case study on cracks and its remedial measures
DESCRIPTION
this project is about the buildings cracks and its repair techniques. most common methods adopted in this project. ppt created with office'13... make it useful for ur work.TRANSCRIPT
![Page 1: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/1.jpg)
PROJECT
![Page 2: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/2.jpg)
CASE STUDY ON BUILDING CRACKS AND ITS REMEDIAL MEASURES
S
UBMITTED BY H
.SADHAM HUSSAIN 11117203 R
.RUPA MANIKANDA PRABU 11117202 S
.SANKAR 11117205 A
.ASHIK ELAHI 11117168 A
.SASI KUMAR 11117206 R
.ASIP ALI 11117170
UNDER
THE GUIDANCE OF
MR.A.M.GO
WRI SANKAR.B.E.,
LECTURER/
DEPARTMENT OF CIVIL ENGINEERING
![Page 3: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/3.jpg)
INTRODUCTION
Cracks in the building are of comman
occurrence in a bulding
It is due to exceeding stress in a building
components
Causes of the cracks are mainly by increase
in live load and dead load, seismic load etc.,
![Page 4: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/4.jpg)
CLASSIFICATION OF CRACKS
C
racks can be classified into two categories viz.,
S
tructural cracks
N
on-structural cracks
![Page 5: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/5.jpg)
STRUCTURAL CRACKS
I
t arises due to incorrect designs, overloading of
structural components
E
xpenses cracking of foundation walls, beams and
columns or slab etc.,
![Page 6: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/6.jpg)
PHOTO OF STRUCTURAL CRACKS
![Page 7: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/7.jpg)
NON STRUCTURAL CRACKS
T
hey are due to internal forces developed in materials
due to moisture variations, temperature variation,
crazing, effects of gases ,liquids etc.,
T
hey can be broadly classified into vertical, horizontal,
diagonal, smoothened cracks
![Page 8: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/8.jpg)
PHOTO OF NON STRUCTURAL CRACKS
![Page 9: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/9.jpg)
DIRECTION OF THE CRACKS
V
ertical
H
orizontal
D
iagonal
S
traight
T
oothed
V
ariable and irregular
![Page 10: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/10.jpg)
![Page 11: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/11.jpg)
![Page 12: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/12.jpg)
![Page 13: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/13.jpg)
WIDTH OF CRACKS
I
t can be measured through instrument and
tell-tale signs.
T
he changes in the length of the cracks
should be noted.
![Page 14: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/14.jpg)
CRACKS MEASURING DEVICES
DRS DRS CAMERCAMERAA
![Page 15: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/15.jpg)
MOVEMENT SENSOR
BALL DEFORMER
![Page 16: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/16.jpg)
CAUSES OF CRACKS
![Page 17: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/17.jpg)
MAJOR CAUSES OF CRACKS
Movements of the ground
Over loading
Effect of gases, liquids and solids
Effect of changes of temperature
General causes such as vibrations
![Page 18: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/18.jpg)
M
ovements of grounds
D
ue to mining subsidence,
land slips, earthquakes,
moisture changes due to
shrinkable soils.
O
verloading
O
verloading of the building
O
verloading of the building
parts results in cracks
![Page 19: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/19.jpg)
OVERLOADING FORCED MAY BE DUE TO
External ( excessive wind/snow
loads)
Internal ( from heavy machinery
etc.,)
![Page 20: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/20.jpg)
EFFECTS OF GASES, LIQUIDS AND SOLIDS
G
ases
O
nly gases like Co2 ( carbon di oxide ) is likely to produce cracks.
I
t causes Carbonation of porous cement products
L
eads into an overall shrinkage crazing cracks
![Page 21: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/21.jpg)
L
iquids
W
ater is the most commonly used liquid when not taken care it can
be hazardous
C
onstruction water i.e., that in the utilization of water during the
construction process
![Page 22: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/22.jpg)
EFFECTS OF WATER
P
hysical(i.e. due to change in water content)
C
hemical ( directly or indirectly affecting other materials)
![Page 23: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/23.jpg)
GENERAL VIBRATIONS
V
ibrations can cause cracks in buildings only when their
amplitude of vibrations are high.
A
part from vibrations caused due to earthquakes, the vibrations
caused due to heavy machinery, traffic, sonic booms are also
responsible for the occurrence of cracks in buildings.
![Page 24: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/24.jpg)
THERMAL MOVEMENT
A
ll materials expand on heat and contract on cool.
T
hermal movement in components of structure creates cracks due to
tensile of shear stresses
O
ne of the most potent causes of cracking in buildings and need attention
![Page 25: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/25.jpg)
GENERAL PRECAUTION TO AVOIDING CRACKS
B
efore laying up foundation, the type of foundation to be used
should be decided based on the safe bearing capacity of soil.
P
roviding R.C deep beam or an involved T-beam with adequate
reinforcements to withstand the stress due to differential ground
movements. This method is expensive
![Page 26: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/26.jpg)
![Page 27: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/27.jpg)
C
onstruction operations such as cutting for roads drainages etc.,
close to the structures should be avoided this will results in
reduction of soil moisture with consequent shrinkage of soil
beneath the foundation of the structure.
I
n buildings close to the water courses are noticed in many places
![Page 28: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/28.jpg)
PLACING OF CONCRETE
C
oncrete should not be placed in heavy rains unless suitable shelter is
provided.
T
o avoid segregation, concrete should not be dropped from a height of more
than 1m.
W
orking on freshly laid concrete should be avoided
![Page 29: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/29.jpg)
W
hile placing the concrete in R.C.C members the alignment of formwork
should not be disturbed.
C
oncrete should be laid continuously to avoid irregular and unsightly lines.
I
nternal surface of the forms either steel or wood should have even surfaces
and should be oiled so that the concrete may not stick to it
![Page 30: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/30.jpg)
MATERIAL QUALITY
A
ggregate should be hard, sound, durable, non-absorbent and
capable of of developing good bond with mortar.
W
ater shall be clean and free from alkaline and acid materials and
suitable for drinking purposes.
![Page 31: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/31.jpg)
TEST TO BE CARRIED OUT
S
lump test to be carried out for the control of addition of water and
workability.
C
onsistency of concrete should also be tested.
A
slump of 7.5 to 10cm may be allowed for building work
![Page 32: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/32.jpg)
LAYING TECHNIQUE AND CURING METHOD
C
oncrete should be laid in layers and should be compacted
while laying with wooden tamping rods or with
mechanical vibrators until a dense concrete is obtained
A
fter two hours of laying concrete, when the concrete has
begun to harden, it shall be kept damp by covering with
wet gunny bags or wet sand for 24 hours
![Page 33: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/33.jpg)
![Page 34: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/34.jpg)
EVALUATION OF CRACKS
T
o determine the effects of cracks in the building.
F
irst the cracks location and extent should be
noted down for the adopting suitable methods of
repair and the future problems due to that cracks.
![Page 35: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/35.jpg)
C
rack widths should be measured to the accuracy of 0.001
in (0.025mm) using a crack comparator.
M
ovements should be recorded with movement sensors.
B
ased on the reports from the location and width the
suitable methods is adopted
![Page 36: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/36.jpg)
C
rack as narrow as 0.002 in can be bonded by the injection of
epoxy.
E
poxy injection can alone be used to restore the flexural
stiffness.
F
or water retaining structure cracks it can be repaired by the
autogenous healing.
![Page 37: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/37.jpg)
REPAIRING OF CRACKS
R
outing and sealing.
S
titching.
A
dditional reinforcement.
G
ravity filling
G
routing
D
ry packing
P
olymer impregnation
![Page 38: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/38.jpg)
ROUTING AND SEALING
R
outing and sealing of cracks can be used in conditions requiring
remedial repair and where structural repair is not necessary.
R
outing and sealing is used to treat both fill pattern cracks and larger,
isolated cracks.
T
he sealants may be any of several materials, including epoxies,
urethanes, silicones, polysulfide, asphaltic materials, or polymer
mortars
![Page 39: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/39.jpg)
PROCESS OF ROUTING AND SEALING
![Page 40: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/40.jpg)
STITCHING
S
titching involves drilling holes on both sides of the crack
and grouting in U-shaped metal units with short legs
(staples or stitching dogs) that span the crack.
S
titching a crack tends to stiffen the structure, and the
stiffening may increase the overall structural restraint.
![Page 41: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/41.jpg)
T
he stitching procedure consists of drilling holes
on both sides of the crack, cleaning the holes, and
anchoring the legs of the staples in the holes,
with either a non shrink grout or an epoxy resin-
based bonding system
![Page 42: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/42.jpg)
FIGURE SHOWING STITCHING
![Page 43: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/43.jpg)
ADDITIONAL REINFORCEMENTS
Conventional reinforcement-Cracked reinforced concrete
bridge girders have been successfully repaired by
inserting reinforcing bars and bonding them in place
with epoxy .
This technique consists of sealing the crack, drilling
holes that intersect the crack plane at approximately
90º ,filling the hole and crack with injected epoxy and
placing a reinforcing bar into the drilled hole
![Page 44: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/44.jpg)
P
restressing steel-Post-tensioning is often the desirable
solution when a major portion of a member must be
strengthened or when the cracks that have formed must be
closed.
A
dequate anchorage must be provided for the prestressing
steel, and care is needed so that the problem will not merely
migrate to another part of the structure
![Page 45: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/45.jpg)
FIG SHOWING ADDITIONAL REINFORCEMENTS
![Page 46: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/46.jpg)
GROUTING
P
ortland cement grouting-Wide cracks, particularly in
gravity dams and thick concrete walls, may be repaired
by filling with portland cement grout.
T
his method is effective in stopping water leaks, but it
will not structurally bond cracked sections.
![Page 47: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/47.jpg)
GRAVITY FILLING
L
ow viscosity monomers and resins can be used to seal cracks
with surface widths of 0.001 to 0.08 in. (0.03 to 2 mm) by
gravity filling.
H
igh-molecular-weight methacrylates, urethanes, and some low
viscosity epoxies have been used successfully.
T
he lower the viscosity, the finer the cracks that can be filled.
![Page 48: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/48.jpg)
DRY PACKING
D
rypacking is the hand placement of a low water
content mortar followed by tamping or ramming
of the mortar into place, producing intimate
contact between the mortar and the existing
concrete.
![Page 49: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/49.jpg)
POLYMER IMPREGNATION
M
onomer systems can be used for effective repair of some
cracks. A monomer system is a liquid consisting of
monomers which will polymerize into a solid.
T
he most common monomer used for this purpose is
methyl methacrylate.
![Page 50: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/50.jpg)
T
he procedure consists of drying the fracture,
temporarily encasing it in a watertight (monomer
proof) band of sheet metal, soaking the fractures
with monomer, and polymerizing the monomer
![Page 51: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/51.jpg)
CONCLUSION
T
he discussion on our project mainly focused on the
cracks deals with failure due to improper settlement of
foundation and poor construction.
B
y the following discussed remedies and instruction what
we have concentrated helps to reducing the cracks and
move on to the next level in the construction.
![Page 52: CASE STUDY ON CRACKS AND ITS REMEDIAL MEASURES](https://reader036.vdocuments.us/reader036/viewer/2022062303/557c810cd8b42a9f578b4aa2/html5/thumbnails/52.jpg)
Thank you