TOP-DOWN CONSTRUCTION METHOD  Use of diaphragm wall as the side support for the earth  Construction progress upwards and downwards at the same time  Savings in construction time  Schematics and pictures give ideas on ongoing activities during construction Diaphragm Wall Installation Conventional Open-cut & Bottom-up Construction Method (For comparison with Top-Down Method) Conventional Open-cut & Bottom-up Construction Method (For comparison with Top-Down Method) Top-Down Construction Method Top-Down Construction Method Main Advantage of Top-Down Construction Details of Top-Down Construction Method Excavation to Level -1 Excavate to Level -2 Compaction and leveling of basement slab for reinforcement and concrete works Circular ramp beam and wall supported on bored column Excavation work of Level -3 in progress, use of clamp-shell for exc Excavation of Ramp Level -3 to - in progress More excavation work in progress More excavation work of lower levels inprogress Above ground, structure works in progress Typical basement reinforcement slab ready for concreting Concreting of basement slab for top-down construction method Top-down construction work in progress