Example to Determine Stringer Load Per Linear Foot (Refer to Beam Chart for Load Capacity per Linear foot over span)
Mar 31, 2017
L = Length of Concrete by 1′ Wide
Load Per Foot Run on Stringer = L x 1′ x Wt. per Foot of Slab
L x 1’0″ x Wt. Conc. = Weight per Linear Foot on Stringer
8’0″ x 1’0″ x 162.5 lbs. Weight per Linear Foot on Stringer
1300 lbs. = Weight per Linear Foot on Stringer
(REFER TO BEAM CHART FOR LOAD CAPACITY PER LINEAR FOOT OVER SPAN)
Page says you can span over approx. 7.’ with 2 spans. If you use 71/2″ Beam Chart, Page you can span 8′ on 2 spans and this will increase leg load which will have to be rechecked.
NOTE: Design for longest stringer span possible.
7′ span is okay for 61/2″ stringer beam with 9″ slab ‘using L/270 deflecting. Use deflection requirements required by builder, normally either L/360 or L/270. See Beam Charts Page 46-47 for 61/2″ beam and Page 53-54 for 71/2″ beam capacities, note different strengths.
NOTE: Layout measurements used in examples are for easy figuring only. They have no bearing on capacity of system.