Twisted Tall Building Structural Response Under Lateral Wind-Induced Loads

Resumo

The design and construction of tall structures have consistently presented unique difficulties as architectural pushes limits continuously. Such building challenges demands from engineers' innovative structural solutions. Among these problems, a particularly notable one is the definition of twisted tall buildings structural system, which demand breakthrough designs to guarantee stability, safety, and functionality. The first twisted building, Turning Torso in Sweden, is a 190m tower designed by Santiago Calatrava with a total rotation of 90 degrees and its construction was completed in 2005.
Twisted tall buildings, in contrast to prismatic ones, have non-uniform floor layouts and facades that spiral upwards, resulting in a visually appealing architecture. Nevertheless, this aesthetic innovation brings benefits and drawbacks to all building subsystems. Some authors have studied that the facade spiral decrease the natural illumination, other postulated that this shape reduces the magnitude of wind loads but decreases the lateral stiffness of the building.
There are few studies on the structural form and on the response of twisted tall buildings under lateral loads. In this study, the behavior of tall buildings with 120m height under wind-induced loads will be investigated and contrasted between a prismatic model and various twisted ones, increasing the angle of rotation between different stories for each model from 0.5 to 6 degree. The analysis will be performed with procedural generated models in SAP2000 using Python programming language.
The wind load will be estimated for the prismatic model according to the Brazilian Code NBR 6123:2023 and will be applied to the columns nodes each floor. The same numerical value of the load will then be applied to the columns of all twisted models and the only variable will be the twist angle between stories. The objective of this study is to evaluate and compare the maximum story drift, horizontal displacement, and the ratio between cross-sectional pre-dimensioning at the bottom level of the columns according to Brazilian Code NBR 6118:2023 and the total floor area.