Risk Distribution Profile for Differential Column Shortenging Using a Possibility Theory Approach

Abstract

As buildings inevitably increase in height, vertical support elements (e.g. columns and shear walls) in tall buildings are required to carry vertical load increments from a number of floors. Therefore, axial shortening of vertical elements due to long term creep and shrinkage effects is inevitable in reinforced concrete buildings. However, the calculation of reliable values for axial shortening is not a straight forward task. All parameters may be uncertain or may not be available at the design stage. Recently, engineers have also become concerned with differential shortening of adjacent vertical elements, particularly in the lower and basement levels of super high rise structures. Largely varied values and rates for axial shortening of adjacent support elements is not only a concern for vertical deformation, but can critically impact on the performance of horizontal structural elements such as beams and slabs. This research aims to develop a robust possibility-based differential shortening prediction framework, and associated risk distribution profiles, which overcomes the deficiencies in the current models for predicting axial column shortening in reinforced concrete high rise buildings.