Erection Of Steel Structure Erection of steel girder and steel truss bridges Different Methods and Equipments Also for Civil Engineering Students

1. Shree Swami Atmanand Saraswati Institute of Technology
Erection
of
Steel Girder and Steel Truss Bridges
Prepared By :-
Balar Piyush 110763106063
Vekariya Sandeep R. 120763106001
Kakadiya Gaurang A. 120763106002
Balar Jigar H. 120763106003
Guided By :-
Prof. A.P. Satasia
Prof. P. V. Trivedi
Prof. R. R.Tripathi
Railway Bridge & Tunnel Engineering

2. † Contents
 Introduction to Steel Girder Bridges
 Erection of Steel Girder Bridges
 Methods
 Erection of Steel Truss Bridges
 References

3. † Introduction to Steel Bridges
 The steel girder bridge is a structure in which a floor system and roadway,
concrete or timber, is supported by girders, usually rolled section beams which
are plain or encased in concrete
 These are normally used for railways and rarely for highways
 Following data should be collected prior to the erection of these bridges:
 Time estimate for the construction of a bridge
 Condition of proper equipment and machinery
 Condition of bridge site
 Facility for transportation and storage of materials at bridge site
 Necessary supporting system for superstructure
 Availability of steel structures
 Width and depth of flow in the river
 Height of bridge from river bed

4. Methods for erection of steel bridges
Erection by Lifting Method
Erection by Staging
Erection by Floating
Erection by Rolling
Erection by Launching of single girder span
† ERECTION OF STEEL GIRDER BRIDGES

5. † Erection of Steel Bridges
 Methods
 Erection by Lifting Method
 Steel girders upto span of 30 m can be
easily erected if the height is 5 to 6 m
 This method is suitable for rivers which
are dry for the most part of the year
 A platform is created by filling earth to
sufficient height and levelled
 Girders are assembled on the river bed and field riveted/bolted
 They are lifted into position by means of stiff-leg derrick cranes or ordinary
rope worked from anchored crab winches
 The flooring and the bracings are then field connected to the girders placed in
position

7. SOLNA BRIDGE, STOCHOLM, SWEDEN

8. † Erection of Steel Bridges
 Methods
 Erection by Staging:
 Favourable conditions:
 Depth of water in the river is shallow
 Height of superstructure above the river should not be
excessive
 Span should be simply supported
 Staging consists of trestle frames which may be of steel or
timber
 Iron staging is lighter than timber staging and, therefore, can be
easily transported
 Staging is suitably designed and after it is constructed, the
erection of steel girders is commenced on the staging

10. † Erection of Steel Bridges
 Methods
 Erection by Floating:
 Favourable conditions for this method are:
 Depth of water in the river is more
Floating barges/pontoons are used to carry the steel girders
Bridge is assembled on the barges and is floated into position when
complete.
The barges are so positioned that
span is over the final alignment,
when the jacks are used to lower the
span on the bearings.
Finally the barges are sunk by
flooding the tanks

11. Coleman Bridge, York River in Yorktown

12. † Erection of Steel Bridges
 Methods
 Erection by Rolling:
 This method is adopted for erection of continuous girders on deep gorges
 First span near the abutment is erected by any one method of erection
 Girders of the first span are brought to the required position by rolling
them from the abutment through the erected span
 This method is also known as the Incremental Launching Method and has
become very popular for the concrete girders
 Second span is cantilevered when it projects from the erected span and
acquires counter weight for its stability
 This counter weight is provided by the successive span connected to it and
its back

14. † Erection of Steel Bridges
 Erection by Launching of single girder span
 Each girder is first assembled on a
track of rollers behind one of the
abutments and is cantilevered as far
as possible over the span.
 The lifting blocks are then fastened
to the outmost point of the girder
and the heavy wire is coupled to the
winch.
 Rear end of the girder is tied to
another winch which is released
slowly so that sudden forward motion
may no take place.

16. † Erection of Steel Truss Bridges
 These bridges are erected with the help of a stiff derrick traveller and two
false work bents
 Erection procedure may be described in four stages:
 Second stage
 Move traveller (crane) to
B
 Erect false work bent T2
 Assemble the section BC
 First stage
 Erect false work bent T1
 Assemble the section AB

17. † Erection of Steel Truss Bridges
 Third stage
 Move traveller to C
 Remove false work bent T1 from B
and erect it at D
 Assemble the section CD
 Fourth stage
 Move traveller (crane) to D
 Assemble the section DE
 Release the false work bent T1 and T2

19. † References
 ftp://ftp.mdt.mt.gov/research/LIBRARY/NSBASBEGS-1-OL-
STEEL_BRIDGE-AASHTO.PDF
 http://www.deldot.gov/archaeology/historic_pres/hist_bridge_surv
ey/pdf/steel.pdf
 http://www.kwhconstructors.com/img/gallery/williamr.bennettbridg
e/wrb_bridge5.JPG