I’m designing a building in Aurora, CO that will have 10’-0" tall parapets. The building is rectangular 77’x180’. My question is how should the snow drift at the corners of the building be calculated? Should I simply sum the North/South drift and West/East drifts together while using the maximum drift width given by ASCE 7?
I use the MBMA’s drift description from the Metal Buildings Systems Manual. Use the worst case drift in each driection, assuming the parapets are at the edge of the roof and where they overlap in the corner use the worst case. Do not add the drifts together in the corner use the single worst drift width in each direction and miter them together in the corner. See Figure 220.127.116.11©-8: Intersecting Snow Drifts. Page 161 2012 Edition Metal Buidling Systems Manual.
You will have a triangular distribution with the high side at the parapet and then tapering to zero at the drift width. It gets a little funky trying to add the drifts together at the corner of the parapet.
Above is a snippet.