ABSTRACT
On sloping sites the basement may be only partially below ground level. Basements can be waterproofed by one of three basic methods, namely: use of dense monolithic concrete walls and floor, tanking techniques and drained cavity system. Diaphragm walls are structural concrete walls which can be cast in situ or constructed using precast concrete components. Diaphragm walls are suitable for basements, underground car parks and similar structures. Secant piling forms a permanent structural wall of interlocking bored piles. Top down construction is a method associated with deep, multi-level basement construction where intermediate level basement floors are constructed as excavation proceeds downwards. Basement slabs are usually designed to span in two directions and as a consequence have relatively heavy top and bottom reinforcement. Grades or standards of protection against water ingress into substructures vary from utility to habitable. The water tightness of dense concrete mixes depends primarily upon two factors: water/cement ratio and degree of compaction.
