Relationship between the wide-flange steel and the long-term deformation of steel-reinforced concrete columns

In high-rise buildings, column shortening due to creep and shrinkage of concrete is an important issue because it can cause serious problem when it does not considered properly. Moisture diffusion is one of the main reasons of this long-term deformation of concrete. In case of steel-reinforced concrete (SRC) columns which have been widely used for high-rise buildings, however, the moisture diffusion process is quite different from the ordinary RC columns because of the wide-flange steel located inside the column. Wide-flange steel hinders the moisture diffusion, and the long-term shortening of the column is delayed due to the slower diffusion. This research is focused on the relationship between the wide-flange steel and the long-term deformation of SRC columns. In order to find the relationship, the analysis method which adopts the moisture diffusion process is suggested and some parametric study is conducted by using the analysis method. Parameters that can affect the moisture diffusion and the long-term deformation are the size of the column, the geometry of the wide-flange steel, and thickness of concrete cover.