Bridge Details

 

Brief Details

  • Bridge type : Suspension type Balanced Cantilever

  • Central span 1500 ft between centers of main towers

  • Anchor arm 325ft each

  • Cantilever arm 468ft each

  • Suspended span 564ft

  • Main towers are 280ft high above the monoliths and 76 ft apart at the top

  • Bridge deck width 71 ft with two footpaths of 15 ft either side

 

Other features of the Bridge

  • All members of the super structure comprise built up riveted sections with a combination of high tensile and mild steel

  • Between towers bridge deck hangs from panel points in the lower chord of the main trusses with a series of hungers(39 pairs)

  • Road way beyond the tower is supported on ground leaving anchor arm free from deck loads

  • Bridge deck comprises 71 ft carriage way and 15 ft footway projecting either side of the trusses and braced by a longitudinal fascia girder.

 

More about the Bridge

  • The deck system consists of cross girders hung between pairs of hungers  with pinned connection.

  • Six rows of longitudinal stringer girders  span between cross girder.

  • Floor joists supported transversely on top of stringers.

  • They support a continuous pressed steel troughing system.

  • Over which deck concrete is laid out.

 

Joint System of Bridge (Expansion Joints)

  • Longitudinal expansion and lateral sway movement of the deck are taken care of by expansion and articulation joints.

  • There are two main expansion joints, one at each interface between the suspended span and the cantilever arms.

  • There are expansion joints at the towers and at the interface of steel and concrete structures at both approach.

 

Articulation Joints

  • There are total 8 articulation joints.

  • 3 at each of the cantilever arms.

  • 2 in the suspended portions.

  • They divide the bridge into segments with vertical pin connection between them to facilitate rotational movements of the deck.

 

Camber and Traffic clearance

  • Bridge deck has longitudinal ruling gradient of 1 in 40 from either end

  • They are joined by a vertical curve of radius 4000 ft.

  • Cross gradient of deck is 1 in 48 between kerbs and central 4.9mtr. is level to provide tramway housing channel in between troughing.

 

Foundation

  • The main tower is founded with single monoliths which are 55.31 x 24.8 m in plan with 21 chambers

  • Monoliths at Calcutta and Howrah side are founded 31.41 m and 26.53 m in below ground level respectively.

  • Minimum headroom in carriageway is 5.8 m

  • Freeboard for river traffic is 8.8 m

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