Ambient vibration tests on long span suspension bridges

Littler, J.D.

doi:10.1016/0167-6105(92)90144-y

Cited by 10 publications

(6 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Variations of effective damping ratios and natural frequencies with wind speed were found and some indications of aeroelastic modal coupling were identified on the partially constructed bridge (Macdonald & Daniell 2005). In other full-scale studies, Littler (1992) and Brownjohn (1994) on the Humber Bridge, Bietry et al (1994) on the Saint-Nazaire Bridge, Ge and Tanaka (2002) on the Höga Kusten Bridge during construction and Jensen et al (1999) on the Great Belt Bridge, Nagayama et al on the Hakucho Bridge all found some trends of effective aerodynamic damping with wind speed, but coupling between modes and flutter derivatives were not identified.…”

Section: Introductionmentioning

confidence: 85%

Identification of flutter derivatives from full-scale ambient vibration measurements of the Clifton Suspension Bridge

Nikitas¹,

Macdonald²,

Jakobsen³

2011

Wind and Structures An International Journal

View full text Add to dashboard Cite

Abstract. The estimated response of large-scale engineering structures to severe wind loads is prone to modelling uncertainties that can only ultimately be assessed by full-scale testing. To this end ambient vibration data from full-scale monitoring of the historic Clifton Suspension Bridge has been analysed using a combination of a frequency domain system identification method and a more elaborate stochastic identification technique. There is evidence of incipient coupling action between the first vertical and torsional modes in strong winds, providing unique full-scale data and making this an interesting case study. Flutter derivative estimation, which has rarely previously been attempted on full-scale data, was performed to provide deeper insight into the bridge aerodynamic behaviour, identifying trends towards flutter at higher wind speeds. It is shown that, as for other early suspension bridges with bluff crosssections, single-degree-of-freedom flutter could potentially occur at wind speeds somewhat below requirements for modern designs. The analysis also demonstrates the viability of system identification techniques for extracting valuable results from full-scale data.

show abstract

Section: Introductionmentioning

confidence: 85%

Identification of flutter derivatives from full-scale ambient vibration measurements of the Clifton Suspension Bridge

Nikitas¹,

Macdonald²,

Jakobsen³

2011

Wind and Structures An International Journal

View full text Add to dashboard Cite

show abstract

“…In the 1985 study values were estimated by curve fitting to auto spectra and it was demonstrated that using longer records (with assumed stationarity) and hence finer frequency spacing led to convergence at more realistic damping values, with the study by BRE (Littler, 1992) producing estimates as low as 1% for the fundamental vertical mode, although the more achievable lower bound is 2%, confirmed by applying both NExT/ERA and SSI-COV to a complete, but not too windy, day of deck vertical response.…”

Section: Dampingmentioning

confidence: 99%

“…A parallel investigation (in 1985) was carried out by a team from the Building Research Establishment (BRE) (Littler, 1992), who revisited the bridge in 1988. BRE's 1985 test generated six continuous analog recordings of up to 13 hours, while in 1988 a digital tape recorder was left running for eight days, along with an anemometer.…”

Section: The Humber Bridge and Previous Testingmentioning

confidence: 99%

Ambient vibration re-testing and operational modal analysis of the Humber Bridge

Brownjohn

Magalhães

Cunha

2010

Engineering Structures

281

108

View full text Add to dashboard Cite

An ambient vibration survey of the Humber Bridge was carried out in July 2008 by a combined team from the UK, Portugal and Hong Kong. The exercise had several purposes that included the evaluation of current technology for instrumentation and system identification and the generation of an experimental data set of modal properties to be used for validation and updating of finite element models for scenario simulation and structural health monitoring. The exercise was conducted as part of a project aimed at developing online diagnosis capabilities for three landmark European suspension bridges.Ten stand-alone triaxial acceleration recorders were deployed at locations along all three spans and in all four pylons during five days of consecutive one-hour recordings. Time series segments from the recorders were merged, and several operational modal analysis techniques were used to analyse these data and assemble modal models representing the global behavior of the bridge in all three dimensions for all components of the structure.The paper describes the equipment and procedures used for the exercise, compares the operational modal analysis (OMA) technology used for system identification and presents modal parameters for key vibration modes of the complete structure. suspension bridge operational modal analysis structural identification 4

show abstract

“…The frequency variation/duality for mode LS1 was previously observed in 1988 by Building Reseach Establishment (Littler 1992). It is believed that the damping and frequency trends are consistent with high friction at the bearings that inhibit the differential bearing movement that is linked to lateral deformation of the deck shown in Figure 17.…”

Section: Bearing Influence On Dynamic Performancementioning

confidence: 62%