In Plain English
Quick Answer
The force that wind exerts on a building, which the structure must be strong enough to resist.
Definition
Definition
The force exerted on a structure by wind pressure, including positive pressure on windward surfaces and suction on leeward and side surfaces. Wind loads are determined by the design wind speed at the site, exposure category, building height, and the shape of the structure. ASCE 7 provides the standard method for calculating design wind loads in the United States.
Context
Why It Matters in Bidding
Wind load drives the sizing and connection design of the lateral system, cladding, and roofing, so it has a direct line to structural-steel tonnage, anchor counts, and fastener schedules an estimator must take off. Misjudging the design wind speed or exposure category can swing framing and curtain-wall costs significantly and trigger re-engineering during value engineering.
Example
Example
Bidding a coastal warehouse, an estimator notes the high design wind speed and Exposure C condition and prices heavier roof-deck attachment and additional moment connections that a less wind-exposed inland version would not require.
See Also
Related Terms
FAQ
Questions Contractors Ask
How do wind loads affect construction bid costs?
Higher wind loads increase the lateral bracing, connection hardware, anchor bolts, and cladding attachment a building needs, raising steel tonnage, fastener counts, and labor. Roofing and curtain-wall scopes carry uplift-resistance premiums in high-wind zones. Estimators should confirm the design wind speed and exposure category before pricing the structural and envelope packages.
What is the difference between wind speed and wind load?
Wind speed is the basic design air velocity at the site, an input value. Wind load is the resulting pressure force the structure must resist, derived from that speed plus exposure category, building height, shape, and importance factor. The engineer converts speed into design pressures, which then dictate member sizes and connections an estimator prices.
Why does building exposure category matter for wind load?
Exposure category describes upwind terrain roughness, from open water or flat land to dense urban or wooded settings. Open exposures produce higher wind pressures at a given speed than sheltered ones. Because exposure can substantially raise design loads, it directly affects framing and cladding quantities, so estimators should verify it rather than assume the least severe case.
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