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Daniel
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PROJECT : PAGE :
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Tian LiCLIENT :
DESIGN BY :
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JOB NO. : DATE :
REVIEW BY :
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Seismic Design for Special Moment Resisting Frames Based on AISC Seismic - LRFD
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INPUT DATA & DESIGN SUMMARY
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COLUMN SECTION
= >
W14X426
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A dtwbftfSxIxrxryZxk
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12518.71.8816.703.0470666007.274.358693.63
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BEAM SECTION
= >
W36X150
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A dtwbftfSxIxrxryZxk
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44.235.90.6312.000.94504904014.302.475811.69
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STRUCTURAL STEEL YIELD STRESS
Fy =50ksi
THE SMRF DESIGN IS ADEQUATE.
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THE FACTOR GRAVITY LOAD ON THE BEAM
wu =0.25klf
(Continuity column stiffeners 1 x 8
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THE FACTOR AXIAL LOAD ON THE COLUMN
Pu =800kips
with 3/4" fillet weld to web & CP to flanges.
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BEAM LENGTH BETWEEN COL. CENTERS
L =30ft
A doubler plate is not required. )
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AVERAGE STORY HEIGHT OF ABOVE & BELOW
h =12ft
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REDUCED SECTION DIMENSIONS
a =7
in, [0.5~0.75bf]
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b =25
in, [0.65~0.85db]
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c =2.5
in, [ < 0.25bf]
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ANALYSIS
r = (4c2 + b2 ) / 8c =
32.5in
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Sh = dc/2 + a + b/2 =
28.9in
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CHECK BEAM LOCAL BUCKLING LIMITATIONS (AISC Seiemic 02 Tab. I-8-1)
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bf / (2tf ) =
6.38<
0.3 (Es / Fy)0.5 =
7.22
[Satisfactory]
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[ 52 / (Fy)0.5 for AISC Seismic 97, Tab. I-9-1]
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Where Es =29000ksi
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h / tw =52.03<
2.45 (Es / Fy)0.5 =
59.00
[Satisfactory]
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[ 418 / (Fy)0.5 for FEMA Sec. 3.3.1.2]
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CHECK COLUMN LOCAL BUCKING LIMITATIONS (AISC Seiemic 02 Tab. I-8-1)
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bf / (2tf ) =
2.75<
0.3 (Es / Fy)0.5 =
7.22
[Satisfactory]
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[ 52 / (Fy)0.5 for AISC Seismic 97, Tab. I-9-1]
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h / tw =6.09<{
3.14(Es/Fy)0.5(1-1.54Pu/fbPy) =
N/A
, for Pu/fbPy < 0.125
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[ 520 / (Fy)0.5(1-1.54Pu/fbPy) for AISC Seismic 97, Tab. I-9-1]
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1.12(Es/Fy)0.5(2.33-Pu/fbPy) =
59.01
, for Pu/fbPy > 0.125
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{ MAX[ 191 / (Fy)0.5(2.33-Pu/fbPy) , 253 / (Fy)0.5] for AISC Seismic 97, Tab. I-9-1}
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[Satisfactory]
Where fb =0.9
, Py = FyA =
6250kips
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CHECK BEAM - COLUMN RATIO REQUIREMENT (AISC Seiemic 02 Sec. 9.6, Pg. 16)
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SMpc* / (SMpb* ) =
2.50>1.00
[Satisfactory]
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Where
SMpc* = SZc (Fyc - Pu / Ag ) =
6315ft-kips
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SMpb* = S(MRBS + Mv) =
2528
ft-kips, at center of column
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Mv = VRBS Sh = [2MRBS /(L-2Sh)+wu(L-2Sh)/2] Sh=
427ft-kips
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MRBS = CprRyFyb ZRBS =
2196ft-kips
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Ry =1.1
(AISC Seiemic Tab. I-6-1)
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ZRBS = Zb - 2c tf (d - tf) =
417in3
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Cpr = 1.15
(FEMA Sec. 3.5.5.1)
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CHECK BENDING MOMENT AT THE COLUMN FACE
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Mf = MRBS + [2MRBS / (L - 2Sh) + wu(L - 2Sh)/2] (a + b/2)
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 =2485ft-kips<
RyFyb Zb =
2663ft-kips
[Satisfactory]
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CHECK CONTINUITY PLATE REQUIREMENT (FEMA Sec. 3.3.3.1)
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tcf = MIN{ bbf / 6 , 0.4[1.8bbf tbf (FybRyb) / (FybRyb)] 0.5 }=
1.80in<
actual tcf
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(The continuity plates may not be required.)
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tst = tbf for interior connection, or (tbf /2) for exterior connection =
0.94in,USE1.00in, ( 1 in )
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bst = 8in<
95 / (Fyst )0.5 tst =
15.83
in, (LRFD Sec. K1.9)
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[Satisfactory]
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fcPn,st = fcFcr A =
788.2kips
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Where fc =0.85
hst = dc - 2k =
11.4
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K =0.75
K hst / rst < 200
(LRFD B2)
[Satisfactory]
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I = tst (2bst + twc) 3 / 12 =
383in4lc =0.025
(LRFD E2-4, Pg 6-47)
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A = 2bsttst + 25(twc) 2 =
26in2Fcr =35.99
ksi (LRFD Sec.E2, Pg 6-47)
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rst = ( I / A )0.5 =
3.86in
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Pu,st = Ryb Fyb bfb tfb =
620.4kips<fcPn,st
[Satisfactory]
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(Cont'd)
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The best fillet weld size (LRFD Sec.J2.2b)
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w =3/4in
> wMIN =
 5/16in
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< wMAX =
15/16in
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[Satisfactory]
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The required weld length between A36 continuity plates and column web (FEMA Fig 3-6)
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Lw = 0.6tstLnstFy / [(2) f Fw (0.707 w)]
= (1 x 8.4) x 36 / [(2) 0.75 (0.6x70)(0.707x3/4)] =
3.86in
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Where
Lnet = dc - 2(kc + 1.5) =
8.4<
2(Lnet -0.5)
[Satisfactory]
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(Use complete joint penetration groove welds between continuity plates & column flanges.)
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CHECK PANEL ZONE THICKNESS REQUIREMENT (AISC Sec. 9.3 & FEMA Sec. 3.3.3.2)
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tReqD = MAX (t1, t2) =
1.04in
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t1 = Cy Mc (h - db ) / [0.9 (0.6) Fyc Ryc dc (db - tfb) h] =
1.04in
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Where
Cy = Sb / (Cpr ZRBS) =
0.88
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Sb = 2Ib / db =
424in2
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Ib = Ix - (2 c tfb)(0.5db - 0.5tfb)2 =
7604in4
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Mc = SMpb* =
2528ft-kips
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t2 = (dz + wz ) / 90 = (db -2tst + dc - 2k) / 90 =
0.50in12
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Since twc =
1.88in>
tReqD , a doubler plate is
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not required.
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Techincal References:
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1. FEMA 350: "Recommended Seismic Design Criteria for New Steel Moment-frame Buildings.", SAC Joint Venture, 2000.
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2. Alan Williams: "Seismic and Wind Forces, Structural Design Examples", International Code Council, 2003.
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3. SEAOC: "2000 IBC Structural/Seismic Design Manual - Volume 3", International Code Council, 2003.
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4. AISC: "Seismic Provisions for Structural Steel Buildings", American Institute of Steel Construction, May 1, 2002.
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