Angular distortions due to differential settlement in foundation elements is one of the causes of structural damages in concrete framed structures. Differential settlement can either be due to variations in thickness of subsurface soil layers and/or compressibility characteristics, or variations in stress intensity, or due to variations in foundation sizes and types within the same structure.

quartzaardvarkΠολεοδομικά Έργα

29 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

63 εμφανίσεις

Time
-
Dependent

Differential Settlement in Uniform Clay Beds Due to Difference in
Drainage Pattern

Hadi Omran Zaglut Tumi
1

ABSTRACT

Angular distortions
due to d
ifferential settlement
in foundation elements
is

one of the causes
of structural damages in concrete framed structures.

Differential settlement can either be due
to
variations in
thickness of
subsurface soil layers

and/or compressibility characteristics,
or
variations in stress intensity
, or due to
variations in foundation sizes and types within the
same structure.

In cases where the subsurface consists of clayey soils in which most of expected settlement
would be delayed
due to the low hydraulic conductivity,
location

of drainage
media
represents an

important element in
controlling settlement duration. In coastal areas where
complex geomorphological processes are responsible for forming land features, variations in
drainage patterns can be one of strong factors causing time dependent differential
com
pression in apparently uniform beds.

Presence of
open

sand seams below one part of
structure and their absence below the other part can make the consolidation time between the
various parts of the structure quite different. In many cases, seams of sands wi
thin clay beds
can not
be
easily identified in boreholes and ignored in other cases due to being of small
thickness.

Such features
can

make a significant difference

between consolidation duration
below various parts of structure
s
. Despite the fact that the

total consolidation settlement may
ultimately be

the same across the clay bed below structure

on uniform clay beds
, a significant
differential settlement may take place
during the primary consolidation period
before the
ultimate consolidation settlement c
eases.

In this paper, an analysis of consolidation settlement based on 1
-
D consolidation is performed
on a structure erected on uniform clay bed
but having different drainage pattern. The
difference in drainage is facilitated through presence of presumed
various
sand seams below
one part of the structure whereas absent below the other part.
Differential settlement is
evaluated in terms of the ultimate (total) expected settlement and the timing of the maximum
differential settlement
occurrence
is
expressed
in terms of t
90
.
Results of this work
are

expected
to
explain a number of structural performance during consolidation period in areas of similar
geotechnical conditions.

It also expected to demonstrate the effect of sand seams on the time
-
related aspect of

consolidation compression.
i




i

Professor of Geotechnical Engineering, Civil Engineering Department, University of Tripoli, Tripoli, LIBYA.

e
-
mail: haditumi@yahoo.com.