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Abstract Aero‐structural shape design and optimization of bridge decks rely on accurately estimating their self‐excited aeroelastic forces within the design domain. The inherent nonlinear features of bluff body aerodynamics and the high cost of wind tunnel tests and computational fluid dynamics (CFD) simulations make their emulation as a function of deck shape and reduced velocity challenging. State‐of‐the‐art methods address deck shape tailoring by interpolating discrete values of integrated flutter derivatives (FDs) in the frequency domain. Nevertheless, more sophisticated strategies can improve surrogate accuracy and potentially reduce the required number of samples. We propose a time domain emulation strategy harnessing temporal fusion transformers (TFTs) to predict the self‐excited forces time series before their integration into FDs. Emulating aeroelastic forces in the time domain permits the inclusion of time‐series amplitudes, frequencies, phases, and other properties in the training process, enabling a more solid learning strategy that is independent of the self‐excited forces modeling order and the inherent loss of information during the identification of FDs. TFTs' long‐ and short‐term context awareness, combined with their interpretability and enhanced ability to deal with static and time‐dependent covariates, make them an ideal choice for predicting unseen aeroelastic forces time series. The proposed TFT‐based metamodel offers a powerful technique for drastically improving the accuracy and versatility of wind‐resistant design optimization frameworks. 

Contemporary aero-structural design frameworks for wind-sensitive bridges are mostly based on the assessment of aeroelastic responses under synoptic winds. However, holistic design methodologies must address all potential wind scenarios, such as non-synoptic wind events and variations in the angle of attack due to complex terrains. This requires the evaluation of the aeroelastic responses considering the sensitivity of the fluid-structure interaction parameters with the angle of attack. Hence, this study proposes a Kriging-based multi-directional aeroelastic surrogate to emulate the flutter derivatives of bridge decks as a function of the deck shape, frequency of oscillation of the deck, and the mean incident angles of wind. This design tool is pivotal to properly modeling the nonlinear features of flutter derivatives at low reduced velocities and their sensitivity with the angle of attack. The aeroelastic surrogate will be later integrated into aero-structural design frameworks for the shape optimization of bridge decks under non-stationary winds. 

The shape design and optimization of bluff decks prone to aeroelastic phenomena require emulating the fluid-structure interaction parameters as a function of the body shape and the oscillation frequency. This is particularly relevant for long- and medium-span bridges equipped with single-box decks that are far from being considered streamlined and for other girder typologies such as traditional truss decks and modern twin- and multi-box decks. The success of aero-structural design frameworks, which are inherently iterative, relies on the efficient and accurate numerical evaluation of the wind-induced responses. This study proposes emulating the fluid-structure interaction parameters of bluff decks using surrogate modeling techniques to integrate them into aero-structural optimization frameworks. The surrogate is trained with data extracted from forced-vibration CFD simulations of a typical single-box girder to emulate the values of the flutter derivatives as a function of the deck shape and reduced velocity. The focus is on deck configurations ranging from streamlined to bluff cross-sections and on low reduced velocities to capture eventual aerodynamic nonlinearities. The girder cross-section geometry is tailored based on its buffeting performance. This design tool is fundamental to finding the optimum balance between the structural and aeroelastic requirements that drive the design of bluff deck bridges. 

Controlling wind-induced responses is a challenging and fundamental step in the design of wind-sensitive critical infrastructures (CI). While passive design modifications and passive control devices are effective alternatives to a certain extent, further actions are required to fulfill design specifications under some demanding circumstances. Active countermeasures, such as active dampers, active aerodynamic devices, and operational control systems, stand out as a smart alternative that allows extra control over wind-induced responses of tall buildings, long-span bridges, wind turbines, and solar trackers. To make this possible, CI are equipped with operational technology (OT) and cyber–physical systems (CPS). However, as with any other OT/CPS, these systems can be threatened by cyberattacks. Changing their intended use could result in severe structural damage or even the eventual collapse of the structure. This study analyzes the potential consequences of cyberattacks against wind-sensitive structures equipped with OT/CPS based on case studies reported in the structural control literature. Several cyberattacks, scenarios, and possible defenses, including cyber-secure aero-structural design methods, are discussed. Furthermore, we conceptually introduce and analyze a new cyberattack, the ‘‘Wind-Leveraged False Data Injection’’ (WindFDI), that can be specifically developed by taking advantage of the positive feedback between wind loads and the misuse of active control systems. 

The accelerated growth of urban areas in the last decades has led to an unprecedented increase in the construction of wind-sensitive structures, e.g., long-span bridges, tall buildings, wind turbines, and solar trackers. To effectively control undesired wind- and earthquake-induced responses, a plethora of operational technology and cyber-physical systems have been introduced, including supervisory control and data acquisition systems, programmable logic controllers, and remote terminal units. All these systems are potential targets for cyberattacks and have already been attacked in other sectors, including energy, industry, education, and health. This study analyzes this threat to critical infrastructure, quantifies its potential damage, and develops possible countermeasures and cyber-defenses so the structural engineering community can effectively address this emerging challenge. 

This study reports the nonlinear aerostatic stability studies carried out for a suspension footbridge with a curved deck spanning 275 meters over the Miño River between Spain and Portugal. The footbridge's aerostatic performance is controlled by its highly aesthetic but complex three-dimensional configuration, the high slenderness of the deck, the construction process, and the aerodynamic characteristics of the triangular 4.5-meter-wide bluff deck cross- section, which demands a detailed aerodynamic study. The analysis is conducted using a nonlinear modal-based method recently developed by the authors. The deck's rotation is driven not only by the aerodynamic moment-induced rotation but also by the drag-induced rotation due to the configuration of the cable supporting system and, very significantly, by the lift- induced rotation due to the deck's curvature. 

Vortex-induced vibration (VIV) of deck girders frequently drives the wind-resistant design of wind-sensitive bridges from the preliminary to final design stages. Shaping bridge decks is a proven strategy to mitigate VIV. While significant shape modifications are commonly restricted to preliminary design stages, only minor medications are possible at advanced design stages, typically involving adding flow modifiers or changing the shape and location of existing appendages. These mitigation strategies have been implemented in the last decades by carrying out expensive wind tunnel campaigns and following heuristic design rules. This paper proposes an experimental data-driven adaptive surrogate-based optimization approach to systematically identify optimum deck shapes that minimizes the economic cost of the bridge while fulfilling the VIV project specifications. The methodology is conceived to carry out simultaneously the general and detailed shape design of the final deck configuration by harnessing a sequential sampling plan aiming at reducing the sectional model construction costs. The proposed holistic design framework is successfully applied to a real application case involving 26 wind tunnel tests of 1.8-meter wide sectional models to figure out the optimal gap distance and location of maintenance tracks of a twin-box deck equipped with all the appendages included in the final deck design.