Pile Cap Design_columns

Job ref

Project

Calc sheet no

Part of structure

rev / 0

Drawing ref.

Calc by

Check by

Date Sep-13

Ref

Calculations

Date Nov-09

Output

Design of pile cap - PC4 Line of critical shear Dia. Of pile

=

450 mm

Offest from pile

=

150 mm

Column width

=

600 mm

Pile spacing (2L)

=

1350 mm

Depth of pile cap

=

750 mm

Width of pile cap (B)

=

750 mm

Bottom cover

=

75 mm

Side cover

=

Ultimate axial load (N)

=

Materials f cu = cu

B

Φ /5

2L

50 mm 1800 kN

f y

=

35 N/mm2 500 N/mm2

Gm

=

1.25 (parti al al s af af te tey factor for concr et ete - shear)

Gm

=

1.15 (partial saftey factor for steel)

Design for main reinforcement: Effective depth of pile cap (d)

=

653 mm

According to Truss theory: Tension to be resisted by main reinforcement, T

= (N x L) L) / (2 x d) d) = 1800 1800 x 675 675 / (2 (2 x 653) 653) =

930.3 kN

According to Flexural theory: Moment parallel to X axis K = M / fcu b d

2

Z = d(0.5 + √(0.25 - K / 0.9))

= =

0.054

=

611.14 mm

608 kNm

Therefore Tx

=

994.0 kN

Area of steel required

= T / (0.8 (0.87 7 x fy) fy) = 9940 994040 40 / (0.8 (0.87 7 x 500 500)) =

Dia. Of bars using for main reinforcement

=

No. of bars required

=

2286 mm

2

20 mm 7.28

Provide No. of bars

=

9 Nos

Area of steel provided

=

2827 mm

BS 8110

Spacing of main bars

=

78.3 mm

Table 3.25

Percentage of steel

=

2

OK

0.5 % > 0.13 % OK

Job ref

Project

5074908

Newport Station Regeneration

Calc sheet no

Part of structure

9 / 9

Car Park - Design of Pile Caps for Columns Drawing ref.

Calc by SJ

Ref

Chec k by

Date Jun 08

CMN

Calculations

= (N / 2) / (B x d) 2

=

1.84 N/mm

100 As / bv d

=

0.58 %

Design strength of concrete for shear resistance

=

35 N/mm

(400 / d) Design shear resistance ( v c)

= =

0.88 0.52 N/mm2

Critical section from face of the column (av)

= (675 - 300 - 0.3 x 450)

Enhanced shear stress

=

<

5 N/mm

2

OK

BS 8110 Table 3.8

(1/4)

= 3.4.5.8

2

240 mm 2.83 N/mm

2

>

1.838

Hence, shear links are not required. However provide nominal T12 links @ 200 c/c . Side face reinforcement: 3.12.5.4

Dia. Of bar used for side face reinforcement Spacing of bar

Date

Output

= (1800 / 2) / (750 x 653) 3.4.5.2

/ 0 Jun-08

Check for shear: Shear stress along critical section (v)

rev

=

16 mm 2

= ( ϕ x f ) /b =

256 mm

Hence, provide side face reinforcement - 2 nos. T16 bars

OK

Job ref

Project

Calc sheet no

Part of structure

rev / 0

Drawing ref.

Calc by BVR

Ref

Check by

Date Sep-13

Date Nov-09

Calculations

Output

Design of pile cap - PC2 (For 750x300 column)

Y

av

Φ /5

Dia. Of pile ( Φ )

=

450 mm

Offest from pile

=

150 mm

Column width in X-direction

=

600 mm

Column width in Y-direction

=

600 mm

Effective length of pile cap (2 Lx)

=

1350 mm

Effective length of pile cap (2 Ly)

=

1350 mm

Depth of pile cap

=

750 mm

Bottom cover

=

75 mm

Side cover

=


=

3500 kN

Reaction of each pile (N/3)

=

1167 kN

av

2100

2Ly

750

Φ

50 mm 2Lx

X

2100 Materials f cu = f y

=

35 N/mm2 500 N/mm2

Gm

=

1.25 (partial s aftey fac tor for c onc rete - s hear )

Gm

=



=

637.5 mm

Effective length of pile cap (2 Lxy)

=

1509 mm

Tension to be resisted by main reinforcement, Txy

= (2N x Lxy) / (9 x d)

According to Truss theory:

= 2 x 3500 x 754.675 / (9 x 637.5) = Tension to be resisted by main reinforcement, Ty

920.7 kN

= (2N x Ly) / (9 x d) = 2 x 3500 x 675 / (9 x 637.5)

Net tension to be resisted by main reinforcement, Tx

=

823.5 kN

=

2 x Txy cos 26.57

=

2 x 920.74 x cos 26.57

= Net tension to be resisted by main reinforcement, Ty

1647 kN

= 2 x Txy sin 26.57 + 823.53 =

1647.1 kN

According to Flexural theory: Moment parallel to X axis K = M / fcu b d

2

Z = d(0.5 + √(0.25 - K / 0.9))

=

0.023

=

605.63 mm

Moment parallel to Y axis K = M / fcu b d

2

Z = d(0.5 + √(0.25 - K / 0.9))

=

0.015

=

605.63 mm

=

700 kNm

=

437.5 kNm

Therefore Tx =

1155.8 kN

Therefore Ty =

722.39 kN

In X-direction Area of steel required in X-direction

= Tx / (0.87 x fy) = 1647100 / (0.87 x 500) =

2

3786 mm


=


=

Provide No. of bars

=

14 Nos


=

6872 mm 153.8 mm

BS 8110-1


=

Table 3.25

Percentage of steel

=

25 mm 7.714 2

OK

0.44 % > 0.13 % OK

Provide 14 Nos. T25 bars

Job ref

Project

5074908


Calc sheet no

Part of structure

5 / 9


Calc by

Ref

Chec k by

Date

SJ

Jun 08

Calculations

rev / 0

Date

CMN

Jun-08 Output

In Y-direction Area of steel required in Y-direction

= Ty / (0.87 x fy) = 1647100 / (0.87 x 500) =


=


=

2

3786 mm

25 mm 7.714

Provide No. of bars

=

14 Nos


=

6872 mm


=

150 mm

Percentage of steel

=

2

OK


0.44 % > 0.13 % OK

Check for shear: Shear stress along critical section (v)

= (2 N/3) / (B x d) = 2 (3500000 / 3) / (2100 x 637.5) =

1.74 N/mm2

100 As / bv d

=

0.52 %


=

3.4.5.2 BS 8110 Table 3.8

(1/4)


3.4.5.8

<

5 N/mm2

OK

35 N/mm2

= =

Critical section from face of the column (a v)

0.89 0.51 N/mm2 = (2/3)x1350 - 600/2 - 0.3x450 =

465 mm


=

1.4 N/mm2

<

1.74

<

5 N/mm2

FALSE

Hence, shear links are required Check for punching shear: At column face: Punching stress

= N / (u d)

Perimeter of column (u)

=

Punching stress

=

2400 mm 2.29 N/mm2

OK

At Φ/5 from pile face: Punching stress

= N / (u d)

Critical perimeter (u)

=

Punching stress

=

1.54 N/mm2


=

1.39 N/mm2

3559 mm

Hence, shear links are required

Side face reinforcement: 3.12.5.4


=

16 mm 2

= ( ϕ x f ) /b =


256 mm

FALSE

Job ref

Project

Calc sheet no

Part of structure

rev / 0

Drawing ref.

Calc by

Check by

Date Sep-13

Ref

Calculations

Y =

450 mm

Offest from pile Column width in X-direction

= =

150 mm 600 mm

Column width in Y-direction

=

600 mm

Pile spacing in X-direction (2 Lx)

=

1350 mm

Pile spacing in Y-direction (2 Ly)

=

1350 mm

Depth of pile cap

=

750 mm

Bottom cover

=

75 mm

Side cover

=

50 mm


=

K'

=

Nov-09 Output

Design of pile cap - PC1

Dia. Of pile ( Φ )

Date

av2

av1 2100

2Ly

4300 kN

2Lx

X

0.156 2100

Materials f cu =

2

f y

=

Gm

=

32 N/mm 500 N/mm2 1.25 (partial saftey factor for concrete - shear)

Gm

=



=

662.5 mm

According to Truss theory: Reynolds

Tension to be resisted by main reinforcement, Ty

Hand book Tension to be resisted by main reinforcement, Tx

= (2 N Ly)/(4 d) =

2 x 4300 x 675 / (4 x 662.5)

=

2190.6 kN

= (2 N Lx)/(4 d) =

2 x 4300 x 675 / (4 x 637.5)

=

2276.5 kN

=

806.25 kNm

=

806.25 kNm

According to Flexural theory: Moment parallel to Y axis K = M / fcu b d

2

Z = d(0.5 + √(0.25 - K / 0.9))

= =

0.027 629.375 mm

Moment parallel to X axis K = M / fcu b d

2

Z = d(0.5 + √(0.25 - K / 0.9))

= =

0.03 605.625 mm

Therefore Ty

=

1281 kN

Therefore Tx

=

1331.3 kN

In Y-direction Area of steel required in Y-direction

= Ty / (0.87 x fy) = 2190570 / (0.87 x 500) =

2

5035.8 mm

Dia. of bars for main reinforcement

=


=

25 mm

Provide No. of bars

=

12 Nos


=

5890.5 mm

BS 8110-1


=

181.82 mm

Table 3.25

Percentage of steel

=

10.259 2

OK

0.37 % > 0.13 % OK


Job ref

Project

5074908


Calc sheet no

Part of structure

3 / 9


Calc by SJ

Ref

Check by

Date Jun 08

CMN

Calculations

rev / 0

Date Jun-08

Output

In X-direction Area of steel required in X-direction

= Tx / (0.87 x fy) = 2276470 / (0.87 x 500) =

Dia. of bars for main reinforcement

=


=

2

5233.3 mm

25 mm 10.661

Provide No. of bars

=

14 Nos


=

6872.2 mm

BS 8110-1


=

150.00 mm

Table 3.25

Percentage of steel

=

2

OK


0.44 % > 0.13 % OK

Check for shear in Y-direction: Shear stress along critical section (v)

= (N / 2) / (Bx x d) = (4300000 / 2) / (2100 x 662.5)

Table 3.8

=

1.55 N/mm

100 As / bv d

=

0.42 %


=

(1/4)


3.11.4.4.a

32 N/mm

2

<

5 N/mm

2

OK

2

= =


0.88 0.45 N/mm2 = 1350/2 - 600/2 - 0.3*450

Enhanced shear stress = 2 d v c / av

= =

240 mm 2.5 N/mm2

>

1.55

OK

Hence, shear links are not required. Check for shear in X-direction: Shear stress along critical section (v)

= (N / 2) / (By x d) = (4300000 / 2) / (2100 x 637.5)

3.4.5.2

=

1.61 N/mm

100 As / bv d

=

0.52 %


=

2

<

5 N/mm

2

OK

BS 8110 Table 3.8

(1/4)


32 N/mm

2

= =

3.11.4.4.a


1 0.55 N/mm2 = 1350/2 - 600/2 - 0.3*450

3.4.5.8

Enhanced shear stress = 2 d v c / av

= =

240 mm 2.93 N/mm2

>

1.61

<

5 N/mm

OK

Hence, shear links are not required. Check for punching shear: At column face: Punching stress

= N / (u d)

Perimeter of column (u)

=

2400 mm

Punching stress

=

2.76 N/mm

Side face reinforcement: 3.12.5.4


=

= ( ϕ x f ) / 500 =


16 mm 2

256 mm

2

2

OK

Pile Cap Design_columns

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