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Building Code
Building codes are intended to provide for the safe use of buildings and structures under "normal" conditions. The code describes exactly how each part of the building should be loaded and designed. These loads are based on Snow load, Wind Speed, Seismic Coefficient (earthquake), Collateral load and Exposure. These loads will be applied in various "Design Combination" to determine the most critical loading. From these combinations all member sizes and spacing will be determined.
Snow Load
In the northern US, design of a building to withstand snow loading is critical. Snow loading is dependent on several factors. These factors include roof slope, if the structure is heated, if the structure is insulated, if the roof slope is slippery or if it contains high friction that will "hold" the snow on the roof. Our "on-line" pricing system takes the most conservative of these factors into consideration when designing your building.
Wind Speed
As wind blows it places pressure on the building. The exact pressure is based not only on the formulas and tables contained in the specific building code chosen, but also the size and shape of your new building. By entering the Wind Speed, our "on-line" pricing systems will give the optimum member sizes and their spacing.
Seismic Coefficient
This is the influence of earthquake activity on your steel building. The higher this number the more influence seismic has or the greater the seismic loading. Some building codes such as the Uniform Building Code (UBC) or the California Building Code (CBC) also use seismic zone. These also influence seismic design; Zone 0 having the least influence and Zone 4 having the greatest.
Collateral Load
The collateral load is the loading on the building caused by additional construction materials such as a false ceiling, sprinkler system, lighting, Heating/Air-conditioning duct, etc. The following table is recommended loadings for each type of collateral load.
Table 1.1(c): Typical Collateral Loads
Ceilings
Suspended Acoustical Fiber Tile
Suspended Gypsum Board - 1/2"
Suspended Gypsum Board = 5/8"
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1
2
3
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Insulation
Glass Fiber Blanket
Cellular Plastic, per inch of insulation
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Negligible
0.2
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Lighting
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0.1 to 1
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HVAC Ducts, Office/Commercial
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1
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Sprinkler
Dry
Wet
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1.5
3
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Exposure
The characteristics of ground surface irregularities (natural topography and vegetation as well as constructed features) for the site at which the building is to be constructed.
Exposure A - Large city centers with at least 50% of the buildings having a height in excess of 70 feet.
Exposure B - Urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger.
Exposure C - Open terrain with scattered obstructions.
Exposure D - Flat, unobstructed areas exposed to wind flowing over open water (excluding shorelines in hurricane prone regions) for a distance of at least 1 mile.
Roof Live Load
Roof Live load is defined as "Loads that are produced (1) during maintenance by workers, equipment, and materials and (2) during the life of the structure by movable objects but does not include wind, snow, seismic or dead loads." Tributary Reduction is a reduction of the Roof Live Load based on the idea that the larger roof area that is supported by a member; the less likely it is that area will be loaded to its limit. This reduction is allowed by most building codes, but some local jurisdictions do not allow it. Check with your local Building Department to be sure.
Collateral Load
The collateral load is the loading on the building caused by additional construction materials such as a false ceiling, sprinkler system, lighting, Heating/Air-conditioning duct, etc. The following table is recommended loadings for each type of collateral load.
Auxiliary Loads
All specified dynamic live loads, other than the basic design loads, which the building must safely withstand. Examples are loads imposed by crane systems, material handling systems and impact loads.
Design Codes
Regulations developed by recognized agencies establishing design loads, procedures, and construction details for structures.
Examples are: MBMA, AISC, AISI, AWS, etc.
Impact Load
A dynamic load resulting from the motion of machinery, crane ways, elevators and other similar moving forces.
Uniform Load
Load that covers all or part of a beam or surface where, throughout the portion covered, the intensity of load per unit of length or area is the same.
Wheel Load
The maximum load, which is transferred through the wheels of a crane to a crane beam.
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