Design of Shallow Foundation (Isolated Footings)

ANSWER :

Design a square footing for a column size of 400x400. The compression axial load for the load combination of (1.5 DL + 1.5 LL) is 2000 KN. The safe soil bearing capacity is 150 KN/m2 at a depth of 2 metres below E.G.L. Participants are free to go for either a tapered or stepped footing. Besides the total axial load, also account for the self-weight of the footing and soil above it. Assume M25 concrete grade. Do the following checks:

• If the gross bearing pressure under the footing is within safe bearing capacity
• Provide sufficient depth and longitudinal steel for resisting bending and shear
• Sufficient anchorage for column steel into the footing
• If the bearing pressure at column-footing joint is within 0.45 times the maximum concrete compressive strength

Provide a simple sketch showing the size of the footing, maximum and minimum depth of the section, flexural reinforcement in both directions and anchorage of column steel.

Please do go through the solved examples in the document provided with the challenge.

AIM:

TO DESGIN THE SQUARE FOOTING USING THE GIIVEN DETAILS :

INTRODUCTION :

Introduction:

• Footings and other foundation units transfer loads from the structure to the soil or rock supporting the structure.
• The distribution of soil pressure under a footing is a function of the type of soil and the relative rigidity of the soil and the foundation pad.
• Most common types of footings used are:
  • Strip or wall footing
  • Spread footing
  • Stepped footing
  • Tapered footing
  • Pile cap
  • Combined footing
  • Mat or raft footing.

• THIS PROJECT IS DEALING WITH ISOLATED FOOTING FOR A COLUMN OR STREAD FOOTING.

PROCEDURE:

Data are given:

• Column size 400mmx400mm

• Compression axial load for the load combination of (1.5 DL + 1.5 LL) is 2000 KN

• Safe soil bearing capacity at a depth of 2 meters below E.G.L is 150 kN/m²

• Assuming the self-weight of the footing and soil above it as a 10% load

• Grade of concrete=25 kN/m²

• Assuming fy=500 N/mm²

Here a sloped footing is designed.

DESGIN OF SQUARE FOOTING FOR A COLUMN 400X400 MM.

RESULT :

Provide a 3.2x3.2m footing with a depth of 500 mm.

Provide , 22 bars reinforcement of 16mm dia bars in both directions.

Provide anchorage for column and footing at 750mm.

AUTOCAD DESIGN :