INTRODUCTION
IN the beginning of February 2007, Borecut sent out a team to assist Rona-Age (Turkish) repair the sluice gates on the Limpopo bridge situated in Maccaretane, Mozambique. This bridge was built in the 1950’s and the existing sluice gates have decayed over the years leaving them completely inoperable. This became a problem resulting in poor water flow to the rest of the land, effecting farmers all over the region. Rona-Age took on the project which was funded by the Mozambique government to remove the old 39 self controlled sluice gates and build new mechanical versions. Rona-Age attempted numerous ways to cut this concrete of 75 mpa, but realized they needed a specialist for this mammoth sized job. Borecut were contracted to cut 2 openings per gate, 78 in total.
WIRE SAWING THE NIB…
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CUTTING the nib allowed for a clean flat surface to start drilling the wire holes for stage three. The wire saw was anchored to the concrete close to the nib. The pully wheels were positioned to allow for a tight angle to cut. Cutting the nib was the quickest cut of all. Just one hour of cutting was needed to complete. One sling hole of 100mm and sling were used for removal of the nib.
DRILLING 7 METER WIRE HOLE…
EACH wire hole was drilled with a 1,5 meter, 50mm diameter core barrel. Five 1,5 meter extensions were used to achieve the seven meter hole, that would allow the wire to fit through. An average of 3 core barrels were needed per hole. The hole had to be 100% straight and plenty of reinforced steel and hard stone made this job one of the tougher stages. The concrete was 75mpa.
WIRE SAWING EACH SECTION
WIRE sawing this section taking the longest of all the cutting. This 7 meter by 1,5 meter cut took approximately 8 hours to complete. The wire machine was anchored to the top of the opening in line of the two wire holes. The wire was fed down through the one wire hole, through the bottom cut and back up. Once this was complete. a 7 meter high, 1,3 meter wide, 500mm thick concrete slab was wedged in place ready to be removed by crane. Each slab had two sling holes drilled from the facing side and from the top. A Total of 78 slabs were cut. Each slab weighing 13 tons. The concrete measured at 75 mpa with an average size aggregate of 100mm in diameter. Zero mistakes ensured the job getting done in time and before deadline.
REMOVING EACH SECTION…
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