What is maximum permissible differential settlement for isolated foundation on clay as per I.S. code?

Explanation:

IS code specification for permissible settlement:

(i) Total Permissible settlement:

• For isolated footing on clay = 65 mm
• For isolated footing on sand = 40 mm
• For raft footing on clay = 65-100 mm
• For raft footing on sand = 40-65 mm

(ii) Permissible Differential settlement:

• For isolated footing on clay = 40 mm
• For isolated footing on sand = 25 mm

(iii) Permissible angular settlement:

• For high framed structure < 1/500
• To prevent all type of minor damage < 1/1000

Note: For multi-storeyed buildings having isolated foundations on sand, the maximum permissible settlement is 60 mm [ For multistorey buildings having isolated foundations take the higher load as compare to single storey buildings having isolated foundations. So that deflection caused by multistorey building having isolated foundation higher than 40 mm (from the safer side)]