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)

0.01801.04330.09420.08920.098858.014.511319.1
0.01801.04500.08860.08220.096187.922.017129.0
0.02401.36330.1360.1290.13310927.321135.8
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)

0.01800.01800.02400.01800.01800.02400.01800.01800.0240
Y.S.* (ksi)335033335033335033
3.0

3.0

S148211214140196203175245253
D426414573102199313758047821082
3.5

3.5

S109155157103144149129180186
D268261361643626866507493682
4.0

4.0

S831191207911011499138143
D180175242431419580339330457
4.5

4.5

S66949562879078109113
D126123170303294407238232321
5.0

5.0

S537677507073638891
D9289124221215297174169234
5.5

5.5

S446364425860527375
D696793166161223131127176
6.0

6.0

S375354354951446163
D53527212812417210198135
6.5

6.5

S324546304243375254
D424156100981357977106
7.0

7.0

S273939263637324547
D3433458078108636285
7.5

7.5

S243434223132283941
D272637656488515069
8.0

8.0

S213030202829253436
D222230545272424157
8.5

8.5

S182627172425223032
D191825454460353448
9.0

9.0

S162324162223192728
D161521383751302940
9.5

9.5

S152121142020172425
D131318323143252534
10.0

10.0

S131919131818162223
D111115282737222129

* Y.S. = Yield Strength