Broms method.xls

Broms Free Head Piles in Cohesive Soil (OVERTURNING) Moment (working) Leverarm (F.O.S.) Bored Pier Diameter Soil Shear

M = 102.0 kN.m e = 7.5 metres = 1 B = 0.75 metres c= 50 kPa P = 13.6 kN f = 0.04 metres M(max) = 117.57 kN.m g = 1.18 metres L req =

2.35

metres

P=(F.O.S.)M/e (factored) f = P/9cB M(max) = P( e + 1.5B + 0.5f )

g = L req

M max 2 . 25 cB = 1 .5 B + f + g

UPLIFT CHECK

Uplift force (working) Depth Diameter Unit weight of soil Volume of concrete cylinder Depth of small cone y = Volume of small cone =

35.00 1.70 0.75 18.00 0.75 0.650 0.10

kN metres metres kN/m3 m3 metres m3

x= Base of large cone = Volume of large cone = Mass of soil Mass of concrete cylinder Total resistance to uplift = FOS

0.98 2.71 4.53 66.25 18.02 84.28 2.41

metres metres m3 kN kN kN

150.00 10.00 66.27 40.06 106.32 3.04

kPa kPa/m2 kN kN kN

BEARING CAPACITY OF BORED PIER Vertical Down Force Depth Diameter Unit weight of soil Bearing Area Skin Surface area

35.00 1.70 0.75 18.00 0.442 4.006

kN metres metres kN/m3 m2 m2

Allowable bearing Capacity Allowable Skin Friction Base Bearing Capacity Skin Friction Capacity Total Bearing Capacity FOS