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<br />**** DESIGN OF WALL STUDS **** <br /> <br />*** Design of Wall Stud Number 1 *** <br /> <br />2 in. x 4 in. studs at 16 in. spacing <br />Stud height is 7.625 feet--located in interior zone <br />Spruce--Pine--Fir lumber----Number 1--Number 2 grade <br />Plywood siding 15/32 inch, Southern Pine lumber, Stress level Sl <br /> <br />Cross-sectional properties: <br />Composite action between wood stud and plywood siding: <br />Transformed section analysis <br />Elastic modulus of wood stud <br />Elastic modulus of plywood <br />Modular ratio <br />Location of neutral axis: <br />Distance from inside face of stud <br />Distance from exterior face of plywood <br />Cross-sectional area = 11.27678 sq. in. <br />Moment of inertia = 16.51833 in.^4 <br />Section modulus--stud/siding bending in vertical plane: <br />Inside face of stud = 5.877294 in.^3 <br />Outside of plywood = 14.26186 in.^3 <br />Section modulus for plywood bending in horizontal plane <br /> <br />1400000 in.^2 <br />1800000 in.^2 <br />.8035714 <br /> <br />2.810533 inches <br />1.158217 inches <br /> <br />.4394531 in.^3 <br /> <br />Total outward force on stud = 276 pounds <br />Stud moment = 263 ft-lb. <br /> <br />Deflection of plywood between studs as continuous beam = .0055 in. <br />Thickness of plywood divided by two = .234375 in. <br />Plywood bending between studs is analyzed as a continuous beam. <br /> <br />Composite bending stresses in vertical stud: <br />Stud inside face Actual 537 psi Allowable = 2415 psi (adjusted) <br />Plywood exterior Actual 177 psi Allowable 3200 psi (adjusted) <br />Stud shear stress Actual 36 psi Allowable = 112 psi (adjusted) <br />Stud tensile stress Actual 22 psi Allowable = 1020 psi (adjusted) <br />Interaction bending and tension actual/allowable stress ratio total = .2439289 <br />Plywood stress horiz: Actual = 131 psi Allowable = 3200 psi (adjusted) <br />Deflections: <br />Stud : Actual = .0744 in. <br />Plywood: Actual = .0055 in. <br /> <br />Allowable = .5083 in. <br />Allowable = .0888 in. <br /> <br />*** Summary of Design *** <br /> <br />------------------------------------------------------------------------------- <br /> <br />Wall structure satisfies all Code requirements. <br />