Pemadatan Urugan Pasir

RUMUS PEMANCANGAN TIANG.1. Modified ENR, (SF = 6)

C = 2.5 mm, = 0.10 in.Dimana:

ENR= Engineering News Record.

eh = hammer efficiency.Eh = manufacturers hammer energy rating (FL).

s = amount of point penetration per blow (L).

Wr = weight of ram (for double acting hammer include weight of casing). ( F).

Wp= weight of pile including weight of pile cap, all or part of soil plug, driving shoe and

cap block, also includes anvil for double acting steam hammer (F).n= coefficient of restitution.

2. Hileys Formula, (SF = 4)

and

(for double acting hammer), where Eh = W.h, and W = Wr + weight of casing.Where:k1= elastic compression of capblock and pile cap and is a form of PuL/AE.k2= elastic compression of pile and is of a form PuL/AE. k2= elastic compression of soil, also termed quake for wave equation analysis.Values of hammer efficiency depend on the condition of the hammer and capblock and possibly the soil.TypeEfficiency eh

Drop hammers0.75 1.00

Single Acting hammers0.75 0.85

Double Acting or Differential0.85

Diesel hammers0.85 1.00

Representative values of coefficient of restitution for use in the dynamic pile-driving equations.

Materialsn

Broomed wood0

Wood piles (nondeteriorated end)0.25

Compact wood cushion on steel pile0.32

Compact wood cushion over steel pile0.40

Steel on steel anvil on either steel or concrete pile0.50

Cast iron hammer on concrete pile without cap0.40

Contoh perhitungan:

Misalkan dipakai mesin pancang dengan hammer sbb:

Diesel Hammer D-70Wr = 7 ton., dengan tinggi jatuh hammer = 2.10 meter.Max rated energy = Eh = 7 x 2.1 = 14.7 tm.

Hammer efficiency eh = 0.8

Steel Pipe Pile diameter 914.4 mm, Weight of 34 m long pile Wp = 12 ton.

Coeff of restitution n = 0.5

Misal final set 2 mm/blow.

Dengan Modified ENR, didapat

Pu = = 1719 tonDengan safety factor SF = 6, Pall = 1719/6 = 286 ton.

Gaya vertical max pada pile diameter 914.4 mm = 256.59 ton.

Set minimum adalah s =

= = 0.002525 m.

= 2.5 mm/blow.Steel Pipe Pile diameter 1219.2 mm,

Weight of 36 m long pile Wp = 19.2 ton.

Coeff of restitution n = 0.5

Misal final set 2 mm/blow.

Dengan Modified ENR, didapat

Pu = = 1471 ton

Dengan safety factor SF=6, Pall = 1471/6 = 245 ton.

Gaya vertical max pada pile diameter 1219.2 mm = 133 + 67.3 = 200.3 ton.

Set minimum adalah s =

= = 0.003 m.

= 3 mm/blow.5/5

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