Thesis_Pipitone_Giovanni.pdf (33.03 MB)

# Optimal design of building envelopes for passive structural control

thesis
posted on 18.06.2020, 16:07 by Giovanni Pipitone
In the civil engineering field, passive control devices are used to prevent structures from damages caused by a variety of events such as earthquakes, winds, blast and traffic. A control strategy based on the use of \ac{DSF} as passive vibration absorbers has been recently proposed in order to mitigate vibrations induced by environmental hazards on tall buildings.

In this Thesis, the multi-hazard design of different \ac{DSF} layouts subject to seismic and wind actions is investigated through several numerical applications. Both hazards are modelled in a probabilistic framework, taking into account prescriptions of building codes. Firstly, the optimal \ac{DSF} design is found studying the two load cases separately. Particularly, the seismic excitation is modelled using recorded accelerograms and then as a stochastic process defined by its \ac{PSD} function. In the first case, the optimal configurations of the \ac{DSF} are obtained solving four optimisation problems: two minimising the statistics of the structural response (displacement and accelerations) due to each single earthquake record, and two taking into account the average response to the full set of records analysed. In the second case, the objective of the optimisation is the minimisation of the variance of the displacements of the main structure, constrained with respect to the maximum relative displacement between the structure itself and the DSF. Taking advantage of the reduced computational effort, the optimisation has been performed varying the peak ground acceleration, herein considered as intensity measure. The results shown that the proposed layout is capable to absorb the seismic vibration inside a well identified operative range.

A similar approach is used for the wind hazard. However, in this case, the variance of the accelerations of the top storey of the building is used to define the optimisation objective function. A velocity range in which the DSF can reduce the vibrations induced by the wind actions has been found.
Similarities in the mathematical definition of the optimisation problem for the two cases (seismic and wind hazards) allow for approaching the multi-hazard design of the DSF as a multi-objective optimisation problem. In the latter, the Pareto fronts of optimal solutions have been determined varying load intensities and identifying three hazard ranges in which the DSF-dynamic behaviour tends to be different. \\

All the analyses have been conducted considering four different layout of the DSF formed by either one single panel or multiple panels spanning a finite number of storeys. The design problem aims to find the optimal damping ratio and flexural stiffness of the \ac{DSF} and optimal the stiffness of the connection elements. Finally, a comparison among the proposed \ac{DSF} layouts is carried out aiming to identify the best configuration.

## School

• Architecture, Building and Civil Engineering

## Publisher

Loughborough University

2019

## Notes

A doctoral thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.

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## Supervisor(s)

Giorgio Barone ; Alessandro Palmeri

PhD

Doctoral

## This submission includes a signed certificate in addition to the thesis file(s)

I have submitted a signed certificate

## Exports

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