Relevant Codes & Standards for Aluminum Walkway Covers

We have noticed that there is a lot of confusion pertaining to the specifications required for aluminum walkway covers.  The codes & specifications required for aluminum canopies can be difficult to read and understand, so we have listed the most important ones below that relate to aluminum canopies.

International Building Code 2006

(This sections deals specifically with allowable deflection for aluminum canopies)

Table 1604.3 (Deflection Limits), section a.

i. For structural roofing and siding made of formed metal sheets, the total load deflection shall not exceed L/60.  For secondary roof structural members supporting formed metal roofing, the live load deflection shall not exceed L/150.

(This section deals specifically with the required live loading for aluminum canopies)

Table 1607.1 (Minimum Uniformly Distributed Live Loads and Minimum Concentrated Live Loads), Section 30 (Roofs)

i. For Awnings and canopies for “All other construction”, the uniform required Live Load is 20 lbs/ft^2.

(This section deals specifically with the required Occupancy Category for aluminum canopies)

Table 1604.5 (Occupancy Category of Buildings and Other Structures)

i. Aluminum Walkway Covers shall use Occupancy Category II since they do not meet the criteria for I, III, or IV.

For additional engineering and design criteria for aluminum canopies, see the below sections:

ASCE/SEI 7-05

2.4.1 (Basic Combinations for Combining Nominal Loads Using Allowable Stress Design), #2

i. Load combination for aluminum walkway covers shall be:

D+H+F+(Lr or S or R)

D = Dead Load

H = Load due to lateral earth pressure, ground water pressure, or pressure of bulk materials

F = Load due to fluids with well-defined pressures and maximum heights

Lr = Roof Live Load

S = Snow Load

R = Rain Load

6.5.15 (Design Wind Loads on Other Structures)
6.5.10 (Velocity Pressure)
Table 6-1 (Importance Factor for Wind Loads)
Table 6-2 (Terrain Exposure Constants)
Table 6-3 (Velocity Pressure Coefficients, Kh & Kz)
Table 6-4 (Wind Directionality Factor, Kd)
Figure 6-1 (Basic Wind Speed)
Figure 7-1 (Ground Snow Loads for the United States)

3) Aluminum Design Manual 2005

Table 3.3-1 (Minimum Mechanical Properties for Aluminum Alloys)
Table 3.3-2 (Minimum Mechanical Properties for Welded Aluminum Alloys)
Table 3.3-4 (Formulas for Buckling Constants for Products Whose Temper Designation Begins With –T5, -T6, -T7, -T8, or –T9)
Table 3.4-1 (Commonly Used Resistance Factors)
Table 3.4-2 (Coefficient Kt)
Table 3.4-3 (General Formulas for Determining Design Stress from Section 3.4)