Enrica Bernardini

Performance-Based Design of High-Rise Buildings for Occupant Comfort

AbstractThis paper introduces a framework for the performance-based design (PBD) of high-rise buildings with respect to the occupant comfort performance objective. The performance is expressed in terms of the probability—conditional on the wind event intensity—that the fraction of the building occupants on one floor that perceive the motion is greater than a chosen threshold value. The framework is fully probabilistic, and numerous uncertainties affecting both the structural response and the human perception threshold are considered in the assessment of the exceedance probability. In addition, a new database-enabled online analysis module based on the proposed PBD framework [Performance-Based Data-Enabled Design module for Occupant Comfort (PBDED-OC)] is presented. The PBDED-OC allows the assessment of the occupant comfort performance of a tall building by taking advantage of databases of high-frequency base balance measurements or by adopting specific user-supplied wind tunnel data and is envisaged to be...

A First Step towards a General Methodology for the Performance-Based Design of Wind-Excited Structures

Performance-based design (PBD) is becoming the benchmark approach for designing civil structures that rationally meet society’s need for a truly safe built environment. While the principles of PBD have been widely adopted in the field of seismic engineering, the same cannot be said for wind engineering. This paper represents a first attempt to define an appropriate framework to allow the principles of PBD to be fully embraced during the design of building systems to resist severe wind events. Focus is placed on highlighting the necessary steps to reach such a goal, which include the definition of site-specific wind hazard models, of suitable fragility functions as well as of consequence functions that rationally assess damage and losses, while communicating performance in ways that are meaningful to decision-makers. The application of the framework to a case study provides the basis for a discussion on the future challenges that researchers in performance-based wind engineering will have to embrace.

Control of the wind induced response of structures

In recent years, a drive towards the construction of buildings of increasing heights and bridges of increasing span lengths has generated the most fascinating challenges in the civil engineering field. Indeed, the particular sensitivity to wind loads of such extreme structures has to be faced when designing structural systems that have to possess adequate stiffness and damping characteristics to ensure acceptable performance for survivability, serviceability and habitability. In order to meet these needs, several routes can be taken that involve different design aspects. In addition to the modification of the structural system, which is the first and foremost option for the structural designers, these can be divided in the adoption of shape tailoring measures, aimed at improving the aerodynamics/aeroelasticity of the structure, and the introduction of auxiliary motion control devices. In this chapter these two aspects are treated, with the intent of providing the reader with a general overview of the engineering solutions that may be considered for the control of the wind induced response of structures. In particular, discussion on the aerodynamic/aeroelastic shape tailoring is provided, alongside with meaningful examples of application of this strategy to real structures. The possibility of adopting motion control devices is also investigated. The most important typologies of devices for the control of wind induced vibrations are classified according to the principle on which they are based and their main characteristics are illustrated.

A Performance-Based Methodology for the Topology Design of Tall Buildings

Topology optimization methods have recently been used as a tool for conceptual tall building design. These techniques were originally developed in a deterministic setting despite the inherently uncertain nature of the real-world environment. If uncertainties are neglected during the design process there is a possibility that the final constructed designs may perform unsatisfactorily. Thus it is necessary to account for uncertainties affecting the problem, including stochastic environmental loads and time-invariant uncertainties. Furthermore, the dynamically sensitive nature of tall buildings must be considered during the design process. This paper presents a methodology for the topology optimization of tall buildings in this setting using a framework based on the PEER Equation. A novel decoupling approach is developed that defines approximate sub-problems that can be solved using established topology optimization techniques. The successive resolution of the sub-problems until convergence results in an optimal design that satisfies the original performance constraints. A case study is used to demonstrate the validity of this framework.