Multihazard Optimization-Based Simultaneous Design of Multistory Concrete Structures and TMDs

Abstract

High-rise buildings are sensitive to multihazard loads from both short and long-term perspectives. Adding tuned mass dampers (TMDs) is a well-established method to improve the performance of tall buildings, but the cost-benefit of adding TMDs is still a research question to be tackled. To answer this question, a methodology for optimal simultaneous design of reinforced concrete components and TMDs in high-rise buildings is developed for the first time. A cost-benefit focused optimization problem is defined, adopting a monetary cost function that includes direct and indirect costs and the multihazard long-term repair costs. Design variables related to the primary structure and the dampers are selected, as well as a set of constraints. The shear wall rigidities and capacities are included by generating a database of moment-curvature relations, followed by a curve-fitting procedure. An efficient gradient-based algorithm is developed to solve these challenging problems. Using this algorithm, 35 problems are solved, considering three building heights and three metropolitan areas in Israel, with their specific hazard and cost inputs. The results show that for 40-story buildings, adding TMDs is not profitable. For 50-story buildings, this is profitable for Jerusalem, marginally profitable for Tel-Aviv and not practical for Haifa. For 60-story buildings, adding TMDs is profitable for all the locations, with the greatest benefit being detected for Jerusalem, and then for Tel-Aviv in second place. The results are explained by the different building heights, wind load magnitudes and surface selling prices. The framework is shown to be flexible and appropriate for a preliminary TMD profitability assessment.