Vibration of PC Bridge during Failure Process

Kato, M.; Shimada, Shizuo

doi:10.1061/(asce)0733-9445(1986)112:7(1692)

Cited by 71 publications

(26 citation statements)

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“…It must be noted that during test 34 a lower sweep rate was used with respect to the other linear sweeps hence a respectively lower value of frequency was estimated. The scarce influence of N on the modal frequencies in the cables is consistent with the findings of several experimental tests carried out on prestressed beams [1], [5], [10] and can be explained considering a very simple mechanical model of a supported beam of mass per unit length m, length L, subjected to a prestress force N. The n-th natural frequency of vibration is given by [11]: On the contrary, the values of the center-span deflection measured during this phase (T37, T45, T53 in Table 3) decrease linearly with the prestress force N, fitting very well the values given by the simple model of a beam on fix end supports under the dead load q and the tension N in the cables. It must be noted that the deflections during the tests were measured assuming as a reference configuration the one under the dead load q and the initial value of the prestress (N o =232kN): the center span deflection d max reported in Figure 4 is thus the decrease of the deflection due to the reduction of the prestress load, with respect to the reference value at mid span:…”

Section: Phase 1 Detensioning Of Bottom Cablessupporting

confidence: 89%

“…Access to strand anchorage and retensioning of strands is often difficult or even impossible hence the assessment of the structural performance is often carried out basing on indirect features recovered from vibrational response. Several studies focused on the use of dynamic parameters for damage identification in prestressed reinforced concrete beams have been presented in literature [1]- [7]. All the investigations show that the cracking of the concrete section leads to a global reduction of stiffness and to a local increase of curvature that can be reliably detected basing on the structural response to vibrations (provided the fault induces measurable variations of these features).…”

Section: Introductionmentioning

confidence: 99%

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Static and dynamic testing of a damaged post tensioned concrete beam

Limongelli

Siegert

Merliot

et al. 2015

MATEC Web of Conferences

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Abstract. In this paper are reported the results of an experimental campaign carried out on a post tensioned concrete beam with the aim of investigating the possibility to detect early warning signs of deterioration basing on static and/or dynamic tests. The beam was tested in several configurations aimed to reproduce several different phases of the 'life' of the beam: the original undamaged state, increasing loss of tension in the post tensioning cables, a strengthening intervention carried out by means of a second tension cable, formation of further cracks on the strengthened beam. Responses of the beam were measured by an extensive set of instruments consisting of accelerometers, inclinometers, displacement transducers, strain gauges and optical fibres. The paper discusses the tests program and the dynamic characterization of the beam in the different damage scenarios. The modal properties of the beam in the different phases were recovered basing on the responses recorded on the beam during sine-sweep and impact hammer tests. The variation of the first modal frequency was studied to investigate the sensitivity of this parameter to both the cracking of the concrete section and the tension in the cables and also to compare results given by different types of experimental tests

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Section: Phase 1 Detensioning Of Bottom Cablessupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Static and dynamic testing of a damaged post tensioned concrete beam

Limongelli

Siegert

Merliot

et al. 2015

MATEC Web of Conferences

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“…For these tests sinusoidal excitation was applied with an electro-hydraulic actuator. Kato and Shimada (1986) performed ambient vibration measurements on an existing prestressed concrete bridge during a test to failure. A reduction in natural frequencies could be detected as a statically applied load approached the ultimate load.…”

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confidence: 99%

Damage detection algorithms applied to experimental modal data from the I-40 Bridge

Farrar¹,

Jauregui²

1996

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Because the 1-40 Bridges over the Rio Grande were to be razed during the summer of 1993, the investigators were able to introduce damage into the structure in order to test various damage identification methods. To support this research effort, NMSU contracted Los Alamos National Laboratory (LANL) to perform experimental modal analyses, and to develop experimentally verified numerical models of the bridge. Previous reports (LA-12767-MS and LA-12979-MS) summarize the results of the experimental modal analyses and the results obtained from numerical modal analyses conducted with finite element models. This report summarizes the application of five damage identification algorithms reported in the technical literature to the previously reported experimental and numerical modal data.Damage or fault detection, as determined by changes in the dynamic properties or response of structures, is a subject which has received considerable attention in the technical literature beginning approximately 30 years ago, and with a significant increase in reported studies appearing during the last five years. The basic idea is that modal parameters, notably frequencies, mode shapes, and modal damping, are a function of the physical properties of the structure (mass, damping, stiffness, and boundary conditions). Therefore, changes in physical properties of the structure, such as its stiffness or flexibility, will cause changes in the modal properties. Early methods for detecting damage based on changes in the structure's dynamic properties primarily examined changes in the resonant frequencies. However, this parameter has proved to be insensitive to lower levels of damage and does not provide a means to locate the damage. Current methods that have shown promise in both detecting damage at an early stage and locating the damage examine changes in the mode shapes of the structure.The major contribution of this study is a direct comparison of five damage identification methods that were applied to the same experimental and numerical modal data. The experimental data were measured on an actual highway bridge. The numerical data was generated from finite element models of the same bridge that had been benchmarked against the measured response. With the numerical models many more damage scenarios could be investigated to further study the relative accuracy of the various damage identification methods. In all cases, the numerical studies were intended to simulate the measurement techniques that would be used if these methods were to be incorporated into an on-line monitoring system for highway bridges. This restriction implies that dynamic properties must be measured from ambient traffic-induced vibration sources.

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“…the 1980s initiated the investigation of metal and composite beams [14][15][16][17], bridges [18][19][20], the space shuttle [21][22][23], and nuclear plants [24]. Additional damage detection research originating in the late 1980s and the 1990s involved trusses [25][26][27], plates [28][29][30][31][32], buildings [33,34], concrete beams [35,36], shells and frames [37][38][39], horizontal axis wind turbine blades [40], and aircraft structures [41].…”

Section: Historical Perspectivementioning

confidence: 99%

Design and Analysis of Advanced Materials in a Thermal/Acoustic Environment. Delivery Order 0007: Volume 1 - Structural Health Monitoring

Grandhi¹,

Tobe²

2010

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Department of Defense, Washington Headquarters Services, Directorate for Information , 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YY) REPORT TYPE 3. DATES COVERED (From -To)March 2010 0A PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBERWright State University Department of Mechanical and Materials Engineering Dayton, OH 45435 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)Air Force Research Laboratory SPONSORING/MONITORING AGENCY ACRONYM(S)Air ABSTRACTAir vehicles flying at hypersonic speeds encounter extreme thermal, aerodynamic and acoustic loads, utilizing thermal protection systems to shield the main structure from these 1oads.One type of failure in a mechanically attached thermal protection system is fastener failure. Determining structural health monitoring on the fastener health of the thermal protection system is needed and can be completed by analyzing changes in the dynamic characteristics of the system due to fastener failure. The damage detection metrics include the existing modal parameters-modal assurance criterion (MAC), partial (PMAC), and coordinate (CMAC)-as well as two new modal parameters-normalized coordinate MAC and normalized coordinate MAC X summation were investigated. Two new modal parameters were formulated to identify mode shape changes in a structure due to global damage to the structure. Two damage states caused a minimal change to the low-frequency structural dynamics and could not be localized with any of the investigated damage metrics. After the finite element model is validated for the healthy state with free-free boundary conditions, the global boundary conditions and fastener failure damage states are implemented. This damage simulation allows a better understanding of how the damage states cause low-frequency dynamic changes without requiring a experimental data for each of the damage states of interest. SUBJECT TERMSThe damage detection metrics include the existing modal parameters-modal assurance criterion, partial modal assurance criterion, and coordinate modal assurance criterion-as well as two new modal parameters-normalized coordinate modal assurance criterion and normalized coordinate modal assurance criterion summation. The existing modal parameters provide data...

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Vibration of PC Bridge during Failure Process

Cited by 71 publications

References 0 publications

Static and dynamic testing of a damaged post tensioned concrete beam

Static and dynamic testing of a damaged post tensioned concrete beam

Damage detection algorithms applied to experimental modal data from the I-40 Bridge

Design and Analysis of Advanced Materials in a Thermal/Acoustic Environment. Delivery Order 0007: Volume 1 - Structural Health Monitoring

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