P.O.BOX 12443 – JEDDAH 21473 – SAUDI ARABIA TEL : +966-2-2250065 FAX : +966-2-2250073
DESIGN OF FLUST-EXTENDED END PLATE CONNECTION KING SAUD UNIVERSITY
PROJECT : DATE:
Prep. By:
7/23/2010
BUILDING:
S.S.
Check. :
Cert. :
MB
MB
B#24- GRAND FOYER
Members
Joint
CASE NO
CASE OF LOADING DESCRIPTION
1001
500
8
D + L
DESIGN NOTES AND ASSUMPTIONS :
-All Dimensions in mm ,Forces in ton and stresses t/cm2. -This procedure is deigned for bearing type connections only. -The primary assumption in this approach is that the end plate must substantially yield to produce prying forces in the bolts.Conversely,if the plate is strong enough,no prying action occurs and the bolts are loaded in direct tension This simplified assumption allows the designer to directly optimize either the bolt diameter or end-plate thickness as desired. -The threshold when prying action begins to take place in the bolts at 90% of the full strength of the plate or 0.9Mpl If the applied load is less than this value, the end plate behaves as a thick plate and prying action can be neglected in the bolts.Once the applied moment crosses the threshold of 0.9Mpl,the plate can be approximated as a thin plate and maximum prying is incorporated in the bolt analysis. -Intermediate plate behaviour is a transition from T hick to Thin behaviour and considered as a thin behaviour during the analysis. -The factored axial load will be converted into an equivalent moment that will be added to the factored connection moment for axial tension. -The width of end plate ,Which is effective in resisting the applied beam moment shall not be taken greater than than the beam flange width plus 1 inch in the calculations. -The beam flange to end plate weld can be designed for the required moment strength but not less than 60% of the specified minimum yield strength of the connected beam flange. -When the full design strength is not required, the beam web to end plate welds should be designed to develop 60% of the minimum specified yield strength of the beam web. -Stitch bolts are sometimes used between the tension and compression flange end plate bolts especially in deep connections. The purpose of these bolts is to reduce plate separation caused by welding distortions.Because distortions.Because stitch bolts are located near center of gravity of the member,Contribution member,Contribution to connection strength is small and is neglected -The purpose is to design connections Type(FR) or Type"1" which is fully restrained moment connections -Type(1) or "FR" connections are traditionally required to carry and end moment greater than or equal to 90% of the full fixity end moment of the beam and not rotate more than 10% of the simple span rotation. -This procedure is based on Yield line technique to determine end plate thickness and to predict the tension forces Considering the prying actions. -Yield line are the continous formation of the plastic hinges along a straight or curved lines. -Thick plate behaviour is taken place when plastic hinges is not formed in the split-tee flange and the prying force value is equal to "zero". -Thin plate behaviour is taken place when plastic hinges is formed in the split-tee flange and the prying force value is not equal to "zero". -All loads and internal forces comply with LRFD method (internal forces in ASD Could be muliplied by 1.5). -Flush End plate connections are typically used for light loads or near moment inflection point. -All Shear Forces assumed to be resisted by compression bolts -Bolts in tension may be tightened to 70% of the bolt tensile strength or could be snug tightened (for Bolts A325 Only) -This spreadsheet is designed to check the connection strength for the following limit states : -Connection Strength Based on End plate Yielding. -Connection Strength Based on bolt rupture without prying action. -Connection Strength Based on bolt fracture w/prying action. -Effect of axial forces will be neglected incase the axial force is compression.
NOTATIONS
ɣr-Load Factor to limit connection
h0-distance from the compression side of the beam to the outer bolt centerline in extended end plate connection h1-distance from the compression side of the beam to the farthest inner load-carrying bolt line. h2-distance from the compression side of the beam to the second farthest inner load-carrying bolt line. h3-distance from the compression side of the beam to the third farthest inner load-carrying bolt line. h-Total depth of the beam Mpl-Connection strength for limit state of end plate yielding Pf,i-distance from the bolt centerline adjacent to beam tension flange to the near face of the beam tension flange Pf,O-distance from the outer bolt centerline to the outer face of the beam tension flange Ps,o-distance from the outer bolt centerline to the outer face of the stiffener in four-bolt flush connection with stiffener between bolt rows Pext-End-plate extension beyond the exterior face of the beam tension flange Ft-Tensile strength of bolts Ab-Nominal Bolt area Mnp-Connection strength for the limit state of bolt fracture with no prying action ai-Distance from the interior bolt centerline to the prying force = 3.682 (tp / db)^3 - 0.085 ao-Distance from the exterior bolt centerline to the prying force = Min of (3.682 (tp / db)^3 - 0.085 , Pext-Pf,o ) d(0,1,2)-Distance from the Compression flange centerline to the centerline of "n" bolt Q max,o-Maximum Possible Prying force for exterior bolts Tb-Specified pretension load in high strength bolts Table J3.1,AISC(2000) or if if snugg tight,recommended percentage of Table J3.1 based on bolt diameter Lp-Spacing between bolt rows centerlines in compn zone tw-Thickness OF the beam web Mnw-Connection Strength Based on Welding to the end plate
rotation at ultimate moment to 10% of simple span rotation db-nominal bolt diameter tp-End Plate Thickness bp-End Plate Width h-Total Beam depth g-Bolt Gage Y-Yield line mechanism parameter Fyp-End plate material yield stress s(1/2 √bp*g)-Distance from the innermost bolt centerline to the innermost yield line Pb-distance from bolt CL to bolt CL Ps,i-distance from the first interior bolt centerline to the inner face of the the stiffener in four-bolt flush connection with stiffener inside bolt rows de-End-plate extension beyond the exterior bolt centerline =pext-pf,o tf -Beam Flange Thickness Pt-Bolt material Ultimate tensile load capacity ,proof load = Ab x Ft W'-bp/2-(db+1/16) Fi'-Flange force per bolt at the thin plate limit when calculating Q max,I for end plate configurations = *tp2Fpy(0.85bp/20.8w') πdb3 Ft/8+/(4Pf,i)
Q max,i-Maximum Possible Prying force for interior bolts Mq-Connection strength for the limit state of bolt fracture with prying action. Lc-Clear distance in direction of force between the edge of the hole and the edge of the adjacent hole. bf -Width of the flange beam Iwxx-Welds moment of inertia about the major axis of the beam
A)DESIGN INPUT Type of Connection
Extended.End.Plate
Type of Bolt A325N
Bolts Arrangement Stiff. Arrangement Tension flange weld FExx =
E.4
tp =
10
MM
bp =
203
MM
h= Fyp =
600
MM
g= h0 =
3.52
t/cm2
h1 =
565.00
MM
Fup =
5
t/cm2 h2 =
600.00
MM
Type OF Tightening
Unstiffened Fillet Weld 4.09
t/cm2
Snug Tightening
tf =
10.00
MM
bf =
200.00
MM
tw = db =
13.00
MM
19.05
MM
76.20
MM
673.00
MM
Pf or Pf,i =
44.45
MM
Pf,o =
63.5
MM
h3 =
500.00
MM
Pb =
65
MM
Ps,o =
34.93
MM
Ps,i =
31.75
MM
Ps =
20.00
MM
Pext =
127
MM
Mu =
2018
ton.cm
Tu = Sf =
0
ton
18
MM
Sw =
4
MM
No.Of bolt rows in Compn = No.Of bolt cols in Compn =
Lp =
2 2 60
MM
B)DESIGN PARAMATERS ɣr = s= pf ,i = de =
668.00
MM
Ft =
6.33
t/cm2
62.19
MM
d0 = d1 =
560.00
MM
Ab =
2.85
CM2
44.45
MM
d2 =
0.00
MM
Y=
481.9
CM
63.5
MM
d3 =
0.00
MM
w' =
8.05
CM
18.04
ton
Q max,i =
6.05
ton
3.95
ton
Q max,o =
6.14
ton
1
ai =
1.14
CM
Pt =
ao =
1.14
CM
Fi' =
2.76
ton
Tb =
cm4 124501 Connection Behaviour
Lc =
Fo' = Iwxx =
ton Mu = 6.31 2018.00 MM Fnv = 38.95 3.38 Thin Plate Behaviour(W/Prying action)
ton.cm t/cm2
C)LIMITS OF APPLICABILITY 1)
25 64 70 400 152 9.5
2) 3) 4) 5) 6)
≥ Pf ≥ ≥ ≥ ≥ ≥ ≥
Pb g h bp tf
64 130 178 610 260 26
≥ ≥ ≥ ≥ ≥
OK OK OK OK OK OK
D)Calculation of Connection Strength i)Limit state of End-Plate Yielding(Mpl) ɸb = 0.9 Mpl = Fpy * tp2 * Y = ɸbMpl/ɣr
=
1696.18 t.cm t.cm
1527
ii) Limit state of Bolt Rupture(Mnp) without prying action. ɸ = 0.75 Mnp = = [ 2 Pt (Σdn) ] 4431.10 t.cm Mnp/ Mpl =
2.61
ɸMnp
=
t.cm
3323
iii) Limit state of Bolt Rupture(Mq) w/prying action a)Case of Extended End Plate Connection ɸ = 0.75 Mq = [2*(Pt-Q max,o)d0 + 2(Pt-Q max,i) (d1 + d3) + 2Tb*d2 ] [2*(Pt-Q max,o)d0 + 2Tb (d1+d2+d3) ] [2*(Pt-Q max,o)*(d1+d3) + 2Tb (d0+d2) ]
b)Case of Flush End Plate Connection ɸ = 0.75 Mq = [ 2(pt-Qmax)(d1+d2) ] [ 2Tb(d1+d2) ] Max
[2Tb (d0+d1+d2+d3) ] Max
ɸMq
=
t.cm
2200
Thin Plate Behaviour(W/Prying action)
iv) Limit state based on shear strength of bolts ɸ = 0.75 ɸRn
=
ɸ Fnv Ab
=
29
ton
(AISC 360-05 J3-1)
iiv) Limit state based on Bearing strength at bolt holes ɸ = 0.75 ɸ2.4dtFupn ɸRn = ɸ1.2LctFupn ≤ ɸ1.2LctFun = 70.11 ton ɸ2.4dtFupn = 68.58 ton ɸRn
=
69
iv) Limit state based on welding to end plate ɸ = 0.75 ɸFw = ɸ 0.6 FExx = 1.84 ɸMnw = ɸFw Iwxx / yw ɸMnw = t.cm 7416
(AISC 360-05 J3-6a)
ton
t/cm2
Connection Strength
Mu(t.cm)
Qu(ton)
Mnw(t.cm)
1527
29
7416
