Inspection and maintenance of bridge

INSPECTION AND MAINTENENCE
OF R.C.C. AND STEEL BRIDGE
PRESENTED BY:AKASH
SHAH
IINSPECTION AND MAINTENENCE OF R.C.C. AND STEEL BRIDGE
1

CONTENT
 INTRODUCTION
 INSPECTION OF BRIDGES
 BIM RATING SYSTEM
 REMEDIAL ACTION
 FACTOR AFFECTING BRIDGE DURING SERVICE
 REBUILDING OF BRIDGE
 STRENGTHNING OF BRIDGE
 GENERAL WORK OF MAINTENENCE
2

WHAT IS BRIDGE?
 A bridge is an arrangement made to cross an obstacle in the form of a low ground or a
stream or a river or over gap without closing the way beneath.
 The bridges are required for the passage of railways, roadways, footpaths and even for the
carriage fluids.
 A Bridge is a structural marvel which is generally used to pass any type of obstruction that
can slow the life of people.
3

INTRODUCTION
 For safe & smooth traffic flow , it is necessary to have the maintain of bridges periodically.
This maintenance is essentially consist of structural maintenance rehabilitation and
replacement. It provides guideline for the engineer to adopt cost effective decisions
regarding maintenance work for bridges canal, tunnel etc. To achieve desire result require
constant alertness & through inspection.
 what is the meaning of maintenance?
 Maintenance of bridge means the up-keeping of the bridge component in good and
serviceable condition so as to ensure longer life of bridge as envisaged at the time of
design and construction.
4

THE TERM OF MAINTENANCE
 It is maintenance services to ensure normal and safe utilization of bridge structures.
 These works consist mainly of inspection, maintenance, repair and replacement, if
necessary, of expansion joints, bridge deck, drainage system, railings and barriers,
pavement, bridge bearings, etc., as well as anti-corrosive protection of some elements,
mostly ally limited to the current works performed systematically by painting.
5

 Even if the bridges are well designed and properly constructed, periodic maintenance, if
needed, is very essential to keep them in good serviceable condition. Therefore, the
bridges should be regularly inspected and properly maintained.
6

 Why we need to maintain the bridge?
It is necessary for the following factors,
1) Cost
2) Life time
3) Very important structure
4) Purpose etc.
7

DETERIORATION OF BRIDGES
1) Defective design of bridges
2) Due to contact of water various parts of bridge. Corrosion, erosion, scoring etc.
3) Resisting to weathering effect
4) Temperature changes
5) Poor quality of construction materials and workmanship
6) Natural hazard like cyclone, earthquake, flood, Tsunami etc.
8

DAMAGES OF BRIDGES
1) Cracks in concrete
 absence of expansion joint
 Lack of water tightness
 Dew to excess water in concrete
 Inadequate cover in concert
 Due to fatigue some components of strength of the steel structure and developed cracks
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2) Corrosion of the structure of steel work:
The steel structural or structural steel of a bridge require constant attention as is corrode due
to weathering action. The structure become weak in this problem is not promptly attended.
The rate of corrosion of steel depended on the quality of concrete depth of cover provided
below the reinforcement and degree of quality control. Also drain water failing on a structural
part of a bridge may cause damage of structural steel.
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3) Other defect of bridges:
 Expansion joint distress
 Crack in metalwork
 Damaged structural member
 Foundation settlement and movement.
11

INSPECTION OF BRIDGES
The inspection can be broadly classified in two categories:
1) Detailed inspection
2) Routine inspection
 Detailed inspection:-
 The detailed or in depth inspection involves the visual examination of all the structure and
sub structure it is carried out in following two category, elements
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1)General : a check list pf item is inspected either visually or with aid of standard instrument
in the general inspection. It is carried out once in two years.
2) major: it conclude 5-6 year or even in smaller interval depending upon the bridge design
of structure. The structural analysing is done by the experienced bridge engineers soon after
the occurrence of calamities such as flood and earthquake or the passage of high intensity
loading.
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Some trouble spot to be checked during inspection like,
 Behaviour of expansion joints
 Damaged structural members
 Deterioration and cracks in concrete.
 Excessive movement
 foundation settlement and movement loose connection etc.
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 Routine inspection :-
 The routine inspection look after the general examination of structure at regular interval
and the spot having outward physical defects are immediately repaired. The routine
inspection is generally applicable for short span bridge. The routine inspection conducted
prior to the monsoons and data and details are recorded on a Performa. A post monsoons
inspections is also conducted in order to compare the data and check deterioration.
 The main parts of the bridge should be inspected follows during detail inspection:
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 Inspection of foundations
 Inspection of substructure
 Inspection of super structure
 Inspection of approach roads
 Inspection of bearing inspection of waterway
 Inspection of embankment
 Inspection of scour
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QUALIFICATION OF PERSON INSPECTION
 They should be qualified engineer having 10 year experience in bridge construction &
inspection.
 They shall be responsible for through field inspection and recommendation for correction
of damage.
 They must be very familiar with design and construction features of the bridges and they
must be capable of analysing the structural deficiency.
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INSPECTION INSTRUMENTATION
 Electronic strain gauges for measurement of strains in concrete and steel.
 Ultrasonic pulse velocity apparatus for detection of cracks in concrete.
 Rebound hammer for in-situ measurement of compressive strength or grade of
concrete
 Snooper –crawler and adjustable ladders
 Magnetic detector for measuring thickness of concrete cover and for locating
reinforcement bars
 Vibration measuring equipment
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 Hydraulic jacks, pressure traducers or load cells for measurement of forces
 Electrical resistance meter
 Pachometer to locate and measure the size of steel bars embedded in concrete
 Optical microscope with light source to measure the width of cracks on the surface of
concrete
 Mechanical extensometer or demec gauge with stainless steel targets for measuring
surface strains on concrete under loads
 Dial gauges for measurement of deflections at soffits of deck slab an
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ULTRASONIC PULSE VELOCITY APPARATUS FOR
DETECTION OF CRACKS IN CONCRETE.
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REBOUND HAMMER FOR IN-SITU MEASUREMENT
OF COMPRESSIVE STRENGTH OR GRADE OF
CONCRETE
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MAGNETIC DETECTOR FOR MEASURING THICKNESS
OF CONCRETE COVER AND FOR LOCATING
REINFORCEMENT BARS
22

VIBRATION MEASURING EQUIPMENT
23

ELECTRICAL RESISTANCE METER
24

PACHOMETER TO LOCATE AND MEASURE THE
SIZE OF STEEL BARS EMBEDDED IN CONCRETE
25

BIM RATING SYSTEM
RATING COMMENTRY MAINTAINCE
PRIORITY
9 VERY GOOD NEW CONDITION NO REPAIR IN
FORESSEBLE FUTURE
8 ALMOST NEW CONDITION NO REPAIR IN
FORESSEBLE FUTURE
7 GOOD COULD BE UOGRED NEW
CONDITION WITH VERY LITTLE
EFFORT
NO REPAIR NECESSARY
AT THIOS TIME
6 GENERALLY GOOD CONDITION .
FUNCTIONING AS DESIGNED
WITH NO SIGNS OF DISTRESS OR
DETERIORATION.
NO REPAIR NECESSARY
AT THIS TIME
5 ADEQUATE ACCEPTABLE CONDITION AND
FUNCTIONING AS INTENDDED
NO REPAIR NECESSARY
AT THIS TIME
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4 BELOW MINIMUM ACCEPTABLE
CONDITION
LOW PRIORITY FOR
REPAIRS
3 POOR PRESENCE OF DISTRESS.NO
FUNCTIONING AS INTENDED
MEDIUM PRIORITY FOR
REPLACEMENT REPAIR
2 HAZARDOUS CONDITION OR SEVER
DISTRESS
HIGH PRIORITY FOR
REPLACEMENT
1 DANGER OF COLLAPSE AND/OR
DANGER TOMUSERS
BRIDGE CLOSURE,
REPLACEMET,REPAIR,AND
/OR SIGNING REQUIRED
AS SOON AS POSSIBLE
N NOT ACCESSIBLE ELEMENT CANNOT BE VISUALLY
INSPECTED
X NO APPLICABLE ELEMENT NOT ACCEPTABLE TO THIS
BRIDGE
27

PURPOSE OF RATING EXISTING BRIDGES:
 To afford safety to the traffic and public
 To avoid immediate reconstruction of existing bridges leading to the substantial saving of
money and materials construction
 To ensure smooth flow of traffic on existing old bridges without imposing serious
unnecessary restrictions.
 To suggest ,ensure which would guarantee the safe use of existing bridges during the
remaining period of their useful life.
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 During the rating thoroughly inspected so as to determine its physical condition and the inspection
engineer must be well conversant with the design aspects as well as construction feature of bridge
structure.
 The field investigation and inspection are properly recorded in the form of detailed sketches and self
explementary notes.
 the collection of field data after through inspection of the existing bridges is the most difficult part of
the existing bridges is the most difficult part of rating and it should ne entrusted to the expert only.
29

THE FOLLOWING REMEDIAL ACTION CAN BE
TAKEN
 Repair
 Replacement
 Rehabilitation
 Strengthening
 Modernization
30

REPAIR
 means to mend, to put into good shape or working order
again, to recondition, to renovate, to restore and to
correct. Repair concerns rather the local damages of
structural members or bridge element than the overall
structure.
31

REPLACEMENT
 Means to substitute to change and to exchange.
 Some element of bridge structure ,mostly eqipment element are usually replaced
example ., expansion joints bearing, barrier etc.
 Sometimes structural members are also replaced, if necessary e.g., deck element
secondary or bracing element etc.
 Replacing a whole bridge is consider the last resort in the process of upgrading the
existing infrastructure.it is drastic measure and possibly the costliest.
32

REHABILITATION
 Means to restore to make suitable to put back in good condition , to bring back to full use
, to renew and to revive.
 Rehabilitation concern mostly the whole bridge structure, including its primary structural
members.
33

STRENGTHENING
 Means to increase load carrying capacity by adding more material ,
additional component
Example : External prestressing and so on.
34

MODERNIZATION
 It is form of upgrading by adding new feature, example, new traffic flow arrangement
,new signs, new lighting, new barriers.
 This term is commonly applied to structures designed and construction prior to availability
of those modern features.
 However modernization can also be considered in wider meaning. For instance
,upgrading of the bridge requires in many cases its strengthening ,new traffic flow
arrangement require the widening of the bridge deck and so on.
35

RETROFIT
 It is strengthening procedure applied to an existing structure, not necessarily although in
many cases related to seismic strength.
 It is applied usually after it is found that the original design is not sufficient in light of
newly gained experience .
36

 All the above mentioned terms define various actions concerning bridge works of
different scale and importance
 However, it is very difficult to consider these actions as fully separate ones. For
instance,rehabilitation of a bridge often requires its adequate strengthening or
replacement and repair of some of its elements, etc.
 Therefore, repair, replacement, rehabilitation, strengthening and modernization have
usually many relations to each other and they may be considered to be the components
of maintenance in its wider meaning
37

FACTORS ACTING ON BRIDGE DURING
THEIR SERVICE
 Bridge structures are subjected to many types of loadings and other influences resulting
both from the live loads (mostly traffic effects) and exposure of the structures to the
weather and environmental effects of various nature. The most important factors acting
on bridges during their service are schematically shown in Figure.
38

39

An existing bridge in full or in part may be required for one or more of the following factors:
Damage
Excessive maintenance cost
Obsolescence
Weathering
REBULIDING OF BRIDGES
40

 The entire bridge structure deserves to be replaced or rebuilt under the following
circumstances:
1. It has become too weak to take up the present day loads or traffic pattern.
2. It has been considerably damaged due to corrosion of reinforcement, ageing, etc.
3. It has become structurally overstressed due to hazards like floods, earthquake, falling of
boulders.
4. It is not suitable due to faulty design and construction practices.
41

 The most common form of distress in bridge structures are as follows;
1. Corrosion of reinforcement;
2. Displacement of deck;
3. Flexural and shear cracks;
4. Movement of abutments;
5. Sinking of wells;
6. Snapping of prestressing cables;
7. Tilting of piers;
8. Topping of bearings.
42

 Repair programs frequently used one of the following specialized techniques;
1. Asphaltic concrete wearing coat W.B.M. AND lime concrete were removed and corrugated were
exposed.
2. New plates were welded to the portion which were added.
3. Wherever corrosion occurred, reinforcing plates were intact.
4. Reinforcement bars were placed over the cross girder for a width of about 1.5m and cement
concrete was cast to stiffen the deck.
5. Sand blasting was done and then steel structure was painted with zinc rich epoxy and aluminum
paint.
43

STRENGTHNING OF BRIDGES
 The present day sudden explosion of heavy road traffic has posed the problem of testing
and strengthening the existing bridges. It is quite clear that the weakest bridge on a
particular route will be the deciding factor for the capacity of road or highway.
 The method are applied to Work out the safe bearing capacity of an existing bridge:
1. Correlation method.
2. Load testing .
3. Theoretical method .
(i) Strengthening of bridge sub-structure;
(ii) Strengthening of bridge super-structure;
44

(i)STRENGTHENINF OF BRIDGE SUB-STRUCTURE:
a) Masonry pier;
b) Other material;
(ii)STRENGTHENINF OF BRIDGE SUB-STRUCTURE:
a) Continuous bridges;
b) Masonry arch bridges;
c) R.C.C. beam and slab bridge;
d) R.C.C. bridge;
e) Steel bridge;
f) Suspension bridges;
45

GENRAL WORKS OF MAINTENANCE
General Methods – Concrete
1. Removal and replacement of deteriorated
concrete
2. Filling cracks
3. Coating and sealing concrete surface
46

• General Methods - Steel
1. Protect it from exposure to electrolytes
2. Painting
3. Galvanizing
 General Methods – Timber
1. control moisture content of the wood
47

 General work : Substructure – Maintenance
• Material deterioration
– protective coatings
– preservatives
• Foundation settlement and earth pressure
– subsurface drains
– struts
– regarding soil profile
• Impact damage
– guard rails and energy dissipaters
– fenders or steel plates on abutments and piers
48

 Superstructure - Maintenance
• Inspection
• Good protection system
– coatings - preservatives
– sealers - patching
– paints - crack filling
• Pressure washing and cleaning
• Strengthening
49

 Deck:
• Most susceptible to deterioration
– de-icing salts, acid rain
– ultraviolet rays
– mechanical abrasion
• Requires a lot of maintenance and repair
• Protects rest of structure
50

• Concrete Decks:
• De-icing salt is main menace
– causes reinforcement to corrode
– concrete spalls
– potholes
• Design and construction features to control deterioration
– optimum cover for reinforcement
– good drainage - silica fume
– smaller skews - low w/c ratio
– thicker slabs - good consolidation
– air-entrained concrete - low shrinkage
51

• Main preventative maintenance goal is to control salt and moisture penetration
– keep deck clean and drains operating properly
– add drains in low spots
– monitor deck for chloride contamination
– fill cracks
– asphalt sealing
– polymer overlays
– concrete sealers
– bituminous concrete overlays with waterproof membrane
52

CURBS AND RAILINGS
• Deteriorate with time
– cracking and spalling - corrosion
– salt damage - collision
• Replacement can be minimized
– appropriate sealers, coatings and paint
– galvanized steel
53

DECK DRAINS
• Can cause hazardous traffic situations
• Can lead to deterioration of deck and other bridge elements and erode the soil
backfill
• Typical problems include:
– ponding of water on bridge deck
– poor drainage allows de-icing salts to deposit on deck and other bridge
elements
– plugged downspout will burst in freezing weather
• Regular cleaning is best maintenance
54

APPROACH ROAD
• Approach bump
• Guardrail
– connection to bridge rail
– transition stiffness
• Drainage
– trough drains
• Erosion of head slopes and ditches
• Signing
– vertical clearance
– load limit
– delineators
55

THANK YOU
56

Inspection and maintenance of bridge

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