- Dynamic properties of an eleven-span motorway bridge at different levels of excitation
- G-W Chen ; S. Beskhyroun ; P. Omenzetter
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Bridge management ; Bridges ; Structural dynamics
- Keywords: Bridges ; dynamic properties
- Description
- Bridge dynamic properties measured under a given vibration intensity condition would give a true picture of the behaviour for that particular condition. However, the use of the model derived from such data may not be reliable when applied
for the prediction of response under a different vibration intensity condition. Therefore, it is necessary to investigate the structural dynamic behaviour at different levels of excitation in detail. This paper focuses on the experimental investigation of modal property variability at different levels of excitation. Both weak ambient vibration tests
(induced by nearby traffic, wind and possibly microtremors) and forced vibration tests
with different applied input force induced by eccentric mass shakers were performed on
the Nelson St off-ramp bridge (an 11-span post-tensioned concrete, box girder structure forming a part of the motorway network in Auckland’s CBD). Three separate system identification methods, namely peak-picking (PP), the frequency domain decomposition (FDD) and the data-driven stochastic subspace identification (SSI) method, were applied
for accurate structural modal parameter identification. It was found that the three output
only identification techniques are able to extract natural frequencies of the structure reliably, while the time domain SSI method yields the best mode shape estimates and PP may not be able to give accurate mode shape estimates for some modes. The variability of the dynamic properties for the 1st vertical and lateral bending modes was examined. A
general trend of decreasing natural frequencies and increasing damping ratios was observed with increased level of vibration intensity.
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- Study on the fundamental period of vibration of steel moment resisting frames
- M.T. Naqash
- Book Title / Journal: International Journal of Advanced Structures and Geotechnical Engineering
- Year: 2014 , Volume: 3 , Series:
- Structural dynamics
- Keywords: Fundamental period ; Eurocode 8 ; Drift limitations ; Moment resisting frames
- Description
- This paper aims at addressing the variation of fundamental period when the ductility and the damageability criteria varies. In order to investigate the influence of drift limitation on the fundamental period of vibration a huge parametric study using modal dynamic analysis, composed of 144 designed cases of steel moment resisting frames has been conducted. These are compared with the code prescribed fundamental period. It is observed that as the drift limitation varies from the more relax to the most stringent the fundamental period decreases and therefore the stiffness of the frame increases. The obtained period from the code are in the same range to the one obtained from the modal analysis when the strict drift limit is employed in the design.
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- Lateral-force resisting mechanisms of flexure-dominant multi-story structural walls sustained on soft-first-story
- M. Sakashita ; Y. Idosako ; X. Feng ; M Nishiyama
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Structural dynamics ; Earthquake engineering
- Keywords: soft story ; lateral force
- Description
- This paper presents lateral-force resisting mechanisms of flexure-dominant multi-story structural walls on a soft-first-story. Two reinforced concrete specimens consisted of the 3-story-high structural wall on the soft-first-story were constructed in 1/3-scale and tested under cyclic loading simulating earthquake motions. The test variable was the longitudinal reinforcement ratio in the boundary beam of the 2nd floor, which was
1.19% or 2.56%. The structural walls yielded in flexure as intended, which, however, did not result in the concentration of deformation only on the 2nd story. The reason is that the boundary beam yielded in flexure and tension, and a yielding mechanism other than intended was formed. The difference in load capacity between the two specimens was not
of significance. The mechanism needed as large drift angle as approximately 2% to attain the design lateral load capacity. The beam-column joints on the 2nd floor failed, which resulted in an inability to sustain the axial load.
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- Dynamic characteristics of a bridge using ambient vibration measurements and finite element analysis
- H. Madokoro ; T. Nishida ; N. Shimoi ; C. Cuadra
- 2nd European Conference on Earthquake Engineering and Seismology, Istanbul, Turkey
- Book Title / Journal:
- Year: 2014 , Volume: , Series:
- Structural dynamics
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- Estimate of fundamental period of reinforced concrete buildings: code provisions vs. experimental measures in Victoria and Vancouver (BC, Canada)
- L. Chiauzzi ; A. Masi ; M. Mucciarelli ; J.F. Cassidy ; K. Kutyn ; J. Traber ; C. Ventura ; F. Yao
- Book Title / Journal: 15th World Conference on Earthquake Engineering
- Year: 2012 , Volume: , Series:
- Structural dynamics
- Keywords: Fundamental period ; reinforced concrete buildings ; ambient vibration ; Canadian buildings
- Description
- The fundamental period of a group of reinforced concrete (RC) buildings located in the cities of Victoria and Vancouver (British Columbia, Canada) has been estimated using ambient vibration data. As result a preliminary height- dependent relationship has been derived for a fully elastic condition. The regression returns very similar values respect to those obtained in other countries using the system identification technique based on ambient vibrations. As expected, the results show that building periods estimated based on simple equations provided by earthquake design codes in Europe (EC8) and North America (UBC97 and NBCC-2005) are significantly greater than the periods computed using ambient vibration records on the monitored buildings.
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- Case Studies of Damage to 19-storey irregular steel moment-frame buildings under near-source ground motion
- S. Krishnan
- Earthquake Engineering and Structural Dynamics. Vol. 36(7), July 2007. Wiley Interscience. John Wiley & Sons Ltd
- Book Title / Journal:
- Year: 2007 , Volume: , Series:
- Structural dynamics
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- The ensemble statistics of the response of structural components with uncertain properties
- A.W.M. Brown
- PhD Thesis, Engineering Department, Cambridge University
- Book Title / Journal:
- Year: 2003 , Volume: , Series:
- Structural dynamics
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- Damping Models for Structural Vibration
- A. Sondipon
- PhD Thesis, Engineering Department, Cambridge University
- Book Title / Journal:
- Year: 2000 , Volume: , Series:
- Structural dynamics
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- Prediction of Floor Vibration Response Using the Finite Element Method?.
- M. J. Sladki
- MSc Thesis, Virginia Polytechnic Institute and State University.
- Book Title / Journal:
- Year: 1999 , Volume: , Series:
- Structural dynamics
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- Vibration Criteria for Long-Span Floors?.
- D.E. Allen ; J. E. Rainer
- National Research Council of Canada, Reprinted from Canadian Journal of Civil Engineering, Vol.3, No.2, pages 165-173.
- Book Title / Journal:
- Year: 1976 , Volume: , Series:
- Structural dynamics
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