Consider the structure shown in Fig. 5.24. The wall is identical to that addressed in the previous examples, with the exception of two openings, each measuring 9 ft in plan. These openings divide the wall into three smaller wall segments.
Assume that the applied shear is divided equally among the three wall segments; that points of inflection exist at the mid-height of each wall segment; and that axial forces in the wall are negligible. Then the moments and shears, can be determined by statics, where L is the 10-ft height of the wall segments. A free body of one wall segment is shown in Fig. 5.25.
The rest of the design proceeds as before. The shear area of the wall segments is reduced in proportion to the plan length of each segment, compared to the plan length of the original unperforated wall. The moment of inertia of the segments, however, is considerably less than the moment of inertia of the original unperforated wall.