Staircase Reinforcement
Reinforcement ratio = - = 0.0051
1000 x 149
Near support
VRd1 = 0.35 x (1.6 - 0.175) x (1.2 + 40 x 0.0051) x 149 = 104.3 kN 4.3.2.3
Eqn 4.18
1/ > V = 44.9 kN, hence no shear reinforcement required
2.9.7 Deflection
Reinforcement ratio at mid-span = 0.51%
Concrete is lightly stressed, hence basic span/effective depth ratio is 32. Table 4.14
Since f. = 460, this should be modified to:
32 x 400/460 x 754/601 = 34.9 4.4.3.2(4) Actual span/effective depth ratio = 5060/149 = 34 < 34.9....... OK
2.9.8 Cracking
As for floor slab in Section 2.3.8
Minimum area of reinforcement = 183 mm2/m 4.4.2.2
Thickness of waist = 175 < 200 mm 4.4.2.3 (1) No further check is necessary.
2.9.9 Tie provisions
E-W internal tie, the minimum area required = 91 mm2/m BS 8110
Total area for staircase = 91 x 3 = 273 mm2
Provide 2T12 tie bars each side of staircase in adjacent slab
2.9.10 Reinforcement details
- The reinforcement details are shown in Figure 2.17.
Figure 2.17 Staircase reinforcement details
Figure 2.17 Staircase reinforcement details
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