Pile Head Stress Calculations

Calculation of Permissible Stresses in Pile head Concrete grade Plan size of Pile head B D Area Ram dia of Jack Ram area No of Jacks Loaded area Thickness of the plate Dispersion of load in the steel plate Dai meter of loaded area on Pile Head

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M 35 1750 mm 1750 mm 3062500 mm2 410 mm 132025 mm2 4 Nos 528102 mm2 30 mm 1 in 2 410+2x30+2x30 530 mm Loaded area on concrete per jack 3.14x530^2/4 220618 mm2 Loaded area on concrete from four jacks (A2) 882473 mm2 Dispersed area - (A1) = 1750x1750 3062500 mm2 Permissible bearing stress = SQRT (A1/A2) * 0.25 * fck) IRC:21 - Clause : 307.1 = 16.3 N/mm2 SQRT(A1/A2) Shoud not exeed 2 1.9 <2 Ok Check for Bearing stress & Compressive stress in concrete Bearing stress Area - A2 = 882473 mm2 Total Load on pile head = 1250 t Bearing stress = 14.16 N/mm2 <16.3 N/mm2 Ok Direct compressive stress Total Load on pile head = 1250 t Area - A1 = 3062500 mm2 Direct compressive stress = 4.08 N/mm2 <8.75 N/mm2 Ok

Design of Pile Head Load carrying capacity of pile head Designed as a short column. Axial load, P = 1250 ton Grade of concrete = Fck =

35 N/mm2

Steel Yield strength = Fy = 415 N/mm2 Pile head Width = 1750 mm Pile head Length = 1750 mm Pile head Depth = 2500 mm Ac = ### mm2 Provided Main steel reinforcement Dia of long. Bar = 20 mm No. of. Long. Bar provided= 24 Nos. Provided steel area, Asc = 7539.82 mm2 As per IS 456 : 2000 clause 39.3 Pmax = 0.4 fck Ac + 0.67 fy Asc Pmax = 4573 ton > P, OK Minimum 0.15% steel = 4593.75 mm2 < 7540 sqr.mm, OK Tie reinforcement As per IS 456 : 2000 clause 26.5.3.2 c Dia ≥ 0.25 x dia of long. Bar = 5 mm Dia of ties provided = 10 mm Pitch of tie = Least lateral dim. of column (or) = 1750 mm Pitch of tie = 16 times long. Bar dia (or) 320 mm Pitch of tie = 300 mm Provided pitch = 300 mm