The construction of diaphragm wall within the scope of Üsküdar Hakimiyeti Milliye Bazaar and Underground Parking Project; consisting of 874 car parks and 136 independent commercial areas has been completed last week whereas construction of top-down piles still continues. For the realization of the 17m deep excavation pit of 4 basement floors in a safe and economical way by the Top-Down Construction method, 15,600m² diaphragm wall with a thickness of 1.0m and a maximum depth of 35m; 7,000m top-down piles with a diameter of 85cm and a maximum length of 38m were designed by Kasktaş. It has planned to provide a significant advantage in the total construction time because of the selected and designed shoring system; Top-Down Construction Methodology; which enables the 5-storey building’s construction works and excavation works to be performed in a simultaneous manner.