Hollow-core slabs construction speed impresses engineers

SPEED of installation, quality finish and cost-effectiveness of the prestressed hollow-core floor slab system impressed engineering professionals involved in the 60-room addition to the Protea Hotel in Hilton, KZN. One engineer for the main contractors estimated the work was completed a month sooner than had conventional concrete flooring slab techniques been used.

The system is relatively new to KwaZulu-Natal, and speed of construction was listed as a prime reason for using Echo Prestress flooring panels on the project, a self-contained block adjacent to the existing hotel.

The architectural design was ideally suited for the hollow-core panel system, since it allowed for a convenient repetition of slab sizes, 120mm and 150mm thickness slabs forming the floors on the second and third levels. The slabs were manufactured by Echo Prestress Durban.

The main structure was constructed of load-bearing masonry, but open areas were re- required for lounges, restaurants, reception and kitchen areas. To meet this need, in-situ reinforced concrete beams were cast by the main contractor, Gordon Verhoef & Krause (Natal) (Pty) Ltd.. The beam design was a composite beam and slab configuration, making possible a reduced depth of beam protruding below the slab.

The angle of the end-wall of the hotel required a triangular shaped slab. This was easily achieved by means of on-site, as-built dimensions, checked prior to the manufacture of the slab, which provided a perfect fit on the day of installation. This illustrated the innovative and flexible qualities of the hollow-core concrete panel system. Walkway ducts on the inside of the hotel were also accommodated by purpose-made factory-cut openings in the slab.