Guidelines Given by RDSO,LUCKNOW REGARDING BRIDGE DESIGN.

1. BRIDGE RULES
Presented By
Mohammad Furqan
J.E (Bridge),PA
Presented To
Mohammed Faiz
XEN(B & F) MMR
1
GOVERNMENT OF INDIA
MINISTRY OF RAILWAYS
(Railway Board)

2. PURPOSE
• Specifying the rules/loads for
– Design of superstructure & substructure of
Bridges
– Assessing the strength of existing Bridges
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3. SCOPE
• Loads specified shall be used for
– All Railway Bridges
– Turn Table girders
– Foot Bridges but excluding Road Bridges
• Design detailing shall be controlled by
appropriate code of practice
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4. LOADS
• Loads specified in Bridge Rules :
 Dead Loads
 Live Loads
 Dynamic effects
 Forces due to curvature or eccentricity of Track
 Temperature effect
 Friction resistance of expansion bearings
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5. LOADS CONT.
 Longitudinal Forces
 Racking forces
 Forces on parapets
 Wind pressure effects
 Forces & Effects due to earthquake
 Erection forces and effects
 Derailment loads
 PQRS loads
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6. 1. DEAD LOAD
• Weight of structure
• Permanent Load carried on it
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7. 2. LIVE LOAD
• History
• Present Live Loads
– For Railway Bridges / Rail-cum-road Bridge
– For Foot Bridge / Footpath 4.8 KN/m²
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8. BRIDGE LOADING STANDARDS HISTORY
FOR BG (1676 mm)
LoadingLoading
Std.Std.
YearYear Max. Axle LoadMax. Axle Load
Engine (t)Engine (t)
TrailingTrailing
LoadLoad
(t/m)(t/m)
Long. Force (t)Long. Force (t)
TractiveTractive
Effort (t)Effort (t)
Braking ForceBraking Force
Std. BStd. B 19031903 18.018.0 1.20 t/ft1.20 t/ft -- --
BGMLBGML 19261926 22.922.9 7.677.67 47.647.6 10% of T.L.10% of T.L.
RBGRBG 19751975 22.522.5 7.677.67 7575 20% of T.L.20% of T.L.
MBGMBG 19871987 2525 8.258.25 100100 13.4% of T.L. + 25% of13.4% of T.L. + 25% of
Axle Load.Axle Load.
HMHM 19951995 3030 12.0012.00 135135 -do--do-
25 T25 T 20082008 2525 9.339.33 126126 -do--do-
DFCDFC 20082008 32.532.5 12.1312.13 126126 -do--do-
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11. 3. DYNAMIC EFFECT
• Augmentation in load due to dynamic effects should be
considered by adding a load Equivalent to a Coefficient
of Dynamic Augment (CDA) multiplied by the live load.
• For Railway Bridges (Steel)
– CDA for BG Single Track
• CDA = 0.15 + 8 / (6+L), Max. Value-1.0
where L is
i) Loaded length giving maximum stress
ii) 1.5* Spacing of cross girder ( For Stringers)
iii) 2.5* Spacing of cross girder (For Cross girder)
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12. 4. FORCES DUE TO CURVATURE OR
ECCENTRICITY OF TRACK
• On ballasted deck, even on straight line
– Designed for 100mm eccentricity
• On a curved Bridge
– Designed for centrifugal action of moving load
taking all tracks occupied
– Horizontal load due to centrifugal force is
C = WV² /12.95R t/m run
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13. 5. TEMPRATURE EFFECT
• Applicable for
– Portion of Bridge not free to expand or contract
– Temperature limits be specified by Engineer.
• Coefficient of expansion
– For steel & RCC -- 11.7x10*-6 per degree C
– For plain concrete-- 10.8x10*-6 per degree C
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14. 6. FRICTIONAL RESTISTANCE OF EXPANSION
BEARING
• Coefficient of frictional resistance of
expansion bearings are
– Roller bearing 0.03
– Sliding bearings of steel on
• Steel on Cast Iron or Steel 0.25
• Steel on Ferro bestos 0.20
• Steel on Hard copper alloy 0.15
– Sliding bearing of PTFE / Elastomeric 0.10
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15. 7. LONGITUDINAL FORCES
• One or more of following reasons
– Tractive Efforts
– Braking Force
– Resistance to movement of bearing
– Due to LWR over bridges.
– should not be more than the limiting resistance
at the bearing.
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16. 8. RACKING FORCES
• Not Accounted for calculating stresses in
main girder
• For design of lateral bracing
• additional lateral force of 5.88 kN/m as moving
load in addition to wind and centrifugal force.
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17. 9. FORCES ON PARAPETS
• Minimum height
– one meter above adjacent roadway/foot way
surface
• Designed for a lateral horizontal and a vertical
force of
– 1.47 kN/m applied simultaneous at top of the
railing/parapet
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18. 10. WIND PRESSURE EFFECT
• Basic Wind pressure
– Equivalent static pressure in the wind ward
direction ‘P’.
– Depends on appropriate wind velocity chosen
as per
• local meteorological records & degree of exposure
• Map given in IS 875 Part III, be used in absence of
meteorological records
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19. 11. Wind Pressure Effect Cont.
• Wind Pressure for railway / foot bridges
– Wind pressure specified shall apply to
• all loaded / unloaded bridges provided
• Bridges does not carry live loads when wind
pressure at deck level exceeds 1.47 kN/m² For BG.
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20. 12. Forces and Effect due to
Earthquake
• Seismic Force
– Acts in three mutually perpendicular directions
• Horizontal (Two Directions)
• Vertical
– For determining seismic forces country is
divided in 4 zones
• Basic horizontal Seismic Coefficient defined for
each zones
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22. Seismic Force Cont.
– Slab, box and pipe culvert need not be designed for
seismic forces
– Consideration of Seismic forces for design of bridge in
different zone
Zone II(.02) & III(.04) -for bridges of overall length
>60m or span >15m
Zone IV(.05) &V(.08) -all bridges
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23. 13. ERECTION FORCES AND
EFFECTS
• Erection Forces to be considered
– Weight of all permanent and temporary material
– All other forces and effects which can operate on
any part during erection
• Allowance be made in design for stresses set
up in any member during erection.
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24. 12. DERAIRELMENT LOADS
• Derailment loads for BG for ballasted deck
bridges as per appendix XXV.
• Load specified shall be applied at top of
ballast
• Load assumed to disperse at a slope of half
horizontal to one vertical.
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26. 13. LOAD DUE TO PLASSER’S QUICK
RELAY SYSTEM (PQRS)
• PQRS is a process wherein old rail along
with sleeper removed & replaced by NEW
Rail.
• Load due to working of Plasser’s Quick
Relay System for BG
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27. 14. ASSESSING STRENGTH OF
EXISTING BRIDGES
• As per existing Bridge Rules except
– Modification in CDA
– Modification in Longitudinal Forces
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