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R12 @ 300

2.4.6 Deflection

Reinforcement percentage at centre of 8 m span 4.4.3.2

Interpolating between 0.15 and 0.5%, basic span/effective depth ratio for end NAD span = 40 Table 7

To modify for steel stress multiply by 400/460

To modify for T section multiply by 0.8

To modify for span > 7 m multiply by 7/8

Therefore permissible ratio = 40 x (400/460) x 0.8 x 7/8 = 24.3 Actual ratio = 8000/450 = 17.8 OK

2.4.7 Cracking

For estimate of steel stress under quasi-permanent loads 4.4.2.2

Ultimate load = 64.8 kN/m

Table 1

Quasi-permanent load = 0.3 x 20 + 25.8 = 31.8 kN/m tuu OI.O ?

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