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

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.

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.

EXTENSIVE TESTING PERFORMED DURING JANUARY AND FEBRUARY 2005 WHICH INCLUDED BOTH DESTRUCTIVE AND NON-DESTRUCTIVE METHODS . A REPORT CONTAINING ALL DATA INCLUDING LABORATORY 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 THE STRUCTURE.

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.

CORROSIVITY INDEX FOR KARACHI

SPECIFIC CONDITIONS OF THE CONTRACT AND REQUIREMENTS 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.

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)

HYDROBLASTING: REMOVING UNSOUND CONCRETE

HYDROBLASTING BY UHPWB

SELECTION OF REPLACEMENT CONCRETE AND PROTECTION SCHEME WEBER SBD MULSIFIX SPRAY CONCRETE IS USED . THE PRODUCT IS SHIPPED FROM UK . DUE TO THE TIDE, OPEN TIME FOR REPAIRS WERE VERY SHORT. THEREFORE A SPECIAL PRODUCT WHICH COULD BE IN CONTACT WITH SEAWATER WITHIN 4 HOURS AFTER APPLICATION HAD TO BE CHOSEN. 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.

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 NON REPAIRED AREAS.

GENERAL VIEW OF THE JETTY

GENERAL VIEW BEFORE THE REPAIRS

SEVERE TIDAL CONDITIONS DAMAGE AT PILE CAPS

EXTEND OF DAMAGE AT PILE CAPS

DAMAGE ON RUNWAY BEAMS

EXTENSIVE TESTING CARRIED OUT PRIOR TO COMMENCEMENT OF THE POJECT

CONDITION OF REINFORCING BARS AFTER 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

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

REPLACEMENT OF REINFORCING BARS

PRIMING WITH LATEX MODIFIED CEMENTITOUS SLURRY

PREPARED SURFACES READY TO RECEIVE SPRAY CONCRETING

WETTING PRIOR TO SPRAY CONCRETING

FAST SET SPRAY CONCRETE APPLICATION

FAST SET SPRAY CONCRETE APPLICATION

STRIKING OFF

APPLICATION OF RESIN BASED CURING COMPOUND

AS FINISHED SURFACES

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

BEFORE AFTER

BEFORE AFTER

BEFORE AFTER

ONE YEAR AFTER THE REPAIRS BEFORE THE REPAIRS ONE YEAR AFTER THE REPAIRS

ONE YEAR AFTER THE REPAIRS BEFORE THE REPAIRS ONE YEAR AFTER THE REPAIRS

ONE YEAR AFTER THE REPAIRS BEFORE THE REPAIRS ONE YEAR AFTER THE REPAIRS