Important Notes About Bridges

Bridge :-

Bridge is a structure having a total length of above 6 meters between the inner faces of the dirt walls for carrying traffic or other moving loads over a depression, or obstruction such as channel, road and railway.


According to Total Length of Bridge:

a Minor Bridge A minor bridge is a bridge having a total length of from 6 m to 60 m
b Major Bridge A major bridge is a bridge having a total  length of above 60 m
c  Culvert If overall total length is less than 6 m ; then it is a culvert
d Small Bridges Small bridge is a bridge with overall length of bridge between 6 m to 30 m having  a span not less than 10 m.

According to Function:-

  • Acquaduct (Canal over a river)
  • Via duct (Road or railway over a valley)
  • Pedestrian (Foot over Bridge)
  • Highway Bridge – Grade Separators (Fly over, VUP, PUP, RCC Box with once cell or multi cells)
  • Railway Bridge – (ROB) or (RUB)
  • Road-cum-Rail Bridge
  • Pipe-Line Bridge

According to Material (Super-Structure Material) :-

  • Timber Bridges
  • Masonary Bridges
  • Steel Bridges (Rivetted or Welded)
  • Reinforced Concrete Bridge (RCC)
  • Pre-stressed Concrete Bridge (RCC)
  • Composite Bridge (Steel Trusses + RCC Deck Slab)

According to type of Super Structure :-

  • Slab Bridge
  • Beam Bridge
  • Truss Bridge
  • Arch Bridge
  • Suspension Bridge
  • Cable Bridge

According to inter span relations:-

  • Simple Deck Slab Bridge
  • Continuous Deck Slab Bridge
  • Deck Slab with Cantilever Bridge

According to Position of floor of super structure:-

  • Deck Slab Bridge
  • Through Bridge
  • Semi or half through Bridge
  • Suspension Bridge

According to H.F.L. (Highest Flood Level) :-

  • High level Bridge
  • Submersible Bridge
  • Cause Way
  • Vented Cause Way

According to the anticipated type of service:-

  • Temporary
  • Permanent
  • Military (Pontoon, Bailey)
  • Boat Bridge

Types of Culverts:-

  • Hume-pipe culverts
  • Slab Culverts with Masonary (Brick or stone) Sub structure with open foundations or inverted arch foundation) or RCC Box culvert (one cell or two cell)

Components of a Bridge:-

  • Decking consisting of slab, ginders, trusses etc.
  • Bearings for Decking
  • Pedestals for bearings
  • Abutments and piers
  • Abutment cap or pier cap
  • Foundations for the abutments and piers
  • River training works
  • Approache slabs to the Bridge
  • Hand rails, Guard stones; RCC Crash Barrier

Importance of Bridges

  • To facilitate the crossings of rivers, canals, choes; railway lines; valleys and roads, for the sake of smooth flow traffic.
  • Symbol of developments
  • Great battles have been fought for cities and their bridges. The mobility of an army at war is often affected by the availability or otherwise of bridges to cross-rivers. That is why military training puts special emphasis on learning how to destroy existing bridges while retreating and how to build new ones quickly while advancing.
  • Failure of existing bridge may result in serious loss of life.
  • Since the primitive man was a wanderer in search of food and shelter, so the first structures he built were bridges.

List of Main Codes for R.C.C. Bridges :-

(A)       IRC-Codes 

1 IRC-5 (Section – 1) General Features of Bridges
2 IRC-6 (Section-II) For Design Loading of Bridges
3 IRC-54 Under Passes of Vehicular Traffic
4 IRC-18 Design Criteria for Prestressed conctete Road Bridges


5 IRC-83 (Part II) For Elastomeric Bearings
6 IRC-83 (Part III) For Pot cum PTFE Bearings
7 IRC-21 (Part III) Cement concrete (Plain and Reinforced
8 IRC-78 (Section VII) Foundation and substructure
9 IRC-13 For small Bridges and Culvets
10 IRC-SP-69 Expansion Joints
11 IRC-SP-71 Guide lines for Design and construction of Pre-cast-Pre-tensioned Girders for Bridges
12 IRC-87 Design and erection of False work
13 IRC-89 River training work
14 IRC-107 Bitumen Mastic wearing courses
15 IRC-103 Guide lines for Pedestrian Facilities

(B)       Indian Standard Codes 

1 IS-2911-Part-1

Section II

Section III


Bored cast in situ Piles

Driven Pre-cast Piles

2 IS-2911 (Part IV) Load Test on Piles
3 IS-1343 Code of Practice for Pre-stressed concret
4 IS-456 Cement concrete

(C)       Specifications 

(i)        Punjab PWD (B &R) Specifications

(ii)        MOST – Specifications

(iii)       Punjab Schedule of Rates

(iv)       Standard Data Book (MOST)

Life Bridges:- 

For permanent bridges; life span has been considered as 100 years.

Design Discharge:- 

(1)        The water discharge of the river at the highest flood level recorded for the last 50 years is considered for  design. Due consideration is given for the Dams on Upstream side.

(2)        Full supply level water discharge for canal is considered.

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