Punching shear edge column with hole

Check columns D1 and D3 for 200 x 200 mm hole adjacent to column.

tttttt vRdc for various values of d and p is available from Concise EC2[10] Table 15.6.

As previously described use 4 H20 U-bars each side of column for transfer moment.

Assuming internal support, VEd = 516.5 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

Allowing for hole, u0 = 1150 - 200 = 950 mm d as before = 250 mm vEd = 1.4 x 516.5 x 103 / 950 x 250 = 3.06 MPa vRd.max as before = 5.28 MPa .-. OK

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

P, VEd and d as before u1 = control perimeter under consideration. For punching shear at 2d from edge column columns u1 = c2 + 2c1+ nx 2d = 2771 mm Allowing for hole 200 / (c1 / 2): x / ( c1 / 2 + 2d) 200 / 200: x / ( 200 + 500) .'. x = 700 mm u1 = 2771 - 700 = 2071 mm vEd = 1.4 x 516.5 x 103 / 2071 x 250 = 1.40 MPa vRd.c = 0.18 / rc x k x (100 PlQ0333

where

P = (PxPly)05 where px, ply = areas of bonded steel in a width of the column plus 3d each side of column. p = (perpendicular to edge) 8 no.H20 T2 + 6 no.H12 T2 in

2 x 720 + 400 - 200, i.e. 3190 mm2 in 1640 mm. plx = 3190 / (240 x 1640) = 0.0081 py = (parallel to edge) 6 no.H20 T1 (5 no. are effective)

+ 1 no. T12 T1 in 400 + 750 - 200, i.e. 1683 mm2 in 950 mm. pY = 1683 / (260 x 950) = 0.0068 p = (0.0081 x 0.0068)05 = 0.0074 fck = 30

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

; for various values of d and p is available from Concise EC2 [10] Table 15.6

<6.4.3(2), 6.4.5(3)> <Fig. 6.21N & NA>

.'. punching shear reinforcement required

Punching Shear Check For Edge Column

Figure 3.24

Flexural tensile reinforcement adjacent to columns D1 and D3

Figure 3.24

Flexural tensile reinforcement adjacent to columns D1 and D3

Perimeter required where punching shear links no longer required uout = 516.5 x 1.4 x 103 / (250 x 0.64) = 4519 mm Length attributable to column faces = 3 x 400 = 1200 mm Angle subtended by hole from centre of column D1 (See Figures 3.24 & 3.27) 2 tan-1(100 / 200) = 2 x 26.5° = 0.927 rads.

= say (4519 - 1200) / (n- 0.927) = 1498 mm from face of column

Perimeters of shear reinforcement may stop 1498 - 1.5 x 250 = 112.3 mm from face of column

Shear reinforcement:

As before, sr max. = 175 mm; st max. = 350 mm and f ywd.ef

For perimeter u1

Asw > (vEd - 0.75vRd,c) sr U1 / ^fwdf per perimeter

= (1.40 - 0.75 x 0.64) x 175 x 2071 / (1.5 x 312) = 712 mm2 per perimeter Aswmin > 0.08 x 3005 (175 x 350) / (1.5 x 500) = 36 mm2

Using H8 (50 mm2) max. spacing = min[50 / 0.3; 1.5d]

= min[147; 375] = 147 mm cc No good Try using H10, max. spacing = 78.5 / 0.34 = 231 mm cc, say 175 cc

.'. Use min. H10 (78.5 mm2) legs of links at 175 mm cc around perimeters perimeters at 175 mm centres

Check min. 9 H10 legs of links (750 mm2) in perimeter u1, 2d from column face.

Note: As the requirement for these columns is for H10 links change ALL links to H10 to avoid potential problems on site

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