Punching shear edge column

Assuming penultimate support, VEd = 1.18 x 516.5 = 609.5 kN

Check at perimeter of column

P = factor dealing with eccentricity; recommended value 1.4 VEd = applied shear force U = control perimeter under consideration.

For punching shear adjacent to edge columns u0 = c2 + 3d < c2 + 2c1 = 400 + 750 < 3 x 400 mm = 1150 mm d = as before 250 mm vEd = 1.4 x 609.5 x 103 / 1150 x 250 = 2.97 MPa

VRd.max as before = 5.28 MPa

Check shear stress at basic perimeter u1 (2.0d from face of column)

where

P, VEd and d as before u1 = control perimeter under consideration.

For punching shear at 2d from edge column vE VR

where

-- 1.4 x 609.5 x 103 / 2771 x 250 = 1.23 MPa : 0.18 / Yc x k x (100 pfck)0333

1.89

P = (PxPly)05 where px, py = areas of bonded steel in a width of the column plus 3d each side of column. px = (perpendicular to edge) 10 no.H20 T2 + 6 no. H12 T2 in 2 x 750 + 400, i.e. 3818 mm2 in 1900 mm. px = 3818 / (250 x 1900) = 0.0080 py = (parallel to edge) 6 no. H20 T1 + 1 no. T12 T1 in 400 + 750 i.e. 1997 mm2 in 1150 mm. pY = 1997 / (250 x 1150) = 0.0069 p = (0.0080 x 0.0069)05 = 0.0074

<Concise EC2 Table 15.3> <6.4.3(2), 6.4.5(3)>

columns u1 = c2 + 2c1+ nx 2d = 2771 mm area of shear reinforcement required for any other perimeter should be based on this value, Asw / ut together with the requirements for minimum reinforcement and spacing of shear reinforcement (see Clause 9.4.3).

vRd,c = 0.18 / 1.5 x 1.89 x (100 x 0.0074 x 30)0333 = 0.64 MPa

.'. punching shear reinforcement required

<See also Concise EC2 Table 15.6tftttt>

Punching Shear

Figure 3.23

Flexural tensile reinforcement adjacent to columns C1 (and C3)

Figure 3.23

Flexural tensile reinforcement adjacent to columns C1 (and C3)

Perimeter required where punching shear links no longer required uout = 609.5 x 1.4 x 103 / (250 x 0.64) = 5333 mm

Length attributable to column faces = 3 x 400 = 1200 mm radius to uout from face of column = say (5333 - 1200) / n= 1315 mm from face of column

Perimeters of shear reinforcement may stop 1370 - 1.5 x 250 = .940 mm c(Exp. 6.54)>

Shear reinforcement

As before, sr max. = 175 mm; st max. = 350 mm and fywd.ef = 312 MPa from face of column <6.4.5(4) & NA>

For perimeter u1

= (1.23 - 0.75 x 0.64) x 175 x 2771 / (1.5 x 312) = 777 mm2per perimeter

Asw.min > 0.08 x 3005 (175 x 350) / (1.5 x 500) = 36 mm2

/.Use H8 (50 mm2) legs of links at 175 mm cc around perimeters perimeters at 175 mm centres

Check min. 16 H8 legs of links (800 mm2) in perimeter u1, 2d from column face

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