Bridge Structures最新文献_第8页

Multi-sensor measurement of dynamic deflections and structural health monitoring of flexible and stiff bridges 柔性和刚性桥梁动挠度多传感器测量及结构健康监测

IF 0.6

Bridge Structures Pub Date : 2019-01-01 DOI: 10.3233/BRS-190152

S. Stiros, P. Psimoulis, F. Moschas, V. Saltogianni, E. Tsantopoulos, P. Triantafyllidis

{"title":"Multi-sensor measurement of dynamic deflections and structural health monitoring of flexible and stiff bridges","authors":"S. Stiros, P. Psimoulis, F. Moschas, V. Saltogianni, E. Tsantopoulos, P. Triantafyllidis","doi":"10.3233/BRS-190152","DOIUrl":"https://doi.org/10.3233/BRS-190152","url":null,"abstract":"We investigated the response of bridges of different types to controlled and to wind and traffic-induced excitations; the emphasis was on deflections, derived from recordings of geodetic sensors and accelerometers (output-only analysis). Our focus was to push the limits of the existing experimental techniques, in order to cover not only flexible, but also stiff structures, and to present independently validated results. Our study focused on a 700m long, thindeck cable-stayed bridge, a stiff steel pedestrian bridge, a historic composite (masonry/steel) train bridge and a 30m long, gradually decaying, currently swaying pedestrian timber bridge. Our basic strategy was first to develop data measurement and processing techniques using controlled (supervised learning) experiments, and then, (1) use collocated, redundant and distributed geodetic sensors (GPS/GNSS and Robotic Total Stations, RTS), as well as accelerometers, in order to record bridge excitations, especially controlled excitations leading to free attenuating oscillations; (2) develop techniques to denoise recordings of various sensors based on structural/logical constraints and sensor fusion, compensating for the weaknesses inherent in each type of sensor), validate results and avoid pitfalls; (3) monitor the episodic and gradual decay of a pedestrian bridge, through repeated surveys under similar loading and environmental conditions and using similar instrumentation. The output of our studies is to confirm the potential of modern sensors to measure, under certain conditions, reliable mm-level dynamic deflections even of stiff structures (3-6Hz dominant frequencies) and to provide firm constraints for structural analysis, including evidence for changes of first modal frequencies produced by structural decay, even to identify dynamic effects such as foundations response to dynamic loading. The first is the problem of metrology, corresponding to questions of the type: what is the range of displacements of a bridge that can be measured by geodetic sensors, whether an apparently “good” measurement of dynamic displacement is reliable, and under which conditions and with which techniques it is possible to measure dynamic deflections of a stiff or a flexible bridge using instantaneous GPS positioning which is contaminated by long-period noise (see Figure 1). The second is the problem of structural significance of measurement-derived displacements. A common question arising is whether and under which conditions analysis of deflection measurements can lead to estimates of natural frequencies of a structure. In this article we review unpublished and previously presented results and ideas from monitoring deflections of several bridges of different types in Greece, both long-period and stiff structures (roughly, modal frequencies below or above 1Hz), using a specific methodology which was developed, and summarize some conclusions of broader importance for the response of bridges to various excitations","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BRS-190152","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69852598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}