You need to design a project for a client that lives at 768 Head St. San Francisco, CA. The home is a single family home two story building. They want an additional story designed above the existing building with a 4-12 pitch roof with 7’ walls. The addition has triggered a seismic upgrade at the garage level.
Section 1: Gravity loads
1. Verify all existing members for gravity loads (joists, beams, exterior studs, etc). 2. Design new roof and floor with appropriate materials.
Section 2: Lateral loads
3. a) find appropriate weight from your new design to be used in finding the base shear. V=Cs*W. I want W for your design.
b) Using a W of 120,000 lb find the base shear (V) and design the first floor shear walls based on this V value.
4. a) Find the appropriate weight from your new design that is tributary to the new third floor diaphragm.
b) Using a W of 80,000 lb in the transverse direction find the diaphragm force on the third floor and design a new floor to meet the demands of the force.
5. The project should be presented with drawings and calculations.
All exterior walls have 7/8” straight sheathing with 7/8” stucco
All interior walls on second and third floor have insulation with 5/8” gypsum board. The second floor has (E) 3/4” diagonal sheathing with 3/4” hardwood floors.
New deck in back yard at second floor height. Dimensions will be 8’ x 20’