XN000022-1993-03-16 — Page 9

TUESDAY, MARCH 16, 1993

WORK ON BRIDGE FORGES AHEAD

LANTAU

IN

AN IMPORTANT EARLY MILESTONE IN THE CONSTRUCTION OF THE FIXED CROSSING HAS BEEN REACHED WITH THE COMPLETION OF THE "SHOES" WHICH ONE OF THE HUGE TOWERS OF THE TSING MA BRIDGE WILL STAND.

THE TWO MASSIVE CAISSONS OF REINFORCED CONCRETE, WHICH ARE HEIGHT OF A SIX-STOREY BUILDING, ARE NOW ANCHORED OFF LANTAU READY BE PUT IN PLACE AT THE BASE OF THE TOWER OFF MA WAN ISLAND.

THE

TO

THE

THEY WERE CAST ON BOARD A SPECIAL SUBMERSIBLE BARGE AT BRIDGE SITE ON TSING YI ISLAND, AFTER WHICH THE BARGE WAS PILOTED TO NORTH LANTAU JUST BEFORE THE WEEKEND.

OVER TWO DAYS AND INVOLVING SUBMERGED TO ALLOW THE

IN A HIGH PRECISION OPERATION SEVERAL TUGBOATS, THE BARGE WAS GRADUALLY CAISSONS TO BE FLOATED FREE AND SECURED.

A SPOKESMAN FOR THE HIGHWAYS DEPARTMENT SAID TODAY (TUESDAY) THAT THIS WAS THE FIRST TIME SUCH AN OPERATION HAD BEEN CARRIED OUT IN HONG KONG AND THAT EVERYTHING WENT SMOOTHLY.

"I

"THE SUBMERSION AND REFLOATING OF THESE GIANT CONCRETE BOXES WAS A DRAMATIC SIGHT, HE SAID, "AND A HIGHLY VISIBLE SIGN OF THE RAPID PROGRESS BEING MADE ON THE BRIDGE.

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THEY WILL BE TOWED TO THE BRIDGE SITE AND PLACED ON A SPECIALLY PREPARED SEABED WHEN FOUNDATION EXCAVATION AND PREPARATION IS COMPLETED AT THE MA WAN TOWER IN THE NEXT FEW WEEKS.

EACH CALSSON IS 20 METRES BY 28 METRES AND 17 METRES TO 19 METRES HIGH. THE LOWER PORTION OF EACH CAISSON CONTAINS HOLLOW CELLS THAT WILL BE FLOODED ΤΟ GRADUALLY SUBMERGE THEM AT THE PRECISE LOCATION OF THE TOWER FOUNDATION.

THE SPACE LEFT BETWEEN THE CAISSONS AND THE FOUNDATION BED ROCK WILL BE FILLED WITH TREMIE CONCRETE WHICH IS A SPECIAL UNDERWATER CONCRETE PLACEMENT PROCESS. INFILL CONCRETE WILL ADDED ABOVE THE TREMIE CONCRETE WITHIN THE CAISSONS.

THEN BE

THE UPPER 7 METRES OF EACH CAISSON WILL FORM THE REINFORCED CONCRETE BASE FOR EACH TOWER LEG. THESE BASES, TOGETHER WITH THE INFILL AND THE TREMIE CONCERTE, WILL SECURE THE TOWER.

AN ISLAND WILL BE CONSTRUCTED AROUND THE MA WAN TOWER WITH ROCK ARMOUR TO PROTECT IT FROM MARINE TRAFFIC.

THE TSING MA BRIDGE WILL BE ONE OF THE LONGEST SUSPENSION BRIDGES IN THE WORLD, AND THE LONGEST CARRYING BOTH ROAD AND RAIL TRAFFIC.

TOGETHER WITH THE KAP SHUI MUN BRIDGE, IT FORMS THE LANTAU FIXED CROSSING, WHICH IS ONE OF THE 10 PROJECTS IN THE AIRPORT CORE PROGRAMME. THE CROSSING IS DUE TO BE COMPLETED IN MAY 1997.

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