Tall Building Structure
Abstract: This article mainly analyzes the Tall Building Structures. Including Shear-Wall Systems, Rigid-Frame Systems, Tubular Systems. Through the analysis of the most common structure styles for the high-rise architecture. We conclude that during the design progress, the reasonable style should be adopted economically .
Key words: high-rise system load
⒈Introduction
Tall towers and buildings have fascinated mankind from the beginning of civilization ,their construction being initially for defense and sequently for ecclesiastical purposes. The growth in modern tall building construction,however,which began in the 1880s,has been largely for commercial and residential purposes,but it is difficult to define a Tall Building Structure. One may say that a low-rise building ranges from 1 to 2 or 3 stories. A medium-rise building probably ranges between 3 or 4 stories up to 10 or 20 stories. Thus a high–rise building is probably one that has at least some 10 stories or more.
Although the basic principal of vertical and horizontal subsystem design remain the same for low-, medium-or Tall Building Structure, when a building gets high the vertical subsystems become a controlling problem for two reasons. Higher vertical loads will require larger columns , walls, deflections produced by lateral forces are much larger and must be carefully provided for.
The vertical subsystems in a high–rise building transmit accumulated gravity load from story to story , thus requiring larger column or wall sections to support such loading. In addition, these same vertical subsystems must transmit lateral loads , such as wind or seismic loads ,to the foundations. However , in contrast to vertical load, lateral load effects on buildings are not linear and increase rapidly with increase in height. For example, inder wind load, the overturning moment at the base of building varies approximately as the square of the height of the building, and the lateral deflections at the top of a building may vary as the fourth power of building height, other things being equal. Earthquake produces an even more pronounced effect.
When the structure for a low –or medium –rise building is designed for dead and live load , it is almost an inherent property that the columns, walls, and stair or elevator shafts can carry most of the horizontal forces. The problem is primarily one of shear resistance. Moderate addition bracing for rigid frames in “short” buildings can easily be provided by filling certain panels (or even all panels)without increasing the sizes of the columns and girders otherwise required for vertical loads.
Unfortunately, this is not so for Tall Building Structures because the problem is primarily resistance to moment and deflection rather than shear alone. Special structural arrangements will often have to be made and additional structural material is always required for the columns, girders, walls, an slabs in order to make a Tall Building Structure sufficiently resistant to much higher lateral loads an deformations.