A case study on The Leaning Tower Of Pisa A case Study on Infinity Tower Dubai, Marina. Teton Dam failure case study.

1. Topic: A Case Study on Structures
Department: Civil Engineering (06)
Submitted by:- Batch B
Subject:- Soil Mechanics (2150609)

2.  Geological problems encountered
i. A case study on The Leaning Tower Of Pisa
ii. A case Study on Infinity Tower Dubai, Marina.
iii. Teton Dam failure case study.

3. A Case Study on the
LEANING TOWER OF
PISA

4.  Located in PISA, Italy at the
'Piazza dei Miracoli' square.
 Bell tower for the Cathedral.
 Renowned all over the world
for its peculiar inclination.
 Popular tourist hotspot.
Building was shut down to
tourists in 1990, but has open
up because of extensive
restoration efforts by
government agencies.
 Building reopened in April,
2001.

5. Location of tower – ground
comprised of layers of sand & clay.
Layers ran parallel except under the
foundation of the tower, where it
formed a bow shape.
The unstable mixture of soil
material caused the soil to compact
at a different rate, causing the
tower to sink 30-40 cm.

7.  The unstable mixture of soil – caused the
tower to sink to the south side.
 Soil at south side compressed faster than
the north side – weight of the tower was
the main factor of tilt.
 Tilting was also due to the fluctuations of
the water levels.
 This caused the tower to keep shifting, as
well as rotate…later discovered by
scientists that the tower’s position shifted
in relation to the ground water level.

9.  Contractors removed soil from the north side
with drilling equipment.
 The tower started to sink on the north side,
therefore reducing some of the stress that
was building up on the south side.
 Suspension cables were loosely fitted to the
tower so it could pull back the tower incase
it started leaning

10.  The construction failure is
only due to the unsettlement
of soil underneath the
structure.
 The amount of water content
in the soil is more.
 Soil extraction helps the
structure to stabilize for a
long time without any tilt.
 A minimum amount tilt is
provided to attract the
tourist.

11. Infinity Tower, Dubai
Marina

12.  Hundreds of workers on-site are said to have had a
lucky escape. The excavation work of “the tallest
building with a twist”, the Infinity Tower, was
almost nearing completion.

14.  A loud sharp sound was heard. Later, sand
was noticed pouring down on all sides. The
Eighty storey tower, worth Dh.700 million, is
said to have a ninety degree twist.
 The incident happened as the workers were
assisting the project owners and the piling
contractor with the foundation works on site
20 meters below Ground level.

17.  The failure of the Teton Dam during initial
filling of the reservoir on June 5, 1976
killed fourteen people and caused
hundreds of millions of dollars in property
damage downstream. A thorough
investigation identified the causes of the
failure and suggested improvements for
the design and construction of earthen
dams

19.  On June 3, 1976 several small seepages
were noticed in the north abutment wall.
Pictures were taken and these leaks were
reported to the Bureau of Reclamation.
This led to more frequent inspections of
the dam. It was now to be inspected
daily, and readings were to be taken
twice weekly instead of once a week. On
June 4, 1976 wetness was noticed in the
right abutment and small springs were
beginning to appear .

20.  Study of the dam's environment and
structure placed blame for the collapse on
the permeable loess soil used in the core and
on fissured (cracked) rhyolite in the
abutments of the dam that allowed water to
seep around and through the earth fill dam.
The permeable loess was found to be
cracked. It is postulated that the
combination of these flaws allowed water to
seep through the dam and led to internal
erosion, called piping, that eventually caused
the dam's collapse.

21.  The cause may be the flow of water under
highly erodible and unprotected fill,
through joints in unsealed rock beneath
the grout cap and development of an
erosion tunnel. The second was "cracking
caused by differential strains or hydraulic
fracturing of the core material."

23.  Different region of the world have different
geological conditions.
 So while planning to construct any civil
engineering structure like dam, bridge ,
building, tunnel it is must that we consult a
geological engineering to know about the soil
below the structure.

24.  http://www.geol.ucsb.edu