Efficiency of Tubular Framing for Medium-Height Buildings

A tubular-framed high-rise building has its main structural frame on its perimeter. The columns are closely spaced, so that the structural behavior of this perimeter frame will approximate that of a tube in resisting applied loads. 1 This type of framing is generally applied to tall structures with 40 or more stories, although it has been used for buildings as low as 22 stories. This is because its main advantage is in resisting wind loads, which become more important as the height of the building increases. Furthermore, shear lag, which reduces the effectiveness of the tubular frame in resisting wind loads, is smaller in tall buildings. To evaluate this framing method for medium-height buildings ranging between 20 and 40 stories, comparative designs were made of a 20-story building whose arrangement was representative of this type of structure. Three types of frames were compared: (1) a simple building frame, (2) a rigid building frame, and (3) a tubular building frame. Cost estimates were obtained for the latter two designs.