Inspection of Steel Bridges

1. Inspection of SteelBridges APW

2. ON INDIAN RAILWAYS NUMBER OF BRIDGES AS ON 31.03.2014 More than 100 years old= 36,470 More than 140 years old= 6,680

3. BRIDGE ORGANISATION PCE PCE

4. Bridge Inspections..

5. BRIDGE INSPECTION Systematic observation of condition and behaviourof various components/ parts of a bridge is called Bridge Inspection

7. AIMS OF BRIDGE INSPECTION • To assess structural soundness and fitness for use • To identify trouble at the earliest stage • To keep a systematic record of condition and behaviour (Data Bank) • To plan repair and rehabilitation strategy and programme

8. SOME PHOTOGRAPHS • Photographs of bridges showing failure of bridge components due to lack of proper inspection and lack of timely corrective/remedial action against the notice of defects…is Shown in the Next Slides

10. After collapse of spandrel wall

11. Case Study • Bhusawal Division Case Study

12. IRBM PROVISIONS FOR INSPECTIONS

13. IRBM Para102,117 • On Indian Railways, bridges are required to be inspected once a year before the monsoon at the inspector level and once a year after the monsoon by Assistant Engineer as per the provisions in Indian Railways Bridge Manual.

14. IRBM Provisions • 102. Inspection of Bridges • a) The Assistant Engineer shall inspect every Bridge including Road over / under Bridges once a year by a date specified by Chief Engineer after monsoon.

15. Part of Inspection Details for Assistant Engineer (related to Steel Bridges) • ii) General condition of steel work of girders and bearings with special attention to places liable to corrosion. • iii) General condition of all RCC, Composite and PSC girders and their bearings.

16. 104. Maintenance of Bridges and Structures • 1. He shall be responsible for the maintenance and repairs to foundations, flooring, sub structures, protective works, bed blocks, track over bridges and the approaches including guard rails and other appurtenances, pipes, RCC Boxes, superstructure of all arches, RCC and PSC slabs, steel work of girder spans less than 12.2 m clearand other type of bridges except composite, RCC, PSC and steel girders of spans 12.2 m and more. • 2. All other steel structures like FOB, Sheds / Shelters etc. • 3. He should arrange for the expeditious repairs, as and when required.

17. DUTIES OF ASSISTANT (BRIDGE) ENGINEER/DIVISIONAL (BRIDGE) ENGINEERIN CHARGE OF BRIDGES IN DIVISION • 105. Inspection of Bridges and other structures • 1. The officer nominated to be in charge of the Bridges shall scrutinize the Bridge Inspection register sent by Bridge Inspector and after necessary inspection of Bridges endorse a certificate of scrutiny and forward it to the Dy. Chief Engineer/Bridges by a nominated date. • 2. He shall inspect • a) All overstressed girders where camber loss is noted &such bridges which have been referred to him by BRI.

18. b) Such bridges which call for his inspection, based on scrutiny of the Bridge Inspector's registers. • c) 10% test check of the bridges inspected by Bridge Inspectors every year. • 3. He will inspect all such steel structures as ordered by the Chief Engineer at specified intervals.

19. 106. Maintenance of Bridges and other structures • 1. He will be responsible for • a) Painting, rivetting, welding and other repairs to the steel work of all girder bridges of clear spans 12.2 m and above and also for repair and maintenance of the superstructure of all prestressed concrete, composite and RCC girder bridges. • b) The maintenance of bearings of all girder bridges including oiling and greasing.

20. c) He will render help to the Divisional (open line) staff for heavy repairs of steel work in girder spans of less than 12.2m clear as cannot be taken by Divisional staff. • 2. He will also maintain the other steel structures as ordered by the Chief Engineer.

21. Under Water Inspections

22. Under Water Inspection (1107/2 d.) • d) Under-water substructure inspection: • The sub-structure of the bridges which are normally underwater should be inspected by adopting suitable methods which may include engaging of divers and special equipments: • i) Routine/swim by inspection should be done once a year • ii) Detailed inspection should be done once in five years. • iii) Special inspection-as considered necessary”

23. Health Monitoring of Very Important Bridges (1107 16) • It should be done periodically by an independent agency. • Health monitoring will include corrosion monitoring, deterioration of material, system damage, retrofitting, etc. • The periodicity of health monitoring is recommended as given below. • Aggressive environment (Extreme, Very severe & Severe) Other than

25. WORKS/P.WAY INSPECTORS • As per Para 118 (1) of IRBM – Will be responsible for up-keep and maintenance of all the items of bridges • Schedule(117):Inspect All Bridges/ROB/RUB Once a year prior to monsoon • What to inspect:- Foundation, flooring, substructure, bed blocks, protection work of all bridges including ROB/RUB • Super structure of Steel work of spans less than 12.2m(Detailed inspection once in a 5 years), RCC/ PSC slabs, RCC boxes and masonry bridges. • Marking HFL, Danger level, Obstruction to Waterways etc

26. P. WAY INSPECTORS • As per Para 117 (2) of IRBM • Track on bridge & its approaches • Guard rails, foot path, notice boards, name boards, trolley refuges, sand bins etc. • Clearing of waterway of Bridges • Posting of bridge watchman wherever necessary & ensure their effective functioning

27. BRIDGE INSPECTOR(Para107 ,201,1102) • 1. He is responsible for carrying out detailed inspection of : • a) All welded, RCC, PSC and Composite Girders within one year of installation. (ACS 33 dtd .21.03.2016) • b) Girders (1102 which are overstressed)kept under observation,(at least)once a year or at intervals specified by the Chief Bridge Engineer. • c) Floor system of early steel girders once a year(Other members once in five years). • d) Superstructure including bearings of all Steel girders of span 12.2 m and above, RCC, PSC and composite girder bridges once in five years on planned basis. • (1102 The steel work and bearings of all girders 12.2 m clear span and above including that of road under/over bridges once in five years, about 20% of the inspection being carried out every year).

28. e) Other nominated steel structures, being maintained by him, once in five years. • f) Proper installation of Bearing before allowing traffic on any Bridge. (ACS 33 dtd .21.03.2016) • He shall maintain the following structures in good condition by taking immediate action to carry out necessary repairs, painting, oiling and greasing, etc. • a) Superstructure and bearing of all Steel bridges of span 12.2m and above, PSC, RCC and composite girders. • 1102 Superstructure of all prestressed concrete bridges, composite girder bridges once in five years, the initial inspection being carried out one year after installation.

29. b) Other steel structures as specified by Chief Engineer. • 1102 Welded girders once in three years, the initial inspection being carried out one year after installation. • 4. He will be responsible for the erection of steel girders for all major bridges, PSC girders. • 5. He will be responsible for the erection of workshop structures and Flood light towers, if ordered by the Chief Engineer. • 6. He will be responsible for the accountal and periodical verification of stores, tools and plants in his charge.

30. 110. Accompanying on Inspections of Higher officials • When the Bridge Inspector accompanies a periodical/ special inspection by the higher officials, he should have with him the following registers and documents pertaining to his section, other than the codes and manuals mentioned in para 108.

31. a) Relevant Working Time Tables • b) Inspection registers for steel work for bridges • c) Rivet testing register • d) Weld test register • e) RCC, PSC Bridge/ Composite Girder, Bridge Inspection register • f) Annual inspection register for overstressed girders • g) Up to date plans and files of bridge rehabilitation or regirdering works in progress and which are being inspected

32. 112. Action in case of emergency • On receipt of intimation of the occurrence of an accident (including breaches) affecting any part of the bridge or approaches or restricting free passage of trains, the Bridge Inspector should proceed to site by the quickest available means. • On the way he should collect information regarding the damage, the men and material requirement at site for restoration and arrange for their movement and seek instructions regarding the restoration form the Assistant Engineer.

33. 201 • 3. Bridge Inspectors: • The Bridge Inspector shall be responsible for the maintenance of: • a) The steel work of all the girder bridges with clear span of 12.2m and above • b) Superstructure of all RCC, prestressed concrete and composite girder bridges and • c) The bearings of all the above bridges.

34. 3. The Divisional Engineer (Bridges) / Assistant Engineer (Bridges) and his officials shall be responsible for the painting, rivetting, welding and other repairs to the steel work of all girder bridges of clear span 12.2m and above, all prestressed concrete bridges (except slabs), composite girder bridges and RCC girders. • They shall also be responsible for the maintenance of bearings and holding down bolts of all bridges.

35. Type of Inspections Routine OR General inspection • This consists of broad general visual inspection by AEN once a year. Detailed inspection • This is known as technical inspection where thorough examination of each component of superstructure is carried out once in 5 years. Special Inspection • After an accident on the bridge • After an earthquake in the area OR after unusual floods • If signs of weaknesses are revealed by the general inspection

36. Planning Inspections • Go through previous Inspection records • Go through history of the bridge • Go through drawings of the girders to identify critical locations • Plan for temporary inspection arrangements • Plan inspection tools to be taken • Plan staff to attend inspections • Plan safety arrangements

37. Preliminary Arrangements • Install inspection arrangements in position • Divide the inspection area into convenient sub parts for inspections • Keep arrangements for recording of inspection results handy • Test the safety arrangements

38. Inspections SAFETY IS FOREMOST • Wear suitable dress • Proper temporary arrangements • Properly trained manpower • No short cuts at any cost • Lookout men and protection wherever required

39. Carrying out Inspections • Work systematically from one side to other or from top to bottom or from bottom to top etc. • Inspect carefully each sub division of the girder • Keep time factor into mind • Inspect each sub-part in one go and do not break in-between • Record inspection results in rough simultaneously with inspections

40. Why Maintenance of Steel Girder is required ? • Bridge represent a considerable capital asset in Indian Railways. • None of bridge can live its full life unless provided with protective painting causing corrosion in members resulting replacement of super structure also. • The adage “Prevention is better than cure” is eminently true for steel structure. • steel structure gives warning before failure. • Inspection is a part of maintenance work which helps to live the superstructure its designed life.

41. Maintenance of Steel Girders • Cleaning • Painting • Patch painting • Periodic painting • Metallising • Epoxy painting • Greasing of bearings • Problems related to bearings • Replacement of loose rivets • Repairs/ replacement of members • Strengthening

42. MAINTENANCE OF SUPER STRUCTURE - STEEL GIRDERS • 212. Loss of camber in steel girders • 1. Steel triangulated (open web) girders are provided with camber to compensate for deflection under load. • Out of the total design camber, the part corresponding to dead load is called dead load camber. • The balance is called live load camber which should be available as visible and measurable camber in the girder when not carrying load.

43. 2. Loss of camber can be mainly attributed to : • a) Overstressing of members beyond the elastic limit • b) Overstressing of joint rivets • c) Loose rivets • 3. Rectification measures : • a) If it is established that the loss of camber is due to 2 (a) above which can be due to running of heavier loads or heavy loss of section of bridge member due to corrosion, action should be taken to strengthen the girder with proper camber or replace the girder.

44. b) In case the loss of camber is due to overstressing of joint rivets the joint should be redesigned and rivets and gusset plates replaced as required after providing the designed camber. • c) All the loose rivets should be replaced by sound rivets and proper camber provided.

45. Check the camber • In Plate girder upto span 35.0 m no camber is provided as per Steel Bridge Code Clause 4.16.1. • Camber to be recorded for Open web girders • Camber to be recorded at nominated points on the cross girders or bottom chord as feasible • Separate camber reading for G1 and G2 • Camber reading to be taken in one go. If train comes in between, the complete set of readings shall be taken again • Camber readings to be taken carefully to nearest millimeter and at the ambient temperature as mentioned in stress sheet and compared with initial camber

46. Loss of camber (212) • Heavy overstressing - Loss of cross section due to corrosion or increased load then the design load / fatigue or due to age of structure – Strengthen/ Replace • Overstressing of joint rivets at splice joint in plate girder and at panel point in open web girder- Redesign joint/and replace rivets and gusset plates • Play between holes and rivetsdue to elongation of holes or crushing of rivet shank- Replace loose rivets

47. Inspection of Steelwork • Locations subject to excess wear and tear • Locations exposed to the elements and accumulating dust/ moisture. • Secondary members such as bracing, gussets etc • Holding down bolts • Appurtenances such as inspection arrangements, railings, ladders, expansion arrangements etc.

48. INVESTIGATION OF CRACK 7 MM DIA HOLE AT EXTREMITIES OF CRACK 213(1) • LOCATION • ORIENTATION • SIZE • BREATHING OR NOT

49. Inspection of Steelwork-Cracks • Locations critical from the loading point of view • Maximum shear location • Maximum bending location • Bearing and nearby area • Bearing Stiffener • Splice Locations • Locations liable to be hit by vehicles/ boats etc

50. Fatigue Cracks • Is tendency of metal to fail at lower stress level subjected to cyclical loading then static loading • Are common where stress concentration due to sharp corners and abrupt change of cross section • Due to growing volume of traffic at greater speed and higher axle load • It is in the form of cracking of steel section due to repeated stresses.