REHABILITATION AND REFURBISHMENT OF IRON ORE AND COAL BERTH JETTY AT PORT QASIM KARACHI, PAKISTAN

1. REHABILITATION AND REFURBISHMENT OF IRON ORE AND COAL BERTH JETTY AT PORT QASIMKARACHI, PAKISTAN

2. BACKGROUND • CONSTRUCTION OF THIS JETTY COMPLETED IN 1979. • PARTIAL REPAIRS CARRIED OUT IN 1989 DUE TO CORROSION. PROBLEMS ENCOUNTERED, • DETERIORATION CONTINUED , LIMITED REPAIRS CARRIED OUT WERE NOT SUCCESSFUL. • DETAILED SURVEY CARRIED OUT IN 2002 TO ESTABLISH THE CAUSE OF DETERIORATION . EXTENSIVE REPORT COMPILED . • REHABILITATION PROJECT WAS TENDERED OUT ON INTERNATIONAL COMPETITIVE BIDDING BASIS IN SEPTEMBER 2004. • THE PROJECT COMMENCED OFFICIALY ON 15 DECEMBER 2004.

3. EKON’S SCOPE OF THE PROJECT TESTING & SURVEY To establish the updated condition of deterioration and therefore to determine the extend of final repair . REPAIR OF STRUCTURAL ELEMENTS Repair of structural elements such as pile caps and beams. PROTECTION OF THE STRUCTURE To prevent further damage after the repairs completed. CATHODIC PROTECTION Cathodic Protection of Tubular Steel Fender Piles.

4. EXTENSIVE TESTING PERFORMED DURING JANUARY AND FEBRUARY 2005 WHICH INCLUDED BOTH DESTRUCTIVE ANDNON-DESTRUCTIVE METHODS . • A REPORT CONTAINING ALL DATA INCLUDINGLABORATORY RESULTS COMPILED AND PRESENTED TO EVALUATE THE EXTEND OF THE REPAIR . • RESULTS OF THE SURVEY AND TESTING INDICATED THAT THE DEPTH OF CHLORIDE CONTAMINATION IS UP TO 80 MM INTO THE CONCRETE, WHICH MEANT INEFFECTIVE COVER THEREFORE SEVERE CORROSION OF THE MAIN REINFORCEMENT. • THE PROBLEM WAS WORSE ON PILE CAPS CARRYING THESTRUCTURE.

5. ENVIRONMENTAL CONDITIONS AROUND COAST OF KARACHI SEVERE CONDITIONS : • HIGH SALINTY ( 52,000 ppm at +0.20 LM ). • HIGH SEA WATER TEMPERATURE (AVERAGE 22-29 °C). • TIDE BEING APPROXIMATELY IN BETWEEN -0.49 AND 3,84 METERS, • POLLUTION : SULPHATES (3,799 ppm) • REPORTS INDICATE METAL LOSS OF 10 MM IN 15 YEARS.

6. CORROSIVITY INDEX FOR KARACHI

7. SPECIFIC CONDITIONS OF THE CONTRACT ANDREQUIREMENTS OF THE CLIENT. • THE JETTY SERVES THE ONLY STEEL PLANT IN PAKISTAN. IRON ORE AND COAL UNLOADED AND CONVEYED TO THE PLANT VIA THIS JETTY. • NO DISRUPTION TO SHIPPING SCHEDULE COULD BE ALLOWED. • TIDAL CONDITIONS ARE SEVERE GIVING ONLY MAX FOUR HOURS/DAY OF OPEN TIME TO WORK ON PILE CAPS. • SPECIAL PRODUCTS AND TECHNIQUES NEEDED.

8. REPAIR METHODOLOGY OF STRUCTURAL ELEMENTS • CONCRETE COVER ON STRUCTURAL ELEMENTS ESPECIALLY THE PILE CAPS WERE REMOVED MINUMUM 25 MM BEYOND THE REINFORCING BARS ALLOWING REPLACEMENT OF CONCRETE AT THICKNESS OF 110MM. • ALREADY SCALED OFF CONCRETE IS FIRSTLY REMOVED BY ELECTROPNEUMATIC BREAKERS . IN DEPTH REMOVAL OF CONTAMINATED CONCRETE WAS FURTHER CARRIED OUT BY USING ULTRA HIGH PRESSURE WATER BLASTING (HYDRODEMOLITION)

9. HYDROBLASTING: REMOVING UNSOUND CONCRETE

10. HYDROBLASTING BY UHPWB

11. SELECTION OF REPLACEMENT CONCRETE AND PROTECTION SCHEME WEBER SBD MULSIFIX SPRAY CONCRETE IS USED . THE PRODUCTIS SHIPPED FROM UK . • DUE TO THE TIDE, OPEN TIME FOR REPAIRS WERE VERY SHORT.THEREFORE A SPECIAL PRODUCT WHICH COULD BE IN CONTACT WITHSEAWATERWITHIN 4 HOURS AFTER APPLICATION HAD TO BECHOSEN. • SELECTED PRODUCT CAN FACE SEA WATER WITHIN 3 HOURS • RAPID SETTING VERSION OF THIS PARTICULAR PRODUCT IS USED ON THE PILE CAPS WHERE AS STANDARD TYPE IS USED FOR SECTIONS OUTSIDE TIDAL ZONE. • THE PRODUCT IS READY TO APPLY . IT IS FACTORY CONTROLLED , NO SITE MIXING OR ANY ADDITION OF ANY OTHER COMPONENT AT SITE EXCEPT WATER THEREFORE ELIMINATING ANY SITE ERRORS.

12. BY FORMULATION IT IS POLYMER RICH , SHRINKAGE CONTROLLED AND HAS VERY LOW PERMEABILITY TO INGRESS OF WATER AND CHLORIDES COMPARED TO ORDINARY CONCRETE . • IT HAS A COMPATIBLE COEFFICIENT OF THERMAL EXPANSION AND HAS A VERY HIGH FLEXURAL AS WELL AS COMPRESSIVE STRENGTH . (50N/mm2 IN 28 DAYS STANDART CONCRETE 35-38 N/mm2 IN 28 DAYS) • IT COMPLIES WITH UK,DEPARTMENT OF TRANSPORT CODES. PROVEN AND CERTIFIED SYSTEM . • IT WAS OF PARAMOUNT IMPORTANCE THAT CONCRETE IS PROTECTED AFTER THE REPAIRS TO PROLONG THE LIFE OF THE STRUCTURE.POLYMER IMPREGNATION BY USING SILANE RESIN WERE APPLIED TO THE WHOLE STRUCTURE ENCAPSULATING THE REPAIRED AS WELL AS NONREPAIRED AREAS.

13. GENERAL VIEW OF THE JETTY

14. GENERAL VIEW BEFORE THE REPAIRS

15. SEVERE TIDAL CONDITIONS DAMAGE AT PILE CAPS

16. EXTEND OF DAMAGE AT PILE CAPS

17. DAMAGE ON RUNWAY BEAMS

18. EXTENSIVE TESTING CARRIED OUT PRIOR TO COMMENCEMENT OF THE POJECT

19. ALREADY SCALED OFF CONCRETE WAS FIRSTLY BROKEN AWAY BY LOW IMPACT BREAKERS. IN DEPTH REMOVAL BEHIND STEEL WAS CARRIED OUT BY UHPWB CONDITION OF REINFORCING BARS AFTER THE REMOVAL OF COVER

20. ULTRA HIGH PRESSURE WATER BLASTING IN DEPTH REMOVAL OF CONCRETE

21. REPLACEMENT OF REINFORCING BARS

22. PRIMING WITH LATEX MODIFIED CEMENTITOUS SLURRY

23. PREPARED SURFACES READY TO RECEIVE SPRAY CONCRETING

24. WETTING PRIOR TO SPRAY CONCRETING

25. FAST SET SPRAY CONCRETE APPLICATION

26. FAST SET SPRAY CONCRETE APPLICATION

27. STRIKING OFF

28. APPLICATION OF RESIN BASED CURING COMPOUND

29. AS FINISHED SURFACES

30. CORES TAKEN FOR TESTING AFTER APPLICATION SPRAY CONCRETE PARENT CONCRETE PARENT CONCRETE SPRAY CONCRETE

31. BEFORE AFTER

32. BEFORE AFTER

33. BEFORE AFTER

34. BEFORE THE REPAIRS ONE YEAR AFTER THE REPAIRS

35. BEFORE THE REPAIRS ONE YEAR AFTER THE REPAIRS

36. BEFORE THE REPAIRS ONE YEAR AFTER THE REPAIRS