Basic development length for hooks = (0.02×ψe×fy×db)/√(f'c) ≥ 8db or 150 mm.
Simplified: Use 10×db minimum.
Problem: Design a simply supported rectangular beam, span 6m, wu = 30 kN/m, f'c=21 MPa, fy=414 MPa.
This simplified method yields a safe, code-compliant beam.
The simplified design assumes tension steel only, concrete resists compression. simplified reinforced concrete design 2015 nscp pdf 2021
Step-by-step simplified process:
Simplified shortcut (for beam b × d):
If Mu is known,
≈ Require As = Mu / (0.9 fy × 0.9 d) Basic development length for hooks = (0
This approximation works for preliminary sizing.
While the 2015 NSCP serves as the primary reference for the calculations above, the 2021 NSCP (released by the ASEP) updates these provisions, particularly regarding Earthquake Engineering.
In the context of 2021, simplified design must acknowledge: This simplified method yields a safe, code-compliant beam
Beams are primarily designed to resist bending moments (flexure). A "singly reinforced beam" is the most common simplified scenario.
| Parameter | Value / Formula | |-----------|----------------| | Min. f'c for structural | 20.7 MPa (21 MPa typical) | | Min. fy for main bars | 275 MPa (but 415 MPa common) | | φ – flexure | 0.90 | | φ – shear/torsion | 0.75 | | φ – compression (tied) | 0.65 | | φ – bearing | 0.65 | | Modulus ratio n | ( E_s/E_c \approx 8 ) to 10 | | Unit weight concrete | 23.6 kN/m³ | | ρ_min (beams) | max(1.4/fy, 0.25√f'c/fy) |
Before designing, you must know the materials. The 2015 NSCP (2021 updates) specifies:
