Example of Interaction Diagram by the Strength Approach (Spreadsheet Calculation)

Construct the moment-axial force interaction diagram by the strength approach for a nominal 8-in. CMU wall, fully grouted, with fm′ = 1500 lb/in.2 and reinforcement consisting of #5 bars at 48 in., placed in the center of the wall.

The effective width of the wall is 6t, or 48 in. The spreadsheet and corresponding interaction diagram are shown in Fig. 6.18. As noted above in the example of Sec. 6.3.3, the results are interesting. Because the reinforcement is located at the geometric centroid of the section, the balance-point axial load (about 100,000 lb) does not correspond to the maximum moment capacity.

Plot of Strength Interaction Diagram by Spreadsheet

The moment-axial force interaction diagram (strength basis) as plotted by spreadsheet is shown in Fig. 6.18. Relevant cells from the spreadsheet are reproduced in Table 6.2.