A Wireless Sensor Network (WSN) for Structural Health Monitoring (SHM) is designed, implemented, deployed and tested on the 4200 ft long main span and the south tower of the Golden Gate Bridge (GGB). Ambient structural vibrations are reliably measured at a low cost and without interfering with the operation of the bridge. Requirements that SHM imposes on WSN are identified and new solutions to meet these requirements are proposed and implemented. In the GGB deployment, 64 nodes are distributed over the main span and the tower, collecting ambient vibrations synchronously at 1 kHz rate, with less than 10 mus jitter, and with an accuracy of 30 muG. The sampled data is collected reliably over a 46-hop network, with a bandwidth of 441 B/s at the 46th hop. The collected data agrees with theoretical models and previous studies of the bridge. The deployment is the largest WSN for SHM.

http://glaser.berkeley.edu/glaserdrupal/pdf/EECS-2006-121.pdf

Health monitoring of civil infrastructures using wireless sensor networks

Structural health monitoring (SHM) is a term increasingly used in the last decade to describe a range of systems implemented on full-scale civil infrastructures and whose purposes are to assist and inform operators about continued 'fitness for purpose' of structures under gradual or sudden changes to their state, to learn about either or both of the load and response mechanisms. Arguably, various forms of SHM have been employed in civil infrastructure for at least half a century, but it is only in the last decade or two that computer-based systems are being designed for the purpose of assisting owners/operators of ageing infrastructure with timely information for their continued safe and economic operation. This paper describes the motivations for and recent history of SHM applications to various forms of civil infrastructure and provides case studies on specific types of structure. It ends with a discussion of the present state-of-the-art and future developments in terms of instrumentation, data acquisition, communication systems and data mining and presentation procedures for diagnosis of infrastructural 'health'.

/pdf/structural-health-monitoring-of-civil-infrastructure-3bh4epxsu5.pdf

Structural health monitoring of civil infrastructure

This paper surveys an area of nonlinear functional analysis and its applications. The main application is to the existence and multiplicity of periodic solutions of a possible mathematical models of nonlinearly supported bending beams, and their possible application to nonlinear behavior as observed in large-amplitude flexings in suspension bridges. A second area, periodic flexings in a floating beam, also nonlinearly supported, is covered at the end of the paper.

Large-amplitude periodic oscillations in suspension bridges: some new connections with nonlinear analysis

An overview of modeling and experiments of vortex-induced vibration of circular cylinders

Vibration serviceability of footbridges under human-induced excitation : a literature review

This book provides detailed information on the design of wind resistant structures. It includes material on building code provisions for wind loads on low rise buildings. It provides engineers with up-to-date methods and standards for the construction of wind-resistant structures and reflects the increased use of instrumentation and computers to predict structural loading and the creation of more stringent building codes.

Wind effects on structures : fundamentals and applications to design

The writers compare the flutter phenomena of the suspension bridge and the airfoil and employ a free-oscillation experimental method to measure model bridge flutter coefficients analogous to airfoil flutter coefficients. They employ the airfoil as a check on the experimental method, both as a theoretical backdrop and to test out the nature of aerodynamic oscillatory forces under exponentially modified motion. A short catalogue of bridge deck flutter coefficients is then experimentally obtained and presented covering a range of bridge deck forms. Detailed results are described to account for a number of phenomena observed in the wind tunnel and in the field.

Airfoil and Bridge Deck Flutter Derivatives

The action of flexible bridges under wind, I: Flutter theory†

Analytical determination of the flutter and buffeting responses of long-span suspended bridges to wind excitation has predominantly been accomplished by single-mode-based methods. Proclivity towards design and construction of even longer span bridges has elevated the possibility of aerodynamic coupling of the flexural and torsional modes of vibration. A comprehensive, frequency-domain procedure developed to capture this multimode aeroelastic and aerodynamic response is presented in this paper. This new procedure is applied to evaluate the coupled response of a cable-stayed bridge. A quantitative assessment of the modal interactions at flutter and in the buffeting response is made to highlight the presence and effects of modal coupling. The multimode responses are then compared to single-mode and pseudomultimode results. As an extreme example, the bridge deck flutter derivatives were replaced with those of an airfoil to further investigate the ability of this approach to capture aeroelastic and aerodynamic coupling.

Robert H. Scanlan

Papers

Wind effects on structures : fundamentals and applications to design

Airfoil and Bridge Deck Flutter Derivatives

The action of flexible bridges under wind, I: Flutter theory†

Coupled flutter and buffeting analysis of long-span bridges

The action of flexible bridges under wind, II: Buffeting theory