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INTEGRAL BRIDGES
INTEGRAL BRIDGES
Presented by: Safar.N.N S7, Roll no:59 Civil Engg DeptGuided by: Dipu.V.S Lecturer Civil Engg Dept
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INTRODUCTIO
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Integral bridges in simple words, can be defined as bridges without joints. Integral bridges are characterized by monolithic connection between the deck and the substructure (piers and abutments). They span from one
abutment, over intermediate support to the other abutment, without any
joint in the deck. Integral bridges have been constructed all over the world
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WHAT IS AN INTEGRAL
BRIDGE?
Bridges constructed without any
expansion joint (between spans or
between spans and abutments) and
without any bearings are called
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CHARACTERISTICS OF
INTEGRAL BRIDGES
The integral abutment bridge
concept is based on the theory that due to the flexibility of the piling, thermal stresses are transferred to the substructure by way of a rigid connection between the
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MOTIVATION BEHIND INTEGRAL
BRIDGES
To eliminate expansion joints in the deck
When earthquake forces are predominant or
when consideration like increased resistance to blasts the integral bridge concept is an
excellent option.
Less expensive
Improved durability
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WHY GO FOR INTEGRAL
BRIDGES?
The expansion joints and bearings, by virtue of their functions are sources of weakness in the bridge and there are many examples of distress in bridges, primarily due to poor performance of these two elements
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Leaking of expansion joints and seals permit the surface run-off water from roadway
Continual wear and heavy impact from repeated live loads as well as continual stages of movement from expansion and contraction
Impact loadings from heavy commercial vehicles
Elastomeric bearings can split and rupture due to unanticipated movements, or ratchet out of position.
Malfunctioning of bearings can lead to unanticipated structural damage Joints and bearings are expensive
PROBLEMS OF EXPANSION
JOINTS AND BEARINGS
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INTEGRAL ABUTMENT
The integral abutment is defined
as abutment, which is connected
to the bridge deck without any
movement joint for expansion or
contraction of the deck
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WHY GO FOR INTEGRAL
ABUTMENTS
1.Simple Design
2.Joint less construction 3.Resistance to pressure 4.Rapid construction
5.Ease in constructing embankments
6.No cofferdams
7.Vertical piles (no battered piles) 8.Simple forms
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10.Reduced removal of existing elements 11.Simple beam seats
12.Simplified widening and replacement 13.Lower construction costs and future maintenance costs
14.Improved ride quality 15. It Design efficiency
16.Added redundancy and capacity for catastrophic events
17.Improve Load distribution
18.Enhance protection for weathering steel girders
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PLANNING
CONSIDERATIONS
1.Length of the Structure 2.Climatic Condition
3.Seismic Zone
4.Type of Superstructure 5.Type of Abutments
6.Type of Foundations And Sub-Soil Conditions
7.Geometry of the Structure
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RECOMMENDED QUALITY
IMPROVEMENT PRACTICE FOR
INTEGRAL BRIDGES
Develop design criteria or office practices for
designing integral abutment and join less bridges
In extending the remaining service lives of
existing bridges
exchange information in the areas of design,
construction and maintenance of joints and joint less bridges
The decision to install an approach slab should
be made by the Bridges and Structures Office, with consultation from the Geotechnical group
Standardize practice of using sleeper slabs at
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1. Simplified details for construction
2. Reduced life cycle cost and long term maintenance
3. Improved design efficiency Improved riding quality
4. Added redundancy with improved seismic performance Ease in constructing embankments
5. Elimination of water leakage on critical structural elements
6. Lesser tolerance restriction due to elimination of bearings and expansion joints
7. Faster construction
8. Simplified widening and replacement detail Useful for strengthening of existing bridges
ADVANTAGES OF INTEGRAL
BRIDGES OVER CONVENTIONAL
BRIDGES
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ILLUSTRATIVE
EXAMPLE
1. Dankuni-Palsit Flyover
It is situated at the durgapur Expressway. The span arrangement for the overpass is15m + 2x22.0 m + 15m,continuous over the support. The deck is RC solid slab type integral with the twin piers. The bridge is a joint less bridge without any expansion joint over intermediate piers without any bearings
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2. Kalkaji Flyover
A 150m integral flyover has been provided at the vital T-junction on Ring Road near Kalkaji Temple. The typical five span continuous deck (25m + 30m + 40m + 30m + 25m), has a voided slab reinforced concrete deck with a depth of 1.70m, which was hunched and increased to 2.20m at the piers supporting the 40.0m obligatory main span.
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CONCLUSION
In conclusion, it must be said
that the final product represented by the integral bridge is vastly
superior in performance in
service conditions as compared to traditional bridges with bearings
References
Alok Bhowmick,2005, Design and detailing of integral
bridges:Suggested guidelines;The Indian Concrete
Journal,79(9),pp 43 – 50.
Alok Bhowmick,2003,Design and construction of integral
bridges- An innovative concept, The Indian Concrete
Journal,77(7),pp 22 – 35.
www.nabro.unl.edu www.cbdg.org
1. WALLBANK, E. The performance of concrete in bridges – a survey of 200
highway bridges, HMSO, London, 1989, 96pp
2 NICHOLSON, B. Integral abutments for prestressed beam bridges, British
Precast Concrete, Federation, Leicester, 1998, 84pp.
difficult to accommodate in design.
ENGLAND, G., TSANG N. and BUSH, D. Integral bridges: a fundamental
approach to the time–temperature loading problem, Thomas Telford, London,
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