A comparative study on the differential axial shortening in high‐rise buildings

Abstract

Differential axial shortening (DAS) between columns and core, due to timedependent phenomena and elastic deformation, is a very important aspect to be considered in the design of concrete high-rise buildings. This research compares the DAS of 250-and 500-m-tall buildings considering different materials for the columns and core. In fact, a parametric study is performed to evaluate the effects on DAS when using composite, reinforced concrete (RC), or highperformance concrete (HPC) columns, such as an RC or lightweight aggregate RC (LWARC) core. A finite element commercial software has been validated and then employed to estimate the DAS. All studied cases are defined on the basis of the Cristal Tower, located in Madrid, to provide reliable estimates of DAS. Results illustrate that columns made of HPC present lower DAS at infinite time and required diameters similar to the composite solution. Furthermore, an LWARC core shows higher axial shortenings compared to the RC alternative. For these reasons, the combination of HPC columns with the LWARC core is presented as a promising solution to reduce the effects of DAS in tall buildings.