Practice in WOOD COLUMN AND CONNECTION DESIGN – due beginning of class, December 12
Use WoodWorks to answer the questions in this assignment.
NOTE: You are being graded on your ability to accurately assess and input information into the software. Read each question carefully.
—————
1. A 2 x 4 exterior stud wall is 8 ft tall. The studs are No.2 Southern Pine at 16 in. o.c. The studs support the following vertical loads per foot of wall with an eccentricity of 0.5 inches: D = 800 plf, L= 800 plf, Lroof (construction) = 400 plf. In addition, the wall carries a uniform wind force of 15 psf (horizontal). Sheathing provides lateral support in the weak direction.
i) Print the “design check calculation sheet” and submit.
ii) What failure mode causes this beam-column to fail? Read section 7.12 of your text and then explain in your own words what this failure mode means.
iii) Besides increasing the stud size to 2x6s, suggest two separate and practical things that could be done to make this stud wall design work. Prove that the two individual solutions work with printouts of the “design check calculation sheets”.
2.A 10 ft long built-up (n-ply) column, is comprised of 2 – 2 x 6s No. 1 D. Fir-Larch. There is no intermediate bracing, no eccentricity and the end supports are pinned.
i) Assuming the column is nailed together, what live load can it safely support in compression? Print the Design Check Calculation Sheet and submit.
ii) What load could the same column support if it were solid and not nailed? In other words, what load could a 10 ft long 3 in x 5.5 in (actual dimensions) solid column of No. 1 D. fir-larch support? Print the Design Check Calculation Sheet and submit
Note: You should find that the nailed column capacity is 60% of the solid column capacity, which is the reduction factor for nailed built-up columns that was given in class.
3. Complete Connections Tutorial 12 (on page 157) on Lapped Shear Connections.
i) Now select the connection type Lapped Shear, Wood-to-wood with two wood side members configuration (no skew) and enter all other data the same as the tutorial.
Print the design results for 2 rows of 2 bolts with 3/4 inch diameter.
ii) What is the most likely failure mode (i.e. the yield limit value) for each bolt?
iii) What is the value for the geometry factor?
iv) Read page 13.25 in your text on the Geometry factor. Then, in your own words, explain what the geometry factor accounts for.
v) Why, exactly, is the Geometry factor less than 1 in this case?