Civil Engineering October 2022 | Vol 30 No 9

10 October 2022 Civil Engineering “Bank-pad abutments were cast onto a single row of piles in two lifts. The first abutments were cast above new piles, which varied in depth between 13 m and 19 m at either abutment end. The pile diameters were designed with sufficient flexibility to accommodate deck movement and the back-ends of the abutments were backfilled with rounded aggregate, which allows for ratcheting movement within the fill and prevents the build-up of stresses behind the abutment,” says Van Wyk. Concrete Manufacturers Association member, Cape Concrete cast nine 22.8 m prestressed beams for the new structure: seven internal beams weighing 25 tonnes apiece, and two edge beams at 35 tonnes each. The edge beams are non- symmetrical with thicker sides and flat face finishes. Four beams were used in the construction of Phase 1 on the southern side of the bridge and five are being used for Phase 2 on the northern section. Both edge beams were designed to support the cantilevered walkways with protruding transverse pull-out bars. CONSTRUCTION PROCESS Ricardo De Sa, construction manager at Martin & East – the project contactor – says that a temporary barrier was placed The edge beam in Phase 1 is lowered into position Workers insert rebar through sleeves situated in the beams’ lower web sections