Question

How is a launching girder supported in the erection stage?

Answer 1

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The methods of erection of some temporary/semi-permanent steel bridges such as Bailey or Callender-Hamilton have been illustrated. The same methods of erection are used in many permanent steel bridges. The erection of steel truss bridges may be done by using erection cranes. , construction of Howrah Bridge, a cantilever truss bridge.

Howrah Bridge, Calcutta

Erection and Launching of Portable

Erection and Launching of Callender - Hamilton

The erection of the anchor span (where there was no water) was done over false-work by creeper cranes. In the river portion, false work was not possible as there was considerable depth of water and as such the truss starting from the tower up to the centre of the suspended span was erected by creeper cranes by cantilever method of construction.

The anchor span held by the end tie provided the necessary stability for the cantilever construction. A temporary tie was also used at top chord level at the junction of the cantilever and suspended span for cantilever construction of the suspended span.