2007–2010 | Seoul KOREA
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 in cast-in-place concrete with shear walls enclosing circulation cores at each end between which are 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 structural renovation work included the removal of the existing cast-in-place concrete spandrels at each level to facilitate installation of a new all-glazed curtain wall, and the replacement of the East stair core shear walls with structural steel braced frames 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 lateral system was augmented with steel braced frames to resist lateral loads without the use of interior moment frames.
The new wing is structurally isolated from the renovated tower and is framed in steel with concrete on metal deck slabs. A cast-in-place concrete basement structure provides 5 levels of parking below the new wing.