REPAIR AND REHABILITATION OF STRUCTURES

1. MAINTENANCE OF CONCRETE
STRUCTURES
Course Instructor
Dr.S.P.SANGEETHA
VICE PRINCIPAL (ACADEMICS)
PROFESSOR - DEPT OF CIVIL ENGINEERING
AARUPADAIVEEDU INSTITUTE OFTECHNOLOGY

2. Contents
1. Maintenance, repair and rehabilitation
2. Facets of Maintenance
3. Importance of Maintenance various aspects
of Inspection,
4. Assessment procedure for evaluating a
damaged structure
5. Causes of deterioration

3. Definition:
Maintenance of building is defined as
the work done to keep the civil engineering
structures in working condition so as to
enable them to carry out the functions for
which they are constructed.
MAINTENANCE

4. Necessity of maintenance
The maintenance of structures is done to
meet the following objectives.
· Prevent damages and decay due to
natural agencies and wear & tear
- to keep them in good appearance and
working condition.
· Repair defects occurred in structures
and strengthen them, if necessary.

5. MAINTENANCE WORK ON DAM STRUCTURE

6. Classification of Maintenance Work:
· Preventive Maintenance
· Remedial Maintenance
· Routine Maintenance
· Special Maintenance

7. Preventive Maintenance:
-Before the defects occurred or
damages developed

8. Remedial Maintenance:
-after the defects or
damage occurs in the structures.
It involves the following basic steps.
• Finding the deterioration .
• Determining the causes.
• Evaluating the strength of the existing
structures.
• Evaluating the need of the structures.
•Selecting and implementing the repair
procedure

10. Routine Maintenance:
• Maintenance attended to the structure periodically.
• It depends upon specifications and materials of structures
,purpose , intensity and condition of use .
•It is done by the fund provided annually, which is normally
1.5% of the cost of construction.
•It includes the inspection, planning the programme and
execute.
•It includes white washing, patching repair to plaster,
replacement of fitting and fixtures, blinding of road surface.

11. Special Maintenance:
• work not covered in routing programme or the
annual repair
- is done under special condition
• It may be done for strengthening and updating
of the structure
- to meet the new condition of usage or to
increase its serviceability.
•It include particular or complete renewal, such
as renewal of floors, roofs etc

12. Special Maintenance

13. Causes which necessitate the
maintenance:
The causes which effects the service
and durability of the structure are as
follows:
· Atmospheric Agencies
1. Rain 2. Wind 3. Temperature.
· Normal wear and tear.
· Failure of structure.

14. Atmospheric Agencies
1. Rain:
-important source of water which affects
the structure in the following ways.
Physical:
Dissolving and carrying away minerals as it
is universal solvent.

15. Expansion and contraction:
- materials subjected to repetitive
expansion and contraction
- while they become wet and dry and
develop the stresses.
Expansion of water:
- variation of temperature causes the
expansion and construction of absorbed
water affects the micro structures of the
materials.

16. Erosion:
Abrasion of the structure materials is quite
evident effect of the water.
Spillway damage

17. Chemical:
Water contains acids and alkali and
other compound in dissolved form, acts
over the material
-which is known as chemical
weathering.
H2S corrosion on the concrete
walls

18. 2.Wind:which transports the abrasive
materials and assists the physical
weathering.
3.Temperature: The temperature
variation may also change in the
structure and chemical composition of
the materials.

19. Normal wear and tear:
During the use of structure it is subjected
to abrasion and there by it losses
appearance and serviceability.
Concrete damage was found to be a serious threat
to the structural integrity of spillway.

20. Failure of structure:
-behavior of structure not in
agreement with expected condition of
stability
-or lacking freedom from necessary
repair or non- compliance with desired
use of and occupancy of the completed
structure.

21. The causes of failure may be broadly
grouped as:
· Improper design.
· Defective construction.
· Improper use of structure
· Lack of maintenance.

22. Inspection of a Building:
Inspection of a building and any other
civil engineering structure is routine duty of
person in charge maintenance.
-It means keen, analytic and dynamic
observation regarding
• the change in condition of the structure
deterioration
• reason and the causes, failure
• concluding the remedies for the same.

23. The inspections should be made on the
following points.
• Condition of wall paint.
• Condition of paint on wood- work.
• Condition of flooring
• Roof leakage, leakage. if any
• Dampness in wall or floors, if any
• Condition of service fittings.
• Drainage from terrace or pitched like

24. ·Growth of vegetation, if any
·Structural defects like
1. Crack
2. Settlement
3. Deflection (sagging)

25. IMPORTANCE OF MAINTENANCE
• Improves the life of structure
• Improved life period gives better return on investment
• Better appearance and aesthetically appealing
• Better serviceability of elements and components
• Leads to quicker detection of defects and hence remedial measures
• Prevents major deterioration and leading to collapse
• Ensures safety to occupants Ensures feeling of confidence on the user
• Maintenance is a continuous cycle involves every element of building
science namely

26. FACETS OF MAINTENANCE
a)Emergency maintenance: Necessitated by unforeseen breakdown drainage or
damage caused by natural calamity like fire, floods, cyclone earthquake etc.
b) Condition Based maintenance:Work initiated after due inspection
c) Fixed time maintenance:Activities repeated at predetermined intervals of time.
d) Preventive maintenance:This is intended to preserve by preventing failure and
detecting incipient faults (Work is done before failure takes place)
e) Opportunity maintenance:Work did as and when possible within the limits of
operation demand.
f) Day-to-Day care and maintenance
g) Shut down maintenance:Thorough overhaul and maintenance after closing a
facility.
h) Improvement plans

27. VARIOUS MAINTENANCE ASPECTS
a) Daily Routine Maintenance
b) Weekly Routine Maintenance
c) Monthly Routine Maintenance
d)Yearly Routine Maintenance

28. STEPS INTHE ASSESSMENT PROCEDURE
FOR EVALUATE DAMAGES IN A
STRUCTURE
i. Physical Inspection of damaged structure.
ii. Preparation and documenting the damages.
iii. Collection of samples and carrying out tests both in situ and in
laboratory.
iv. Studying the documents including structural aspects.
v. Estimation of loads acting on the structure
vi. Estimation of environmental effects including soil structure interaction.
vii. Diagnosis
viii.Taking preventive steps not to cause further damage

29. STEPS INTHE ASSESSMENT PROCEDURE FOR
EVALUATE DAMAGES IN A
STRUCTURE,CONTD…
ix. Retrospective analysis to get the diagnosis confirmed
x.Assessment of structural adequacy
xi. Estimation on future use
xii. Remedial measures necessary to strength and repairing the structure.
xiii. Post repair evaluation through tests
xiv. Load test to study the behavior
xv. Choice of course of action for the restoration of structure.

30. CAUSES FOR DETERIORATION OF
CONCRETE STRUCTURES
i) Design and construction flaws
ii) Environmental effects
iii) Poor quality material used
iv) Quality of supervision
v) Deterioration due to corrosion

31. PREVENTION ASPECT OF
MAINTENANCE
i) Match the materials to the environment
ii) Assess the limitations of a particular material in its
functional context
iii) Combine only materials with similar properties
iv) Protect materials from general deterioration
v) Design level Factors