Building failures – General reasons – classification – Causes of failures in RCC and Steel structures, Failure due to Fire, Wind and Earthquakes. Foundation failure – failures by alteration, improper maintenance, overloading. Retrofitting of structural components - beams, columns and slabs

1. CONSTRUCTION TECHNOLOGY
(For 4h semester B.Tech Degree Students Under Kerala
Technological University)
BUILDING FAILURE
FOUNDATION FAILURE
MODULE VI
VISHNU VIJAYAN
HOD-Department Of Civil Engineering
Baselios Mathews II College Of Engineering
Sasthamcotta, Kollam,Kerala,INDIA
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2. BUILDING FAILURE
FOUNDATION FAILURE
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3. BUILDING FAILURE
• Different factors cause
the failure of concrete
structure such as errors
from design stage to
construction stage and to
occupancy.
• The main causes of
failure of concrete
structures are discussed.
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4. General Reason for Failure of
Concrete Structures?
1. Wrong judgment of proposed site
2. Incorrect selection of materials
3. Errors in design calculation and
detailing
4. Improper construction techniques
and insufficient quality control
and supervision
5. Chemical attacks on concrete
structures
6. External mechanical factors
7. Damage due to earthquake
8. Damage due to fire3/22/2020 4VISHNU VIJAYAN-BMCE

5. Wrong judgment of proposed site
• One of the major reason behind the building
failure.
• Poor assessment of soil condition, using low
quality materials, wrong construction practices,
disobey the building rules and regulations, poor
judgment of ground water table, low bearing
capacity of soil, constructing the buildings at
flood /earthquake prone areas etc..
• Picture: Ernakulum ,Kerala, flat construction
was over the building was tilted to one end
making it "The leaning tower of Kochi."
More info..
• https://www.manoramanews.com/news/spotlig
ht/2019/05/09/maradu-kochi-flat-story.html
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6. Incorrect Selection of Concrete
Materials
• it is necessary to execute construction
process according to the applicable
codes and specifications.
• Failure in the material selection is one
of the major factors that detrimentally
affect the strength and safety of
structure and eventually could lead to
failure.
• Various detrimental factors such as
presence of sulfide in soil or ground
water and the occurrence of freezing
and thawing should be carefully
considered while materials are
selected to prepare concrete mixture.
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7. Errors in Design Calculation and
Detailing of Concrete Structures
• it is recommended that entire design should
check to guarantee that reinforced concrete
section sizes, thicknesses, and reinforcement
spacing and sizes are sufficient to support
the most critical load combinations.
• Code specifications regarding reinforced
concrete elements shall be followed
correctly.
• concrete cover which protects steel bars
from aggressive attacks and fire, maximum
and minimum reinforcement ratio, steel bar
spacing which restricts cracks, lap length and
anchorages.3/22/2020 7VISHNU VIJAYAN-BMCE

8. Improper Construction Techniques and
Insufficient Quality Control and Supervision
• Improper construction methods, poor workmanship, low
quality material and insufficient supervision of construction
process would cause several problems that reduces the
performance of concrete structures substantially and
subsequent failure
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9. Chemical Attacks on Concrete
Structures
• Chloride-Chloride ions penetrate
concrete during and after
construction. High concentration of
chloride corrodes steel bars and
deteriorates concrete.
• Sulphate-It disintegrates concrete
and create path for harmful
substances to attack
reinforcements.
• Carbonation-Carbonation attack
and deteriorate steel bars
• Alkali silica reaction-ASR produces a
gel which its volume increases and
consequently disintegrates concrete.
• Acids-It strongly affect concrete and
removes part of set cement3/22/2020 9VISHNU VIJAYAN-BMCE

10. External Mechanical Factors Causing Concrete
Structure Failure
• There are various types of exterior or
mechanical factors that influence concrete
failure for example restraints against
movement, abrasion, wetting and drying,
freezing and thawing, overloading, structural
alteration, fire resistance and settlement.
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11. Damage due to Earthquakes
Earthquake Damage depends on
many factors:
➢ The size of the Earthquake
➢ The distance from the focus of
the earthquake
➢ The properties of the materials
at the site
➢ The nature of the structures in
the area Ground Shaking
Frequency of shaking differs for
different seismic waves.
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12. The fire-resistant
➢ properties of concrete are fairly easy to understand.
➢ The components of concrete – cement (limestone, clay and
gypsum) and aggregate materials – are chemically inert and
therefore virtually non-combustible.
➢ Concrete also has a slow rate of heat transfer, which means that
concrete walls in a home act as a fire shield, protecting adjacent
rooms from flames and maintaining its structural integrity despite
exposure to intense heat
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13. FOUNDATION FAILURE
➢ The properties of soil have the major influence on the
design, stability and sustainability of foundations to make
it perform its functions
There are three main functions of a building foundation:
1. To sustain and safely transmit the loads from building /
structure to the ground in such a way that it does not impair
the stability or cause damage to the building or surrounding
buildings.
2. The construction of foundations must safeguard the building
against damage by physical forces generated in the subsoil.
3. Foundations must resist the chemical compounds present in
soil to prevent corrosion to reinforcement.3/22/2020 13VISHNU VIJAYAN-BMCE

14. Foundation failure due to Soil
Movement:
• When water present between soil particles is
removed, the soil tend to move closer
together. When water is absorbed by soil, the
soil starts to swell.
• This movement of soil is based on the type of
soil. Large movement is seen with clayey soils
than sandy soils. These kind of movement of
soil due to change in water content affects the
foundation settlement.
• Foundation tends to settle to and excessive
settlement of foundation may lead to
differential settlement and damage to the
structure.
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15. Soil movement can occur due to following:
1. Presence of vegetation or remains of old cut tress
2. Presence of mining areas
3. Shrinkable soils
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16. Remedies for foundation failure due
to soil movement:
1. Use of pile foundations where the soil is
shrinkable, so that forces are
transferred to the hard strata or rock.
2. Taking the foundation levels down to
avoid foundation on shrinkable soils.
3. The vegetation is removed from the
construction site and its roots are
removed. Any cavity due to roots of
vegetation shall be compacted and filled
with concrete.
4. Presence of any mining areas needs to
be inspected and professional help shall
be taken while construction new
buildings in such areas.
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17. Foundation failure due Settlement of
Soil Fill
• If the building is constructed
on a newly developed land
by soil filling, the foundation
on such soils tend to settle
more with time as long time
is needed for such soil to
settle and become compact
to resist the loads from the
building foundation.
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18. Remedies:
• It shall be ensured that such soils are
adequately compacted before construction
begins on them.
• The foundation depth shall be increased to the
hard strata or rock below the filled soil
• pile foundations shall be used to prevent
subsidence of foundation.
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19. END…
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