SPECIFICATION FOR THE DESIGN OF - Transcon Steel

Commentary on the Prescriptive Method for One and Two Family Dwellings - 2004 75
V n = 3,388 lb
V a = V n /Ω = 3,388/1.67 = 2,029 lb
ΦV n = 0.90(3,388) = 3,049 lb
Clip Spacing = 3,049/346 = 8.81 feet
Space blocking at 8-foot maximum and at each end.
E11.8 Stabilizing Clip at Eave Block
Tested value for 54 mil block = 3,930 lb
Simpson recommends using Ω = 2.5, which would
correspond to Φ = 0.56. (Use Φ = 0.55) 1”
V a (test) = 3,930/2.5 = 1,572 lb
With Ω = 1.67: 3,930/1.67 = 2,353 lb
6”
ΦV a (test) = 3,930(0.56) = 2,200 lb
With Φ = 0.90: 3,930(0.90) = 3,537 lb
Use calculated value for ΦV n = 3,050 lb
½”
V max = ΦV n for the block
Assume 6” blocking depth + 2” to
connection:
V
24”
22”
M Block = (8”)(3.049) = 24.4 in-k
V clip = 24.4/22 = 1.11 k
No. of Screws Required = 1.11/[(0.5)(3)(244)] = 3.03 (assume 43 mil rafters)
Use (4) No. 8 screws
E11.9 Connection of Shear Wall to Floor Diaphragm to Shear Wall Below
Sheathing Screw Spacing 6” 4” 3” 2”
Sheathing Shear capacity, ΦV n (plf) 385 503 701 894 (ICC, 2000a)
No. 8 Screw Capacity 246 246 246 246 (Table C-B1)
Number of No. 8 Screws Required Per Foot 2 3 3 4
E12 Shear Wall Design (High Wind Area)
Design the lateral force resisting system for the example building shown below. Use
Type I braced wall for the side walls and Type II braced walls for the end walls.
E12.1 Design Assumptions
Building Width = 32’
Building Length = 50’
Roof Slope = 3:12
Design Wind Speed = 120 mph Exposure Category B
V