Wind effects on a long span steel roof structure: numerical simulation and equivalent static wind loads

A wind tunnel test is conducted in this study on the scaled model of the Guangzhou International Sports Arena (GISA). Simultaneous pressure measurements are conducted in a simulated suburban boundary layer flow field. A numerical simulation approach using Fuzzy Neural Networks (FNNs) is developed for the predictions of wind-induced pressure time series at roof locations which are not covered in the wind tunnel measurements. On the other hand, the wind-induced response of the roof are presented and discussed, which are directly calculated by the Complete Quadratic Combination (CQC) approach. Furthermore, the correlations between the background and resonant response components are discussed in detail, and the results show that neglecting the correlations between the two components would result in considerable error in the response estimation. Finally, the Equivalent Static Wind Load (ESWL) approach is used to estimate the wind-induced responses of the roof, which are compared with those obtained from the CQC approach to examine the effectiveness of the proposed ESWL approach in the design and analysis of large-span roof structures. It is shown through the example that the FNN and ESWL approaches can successfully predict the wind-induced pressures and responses respectively

Performance of Wind Exposed Structures

PERBACCO (a free Italian acronym for Life-cycle Performance, Innovation and Design Criteria for Structures and Infrastructures Facing Æolian and Other Natural Hazards) is a research project partly funded by the Italian Ministry for University (MIUR) in the PRIN (Progetti di Ricerca di Interesse Nazionale) framework, for the years 2004-05.Within the project, a first attempt has been made to integrate different disciplines aiming at an overall optimization of the performance of a wide range of wind exposed structures and infrastructures, with consequent benefi cial impact on the society.The overall objectives were (a) to provide unifi ed concepts for "expected performance" and "risks induced by æolian and other natural hazards", to be applied to structures and infrastructures over their whole life-cycle, such to be acceptable to stakeholders in the construction process (i.e. from the owner to the end-user), (b) to provide models and methodologies for dynamic monitoring of the performance of structures and infrastructures, to be integrated in appropriately designed procedures, and (c) to collect, refi ne, fi le and disseminate the knowledge available on a European basis, concerning the performance of wind-exposed structures and facilities, in a way such to be of use to Construction Industry. This volume summarises the main results obtained during the Project, with each Section addressing a different class of problems, to which many research Units have contributed. A list of papers containing the main results of the research activities carried out within the Project is also provided in each Section

5 European & African Conference on Wind Engineering

The 5th European-African Conference of Wind Engineering is hosted in Florence, Tuscany, the city and the region where, in the early 15th century, pioneers moved the first steps, laying down the foundation stones of Mechanics and Applied Sciences (including fluid mechanics). These origins are well reflected by the astonishing visionary and revolutionary studies of Leonardo Da Vinci, whose kaleidoscopic genius intended the human being to become able to fly even 500 years ago… This is why the Organising Committee has decided to pay tribute to such a Genius by choosing Leonardo's "flying sphere" as the brand of 5th EACWE

WINDERFUL Wind and INfrastructures

WINDERFUL (an acronym for Wind and INfrastructures: Dominating Eolian Risk For Utilities and Lifelines) is the title of a research project carried out by eight Italian Universities from the end of 2001 to the end of 2003. The project was centred on how "to keep a city running and ensuring quality services during and after major windstorms", avoiding "major failures" of engineering facilities and main infrastructures. The book reports the main results obtained in the project, and for each typology the tool for assessing its reliability are discussed, together with the criteria for its improvement

Buildings and Structures under Extreme Loads II

Exceptional loads on buildings and structures are known to take origin and manifest from different causes, like natural hazards and possible high-strain dynamic effects, human-made attacks and impact issues for load-bearing components, possible accidents, and even unfavorable/extreme operational conditions. All these aspects can be critical for specific structural typologies and/or materials that are particularly sensitive to external conditions. In this regard, dedicated analysis methods and performance indicators are required for the design and maintenance under the expected lifetime. Typical issues and challenges can find huge efforts and clarification in research studies, which are able to address with experiments and/or numerical analyses the expected performance and capacity of a given structural system, with respect to demands. Accordingly, especially for existing structures or strategic buildings, the need for retrofit or mitigation of adverse effects suggests the definition of optimal and safe use of innovative materials, techniques, and procedures. This Special Issue follows the first successful edition and confirms the need of continuous research efforts in support of building design under extreme loads, with a list of original research papers focused on various key aspects of structural performance assessment for buildings and systems under exceptional design actions and operational conditions

Assessment, Diagnosis and Service Life Prediction

Service life prediction is crucial for the adoption of more sustainable solutions, allowing developers to optimize the costs and environmental impact of buildings during their life cycle. An accurate assessment of the service life of buildings requires a thorough understanding of the degradation mechanisms and behaviour of the construction materials. Building pathology assessment methods characterize the deterioration state of buildings, using specific measurable properties as indicators. Based on this information, different service life prediction methodologies can be defined to provide reliable data concerning the most probable failure time of whole buildings and individual components according to their characteristics and their age. This Special Issue provides new perspectives on the existing knowledge related with various aspects of the Assessment, Diagnosis and Service Life Prediction of buildings and their components. The ten original research studies published in this Special Issue result from research centres and university departments of Civil and Construction Engineering, Safety Management, Environmental Engineering, Geotechnical Engineering, and Architecture and the Built Environment, with relevant contributions from experts from Australia, Brazil, the Czech Republic, Hong Kong, Iran, Israel, Norway, Portugal, and Taiwan. The studies included in this Special Issue address topics related to: Building pathology assessment methods; Diagnosis of defects in buildings and components; Appropriate intervention and repair techniques; Deterministic and stochastic service life prediction models

Aerodynamic Flutter and Buffeting of Long-span Bridges under Wind Load

With the continuous increase of span lengths, the aerodynamic characteristics of long-span bridges under external wind excitation have become much more complex and wind-induced vibration has always been a problem of great concern. The present research targets on the aerodynamic performance of long-span bridges under wind load with an emphasis on bridge flutter and buffeting. For the aerodynamic flutter analysis of long-span bridges, the present research investigated the effects of the wind turbulence on flutter stability. The characterizations of the self-excited forces are presented in both the frequency-domain and in the time-domain, and the flutter analysis is conducted under both uniform and turbulent flows. The effect of wind turbulence is directly modeled in time-domain to avoid the complicated random parametric excitation analysis of the equation of motion used in previous studies. It is found that turbulence has a stabilizing effect on bridge aerodynamic flutter. A probabilistic flutter analysis of long-span bridges involving random and uncertain variables is also conducted, which can provide more accurate and adequate information than the critical flutter velocity for wind resistance design of long-span bridges. For the buffeting analysis of long-span bridges, the stress-level buffeting analysis of the bridge under spatial distributed forces is conducted to investigate the effects of wind turbulence on the fatigue damage of long-span bridges. It is found that the increase of the turbulence intensity has a strengthening effect on the buffeting-induced fatigue damage of long-span bridges. For buffeting control, a lever-type TMD system is proposed for suppressing excessive buffeting responses of long-span bridges. The lever-type TMD with an adjustable frequency can overcome the drawback of excessive static stretch of the spring of traditional hanging-type TMD and be adaptive to the change of the environment and the structure itself. To effectively apply the lever-type TMD to future feedback control design, the control performance of the lever-type TMD for excessive buffeting responses of long-span bridges has been studied. The effects of wind velocity and attack angle and the stiffness reduction of bridge girder on the control efficiency have also been investigated to determine the adjustment strategy of the lever-type TMD. It is found that the control efficiency of the lever-type TMD varies greatly with the change of the location of the mass block. The lever-type TMD should be adjusted accordingly based on comprehensive consideration of the environment change and specific control objectives