1. A W12x40 beam is heated to 760°C. Answer the following questions.
What is the W/D factor for sprayed protection?
What is the W/D factor for box type protection?
What is the specific heat of the steel?
What is the thermal conductivity of the steel?
What is the yield strength of the steel assuming it was 36,000 psi at ambient conditions?
2. Using the unprotected steel member in question 1, build a spreadsheet to do the step by step method for estimating the temperature of unprotected steel work exposed to the ISO 834 Standard Fire. Assume a convective heat transfer coefficient of 25 W/m2K and an emissivity of 0.5. Assume the specific heat to remain constant at 600 J/kgK. Use a time step of 30 seconds and an ambient temperature of 20°C. The column is exposed to fire on all four sides. Provide temperatures of the steel member at the following times:
a. t=5 mins
b. t=10 mins
c. t=30 mins
d. t=60 mins
3. What is the fire resistance provided by three layers of 5/8" Type X drywall encasing a W10x45 steel column?
4. Assume you have a restrained siliceous concrete column (f'c=4,000 psi). It needs to have a fire resistance of 2 hours. Answer the following:
a. What is the minimum concrete cover for the reinforcing steel?
b. What is the minimum dimension of the column?
5. Using AFPA's values for β, calculate the residual cross sectional area (in in2) of an 10"x10" wood timber exposed to fire on all 4 sides and exposed to a standard fire for a period of 2 hours.
6. What is the fire resistance rating of a 10"x10" wooden interior column? Assume the column is loaded to 60% of its capacity, its height is 14', and the Ke value is equal to 1.0.