ANALYSIS OF THE RATIONAL DESIGN OF A HIGH-RISE BUILDING USING A SYSTEM OF OUTRIGGERS AND A CORE UNDER SEISMIC AND WIND LOADS

Abstract

The article highlights the analysis of the rational design of high-rise buildings, in particular the use of outrigger and core systems, in order to study their effectiveness under seismic and wind loads. 
 The most rigid design of the outrigger (diagram B), in which vertical ties are located at each step of the perimeter columns, leads to a decrease in the horizontal movement of the top of the building by 24% compared to the building without the use of surface stiffness. However, this option is difficult to implement in practice, because in some points of the structure, for example, in the corners of the stiffness core, there is a significant number of elements with rigid nodes. Of the implemented structures, the greatest gain in movements (21%) is demonstrated by variant D, where the ties are evenly located along the perimeter of the arrangement and ensure the same transfer of horizontal influences [6] to the external columns. This version of the arrangement of connections is structurally much simpler than scheme B, with a small (less than 3%) difference in indicators. 
 The location of corner connections between the corners of the rigid core and the corners of the perimeter arrangement leads to a reduction of horizontal [7] movement by 5% in the absence of vertical connections on the short side, compared to the scheme without corner connections. It is important to note that the angular vertical connections do not compensate for the lack of longitudinal connections (schemes I - displacement of 197 mm, Y - 207 mm and Z - 190 mm). Installing only corner connections reduces the horizontal movement of the top of the building by 12% (scheme K), which is the smallest value compared to other options. 
 The use of the outrigger structure significantly increases the rigidity of the building [8], which in turn allows to reduce the cost of construction due to the reduction of the thickness of the building core and the area of reinforcement. 
 The most justified location of the vertical connections of the outrigger is the one in which they are evenly located according to the building plan, that is, they have the same interval along the entire perimeter. It is not recommended to use schemes where vertical connections are established only on the long side of the building [9], and especially only on the short side.Therefore, the use of a rigid belt in the building contributes to the reduction of horizontal movements at the entire height, effectively minimizes fluctuations caused by the influence of wind load. The use of an outrigger structure significantly increases the rigidity of the building, which in turn allows to reduce the cost of construction due to the reduction of the thickness of the building core and the area of reinforcement. 
 The most justified location of the vertical connections of the outrigger is the one in which they are evenly located according to the building plan, that is, they have the same interval along the entire perimeter. It is not recommended to use schemes where vertical connections are installed only on the long side of the building, and especially only on the short side.