The ground snow load in Eugene is approximately 11 psf at a elevation of 420 feet (OSSC 1608.2.2; http://snowload.seao.org). The ground snow load must be modified in accordance with OSSC 1608.2.2 Table 7.2 for higher elevations. However, the minimum snow load and minimum sloped roof snow load of 20 psf typically govern design (see OSSC 1608.2.3 and 1608.2.4). An additional rain-on-snow surcharge load of 5 psf applies for flat roofs and roofs that constrain runoff. (OSSC 1608.2.5)
Basic design wind speeds for Eugene are as follows (OSSC Table 1609.3):
|Risk Category||V (mph)|
Most structures in Eugene are assigned Seismic Design Category D in accordance with OSSC 1613.2.5. Seismic design parameters should be obtained from https://hazards.atcouncil.org/.