A beach cabin on the Washington coast (100 mph wind velocity) is required to resist a wind pressure of 35 psf. Assuming wood-frame construction, the cabin utilizes a roof diaphragm and four exterior shearwalls for its lateral resisting strategy. Draw an exploded view of the building, and perform a

Question

A beach cabin on the Washington coast (100 mph wind velocity) is required to resist a wind pressure of 35 psf. Assuming wood-frame construction, the cabin utilizes a roof diaphragm and four exterior shearwalls for its lateral resisting strategy.
Draw an exploded view of the building, and perform a lateral load trace in the [latex]N-S[/latex] direction. Show the magnitude of shear [latex]V[/latex] and intensity of shear [latex] u [/latex] for the roof and critical shearwall. Also, determine the theoretical tie-down force necessary to establish equilibrium of the shearwall. Note that the dead weight of the wall can be used to aid in the stabilizing of the wall.

Accepted Answer

[latex]\omega =35 \space psf imes 7.5^\prime=262.5\# /ft.[/latex]

Examining the roof diaphragm as a deep beam spanning 42 feet between shearwalls:

[latex]V=\frac{ \omega L }{2} =\frac{262.5 \# /ft. (42^\prime )}{2} =5,513\# [/latex]

An FBD of the shearwall shows a shear [latex]V^\prime [/latex] developing at the base (foundation) to equilibrate the shear [latex]V [/latex] at the top of the wall. In addition to equilibrium in the horizontal direction, rotational equilibrium must be maintained by the development of a force couple [latex]T [/latex] and [latex]C [/latex] at the edges of the solid portion of wall.

[latex] u =V/[/latex] shearwall length [latex] =5,513\# /15^\prime=368\# [/latex]

[latex]W[/latex] = dead load of the wall

[latex]W=10 \space psf imes 15^\prime imes 15^\prime= 2,250\# [/latex]

Tie-down force [latex]T[/latex] is determined by writing a moment equation of equilibrium. Summing moments about point [latex]A[/latex] ,

[latex]\left[\sum{M_{A}=0 } ight] -V (15^\prime ) +W (15^\prime/2 )+T (15^\prime ) =0[/latex]

[latex] 15 T=5,513 \# (15^\prime )-2,250\# (7.5^\prime )[/latex]

[latex] T=\frac{(82,695 \# ft.)-(16,875 \# -ft.)}{15} [/latex]

[latex] T=4,390\# [/latex]

Question 4.10: A beach cabin on the Washington coast (100 mph wind velocity...

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