Step 2. Bolt Diameter (d). This will determine the Outstanding Leg length required for the stiffener angle. Beam web thickness (tw) Beam End Reaction: R Step 2: Using the Allowable Uniform Load Table. Note: Always provide a top angle. determine values for R1. If the Actual Reaction exceeds the Allowable as obtained from the Tables. Step 5: Check for Supporting Column flange/web or beam web bearing: Determine the load per bolt and compare to allowable bearing values given in Table I-E. . Section K1. determine the required bearing length N to prevent beam web yielding or crippling. Outstanding Leg (OSL) of stiffener angle ( Stiffener Angle Yield Strength (Fy_angle) Beam Yield Strength (Fy). of Bolts (n). The seat plate shall be 3/8” thick and shall extend past the stiffener angle. Based on these values. Actual load shall be less than the allowable bearing load. the top angle could also be placed on one side of the beam web at the top. R3 and R4. As an alternate. determine the stiffener angle thickness required that satisfies the reaction R. beam web stiffeners shall be provided as specified in AISC Manual. Step 1: Establish the Design Inputs: Bolt Type. Conclusion: If the Beam Web Crippling limits the allowable reaction.1 Bolted Stiffened Seated Beam Connections The beam is supported on a seat that is stiffened by a pair of angles. and repeat steps 2 thru 5.b Stiffened Seated Beam Connections 4.3. try with larger bolt size or larger number of bolts or thicker stiffener angle size. pick the bolt diameter and the fasteners required per row that satisfies the required beam end reaction.4. The design of bolted stiffened seat requires the following steps. which provides lateral support to the compression flange.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4. No. etc. except for W14x43 column where B shall be limited to 3”. Based on these values. Beams have to be connected to seat by high-strength A325 or A490 erection bolts or the bottom flange welded to the seat for a length of 2” on each side of the flange.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4. a. the location of the centerline of the bolts (B) shall be the greater of 0. R2. Maximum weld size is column web thickness for one sided connection. Top angle of minimum ¼” thickness shall be welded or bolted in place. For two sided connection maximum weld size is 0. The length of the stiffener shall be such that (B-stiffener thickness) >= 0. R3 and R4. e.b. Fu = 70 ksi Seat Plate Material Stiffener Plate Material Beam End Reaction: R Step 2: Using the Allowable Uniform Load Table. Step 1: Establish the Design Inputs: Beam Yield Strength (Fy).3. Beam web thickness (tw) Weld Electrode E70XX. Where seated connection width. 8” or 9”. . For beams supported off the column web.67 x web thickness for 50 ksi steel. determine the required bearing length N. c. the seat plate shall not be welded to column flanges. Vol I.5 x web thickness for A36 steel and 0. d.50W or 2 5/8”. This will determine the value of W to be used in Table VIII. If the bottom flange is bolted. limit B to 3 ½”.4 x L. where W is the Seat width measured along the beam. Step 3: Seat Plate Width measured along the flange (B) = Flange width + 4 x weld thickness Step 3: Using Table VIII and seat width W as determined in Step 2. b. determine values for R1. Thickness of the seat plate or the flange of a WT shall be minimum 3/8”. The following shall be checked as part of the design. and for a given beam end reaction and weld size. use the procedure in AISC Manual of Steel Construction. f. The design of stiffened seat (welded) requires the following steps. W is 7”. Table VIII.2 Welded Stiffened Seated Beam Connections For the design of welded stiffened seated beam connection. the length of the stiffener ‘L’ can be obtained. CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Also. i. . 0.e. Step 3: Check that the stiffener plate thickness is equal to 2 x weld thickness when material is A36 or at least 1.5 x weld thickness when the material is 50 ksi. Alternately. 2. a double clip angle connection can be proposed. the minimum weld between the seat and the stiffener is 0. reinforcing of the column web to be able to provide a thicker weld can be looked at.4L. If connection capacity as given by AISC Table does not meet the actual reaction. Conclusion: 1.2L on either side of the stiffener. the following shall set the limit of the copes for which a check of the cope is not warranted. Beam cope check shall be done if the cope exceeds the copes given in Table CDS 4.4 Special Considerations for Framed Beam Connections 4. May result in local buckling failure of the web.8.Needs to be considered at the time of beam design and hence is not in the scope of connection design.7 and Table CDS 4. These copes are based on using a 5/16” thick clip angle with ¾” diameter A325SC bolts.a Coped Beams Copes can affect the beam in two ways: DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 1. Hence this check is needed as part of the connection design. . Reduction in out-of-plane rotational restraint which reduces the resistance to lateral torsional buckling . 2.CONNECTION DESIGN STANDARD 4.4. This would require reinforcement of the web. As a design guideline. If No. all = Maximum (Rall.CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG 4. B-2.67. Step 5: Compute Allowable Shear based on cope bending. Fbc using Eqn. . Rall = (Fbc x Sn)/e Step 6: Compute Allowable Web Shear on the reduced section as Vall = 0. Vall) Step 8: Is Rmax. Vol. Manual of Steel Construction. Vol II. Web Reinforcement is required. Excel Worksheet COPE-1 is available for checking beams with top cope. no web reinforcement is required. B-3 Step 3: Compute c/d and determine f using Eqn. Appendix B. B-4 Step 4: Compute Allowable buckling stress. II.4.all > Actual Reaction If Yes.a. B-2. Variables: ho = Reduced beam depth tw = Beam web thickness c = Cope length dc = Cope depth d = Depth of the beam Sn = Reduced Section Modulus of the coped beam section (Obtained from AISC Manual. For ASD design the allowable buckling stress is based on a factor of safety of 1.1 Case 1 .Check of beams coped at top flange only Check cope based on AISC. Table B-1 or calculated if not available in the Table) e = cope length ( c ) + beam setback Fy = Yield-strength of the beam Step 1: Check if c <= 2d and dc <= d/2 Step 2: Compute c/ho and determine k using Eqn. End of beam cope check. Critical buckling stress of the compression portion shall be checked using Eqn. B-1. Rmax. The allowable bucking stress Fbc is computed using Eqn.4 x Fy x tw x ho Step 7: Maximum Allowable Reaction. a.Check of beams coped at top and bottom flanges Check cope based on AISC. all = Maximum (Rall.2 Case 2 .CONNECTION DESIGN STANDARD 4. B-6. Vol II. Table B-1 or calculated if not available in the Table) e = cope length ( c ) + beam setback Fy = Yield-strength of the beam Step 1: Check if c <= 2d and dc <= 0.67. . II. DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Critical buckling stress of the compression portion shall be checked using Eqn. Variables: ho = Reduced beam depth tw = Beam web thickness c = Cope length dc = Cope depth d = Depth of the beam Sn = Reduced Section Modulus of the coped beam section (Obtained from AISC Manual. Allowable buckling stress cannot exceed 0. Fbc using Eqn. B-5. End of beam cope check.2d Step 2: Compute fd = 3.4. If No. Appendix B. The allowable bucking stress Fbc is computed using Eqn. Vol.6Fy. B-6. Rall = (Fbc x Sn)/e Step 6: Compute Allowable Web Shear on the reduced section as Vall = 0.all > Actual Reaction If Yes.5 – 7. Excel Worksheet COPE-1 is available for checking beams with top and bottom copes. no web reinforcement is required. Manual of Steel Construction.5(dc / d) Step 3: Compute Allowable buckling stress.4 x Fy x tw x ho Step 7: Maximum Allowable Reaction. Rmax. Step 4: Compute Allowable Shear based on cope bending. For ASD design the allowable buckling stress is based on a factor of safety of 1. Web Reinforcement is required. Vall) Step 8: Is Rmax. 6*Fywdp) ] x 0. Other option such as Welded Tee Section is also possible but is not the preferred with many fabricators.5. Step 5: Extend the doubler plate at least a distance dc beyond the cope to prevent web crippling. For the design of bolted web doubler plate. Note that the welded web doubler plates and the welded horizontal stiffener plates will be discussed here since these are the most common applications.CONNECTION DESIGN STANDARD 4. Connections. Vol II.5 Design of Web Reinforcement DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Webs can be either reinforced with web doubler plates or web stiffener plates.4 x Fywdp Vwdp shall be greater than Rwdp Step 4: Design the weld between the web doubler plates and the beam web. 4. Check Weld for shear forces and the moment due to eccentricity. . Hence it will not be discussed here.all Step 2: Design Moment for doubler plate design = Mwdp = Rwdp x (c + setback) Step 3: Determine Doubler Plate thickness: twdp twdp = [(Mwdp x 6)/(dwdp2 x 0. The design of these elements will be discussed here. Manual of Steel Construction.a Design of Welded Web Doubler Plates Step 1: Design force for the design of web doubler plate = Rwdp = Actual Reaction – Rmax. Appendix B.5 (assumed two plates provided) Where dwdp = depth of web doubler plate Fywdp = yield strength of the web doubler plate Step 4: Check shear capacity of the web doubler plate: Vwdp = twdp x dwdp x 0. see AISC. increase plate size (thickness or width and repeat Steps 1 thru 4) .CONNECTION DESIGN STANDARD 4.5.6 x Fy_beam)x S / e DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Step 4: Is Rmax_all_revised > Actual Reaction If Yes. e.b Design of Horizontal Stiffener Plates Step 1: Select a plate size to start with. selected plate size is adequate or could be optimized if design margin is high If No. tpl x wpl Where tpl = plate thickness wpl = plate width Step 2: Calculate the reinforced section properties I and S Step 3: Determine Allowable Shear/Reaction as Rmax_all_revised = (0.g. CONNECTION DESIGN STANDARD 5. For design of moment connections with end plate see AISC Manual. pg. Beam to beam moment connections can be made by directly welding the flange of the beam to the supporting girder flange or web.1 thru 5. MC-TBFP-1 and MC-TBFP-2 are applicable for evaluating the moment connection using top and bottom flange plates. 4-116 through 4-125. pg 4-106 through 4-108. Flange plates can be used as well. The design of these connections is concerned with developing the full-plastic moment capacity at the joint.6 . For details of various typical moment connections see Figures 5. Directly welded flange (field welded) b.0 Moment Connections DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG These are rigid frame connections classified as AISC Type 1 connections. Split Tee on top and bottom flanges e. Excel worksheet no. For design of Directly welded flange connection see AISC Manual. Top and bottom flange plate (welded and bolted variety) c. For design of moment connections with flange plates see AISC Manual. Top and bottom angles (rarely used) Other moment connections are also possible. Beam to column web moment connections can be made using connection types ‘a’ or ‘b’ by introducing an extension plate in the column web. pgs 4-100 through 4-105 and 4109 thru 4-115. End Plate d. There are several varieties of beam to column flange moment connections such as a. These trusses resist the lateral forces of wind and seismic of the structure and transmit these forces ultimately to the foundation.0 Truss and Vertical Bracing Connections DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Trusses are used when the span gets large and it becomes uneconomical or unfeasible to use rolled shapes or plate girders. Connections. For details of various typical truss and vertical bracing connections see Figures 6. DESCON uses the Uniform Force Method concept for designing the connections at the supports. say from a rotating equipment or crane runway. The loads in a truss travel as axial loads through the truss members. also called as the vertical bracing system for the structure. The design methodology for a truss connection or vertical bracing connection is similar. Vol II. The connections of the bracing members that form the horizontal truss are called Horizontal Bracing Connections. Typically members that carry gravity loads are called trusses. The same truss when laid on its side can be used as horizontal trusses in a floor to carry the lateral loads. For design of truss connections and vertical bracing connections. Chapter 7. Another use of trusses is to provide stability to a structure against lateral sway and to resist wind and seismic forces. refer to AISC Manual. The connections associated with the diagonal members of the truss with the chord members or at the supports at a column and/or beam are called Truss Connections. The connections for these vertical bracing systems can get very complex based on the magnitude of loading. All truss connections and vertical bracing connections shall be designed using DESCON.CONNECTION DESIGN STANDARD 6.1 thru 6. Such trusses form the lateral force resisting system for a building. etc. .26. Directly bolted to the bottom flange of the beam b. These are typically encountered in industrial structures where grating floors are supported on steel frames and concrete flors are not present to transmit the lateral loads through diaphragm action. horizontal bracing system is employed to carry the lateral loads from the floor to the supports. For design of horizontal bracing support. etc to the supporting girder that eventually transmits it to a lateral load resisting system. the brace load is broken down into its components along the beam’s longitudinal axis and perpendicular to it. Connected to the beam web using a shear tab c.0 Horizontal Bracing Connections DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Horizontal trusses can be used in a floor to carry the lateral loads. Connected to the beam web using double clip angle if load is high For details of various typical horizontal bracing connections see Figures 7. say from a rotating equipment or crane runway.1 thru 7.6 . Hence typical connection is a shear connection oriented horizontally. Usually the load component perpendicular to the beam is negligible unless there is a transfer force at that panel point.CONNECTION DESIGN STANDARD 7. The connections of the bracing members that form the horizontal truss are called Horizontal Bracing Connections. Connected to the beam web using a single clip angle d. a. The brace is welded or bolted to the gusset and the gusset is in turn connected to the supporting beam in the following manner. In such instances. CONNECTION DESIGN STANDARD 8. columns and plate girders for various reasons.4. . Splices can be all welded or all bolted or a combination of welded and bolted connection. or the fabricator chooses to specify a splice for ease of shipping and erection or when the designer chooses to vary the crosssection of the member. For details of various typical splices see Figures 8. Splices can be either simple shear splice or those that provide continuity to a member in which case it shall be designed for both shear and moment. Splices are required when the rolled section are not be available in the lengths required.1 thru 8.0 Splices DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Splices are specified for beams. CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG APPENDIX A CONNECTION CAPACITY TABLES . CONNECTION DESIGN STANDARD DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG APPENDIX B CONNECTION SUMMARY TABLE TEMPLATES . Descon Brace-ASD. Descon Win-ASD. In addition. Descon Brace-LRFD. Version 5. Descon Win-LRFD. several worksheets are available for designing various types of connections.CONNECTION DESIGN STANDARD APPENDIX C Design Software and Worksheets DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG Design of Standard AISC connections using the AISC prescribed methodology can be done using the software “DESCON”.1 c. The list of worksheet is as follows: Connection Type Shear Connection Shear Connection Shear Connection Shear Connection Shear Connection Shear Connection Shear Connection Shear Connection Shear Connection Shear Connection Worksheet No. They are a. There are four modules in DESCON. Version 4. Version 4.0 d. Module ‘c’ can design FEMA-350 connections as well. Modules ‘b’ and ‘d’ are used for designing lateral bracing connections in ASD or LRFD respectively.1 Modules ‘a’ and ‘c’ are helpful for designing shear. moment and splice connections. Version 4.1 b. DCA-1 DCA-2 DCA-3 DCA-4 COPE-1 SSPC-1 SBC-1 SBC-2 SBC-3 SBPC-1 Description Double Clip Angle Connection – Bolted/Bolted Double Clip Angle Connection – Welded/Bolted Double Clip Angle Connection – Bolted/Welded Double Clip Angle Connection – Welded/Welded Beam to Beam Cope check only Single Shear Plate Connection Seated Beam Connection – Unstiffened (Bolted / Bolted and Bolted / Welded) Seated Beam Connection – Stiffened (Bolted ) Seated Beam Connection – Stiffened (Welded ) Single Bent Plate Connection – (Double bolted) . CONNECTION DESIGN STANDARD Shear Connection Moment Connection Moment Connection Moment Connection Moment Connection Moment Connection Bearing Connection Bracing Connection Splicing Connection Splicing Connection Splicing Connection SBPC-2 MC-FW-B-C-1 MC-SW/FB-1 MC-HSS-HSS-1 MC-HSS-WCW-1 MC-WF-HSS-TPL-1 BEARING PLATE-1 BSC-GPL-CB-1 BEAM-SPLICE-CA/FP-1 SPLICE-BEAM-1 SPLICE-COLUMN-1 Single Bent Plate Connection – Welded/Bolted Field Welded Moment Connection between Beam and Column Shop Welded Field Bolted Moment Connection between Beam and Column HSS beam to HSS column Moment Connection HSS beam to Wide flange Column Web Moment Connection Wide flange beam to HSS Column Moment Connection w/ Through Plate Bearing Plate design Checks for Bolt Shear Capacity and Gusset Plate of Cross Bracing Beam Splice using Clip Angle for Web splice and Flange Plate for flange splice Beam to Beam splice Connection Column Splice connection DOC NO: CDS-1 Prep by: JVJ Chkd by: MNG .