24.02.2017 Views

Structural Concrete - Hassoun

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

134 Chapter 3 Flexural Analysis of Reinforced <strong>Concrete</strong> Beams<br />

Figure 3.33<br />

Example 3.11: (a) Plan of slab-beam roof and (b) section A–A.<br />

Solution<br />

1. Determine the effective flange width b e . The effective flange width is the smallest of<br />

b e = L 4 = 15 × 12 = 45 in.<br />

4<br />

b e = 16t + b w =(16 × 4)+10 = 74 in.<br />

b e = Centertocenterofadjacentslabs =(7 × 12)+10 = 94 in.<br />

Therefore, b e = 45 in. controls.<br />

2. Check the depth of the stress block. If the section behaves as a rectangular one, then the stress<br />

block lies within the flange (Fig. 3.30). In this case, the width of beam used is equal to 45 in.<br />

a =<br />

A s f y 2.37 × 60<br />

0.85f cb ′ = = 1.24 in. 0.00333<br />

10 × 16

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!