The Plaza Indonesia Extension project is a 200,000 sq.m mixed-use development consisting of 48-story residential tower, 42-story office tower, 7-story retail podium and 5-level basement. The basement was constructed from the ground floor down, and at the same time the super-structure was constructed from the ground floor up. The project is located in a densely built prime area along Jalan M.H. Thamrin Jakarta. Excavation depth reached 16m, just meters away from the existing podium block of Grand Hyatt Hotel and the Japanese Embassy. When the 5th basement level was completed, the super-structure has reached the 11th floor, saving 11 months in construction time. During construction, the columns and the RC corewalls were supported by composite infill steel boxes, 600x600 mm, embedded into 70m deep diameter 1.8m bored pile.

The building is designed for 2475-year earthquake, more stringent than the required 475-year earthquake as stipulated by the Indonesian Code. To meet this criteria, a special study on the seismicity of Jakarta was conducted, as well as Site Specific Response Analysis for the project location.

This paper describes the design and construction of the Plaza Indonesia Extension building, and the process of the top-down bottom-up construction. The project has been completed in 2009.