1. Overview of Design Methods Allowable Stress Design or Working Stress Method Factor of Safety= Allowable Stress -------------------------- Actual Stress NDS is based on the Allowable Stress Design Method (Which is primarily used in wood, masonry, steel, and concrete)

2. Overview of Loads -Gravity and Lateral Loads Gravity Loads Dead Loads - Building Materials Live Load- people impact loads- percentage increase to live load roof live loads- uniformly distributed (loads imposed during construction and loads caused by fire-fighting equipment) (reroofing operations, HVAC installation and servicing) snow loads- handled separately (uniformly distributed) wind forces handled separately special loads- hydrostatic uplift temporary structures

3. Lateral Loads wind loads- uniformily distributed seismic - horizontal loading Lateral earth pressure Load and Force Combinations (Text Sect. 2.16) DL+FLL+RLL(or snow) DL+FLL+WIND(OR SEISMIC) DL+FLL+WIND+1/2 SNOW DL+FLL+SNOW+1/2 WIND DL+FLL+SNOW+SEISMIC Notes: You either use roof live load or snow load, wind load or seismic load, roof live loads are infrequent, roof live loads is not combined with seismic or wind load