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The Steel Solutions Center is your gateway to powerful tools, facts and project solutions. Clean Columns
Least weight is not least cost.
Least weight is not least cost.
Least weight is not least cost. AISC has been saying saying this for years. Now we'd like to show you. you. Clean Columns calculates the lightest column section required to eliminate stiffener and doubler plates.
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P uc Vus
Beam/Girder
Column Mu
Pub
P ub
Mu Transverse Transverse S tiffeners, if Required
V us P uc
Column Panel-Zone Location of Doubler Plates, if Required
Talk to your favorite fabricator, or consult chapter 3 of Design Guide 13 for more information on the cost of stiffener and doubler plates. Comments? Questions? Visit us online at www.aisc.org/ASKAISC or contact us at
[email protected] or toll free at 866.ASK.AISC
Project:
Sample Project
Client:
Client
Engineer: Remarks:
6/27/2013
Senior Engineer Remarks on this connection evaluation
Clean Columns V3.1 was developed to return the lightest column section which can be used without stiffeners and/or doubler plates to develop a specified percentage of a selected beam's plastic moment capacity, based on the criteria in AISC Design Guide Series #13. The design of the column for axial load capacity is not considered.
1) Verify the Following Assumptions: The effects of composite floor construction are not included in analysis
Puc Vus
Wind or low seismic applications (Structure is designed to meet the requirements in the LRFD Specification with no special seismic detailing)
Column Mu
dm = d - t f (used to convert the beam moment into flange forces) Panel-zones remain nominally in the elastic range N = beam flange thickness (w = 0, ie. no reinforcing fillet weld included)
Pub
Welded flange or flange plate connections only. May be overly conservative for end-plate moment connections 2) Provide the Following Parameters: Fyc = 50 ksi Column Specified Minimum Yield Strength Fyb =
50 ksi
Beam Specified Minimum Yield Strength
Vus =
45 kips
Factored Column Story Shear
Puc =
1200 kips
Pub =
5 kips Factored Beam Axial Load of M φ 80% p Factored Bending Moment in Beams as a percentage of the Beam's Plastic Moment Strength
Mu =
Beam/Girder Transverse Stiffeners, if Required
Vus Puc
Column Panel-Zone Location of Doubler Plates, if Required
Factored Column Axial Load
3) Select a Beam using the pulldown menus below: Nominal Depth
W24
Beam Section
W24x55
4) Choose a Connection Configuration: Beam Connected on One Side Only
* Group 4 or 5 Shape 6) Beam Properties φ Mp =
5) Verify the Connection Location: 503 kip-ft
Plastic Moment Strength
Beams are not Connected Near the Top of the Column
Project:
Sample Project
Client:
Client
Engineer: Remarks:
6/27/2013
Senior Engineer Remarks on this connection evaluation
Clean Column Design Calculations for a W14x398* Column I) Force Transfer in Unreinforced Columns Puc
A) Required Strength for Local Flange and Web Limit States
V us
Design for a W24x55 Beam with 80% of the Nominal Plastic Moment Strength (503 kip-ft) Transferred to the Column Mu = Pub = d= tf =
402 kip*ft 5 kips 23.57 in
Factored B eam E nd Moment
Mu
Factored Beam Axial Load Beam Depth
0.505 in dm = 23.065 in
Pub
Beam Flange Thickness Moment Arm between Flange Forces
Beam/Girder
d m=d −t f Puf =
Column
212 kips
Factored Beam Flange Force (tension or compression)
Transverse Stiffeners, if Required
M u P ub ± P uf = d m 2
Column Panel-Zone Location of Doubler Plates, if Required
Puc
Figure 1. Exterior Column
B) Required Strength for Panel-Zone Shear Moment Connected Beam on One Side Only Vus = 45 kips Factored Column Story Shear Vu =
Vus
Puf
(Tension)
167 kips Factored Total Panel Zone Shear Force For a column with only one moment connected beam
dm
Mu
V u= P uf −V us For a column with two moment connected beams
V u = 2P uf −V us II)
Design Strength of an Unreinforced Column
Puf
(Compression)
f /2
FIgure 2. Beam Flange Forces
Design Check for Column Section: W14x398* Fy = dtop =
50 ksi DNA
A) Panel-Zone Shear Strength
Column Minimum Specified Steel Yield Strength Distance from the column end to the top flange of the beam(s) Vus
Pub
C) Local Web Yielding For calculations purposes, no fillet weld or groove weld reinforcement was used. N= tw =
0.505 in
dc =
18.29 in
Ct =
1.0
Beam or flange plate thickness
1.77 in
Column Web Thickness Column Depth 0.5 if the distance from the end o f the column to the closer face of the beam tension flange is less than d c
=
= 1.0 otherwise k= φRn =
3.50 in
Distance from the outside face of column flange to th e web toe of the flange-to-web fillet
1593 ki ps
Local Web Yiel di ng Design Strength
φR n=1 . 0 x {C t ( 5k )+ N } xF y t w D) Web Crippling For calculations purposes, no fillet weld or groove weld reinforcement was used. N= tw =
0.505 in
dc =
18.29 in
tf =
2.85 in
Beam or flange plate thickness (w=0 because no reinforcing welds are present)
1.77 in
Ct =
1.0
Nd =
0.08
Column Web Thickness
Reinforcing Fillet Weld N
Column Depth Column Flange Thickness = 0.5 if the distance from the end of the column to the closer face of the beam tension flange is less than d c/2 = 1.0 otherwise = 3N/dc if the distance from the column end to the closer face of the beam tension flange is either: (1) greater than or equal to d c/2; or, (2) less than dc/2 and N/d c is less than or equal to 0.2.
(
= φRn =
2959 ki ps
4N
d c
−0 . 2
)
otherwise
Web Cri ppli ng Desi gn Strength
φR n= 0 . 7 5 x 135C t t 2w
{ ( ) }√ 1 + N d
t w
1 .5
t f
F y t f t w
E) Compression Buckling of the Web Buckling is checked for a single compressive force applied at the column flange. tw =
1.77 in
dc = k=
18.29 in 3.50 in
Ct =
1.0
h=
11.29 in
Column Web Thickness Column Depth Distance from the outside face of column flange to th e web toe of the flange-to-web fillet = 0.5 if the distance from the end of the column to the closer face of the beam tension flange is less than d c/2 = 1.0 otherwise Zone of column web subject to compression buckling (out-of plane)
Figure 4. Illustration of parameters N and W
A
d
h
tw
tf
k
W18x311* W18x283* W18x258* W18x234* W18x211* W18x192 W18x175 W18x158 W18x143 W18x130
in2 91.5 83.2 75.9 68.8 62.1 56.4 51.3 46.3 42.1 38.2
in. 22.32 21.85 21.46 21.06 20.67 20.35 20.04 19.72 19.49 19.25
15.45 15.48 15.46 15.56 15.55 15.48 15.54 15.47 15.49 15.50
in. 1.52 1.4 1.28 1.16 1.06 0.96 0.89 0.81 0.73 0.67
in. 2.74 2.5 2.3 2.11 1.91 1.75 1.59 1.44 1.32 1.2
in. 3 7/16 3 3/16 3 2 3/ 4 2 9/16 2 7/16 2 1/ 4 2 1/ 8 2 1 7/ 8
W18x119 W18x106 W18x97 W18x86 W18x76
35.1 31.1 28.5 25.3 22.3
18.97 18.73 18.59 18.39 18.21
15.47 15.48 15.47 15.52 15.46
0.655 0.59 0.535 0.48 0.425
1.06 0.94 0.87 0.77 0.68
1 1 1 1 1
W18x71 W18x65 W18x60 W18x55 W18x50
20.8 19.1 17.6 16.2 14.7
18.47 18.35 18.24 18.11 17.99
15.47 15.48 15.49 15.49 15.49
0.495 0.45 0.415 0.39 0.355
0.81 0.75 0.695 0.63 0.57
1 1 1 1 1
W18x46 W18x40 W18x35
13.5 11.8 10.3
18.06 17.9 17.7
15.56 15.53 15.45
0.36 0.315 0.3
0.605 0.525 0.425
Designation
φ Rn
φ Rn
φ Rn
5933 4627 3539 2617 1999 1492 1184 896 655 506
kips 1345 1151 992 827 706 609 523 451 383 331
kips 916 826 742 660 592 514 449 380 319 269
kips 916 826 742 660 592 514 449 380 319 269
406 327 272 217 170
474 346 258 186 130
303 249 213 167 130
240 187 150 108 68
240 187 150 108 68
1755 1555 1425 1265 1115
198 173 153 138 120
233 194 166 144 119
205 154 120 100 75
185 154 120 100 75
61 32 7 -16 -40
61 32 7 -16 -40
1040 955 880 810 735
122 101 92
125 95 81
78 53 46
78 53 46
-66 -97 -133
-66 -97 -133
675 590 515
PZ Shear Str. φ Rv (kips)
LFB φ Rn (kips)
LWY φ Rn (kips)
WC φ Rn (kips)
CBW φ Rn (kips)
916 826 742 660 592 514 449 380 319 269
2112 1758 1488 1252 1026 861 711 583 490 405
1345 1151 992 827 706 609 523 451 383 331
2283 1930 1618 1337 1113 918 782 647 529 444
3/ 4 5/ 8 9/16 7/16 3/ 8
240 187 150 108 68
316 249 213 167 130
303 255 222 185 157
1/ 2 7/16 3/ 8 5/16 1/ 4
61 32 7 -16 -40
185 158 136 112 91
1 1/ 4 1 3/16 1 1/ 8
-66 -97 -133
103 78 51
Py kips 4575 4160 3795 3440 3105 2820 2565 2315 2105 1910
