Erection of steel Structure

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

6. Erection By Lifting

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

9. Erection by 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

13. 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.

14. Erection by Launching of Kurilpa Bridge, Brisbane, Australia

15. 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 T 2 Assemble the section BC First stage Erect false work bent T 1 Assemble the section AB

16. Erection of Steel Truss Bridges Third stage Move traveller to C Remove false work bent T 1 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 T 1 and T 2

17. References ftp://ftp.mdt.mt.gov/research/LIBRARY/NSBASBEGS-1-OL-STEEL_BRIDGE-AASHTO.PDF http:// www.deldot.gov/archaeology/historic_pres/hist_bridge_survey/pdf/steel.pdf http://www.kwhconstructors.com/img/gallery/williamr.bennettbridge/wrb_bridge5.JPG

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