minipiling-technical-design-information

Technical Design information for SEA-Tech Piles

Load bearing length of pilebond length calculation key factors
L	load bearing length
T	soil skin friction factor (Tult)
Tw	safe working load
Fs	factor of safety
D	drill diameter + enlargement factor
Load bearing length of pile bond length calculation
	installation	soil description	range kN/m2
	drill & grout	cohesion less soil
	1	non- plastic silt	20-30
	2	med- dense sandy silt	50-75
	3	dense silty sand/gravel	100-200
	4	very dense sand/gravel100-300
	drill & grout	cohesive soil
	1	stiff clay	40-60
	2	stiff clay silt	40-60
	3	stiff sandy clay	100-200
	drill & grout	soft rock
	1	weathered mud stone	100-200
	2	weathered sandstone	200-300
	3	weathered shale	100-150
	4	marl and chalk	100-250
Pile Diameter calculation Table
	min pile dia	ground type
	2.0 x drill dia	medium & course cobbles
	1.5 x drill dia	sand & gravelly sand
	1.4 x drill dia	clay & marl
	1.0 x drill dia	sandstone types & rock
Bond Length Calculation
L=	Tw x Fs
	3.142 x D xT
Example using 120mm dia drill bit on 38mm drill bar
required pile load 300kN
L=	300kN x 3
	3.142 x (0.120 +0.05) x150kN/m
L=	900
	84.83
L=	10.60 mtslength of pile
Design information for SEA-Tech Piles
Safe Load Taken on SEA-Tech Piles calculation for safe working load on grout SWL = area of grout ¡Ástrength of grout /4 (4=safety factor) strength of grout = 40N/mm2 after 28 days area of grout = area of pile - area of steel bar example: Using 120mm drill bit with 38mm bar in sandstone. (no enhancement factor) SWL = (120x120-38x38)x(3.142/4)x (40/4) SWL = 102kN calculation for safe working load on SEA-Tech bar SWL on 38mm bar from table is 422kN (yield value) with a safety factor of 2 SWL = 422/2=211 total safe working load of 38mm SEA-Tech pile with 120mm dia bit in sandstone SWL=102+211=313kN example results 1 pile of 38 x 25 SEA-Tech bar with 120mm dia bit installed to 10.6 mts in sandstone SAFE WORKING LOAD OF 313kN