Design guide for concrete pile capsDescripción completa
Design guide for concrete pile caps
This document presents how to design a pile cap using BS8110.1997 British code. CSC TEDDS was used to generate the calculation. Strut and tie method was used. Once the structure has been analysed ...
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CAP
Pelaksanaan Pile Cap
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GENERAL DETAILS OF THE PILES, COLUMNS AND PILE CAP Axial load on column= 35000 kN Column size = 1200 mm x 1200mm square Pile diameter = 1500 mm No. of piles connected by the pile cap = 4 Center to center distance in between piles = 4500 mm
D
C 1200 mm
1200 mm
4500 mm
1500mm
B
A
4500 mm a N
C
C
d
T
N/2
N/2
2L = 4500 mm As this is a symmetric structure
TAB = TBC
=
TCD = TDA=
N 3L2 a 2 12 Ld
Average effective depth of pile cap = 2500 mm Total depth can be taken as about 2625mm allowing for 75 mm cover and bar spacing Width of the cap = 4500+750 X 2+250 X 2 = 6500 mm
TAB = TBC = TCD = TDA=
TAB = TBC
N 3L2 a 2 12 Ld
7688.33 103 N = TCD = TDA= 0.87 460 N / mm 2
= 7688.33 kN TAB = TBC = TCD = TDA = 0.87 fy As 7688.33 kN = 0.87 X 460 As As =
7688.33 10 3 N 0.87 460 N / mm 2
= 19211.22 mm2 Assume 32 mm bars No of bars =
19211.22 = 23.887 bars 322 4
Hence provide 24 Nos of 32 mm diameter bars @ 270 mm spacing As provided
= 24 X 804.25 = 19302 mm2 in both directions
Distribute the bars along the section uniformly as Spacing of piles = 3 times pile diameter 4500 = 3 X 1500 Min r/f check 100 As 100 19302 2 0.2263 0.13 bh 6500 2625
Hence more than minimum provided Check for shear 100 As 100 19302 2 0.238 bd 6500 2500
35000 103 2 Shear stress along the critical section = 6500 2500 =1.0938N/mm2 < 1.733 N/mm2 Hence ok for shear and no shear reinforcement needed Check for punching shear Punching shear check is not necessary as Spacing of piles =3 times pile diameter 3750 =3 X 1500 Shear at the face of the column =