Shaft Bearing Capacity
The vertical bearing capacity of the shaft is given by the formula:
where: | Rs | - | shaft resistance |
As | - | contact area | |
qs | - | skin friction |
Note: The contact area is calculated for rectangular and pile walls, for other cross-sections, it must be defined manually [m2/m, ft2/ft].
Determination of skin friction qs should be part of the geological survey.
Recommended values of peak resistance qs [kPa] can be found in professional literature for specific soils and structure types:
- for sheet piles
non-cohesive soil | |||
qc | 7,5 | 15 | 25 |
qs | 20 | 40 | 50 |
- for driven pile walls
qs | ||||||
non-cohesive soil | cohesive soil | |||||
qc | cu | |||||
s/Deq | 7,5 | 15 | 25 | 100 | 150 | 200 |
ssg* | 30-40 | 65-90 | 85-120 | 20-30 | 35-50 | 45-65 |
ssg=sg=0,1Deq | 40-60 | 95-125 | 125-160 | 20-35 | 40-60 | 55-80 |
- for bored pile walls
non-cohesive soil | |||
qc | 7,5 | 15 | 25 |
qs | 55-80 | 105-140 | 130-170 |
where: | qc | - | cone penetration resistance, CPT [MPa] |
cu | - | total cohesion of the soil [kPa] | |
ssg* | - | settlement at shaft resistance activation | |
ssg=sg | - | limit settlement |
Literature:
EA-Pfähle, ISBN: 978-3-433-03005-9.