The deepest barrette pile construction in Turkey has been successfully accomplished within the scope of on-going Mahall Bomonti İzmir Project. A piled-raft foundation; consisting of “barette piles” (rectangular pile) is designed by KASKTAŞ. The piled-raft foundation is selected as the most suitable foundation system of the ~250 m tall Tower Building, when it is completed. 2,800 mm x 1,200 mm in dimension and 98.5 m deep barette pile was constructed by using a “trench cutter” within soft and deep alluvium deposit and one of the most seismically active places in the world; while complying with the permissible deviation tolerances (1/400) stated in the Technical Specification of the Project. Inclinometers and a gyroscope mounted to trench cutter are used in order to maintain the required tolerences. Moreover, base grouting is executed in order to increase the bearing capacity of the barette.