I fully agree that your anchor rods would have to go down to the footing, but don't see how you can resist 10 kips of lateral force with two 2' wide shear walls. This is 2500 plf of unit shear which is about twice what you can resist with a two-sided shear wall. The Simpson 2' x 10' shear wall...
chipb-
I guess I'll add my two bits worth because this is a problem which has long bothered me. Most residential basements where I am (Seattle) don't get engineered, although at 11' of backfill, these days it may be required. Anyway, the reason they don't fail even though restraint at the top is...
Both chipb and mrstohler suggest that a lower value of the subgrade modulus ks produces a higher bearing pressure, but it seems to me it's just the opposite. A lower ks would permit greater deflection under a concentrated load, resulting in a lower bearing pressure but a higher moment in the...
This sounds to me like a bad idea. Each rafter pair is unstable under lateral or unbalanced gravity forces. It needs a horizontal reaction at the ridge as well as at the plate to prevent collapse. It might be stable if the ridge beam is adequate for the horizontal load, or if the roof sheathing...
Pylko, I respectfully disagree. Notching the top of a rafter to bear on the ridge beam creates a wedge between the bearing surface and a short line of grain, which is vulnerable to splitting with loss of bearing. It is generally a poor practice. Notching the bottom creates no such problem, so...
You probably have a plan structural irregularity type 2, re-entrant corners (UBC table 16-M), and sec.1633.2.9 paragraph 7 would apply if you are is seismic zones 3 or 4. You need to tie the sections together because they will tend to move in different directions.
For steep roofs, I analyze a frame consisting of a rafter pair and a stud, under the influence of the horizontal force. The reactions are four: horizontal and vertical at the bottom of the stud, and longitudinal in each rafter. The equations are four: H, V, & M =0 at the bottom of the stud and...
If the problem is too much flexural stress or shear stress then, as whyun suggests, sister joists are your best bet. If the problem is too much deflection or vibration from a footfall, try this: put in a row of solid blocking at midspan, very tight. Then put a steel strap across the bottom of...
