Floor Framing Design Factors affecting Design of Floor System: Load (weight of material) Size of members Spacing of joists Beams or bearing walls Stress Design Criteria (How joists are sized for proper span) Deflection
GIRDERS Larger principle beam made of steel or wood supported by posts/columns or piers which support the floor joists Can be recessed into foundation wall Joists will set on top of girder Can sit on top of foundation wall Joist will hang off side with Joist Hangers
FLOOR JOISTS Series of parallel support beams which support floor loads and which are supported by Girders, or bearing walls. Types Solid Dimensional lumber (2x __) Wood I-beams Open Web Floor Truss Steel Joists Structural Insulated Panels (SIP)
WOOD I-BEAMS Structural, load-carrying I-joists used in residential and light commercial construction. Composition The flange material for I-joists is typically dimension lumber or laminated veneer lumber (LVL) The web is plywood or OSB. The "I" configuration provides high bending strength and stiffness characteristics.
Bridging Dimensional Lumber Joists have a tendency to sway and deflect over long spans Bridging stiffens flooring Types: Solid Horizontal bridging Cross bridging Span greater than 10' have at least 1 row Span greater than 14-16' have 2 rows of bridging, 5-8 feet apart