Experimental and analytical vibration serviceability assessment of an in-service footbridge

Gheitasi, Amir; Ozbulut, Osman E.; Usmani, S.A.; Alipour, Mohamad; Harris, Devin K.

doi:10.1016/j.csndt.2016.11.001

Cited by 36 publications

(28 citation statements)

References 7 publications

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“…For this reason, several existing guideline documents for the comfort verification of human induced vibrations are based on a double evaluation check. The first one is related to the fundamental frequency of the system object of analysis (see for example [51]). For pedestrian systems with frequency in potential risk of resonance, detailed vibration analyses are commonly required, and these can take the form of refined Finite Element models or simple SDOF calculations.…”

Section: Human Comfort and Vibration Serviceability Assessment Based mentioning

confidence: 99%

“…The potential of the technical documents recalled in this paper, see [21][22][23][24], is to offer practical methodologies for pedestrian systems, based on design charts or SDOF calculation approaches for equivalent, single occupant scenarios. However, according to the literature ( [51][52][53][54][55], etc. ), the possible limitations of these methods still require investigations.…”

Section: Human Comfort and Vibration Serviceability Assessment Based mentioning

confidence: 99%

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Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Bedon

Fasan

2019

Applied Sciences

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The vibration performance of pedestrian structures attracts the attention of several studies, especially with respect to unfavorable operational conditions or possible damage scenarios. Given a pedestrian system, specific vibration comfort levels must be satisfied in addition to basic safety requirements, depending on the class of use, the structural typology and the materials. To this aim, guideline documents of the literature offer simplified single-degree-of-freedom (SDOF) approaches to estimate the maximum expected vibrations and to verify the required comfort limits. Most of these documents, however, are specifically calibrated for specific scenarios/structural typologies. Dedicated methods of design and analysis, in this regard, may be required for structural glass pedestrian systems, due to their intrinsic features (small thickness-to-size ratios, high flexibility, type and number of supports, live-to-dead load ratios, use of materials that are susceptible to mechanical degradation with time/temperature/humidity, etc.). Careful consideration could be then needed not only at the design stage, but also during the service life of a given glass walkway. In this paper, the dynamic performance of an in-service glass walkway is taken into account and explored via field vibration experiments. A set of walking configurations of technical interest is considered, involving 20 volunteers and several movement features. The vibration comfort of the structure is then assessed based on experimental estimates and existing guideline documents. The intrinsic uncertainties and limits of simplified approaches of literature are discussed, with respect to the performance of the examined glass walkway. In conclusion, the test predictions are also used to derive “perception index” data and scales that could support a reliable vibration comfort assessment of in-service pedestrian glass structures.

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Section: Human Comfort and Vibration Serviceability Assessment Based mentioning

confidence: 99%

Section: Human Comfort and Vibration Serviceability Assessment Based mentioning

confidence: 99%

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Bedon

Fasan

2019

Applied Sciences

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“…However, this technique requires a suitable number of accelerometers as well as the application of effective ways to interpret collected data. In paper [28], the authors delivered an analysis of the vibration serviceability of an in-service footbridge. Firstly, ambient vibration tests were conducted.…”

Section: Related Workmentioning

confidence: 99%

“…On the basis of registered data, an operational modal analysis was prepared. The footbridge dynamic response under pedestrian excitation was then completed since the comfort criteria assessment was the main purpose of the research [28].…”

Section: Related Workmentioning

confidence: 99%

“…Taking into consideration the primary function of the pedestrian bridges, the risk of the resonance phenomenon occurring has to be discussed for this type of structure [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In general, the estimation of the modal properties of footbridges is the main component of the general dynamic evaluation of these structures [25][26][27][28]. It must be pointed out that this part of the dynamic investigation has significant value for the design stage of construction as well as being required prior to approval of the structure for public usage, i.e., proof load testing (conduct in order to validate that a structure can carry the design loads) and acceptance tests (conducted before a bridge structure is accepted for exploitation).…”

Section: Introductionmentioning

confidence: 99%

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Full-Scale Experimental and Numerical Investigations on the Modal Parameters of a Single-Span Steel-Frame Footbridge

Drygala

Dulińska

2019

Symmetry

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In this work, an examination on the modal properties of a single-span steel-frame footbridge is presented. The footbridge is situated in Jawornik (Lesser Poland). The footbridge is symmetrical since its main structure consists of two steel frames of the same shape. The boundary conditions for both frames are the same as well. The study was completed on the basis of numerical as well as experimental investigations. For finite element (FE) analysis, a 3-D model of the single-span steel-frame footbridge was created. For the experimental study, a research scheme for in situ tests was developed. Three kinds of excitation techniques were used during the in situ tests: shock excitation, operational vibration, and slow sine sweep testing. Different functions that estimate natural frequencies, i.e., the power spectral density function (PSD) and the frequency response function (FRF), were applied. The modal assurance criterion (MAC) was used as a mathematical tool for the verification of the mode shapes of natural vibrations obtained in experimental and numerical ways. Good compatibility was recognized between the results obtained for experimental and numerical procedures in terms of both the natural frequency and the mode of vibration. The identified and verified values of the five consecutive natural frequencies of the footbridge were smaller than 5 Hz, but they were recognized as being located outside the frequency range defined as having “maximum risk of resonance". The numerical and experimental modal analysis revealed that all modes corresponding to the natural frequencies from the 0–5 Hz range have both a symmetrical and an anti-symmetrical nature. In particular, the first vertical mode, which can play a central role from the serviceability of the footbridge point of view has a symmetrical shape. The results of the research might be applicable to the dynamic study of the structure type considered in the analysis, i.e., for the dynamic assessment of a single-span steel-frame footbridge with a relatively large mass as well as stiffness. The investigation proved that ambient vibration modal experiments are enough for the experimental investigation of the modal properties of the structure.

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Optimal design of the ideal grounded tuned mass damper inerter for comfort performances improvement in footbridges with practical implementation considerations

Angelis

Petrini

Pietrosanti

2021

Structural Contr & Hlth

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Summary The paper focuses on the optimal design of the grounded tuned mass damper inerter (TMDI) in footbridges and on some practical implementation issues. An optimal design procedure is implemented for the perfectly grounded ideal TMDI (infinite stiffness of the connection at the ground plus linear and nondissipative inerter). The procedure is based on reduced‐order models of the footbridge by assuming the frequency ratio and damping factor as design parameters, for a given number of values of the TMDI the inertance and mass ratios aiming at minimizing the maximum acceleration response of the system for users' comfort improvement under performance criteria defined in Human‐induced Vibration of Steel Structures (HiVoSS) guidelines. The procedure is applied to an existing footbridge suffering excessive human‐induced vibrations. After the optimal design of the TMDI has been found, its performances are assessed by the avail of a fully 3D finite element model of the case‐study footbridge, which has been calibrated toward an in situ experimental identification campaign. Alternative proposals for practical implementation of the control system are analyzed. Finally, a performance sensitivity analysis is carried out regarding the deviations from the initial assumption of perfectly grounded TMDI system, by varying the stiffness of the connection at the ground of the ideal inerter. Results show that the proposed procedure makes the TMDI a very efficient control system for footbridges and that changes of the stiffness of the grounded connection drop the beneficial effect of the TMDI, also if consequences of such errors are less than the ones occurring in classical TMDs for detuning or malfunctioning.

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Experimental and analytical vibration serviceability assessment of an in-service footbridge

Cited by 36 publications

References 7 publications

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Full-Scale Experimental and Numerical Investigations on the Modal Parameters of a Single-Span Steel-Frame Footbridge

Optimal design of the ideal grounded tuned mass damper inerter for comfort performances improvement in footbridges with practical implementation considerations

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