Design parameters for shear (Concrete wall: EC2)

Tekla Structural Designer
2021
Tekla Structural Designer

Design parameters for shear (Concrete wall: EC2)

For some of the shear design parameters, additional user defined limits can be applied - where this is the case minimum and maximum values are specified in Design Options > Column > Reinforcement Layout.

Minimum Shear Link Diameter

φw,min = MAX[ 6mm, 0.25 * largest longitudinal bar diameter ]

Maximum Span Region Shear Link Spacing

For design to UK NA, Irish NA, Malaysian NA and Singapore NA: 1

φw,max = MIN[ 20 * smallest longitudinal bar diameter, lesser column dimension, 400mm ]

Note:

For UK NA when concrete class > C50/60 there are separate calculations in clause 9.5.3(3). These are not implemented but a warning is displayed in this situation.

For design to EC2 Recommendations:

φw,max = MIN[ 20 * smallest longitudinal bar diameter, lesser column dimension, 400mm ]

Support Region Shear Link Spacing

For support regions, the maximum link spacing is reduced by 40%. 2

Long Term Compressive Strength Factor for Shear, αccw

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA: 3

αccw = 1.0

Design Concrete Compressive Strength for Shear, fcwd

For design to UK NA, Irish NA, Malaysian NA and Singapore NA:

fcwd = αccw * MIN (fck , 50) /γC

For design to EC2 Recommendations:

fcwd = αccw * fckC

Factor CRd,c4

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA:

CRd,c = 0.18 / γC

Factor k15

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA:

k1 = 0.15

Cracked Concrete Reduction Factor, v

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA: 6

v = 0.6 * (1 - (fck / 250))

Cracked Concrete Reduction Factor, v1

For design to UK NA, Irish NA, Malaysian NA and Singapore NA: 7

v1 = v* (1 - (0.5 * cos(α))

α is the inclination of links.

Note that links in columns are always assumed to be at 90° to column direction.

Therefore v1 = v

For design to EC2 Recommendations:

v1 = v

Minimum Shear Reinforcement Ratio, ρw,min

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA: 8

0.08 * √(fck) / fyk

Maximum Angle of Compression Strut, θmax

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA: 9

cot(θ) = 1

θ = 45°

Minimum Angle of Compression Strut, θmin

For design to10 EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA:

cot(θ) = 2.5

θ = 21.8°

Angle of Compression Strut, θ

For design to UK NA, Irish NA, Malaysian NA and Singapore NA: 11

If NEd ≥ 0 i.e. compression

θ = 0.5 * arcsin(2 * vEd / (0.9 * αcw * v1 * fcwd))

else

cot(θ) = 1.25

θ = 38.7°

For design toEC2 Recommendations:

θ = 0.5 * arcsin(2 * vEd / (0.9 * αcw * v1 * fcwd))

Stress State Factor, αcw

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA:

If σcp ≤ 0

αcw = 1.0

else if 0 < σcp ≤ 0.25 * fcd

αcw = 1.0 + (σcp / fcd)

else if 0.25 * fcd < σcp ≤ 0.5 * fcd

αcw = 1.25

else if 0.5 * fcd < σcp ≤ fcd

αcw = 2.5 * (1.0 - (σcp / fcd))

Minimum Shear Strength , vmin

For design to EC2 Recommendations, UK NA, Irish NA, Malaysian NA and Singapore NA: 12

035 * k1.5 * fck0.5

1 BS EN 1992-1-1:2004 Section 9.5.3(3)
2 Maximum BS EN 1992-1-1:2004 Section 9.5.3(4)
3 BS EN 1992-1-1:2004 Section 3.1.6(1)
4 BS EN 1992-1-1:2004 Section 6.2.2(1)
5 BS EN 1992-1-1:2004 Section 6.2.2(1
6 BS EN 1992-1-1:2004 Section 6.2.2(6)
7 BS EN 1992-1-1:2004 Section 6.2.3(3)
8 BS EN 1992-1-1:2004 Section 9.2.2(5)
9 BS EN 1992-1-1:2004 Section 6.2.3(2)
10 clause 6.2.3(2)
11 clause 6.2.3(2)
12 clause 6.2.2(1)
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