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Masonry Column Design Problem 1 - Check the capacity of a reinforced concrete masonry column for an eccentric load:
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Given a 16-ft high 10-in x 18-in masonry column (f'm = 2000 psi) reinforced with 4 no. 9 bars (fy = 40 ksi) with an eccentric axial load of 20 kips.
First check the adequacy of the column if the eccentricity is 3 in when measured parallel to the short direction. Then check the adequacy of the column if the eccentricity is 3 in measured parallel to the long direction. |
1. From the masonry columns submenu open the reinforced column - compression bending calculation, ColumnCompBend.aspx.
Input the "Title" of the calculation, the "Designer/Checker" information and the variables for the column with the eccentricity of the load measured parallel to the short direction.
Next open the reference "Masonry Design Tables" and determine the allowable steel tensile stress Fs. Enter the remaining variables and click on the "Calculate" button. Read the results.
The column meets all of the design conditions however it is inadequate due to the axial loading is greater than 1/4 the buckling load when eccentricity is measured parallel to the short direction.
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Next, re-enter the variables for the eccentricity measured parallel to the long direction. Click on the "Calculate" button and read the results.
The loading is less than 1/4 the buckling load, therefore the design with eccentricity measured parallel to the long direction is adequate.
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3. Summary
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The column is inadequate for a 20 kip eccentric axial load with eccentricity 3 inches measured parallel to the short direction.
The column is adequate for a 20 kip eccentric axial load with eccentricity 3 inches measured parallel to the long direction.
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