2007–2010 | Seoul KOREA
Located in Seoul, the Jeondong Building project called for the renovation of a 20-story office tower built in 1974 and the addition of a new 11-story adjacent wing with a multi-level parking garage below grade.
The existing tower structure is cast-in-place concrete with stair towers at each end enclosed by shear walls with interior columns and beams forming moment frames. GNA's study of the loading requirements for the structure indicated that the existing moment frames would be inadequate in a code maximum seismic event.
The renovation of the existing tower included the removal of the existing cast-in-place concrete spandrels at each level (for the re-skinning of the tower with an all glazed facade), and the East stair core shear walls were replaced by structural steel braced frame that opened the view to the East. Given the inadequacy of the existing moment frames and the removal of shear walls at one end, the tower lateral system was augmented to include steel braced frames in addition to the remaining shear walls to resist lateral loads without the use of interior moment frames.
The adjacent new building is isolated from the renovated tower and is framed in structural steel with concrete on metal deck slabs. A cast-in-place concrete basement structure provides 5 levels of parking below the new wing.