Structural Design Loads
Plain-language references to the site-driven structural design loads architects and engineers look up early — ground snow load, ultimate design wind speed, seismic design category, and risk/exposure categories per ASCE 7 and the IBC.
Structural Design Loads
Before a structural engineer runs a single calculation, the design is shaped by a handful of site-driven load parameters: ground snow load, ultimate design wind speed, and the seismic design category, each modified by the building's risk category and site conditions. Architects don't size the members, but knowing these values early informs massing, roof slope, lateral systems, and which envelope details will be governed by uplift, drift, or seismic drift.
The pages below explain each parameter in plain language and show how it flows into design. All numeric values are typical or illustrative, framed for orientation only — the authoritative, address-specific values come from the ASCE Hazard Tool, the USGS Seismic Design Maps, and the code edition adopted by your Authority Having Jurisdiction (AHJ).
Pages
- Ground Snow Load (pg) Explained for Architects
Ground snow load (pg) explained — how the mapped ground value maps to roof snow load under ASCE 7, why it varies by region and elevation, and what it means for roof design.
- Seismic Design Category (SDC) Explained for Architects
Seismic Design Category (SDC) explained — how Ss/S1, site class, and risk category set an SDC of A through F under ASCE 7 and the IBC, and what it means for architectural design.
- Structural Design Loads for Denver, CO (Illustrative)
Illustrative structural design loads for Denver, CO — typical ground snow load, ultimate design wind speed, and seismic parameters for early orientation, with the ASCE Hazard Tool giving address-specific values.
- Ultimate Design Wind Speed & Exposure Categories Explained
Ultimate design wind speed (Vult) and exposure categories B, C, and D explained — how ASCE 7 wind maps, terrain exposure, and risk category combine to set wind loads.