Workshop Practices
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This document summarizes the first phase of training at the Central Engineering Workshop. It describes the various sections of the Bridge Engineering Department and their responsibilities, including drawing, templating, cutting, jig fabrication, welding, riveting, sawing, painting, and fabrication of plate girders. It provides examples of work done in each section and concludes with details on site visits to inspect bridges and recommended repairs.
Workshop Practices
- 1. Presentation on First Phase of Training By: MOHD FURQAN J.E (BRIDGE) Presented To: MOHAMMAD FAIZ XEN(B & F),Manmad
- 2. Bridge Engineering Dept. • Bridge Dept. is responsible for upkeep and maintenance of all type of Girder Bridges of 12.2 m and above spans. • Includes Technical inspection of steel structure, oiling & greasing of bearing, painting of structure etc.
- 4. DRAWING SECTION As per work order, Drawing are received from RDSO (Research Design & Standard Organization), Lucknow. Drawing Comprises of these many Sheets. 1.General Arrangement. 2.Stress sheet. 3.Camber diagram. 4.Details of Bearing. 5.Details of Top & Bottom Chord. 6.Details of End Raker & Portal Bracing. 7.Details of vertical & Diagonal. 8.Details of bottom & top chord joint. 9.Details of cross Girder & Stringer/Rail Bearer. 10.Details of Sway Bracing , bottom and Top lateral Bracing. 11.Erection Drawing. 12.Shipping list.
- 6. Stress sheet
- 9. Work done by Drawing Section. • To study updated Drawings Received from RDSO. • To Calculate Its Weight and Cost. • To calculate its Painting Area. • To prepare Estimates & Technical Check of Bills.
- 10. TEMPLATE SHOP • Templating means Setting out Drawing to the Scale on Floor. • Layout is Plotted for Nominal Dim. As well as Camber Dim. • Material List: Means material required for fabrication of bridge. • Working Drawing: Drawing that fabrication unit understands. Note: Templating can be done on Autocad Software instead of Floor also. Template Floor
- 11. Duties of Template Shop. • Layout plotting on Template Floor. • Preparing Material/Cutting List. • To calculate Weight each Member. • To find Painting Area. • Provide working drawing to fabricators.
- 12. CUTTING SECTION • MARKING. • CUTTING TOLERANCE: While Marking, Cutting Allowance as per IS 1852. • GAS REQUIRED: Oxy- Acetylene. • PRESSURE: 1.5 Kg/ sq. cm for Acetylene. for Oxygen it may vary with Thickness. • NOTE: Undercutting & Overcutting shall both be avoided. Thickness (mm) Tolerance (mm) Below 16 3 16-32 4 32-50 5 50 above 6
- 13. Top Flange Cutting by PUG machine Angle Section Cut Stiffeners Cutting by GAS Cutter.
- 14. JIG SECTION • What is JIG? It’s a custom made tool, used to control the Location of Drill holes. Drilling with the Help of JIG. 30.5 m Top Flange JIG.
- 15. -Master Piece: Component of Bridge to its Actual Dimension as per Drawing. - Jig: An Assembly used for Precise Drilling as to obtained Symmetric Pieces. • Note: Each & every time Bushes are checked with Plug Gauge. • Master & JIGs are verified by PCO & RDSO Seperately. Fabricating JIG for Diagonal Member.
- 16. PLUG GAUGE • Simply GO-NOGO Gauge. • Go End should go inside ferrule, that shows diameter of jig hole is ok. • If No-Go End plug gauge goes inside bush hole, bush has to be replaced with new one. Ferrule or Bush Plug Gauge
- 17. Work done by Jig Section • To fabricate Master Piece. • To fabricate New Jigs. • Repair & Maintenance of Old Jig. • Bent Plate of 30.5,45.7,61.0 & 76.2 m Span. Bottom Gusset at Lo
- 18. WELDING SHOP • To Join various Structural members • Types of Joint such as Butt, Tee, Lap and Corner joint are as follows. Fillet Welds
- 19. Members Depicting welded portions.
- 20. Flaws Introduced during Welding. • Incomplete Fusion. • Porosities. • Blow holes. • Undercuts. • Hot & Cold cracks.
- 21. RIVETTING SHOP • Riveted connection are used for connecting various Structural Members. • Rivets are superior to bolts as they are hammered up, while Hot and they contract on cooling thereby causing frictional resistance b/w connected metal surface. • Rivets are heated uniformly to a light Cherry Red Color.(temp. b/w 550-1000 Celsius). • For snap head,Lenth of Grip is calculated L=G+G/8+1.5D
- 22. Types of Rivet Heads
- 23. Riveting
- 24. Defects in Rivets. • Cracked Head. • Over burnt Rivet. • Loose Rivet. • Variable Shank Length. Note:110 gm Hammer is used to detect loose Rivets on site.
- 25. SAW SECTION • Submerged Arc Welding as arc is Submerged Under Flux. • Flux: Granulated flux shields and protects molten weld from atmospheric contamination. • Electrode Wire: SAW filler material usually a standard wire, Electrodes are generally copper coated to prevent rusting and to increase their electrical conductivity.
- 26. Advantages of SAW • Deep weld penetration. • Minimal welding fume or arc light is emitted. • Welds produced are sound, uniform, ductile, corrosion resistant. • Arc is always covered under a blanket of flux, thus there is no chance of spatter of weld. Pieces of slag from Submerged arc welding SAW Undergoing
- 27. PAINTING SHOP Procedure for Painting. 1) First Coat: Zinc Chrome. 2) Second Coat: Zinc Chrome / Red Oxide (Primer). 3) Third Coat: Red Oxide. Procedure for Metalizing. 1) On metalized Surface apply etch Primer. 2) Second Coat: Zinc Chrome Primer. 3) Third Coat: Aluminum Paint as per IS 2339. Note: Surface should be cleaned by sand blasting, wire brush or sand paper before Painting or Metalizing.
- 28. FABRICATION OF PLATE GIRDER • Templating. • Master Jig. • Material List. • Material Cutting. • Edge Grinding. • Tack Assembly. • Full SAW. • Drilling. • Final Finishing. • PCO Inspection • Rectification. • RDSO Inspection • Painting. • Dispatch. WPG Ready For Dispatch WPG Ready For Dispatch
- 29. Site visit @ Bhima Bridge. • Bridge No & Name: 301/1 Bhima Bridge. • Span: 18.3 m @ 23 spans. Purpose: • During Inspection of bridge it was found that cracks were developed at top flange. Solution: • It was suggested to provide cover plate where excessive cracks are visible for time being, after that going to change the whole Top Flange.
- 30. Site Visit @ Godavari Bridge • Bridge No & Name: 193/1 Godavari Bridge. • Span: 22.66 @ 5 Spans. Purpose: • During Inspection of bridge it was found that Bearing Plate 3 in No's got some crack on its surface. Solution: • Old Bearing Plates were Removed and replaced by a New one. • Total 2 hours of block was taken.
- 31. REFERENCE • Bridge Manual. • B1 Specification. • Steel Structure Fabrication for Railways by N.L.Nadgouda. • Inspection & Maintenance of steel girders by IRICEN,Pune. • Bridge inspector's handbook by Northern Publication 1987.