Geotechnical Engineering

DHARM

406 GEOTECHNICAL ENGINEERING

Isolated foundations

Raft foundations

Sl.

Type of Structure

Sand and hard clay

Plastic clay

Sand and hard clay

Plastic clay

No.

MS

DS

AD

MS

DS

AD

MS

DS

AD

MS

DS

AD

mm

mm

mm

mm

mm

mm

mm

mm

1.

For steel structure

50

0.0033L

(^1300)
50
0.0033L
(^1300)
75
0.0033L
(^1300)
100
0.0033L
(^1300)
2.
For reinforced
50
0.0015L
(^1666)
75
0.0015L
(^1666)
75
0.002L
(^1500)
100
0.002L
(^1500)
concrete structures
3.
For plain brick wallsin multistoreyedbuildings(i) For
L H
≤
3
60
0.00025L
1
4000
80
0.00025L
1
4000
not
likely
to be en-
count-ered
(ii
) For
L H

3
60
0.00033L
1
3000
80
0.00033L
1
3000
4.
For water towers
50
0.0015L
(^1666)
75
0.0015L
(^1666)
100
0.0025L
(^1400)
125
0.0025L
(^1400)
and silosNote:
The values given in the table may be taken only as a guide and the permissible settlement and differential settlement in
each case should be decided as per requirement of the designer.
L = Length of deflected part of wall/raft or centre-to-centre distance between columns.H
= Height of wall from foundation footing.
MS
= Maximum settlement
DS
= Differential settlement
AD
= Angular distortion
Table 11.4
Maximum and differential settlements of buildings