Week 12 Challenge
Assume concrete grade to be M 35 and design the section.
Sbc for pier well – 80 tonn/ m2 . decide depth of foundation as per design
1) Difference in active and passive earth pressure:
Active Earth Pressure- (when wall moves away from from fill)-Active state is developed when the wall moves away from the back fill.The active earth pressure is less than pressure at rest because the internal resistance is mobilize in the soil of back fill when wall moves away from the back fill.
The co-ifficient for active earth pressure is designated as Ka.
Where,
Where C: Cohesion of soil
φ: Angle of internal friction
The Pressure Distribution diagram
Passive Earth Pressure- (When th e wall moves towards the backfill) - In passive state the wall is pushed towards the back fill. The passive earth pressure is greater than earth pressure at rest because shearing resistance is built up between two surface of soil mass.
The co-ifficient for active earth pressure is designated as Kp.
Where,
Where C: Cohesion of soil
φ: Angle of internal friction
The Pressure Distribution diagram
Design a well foundation for the Pier
Assume concrete grade to be M 35 and design the section.
Sbc for pier well – 80 tonn/ m2 . decide depth of foundation as per design
ANS
7. Load Combinations (Limit State)
- 2)The steel in steining and kg/cumec(poundage) for all other components of well foundation.
- Weigth of reinforcement in Curb
| Description | No. | Bar Dia | Af (m2) | Dia of Ring | Length(m) | Weight(kg) | |
| w1, Outer Ring | 8 | 16 | 0.000201 | 7.351 | 23.09 | 291.95 | |
| w3, Inner top Ring | 7 | 12 | 0.000113 | 6.267 | 19.69 | 122.51 | |
| w2, Inner bottom Ring | 9 | 16 | 0.000201 | 6.233 | 19.58 | 278.49 | |
| w5, Ring Connector | 120 | 16 | 0.000201 | 5.50 | 1042.96 | ||
| w6, Horz Connector | 960 | 10 | 0.000079 | 0.559 | 331.26 | ||
| Total Reinf | = | 2067.17 | |||||
- Weigth of reinforcement in Well foundation
| Calculation of steel quantity | |||||||
| Dia of Bar | No. | Length | Total Length | Wt/mtr. | Total Wt. | ||
| mm | m | m | Kg | Kg | |||
| Well Steining | Outer Rfc | 12 | 120 | 30.7 | 3690 | 0.89 | 3280 |
| Inner Rfc | 12 | 120 | 30.7 | 3690 | 0.89 | 3280 | |
| Hoop Reinforcement | 10 | 96 | 23.3 | 2236 | 0.62 | 1380 | |
| 10 | 96 | 16.1 | 1543 | 0.62 | 952 | ||
| Well Cap | Main Rfc (top) | 20 | 73 | 8.67 | 633 | 2.47 | 1563 |
| Main Rfc (Btm) | 20 | 82 | 8.82 | 723 | 2.47 | 1786 | |
| Weigth of steel | 12241 Kg | ||||||
| Weigth of Steel in Curb | 2067 Kg | ||||||
| Total weigth of steel | 14308 Kg | ||||||
| Calculation of Volume of Conc. | |||||||
| For Well= | 161.9 | Cum | So, | ||||
| Rqrd. Steel = | 14308/162 | ||||||
| Total= | 161.9 | cum | = | 75.59 | Kg/Cum | ||
3)Well cap design .
- Sketches showing cross section and the steel. Draw everything to the scale
Detailing
