Coastal and Floodplain Construction Inspector's Practice Exam

Given a 51' width structure built in a 100 mph wind zone with a dead load of 15 psf, what is the uplift for trusses with 24" spacing?

1. 1300

2. 1055

3. 895

4. 1140

The correct answer is: 1055

To determine the uplift for trusses in a structure located in a 100 mph wind zone, several calculations are necessary. The uplift load is influenced primarily by the wind pressure acting on the structure. First, it's essential to calculate the wind pressure using the formula: \[ P = 0.00256 \times V^2 \] Where: - \( P \) = wind pressure in pounds per square foot (psf) - \( V \) = wind speed in miles per hour (mph) Substituting the wind speed of 100 mph: \[ P = 0.00256 \times (100^2) = 0.00256 \times 10000 = 25.6 \, \text{psf} \] Next, to find the total uplift force on the trusses, the area that the wind affects must be calculated. Given the width of the structure is 51 feet and the spacing of the trusses is 24 inches (or 2 feet), the effective area per truss subjected to wind is: \[ \text{Area} = \text{Width} \times \text{Truss Spacing} = 51 \, \text{ft} \times 2