SESSION 6 ENDPLATE MOMENT CONNECTIONS BRACING CONNECTIONS 1

SESSION 6 END-PLATE MOMENT CONNECTIONS BRACING CONNECTIONS 1

MOMENT END-PLATE CONNECTIONS • LRFD Vol. II Configurations 4 -Bolt Extended Unstiffened 2

3

Moment End-Plate Connections • LRFD Vol. II Configurations 8 -Bolt Extended Stiffened 4

5

Moment End-Plate Connections • New AISC Design Guide 4 B (Late 2001) Flush Configurations 6

Moment End-Plate Connections • New AISC Design Guide 4 B (Late 2001) Extended Configurations 7

Moment End-Plate Connections LRFD Vol. II Design • 4 -Bolt Extended Unstiffened Assumptions: – No prying forces – Compression side bolts resist all shear 8

Moment End-Plate Connections LRFD Vol. II Design • 4 -Bolt Extended Unstiffened Design Model: – Finite Element Analysis – Regression Equations 9

Moment End-Plate Connections LRFD Vol. II Design • 4 -Bolt Extended Unstiffened Limitations: – Not for seismic design – Pretensioned bolts – bp < bf + 1 in. – g < bf bp g 10

Moment End-Plate Connections Limit States: • Tension Bolt Rupture • End-Plate Flexural Strength • Tension Flange Weld • Web Welds • Compression Side Bolt Shear 11

Moment End-Plate Connections • Tension Bolt Rupture ru = Mu / [4 (d - tf)] ru < frt = 0. 75 Ft Ab Vu A 325 Ft = 90 ksi A 490 Ft = 113 ksi Mu 12

Moment End-Plate Connections • End-Plate Flexural Strength Ffu = factored beam flange force = Mu / (d – tf) pf t wt = 0. 707 t 13

Moment End-Plate Connections • End-Plate Flexural Strength, Continued Ca = depends on Fy of beam, end-plate, and bolt type Cb = (bf / bp)1/2 14

15

Moment End-Plate Connections • End-Plate Flexural Strength Meu < f. Mp = f Fy Zp Zp = plastic section modulus = b p tp 2 / 4 f = 0. 9 16

Moment End-Plate Connections • End-Plate Shear Strength bp Ffu < 0. 75(0. 6)Fu (bp – 2 dh´) tp Ffu < 0. 9(0. 6)Fy bp tp tp 17

Moment End-Plate Connections • Tension Flange Weld – Full penetration welds or fillet welds to resist Ffu – Recommend developing strength of flange 18

Moment End-Plate Connections • Web Welds Weld designed to resist web tension strength 2 db Weld designed to resist shear, Vu 19

Moment End-Plate Connections • Compression Side Bolts Vu Alternate: Design all bolts for shear + tension S f rv > Vu 20

Moment End-Plate Connections • 8 -Bolt Extended Stiffened Assumption: – Compression side bolts resist all shear 21

Moment End-Plate Connections • 8 -Bolt Extended Stiffened Design Model: – Finite Element Analysis – Regression Equations 22

Moment End-Plate Connections • 8 -Bolt Extended Stiffened p Limitations: – Not for seismic design – Pretensioned bolts – bp < bf + 1 in. – g < bf g 23

Moment End-Plate Connections • 8 -Bolt Extended Stiffened Limitations: – Only A 325 bolts – pf < 2 1/2 in. – pb < 3 db (vertical spacing) – 5 1/2 in. < g < 7 1/2 in. – 3/4 in. < db < 1 1/2 in. p g 24

Moment End-Plate Connections 8 -Bolt Extended Stiffened Limit States: • Tension Bolt Rupture • End-Plate Flexural Strength • Tension Flange Weld • Web Welds • Compression Side Bolt Shear • Stiffener Strength 25

Moment End-Plate Connections • Tension Bolt Rupture ru = Mu / [6 (d – tf)] 6 bolts effective (due to prying) ru < f. Ft Ab = 0. 75 Ft Ab A 325 Ft = 90 ksi (A 490 not permitted) Vu Mu 26

Moment End-Plate Connections • End-Plate Flexural Strength Meu = 2 ru (peff / 2) = ru peff ru = Mu / [6 (d – tf)] = force per bolt 27

Moment End-Plate Connections • Weld Design – Same rules as for 4 -bolt • Compression side bolts – Design to resist shear 28

Moment End-Plate Connections • Stiffener Design – Geometry 1" 30° ts > (Fyb / Fys) tw 1" ts 29

Moment End-Plate Connections • Stiffener Design - Welds Ffu / 2 or full pen. Ffu / 2 30

Column Side Limit States at Moment End-Plate Connections Vu Mu Four Bolt Extended Unstiffened 31

Column Side / Moment End-Plate • Limit States – Local Flange Bending * – Local Web Yielding * – Local Web Crippling (K 1. 5) – Web Buckling (K 1. 6) – Panel Zone Yielding (K 1. 7) * Modified per AISC LRFD Vol. II 32

Column Side / Moment End-Plate • Column Flange Bending at Four Bolt End-Plate c 2. 5 c twc Think of end-plate turned 90° Column Flange End-Plate Column Web Beam Flange 33

Column Side / Moment End-Plate • Analyze column flange as an end-plate with tp = tfc bp = 2. 5 c = 2. 5 (pf + tfb + pf) Af / Aw = 1. 0 and previous equations 34

Column Side / Moment End-Plate • Local Web Yielding 1: 1 Slope Lcr Tu or Cu N = tf ± Fy Lcr = tfb + 2 w +2 tp + 6 kdesign 3 1 35

Column Side / Moment End-Plate Same as previous except critical length: f. Rn = 1. 0 Fyc (tfb + 6 k + 2 tp + 2 w) twc k = kdesign • Local Web Crippling Same as previous for flange and flange plate connections 36

Column Side / Moment End-Plate • Web buckling Same as previous for flange and flange plate connections 37

BRACING CONNECTIONS • Light Bracing Connections • Heavy Bracing Connections 38

Light Bracing Connections Tu w. p. 39

Light Bracing Connections Limit States Angles: - Tension Yielding - Tension Rupture - Bearing / Tear Out - Block Shear Bolts: Tu w. p. - Shear Rupture 40

Light Bracing Connections Plate: - Tension Yielding on Whitmore Section - Tension Rupture on Whitmore Section (0. 85 Ag rule applies) - Bearing / Tear Out - Block Shear if more than two rows of bolts in the w. p. direction of force Tu 41

Light Bracing Connections Welds: - Weld Rupture on Whitmore Section - Combined Tension and Shear Tu fv w. p. ft 42

Light Bracing Connections Tu w. p. 43

Light Bracing Connections Limit States Angles: - Tension Yielding - Tension Rupture Tu w. p. Weld: - Weld Rupture 44

Light Bracing Connections Tee Stem: - Tension Yielding on Whitmore Section - Tension Rupture on Whitmore Section - Block Shear T - Shear Yielding u w. p. 45

Light Bracing Connections Tee Flange: - Flange Bending - Shear Yielding - Shear Rupture - Bearing / Tear Out - Block Shear Tu w. p. 46

Light Bracing Connections Bolts: - Combined Shear Plus Tension Column Flange: - Flange Bending - Bearing / Tear Out Column Web: - Web Yielding w. p. Tu 47

Heavy Bracing Connections 48

Heavy Bracing Connections • Gusset plate is welded to beam and bolted to column • No new limit states!! • Forces determined using the Uniform Force Method 49

50

V = T cos q T H = T cos q Hc Vc q Rc b w. p. eb Hb Rb fc o fb ec Vb a 51

Heavy Bracing Connections Combining (1) and (2) and using angle relationships 52

Heavy Bracing Connections Column Forces Beam forces where 53

Heavy Bracing Connections Notes: • Hb should be increased 40% to account for redistribution of forces at gusset-tobeam welds. • Connection at column is a tee hanger • Welds at beam resist shear plus tension See LRFD Volume II for other cases. 54

END OF SESSION 6 55