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Syllabus:
Maintenance- repair and rehabilitation- facets of maintenance- importance of
maintenance various aspects of inspection- assessment procedure for evaluating a
damage structure- causes of deterioration.
Maintenance:
The act of keeping something in good condition by checking or repairing it regularly.
Repair:
Repair is the process of restoring something that is damaged or broken, to good
condition.
Rehabilitation:
The process of returning a building or an area to its previous good conditions.
Facets of maintenance:
The two facets of maintenance are,
Prevention.
Repair.
Necessity of maintenance:
Preventions of damages.
Decay due to natural agencies, wear and tear.
To keep them in good appearance and working condition.
To reduce the causes against building.
Repair of the defects occurred in the structure and strength them.
It will increase the life of building.
It will reduce the risk for occupants.
It will reduce the outgoing expanses.
It will maintain the value of building.
It will save the building at all weathering actions.
Adequate maintenance is important one because repair, and re-habitation of structure
cost is huge.
It will protect the whole structure.
Causes Which Necessity to the Maintenance:
The Causes which necessity to the maintenance affects the service and durability of the
structure.
1. Atmospheric agencies.
a. Rain, b. Wind, c. Temperature.
2. Normal wear and tear.
3. Failure of structure.
1. Atmospheric agencies:
Rain (a):
It is the important source of water which affects the structure in the
Following ways.
i. Physical:
Dissolving and carrying way minerals as it is universal solvent.
ii. Expansion and Contraction:
The material is subjected to reputation expansion and contraction while they becomes wet
and dry and develops the stresses.
iii. Erosion:
Transportation and attrition and abrasion of the materials is quite evident effect of the
water.
iv. Chemicals:
The water available in nature contains acid and alkali and other compound in dissolved
form alts over the material to give rise which is known as chemical weathering.
v. Expansion of water:
The variation of temperature causes the expansion and contraction of absorbed water and
affects the micro structures of the materials.
Wind (b):
It is the agent which transportation the abrasive material and assist the physical
weathering.
Its action is aggravated during rains.
When it is moving with high speed if may contain some acidic gases like co2 fumes.
Which may act over the material and penetrates quite display in the material and
structure.
Temperature©:
The seasonal and annual variation of the temperature.
The surface of material Cause expansion and contraction.
The movement of material bund and adhesion between them is when it is repeat eel.
The development of cracks and the rock may breaker away into smaller units.
The temperature variation may also cause change in the structures and chemical
composition of the material.
2. Normal wear and tear:
During the use of structure it is subjected to abrasion and thereby it losses appearance and
serviceability.
3. Failure of structure: (causes)
Improper design due to incorrect.
Insufficient data regarding use.
Loading and environmental conditions.
Selection of material and poor detailing.
Defective construction.
Poor materials and poor workmanship.
Lack of quality control and supervision.
Improper uses of structure-over loading.
Impurities from industrial fuel burning.
Deteriorating environment.
Sea water minerals, chemicals.
Storage of chemicals for which they are not designed.
Lack of maintenance, lack of up keep.
Lack of proper protection. Precautions and preventions.
Pre-monsoon period:
Two months before rainy season.
Pre monsoon inspection are made do decide the maintenance programme to be done
before monsoon such us,
Cleaning of drains.
Checking of root leakage.
Collection of material and equipment required during monsoon repairs.
Bridges and other structures which are not easily approachable during the monsoon are
inspected fully and repaired if necessary.
Post monsoon inspection:
It is made to repair the damage caused by water.
All replacement renewal and rehabilitation work carried out.
Canal or dam breach.
Collapse of root.
Failure of walls.
They must have a vigilant eye over the structure.
The inspection should be made on the following points:
Condition of wall and wall paint.
Condition of paint on wood work.
Condition of flooring.
Roof leakage, leakage if any.
Dampness in wall or floor.
Condition of services fittings.
Drainage from terrace or pitched roof.
Growth of vegetation if any.
Structural defects like cracks, settlement, and deflection (sagging).
PHYSICAL INSPECTION OF DAMAGED STRUCTURE:
nature of distress, type of distress, extent damage and its classification etc,
preparing and documenting the damages, collecting the Samples for laboratory
testing and analysis,
Information on the loads acting on the existing structure.
1. Describe the steps in the assessment procedure for evaluate damages in a structure.
The following steps may be necessary,
Physical Inspection of damaged structure.
Preparation and documenting the damages.
Collection of samples and carrying out tests both in situ and in laboratory.
Studying the documents including structural aspects.
Estimation of loads acting on the structure
Estimation of environmental effects including soil structure interaction.
Diagnosis
Taking preventive steps not to cause further damage
Retrospective analysis to get the diagnosis confirmed
Assessment of structural adequacy
Estimation on future use
Remedial measures necessary to strength and repairing the structure.
Post repair evaluation through tests
Load test to study the behavior
Choice of course of action for the restoration of structure.
Causes of deterioration: (loss of strength or quality)
Structural failure
Non-structural failure
Structural failure:
Design failure
Constructional failure
Design failure:
Failure due to improper reinforcement.
Improper mix proportion.
Design mix.
Misconception of structural action.
Reinforcement detail.
Diffusion of concentrated loading.
Restrained shrinkage and temperature failure.
Standard for live load and wind loading.
Frequency of live loading. (Floor load, impact and inertia load, crane and lift load,
hydrostatic or earth pressure.)
Other loadings/design allowance for other loading.
Design provisions for wind loading.
Reinforcement grade and type.
Cover specified.
Design of life structure.
Shrinkage of concrete and relative movement between concrete and other materials.
Constructional failure: (varies from design)
Concrete- changes of concrete strength.
Accidental changes of concrete strength.
Use of admixtures not initially specified.
Reinforcement- substation.
Inaccurate spacing/placing.
Displacement.
Splices not as designed/joints.
Wrong reinforcement.
Omission.