General – Presented in the load tables are maximum uniformly distributed specified loads.

Steel – Conforms to ASTM A653/A653M or A792/A792M. Grade 33/230; Yield stress 33 ksi/230 MPa and tensile stress 45 ksi/310 MPa. Grade 50 /345; Yield stress 50 ksi/345 MPa and tensile stress 65 ksi/450 MPa; Grade 80 /550; Yield stress 80 ksi/550 MPa and tensile stress 82 ksi/565 MPa.

Finishes – A25/ZF75, G90/Z275 or AZ50/AZM150. For heavier metallic coatings, refer to ASTM A653/A653M or A792/A792M.

Load Tables – The following information regarding the determination of the specified wind and snow loads is contained in the 2010 Edition of the National Building Code of Canada (NBCC).
Importance factors are applied to both strength (ULS) and serviceability/ deflection (SLS) limit state design considerations. A lower load factor for wind of 1.4, instead of 1.5 for live and snow loads, is now being used. This lower load factor for wind somewhat offsets the higher wind loads (1 in 50 year return) that are now listed in the NBCC by geographic location. The importance category of the end use of the building/structure must also be recognized, such as Normal or Low.

All of this will impact how the load tables are to be used. In an effort to help the design professional with the load tables, the information below was taken directly from Division B, Part 4 (Structural Design) of the NBCC.

Specified Wind Load

W = Iw qCeCgCp

Importance CategoryImportance Factor, Iw
ULSSLS
Low0.80.75
Normal1.00.75
High1.150.75
Post-Disaster1.250.75

Specified Snow Load

S = Is [Ss (Cb Cw Cs Ca) + Sr]

Importance CategoryImportance Factor, Iw
ULSSLS
Low0.80.9
Normal1.00.9
High1.150.9
Post-Disaster1.250.9

The importance factors, Iw and Is, have been incorporated in the load tables, as well as the importance category. The parameters in the boxed-in portion of Equations [1] and [2] must be determined by the design professional in accordance with the NBCC.

Strength – The maximum uniformly distributed specified load based on strength in the load table must be equal to or greater than the specified live load.

Serviceability (Deflection) – The maximum uniformly distributed specified load based on deflection in the load table must be equal to or greater than the specified live load. The effective
moment of inertia for deflection determination was calculated at an assumed specified live load stress of 0.6Fy.

EXAMPLE (Use of Load Table)

Ultra Span Wall (Normal Importance Category) 
Given: (Metric units)
(LLF = 1.4 and Iw = 0.75)
~ Deck thickness, t = 0.762 mm
~ Double span continuous, L = 2.6 m each span
~ Bearing length, N = 50 mm
~ L/240 deflection limit
~ Wind live load, LL = 1.5 kPa

The live load is the value of the boxed-in portion of the specified wind load expression [1].

Solution:
Strength “S”
1) Specified wind live load = 1.5 kPa
2) Maximum specified load (from Load Table)
Is 1.65 kPa

Since 1.65 > 1.5 … OK

3) Check web crippling (N = 50 mm)
a) End reaction = 0.375(1.5)2.6 = 1.46 kN/m (from section property table)
Pe = Pe1 + Pe2 [N/t]1/2 = 2.78 + 0.695[50/0.762]1/2 = 8.41 kN/m

Since 8.41 > 1.46 … OK

b) Interior reaction = 1.25(1.5)2.6 = 4.88 kN/m (from section property table)
Pi = Pi1 + Pi2 [N/t]1/2 = 5.29 + 0.900[50/0.762]1/2 = 12.6 kN/m

Since 12.6 > 4.88 … OK
Deflection “D”
From table L/180 = 3.26 kPa
For L/240, multiply 3.26 by 180/240 = 2.45 kPa
Since 2.45 > 1.5 … OK

  1. Based on ASTM A 653 structural steel.
  2. Values in row “S” are based on strength.
  3. Values in row “D” are based on deflection of 1/180th span.
  4. Web crippling not included in strength calculation. See example.
  5. Limit States Design principles were used in accordance with CSA Standard S136-12.

SECTION PROPERTIES | Per Foot of Width
Base Steel Thickness (inches)Weight [G90] (psf)Yield Stress (ksi)Section ModulusDeflection Moment of Inertia (in4)Specified Web Crippling Data
Midspan

(in3)

Support

(in3)

Pe1

End (lb)

Pe2

End (lb)

Pi1

Interior (lb)

Pi1

Interior (lb)

0.01350.72500.02680.02190.030920.75.1740.26.84
0.01800.94330.04060.03430.043525.96.4750.28.53
0.01800.94500.03850.03260.043039.29.8076.012.9
0.01800.94800.03760.03150.042646.611.790.415.4
0.02401.23330.05710.04760.057948.612.293.816.0
0.03001.53330.07100.06130.072278.719.715225.8
LLF = 1.40; IMPF = 0.75; NORMAL OCCUPANCY = 1.0
LOAD TABLE | Maximum Uniformly Distributed Specified Loads (psf).
Span Length (ft)1-Span

Base Steel Thickness (inches)

2-Span

Base Steel Thickness (inches)

3-Span

Base Steel Thickness (inches)

0.01350.01800.01800.01800.02400.03000.01350.01800.01800.01800.02400.03000.01350.01800.01800.01800.02400.0300
Y.S.* (ksi)503350803333503350803333503350803333
2.0

2.0

S144144206239202251117121175201168217147152219251210271
D450632626620842105010801517150214872020252185011951183117115911985
2.5

2.5

S929213215312916175781121281081399497140161135173
D230324320317431538553777769761103412914356126066008141017
3.0

3.0

S6464921069011252547889759665679711193120
D133187185184249311320449445441598747252354351347471588
3.5

3.5

S474767786682384057665571485071826988
D84118117116157196201283280277377470159223221218297370
4.0

4.0

S363651605063293044504254373855635368
D56797877105131135190188186252315106149148146199248
4.5

4.5

S282841474050232435403343293043504253
D3955555474929513313213117722175105104103140174
5.0

5.0

S232333383240191928322735232435403443
D2940404054676997969512916154767675102127
5.5

5.5

S191927322733161623272229192029332836
D2230303040515273727197121415757567695
6.0

6.0

S161623272228131319221924161724282330
D172323233139405656557593314444435974
6.5

6.5

S141420231924111117191621141421242026
D131818182531314444435973253534344658
7.0

7.0

S121217201620101014161418121218201722
D101515142025253535354759202828273746
7.5

7.5

S1010151714188912141215101116181519
D91212121620202928283848162322223038
8.0

8.0

S991315131678111311149914161317
D71010101316172423233239131918182531

* Y.S. = Yield Strength