Question

A beachfront house is jacked up 10 ft above grade and placed on a set of steel columns. The weight to be supported by each column is estimated to be 150 000 lb. Design a column having a safety factor of 4. The steel alloy has a compressive yield stress Syc =60 Kpsi. (Assumptions: The loading is concentric and column are vertical. Their bases are set in concrete and their top are free.)

Answer 1

To design a column with a safety factor of 4, divide the estimated load by the safety factor to calculate the maximum load the column can safely support. Then, divide the maximum load by the compressive yield stress of the steel alloy to determine the minimum cross-sectional area required for the column. Finally, select an appropriate column based on the determined minimum cross-sectional area.

Step-by-step explanation:

To design a column with a safety factor of 4, we need to calculate the maximum load the column will need to support. The weight to be supported by each column is estimated to be 150,000 lb. To calculate the required strength of the column, we divide the estimated load by the safety factor: 150,000 lb / 4 = 37,500 lb. This is the maximum load the column can safely support.

To calculate the minimum cross-sectional area of the column, we divide the maximum load by the compressive yield stress of the steel alloy: 37,500 lb / 60,000 psi = 0.625 in². This is the minimum cross-sectional area required for the column.

Since the column is vertical and its top is free, the column will be subjected to compressive stress. By taking into account the geometry and design requirements, an appropriate column can be selected based on the minimum cross-sectional area determined.