Continuous Ribbing Floor Framing

If you have two identical length floor joist spans from an exterior foundation wall to a center beam and then on to the opposite exterior foundation wall is there a significant difference between framing this as two simple spans with the joists lapped over the center beam the most common arrangement or using one continuous joist.

Continuous ribbing floor framing. When framing floor openings techniques include the installation of trimmer joists which are double joists that beef up the joists on either side of an opening and headers that run perpendicular between joists. Garage openin g h 6 10 max 12 max with pony wall fully sheathed dwelling r602 10 6 4 garage opening no hold downs required ok on raised floor. The floor framing consists of standard one way joist 66 module pan. In fact if you read the fine print in most of the framing member tables already discussed you will discover that they rely on the presence of a structural panel on top of the framing members.

Best performance of wood frame buildings is obtained when the moisture content of framing lumber at the time the build ing is enclosed with sheathing and interior finish is as close as possible to the condition it will reach in service. Mark mckenzie an engineer from brewster mass. This form of construction is not very common because of the formwork costs and the low fire rating. Once you ve worked out a framing plan with the building material dealer there are a number of things you can do during installation to help ensure the floor works as a system.

Grading rules which conform with american soft wood lumber standard ps 20 provide for framing lumber. Floor framing is only part of the floor assembly the subfloor is also a part of the structural system. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns they are either one way spanning systems known as ribbed slab or a two way ribbed system known as a waffle slab. Continuous frames are moment resisting where the beam to column connections are classified as rigid and are designed to transmit the beam end moments and shear forces into the column.

Mark the position of each floor joist along the sill plate. Floor joists should be spaced no more than 16 inches 41 cm apart from center to center to provide adequate stability. The location of headers and trim joists depends upon the length of the floor opening and the direction of the staircase and these. Use a tape measure to measure 16 inches 41 cm in from the edge of the rim joist and draw a small notch.

No bracing system is required to resist lateral loads and frame stability is provided by the rigidity of the connections and the stiffness of the members only. Figure 1 one way joist concrete floor framing system partial plan code. Design the continuous beam along grid c for the combined effects of gravity dead live and lateral wind loads according to aci 318 11.