Development of reinforcement
CSA A23.3
v1.0.0
File:
Project:
Designer:
Date:

Reinforcement

Conditions
Tension
Compression
Standard Hook
Reinforcing Bars
Size:
Number of bundled bars:
Excess reinforcment
Area of steel required:
mm2
Area of steel provided:
mm2

Material Properties

Concrete
Compressive Strength f'c :
MPa
Reinforcing Steel
Yield Strength, fy :
MPa
Tension Calculation Method
Simplified Method

General Method
Transverse Reinforcement
Transverse reinforcement is reinforcement that is perpendicular to the longitudinal reinforcement being developed.
Atr = total cross-sectional area of reinforcement that is within spacing s and crosses the potential plane of bond splitting through the reinforcement being developed.
s = maximum centre-to-centre spacing of transverse reinforcement within ℓd
n = number of bars or wires being spliced or developed along the potential plane of bond splitting.
Atr:
mm2
s:
mm
n:
mm
Yield Strength, fyt :
MPa
Reinforcement
Minimum cover:
mm (to the centre of the bar)
Centre-Centre spacing:
mm (of the bars being spliced)

Tension Modification Factors

Bar Location Factor, k1
k1 = 1.3 for horizontal reinforcement placed in such a way that more than 300mm of fresh concrete is cast in the member below the development length or splice.
k1 = 1.0 for other cases.
Bar location factor, k1:
Coating Factor, k2
k2 = 1.5 for epoxy-coated reinforcement with clear cover less than 3db or with clear spacing between bars being developed less than 6db.
k2 = 1.2 for all other epoxy-coated reinforcement..
k2 = 1.0 for uncoated reinforcement.
Coating factor, k2:
Concrete Density Factor, k3
Concrete density, k3:
Bar Size Factor, k4
Bar Size Factor, k4 is computed.

Compression Modification Factors

Bar Enclosure factor, kEnclosed
Reinforcement enclosed within spiral reinforcement of not less than 5mm dia and not more than 100mm pitch or within 10M ties in compliance with Clause 7.6.5 and spaced at not more than 100mm on centre?
Enclosed reinforcement?

Standard Hooks in Tension

Modification Factors
(b) for 35M or smaller bars where the side cover (normal to the plane of hook) is not less than 50mm and for 90 degree hooks where the cover on the bar extension beyond the hook is not less than 50mm. [factor = 0.7]
(c) for 35M or smaller bars where the hook is enclosed vertically or horizontally within at least three ties or stirrup ties spaced along a length at least equal to the inside diameter of the hook at a spacing not greater than 3db where the db is the nominal diameter of the hooked bar. [factor = 0.8]
(d) Where anchorage or development for fy is not specifically required for reinforcement exceeding that required by analysis, [factor = (As required) / (As provided)]
(e) Concrete is structural low-density concrete. [factor = 1.3]
(f) Reinforcement is epoxy coated. [factor = 1.2]
Confinement of Hooks
Is both side cover and top (or bottom ) cover over the hook less than 60mm?

Reinforcing

Reinforcing size: 15M
Reinforcing area: 200 mm2
Reinforcing diameter: 16 mm
Reinforcing bundle: 1
fy: 400 MPa

Concrete

f'c: 25 MPa

Tension Development Length

Factors
k1: 1.0
k2: 1.0
k3: 1.0
k4: 0.8
[12.4]
kBundle: 1
Simplified method:
Development length, ℓd = 0.6*k1*k2*k3*k4*fy*db / (f'c0.5) ) * kBundle = 614.4mm

Tension Development length, ℓd = 614.4mm

Compression Development Length

Factors
kEnclosed: 1.0
[12.4]
kBundle: 1
[12.3]
Development Length
Basic development length, ℓdb = 0.24*db*fy / (f'c0.5) = 307.2mm
but not less than 0.044dfy = 281.6mm
Basic development length, ℓdb = 307.2mm
With factors applied: ℓd =307.2mm [but shall not be less than 200mm]

Compression Development length, ℓd = 307.2mm

Standard Hook in Tension Development Length

[12.5.3]
Factors
ka = fy / 400 = 1
kb = 1
kc = 1
kd = (As required) / (As provided) = 1
ke = 1
kf = 1
Development Length
[12.5.2]
Basic hook development length, ℓhb = 100*db / (f'c0.5) = 320mm
[12.5.1]
with factors applied: ℓdh = 320mm
but not less than 150mm or 8db = 150mm

Standard Hook in Tension Development length, ℓdh = 320mm

note: This does not apply to anchorage of shear reinforcement. See Clause 12.13.

This information must be read or used in conjunction with CAN/CSA A23.3. In the event of discrepancies, CAN/CSA A23.3 shall govern.