Optimization of High-Rise Building Retrofitting Against Wind Loads

Abstract

As the height of any structure increases, it becomes slenderer and more sensitive to wind loads. So, any increase in the structure height that was not considered during the initial stages of the design process will cause many structural issues. For such a problem, structural retrofitting is suggested to resist wind loads and satisfy safety and serviceability requirements. The strategy of retrofitting includes adding structural steel wind-resisting systems in the openings of the structural plan. This paper proposes an optimization technique for steel systems used to retrofit high-rise buildings, which aims to reduce the weight of the steel system keeping the building meeting the constraints of lateral displacement at the top of the building using Genetic Algorithm (GA) as an optimization algorithm. Integrated with CSI ETABS, the Visual Basic application is designed to perform this task.  The proposed technique is applied to two cases of reinforced concrete buildings that are vulnerable to wind loads. The first case depicts a sense of consistency within buildings, while the second case exemplifies instances of irregularity in architectural design. Both cases are studied at heights of 15, 18, 21, 24, and 27 stories. The results show that strengthening a building using the optimized steel-braced frame is an efficient technique. The stiffness distribution of the optimum retrofitting system is concluded and formulas describing this distribution are derived.