Reduction of bridge dynamic amplification through adjustment of vehicle suspension damping

Structure and Infrastructure Engineering

2014

Previous research on damage detection based on the response of a structure to a moving load has reported decay in accuracy with increasing load speed. Using a 3-D vehicle-bridge interaction model, this paper shows that the area under the filtered acceleration response of the bridge increases with increasing damage, even at highway load speeds. Once a datum reading is established, the area under subsequent readings can be monitored and compared to the base line reading, if an increase is observed it may indicate the presence of damage. The sensitivity of the proposed approach to road roughness and noise is tested in several damage scenarios.The possibility of identifying damage in the bridge, by analysing the acceleration response of the vehicle traversing it is also investigated. While vehicle acceleration is shown to be more sensitive to road roughness and noise and therefore less reliable than direct bridge measurements, damage is successfully identified in favourable scenarios.

Section: (Approx Location Figure 2) (Approx Location Table 2)mentioning

confidence: 99%

A bridge-monitoring tool based on bridge and vehicle accelerations

Hester

Structure and Infrastructure Engineering

2014

“…The vehicle represents a 2-axle rigid truck with four degrees of freedom: the pitch and vertical displacement of the sprung mass and the displacement of the two unsprung masses. The properties of suspensions and tyres are similar to those of a semi-tractor unit with twin wheels in the rear axle and are summarized in Table 33 2, [40,41] The performance of the method for damage detection will be affected negatively by high levels of noise or road roughness. If the latter excited the modes of vibration of the vehicle sufficiently, the spectrum of the beam accelerations will contain vehicle frequencies in addition to the dominant bridge frequency.…”

Section: Use Of the Beam Acceleration Due To A 2-axle Sprung Model Onmentioning

confidence: 99%

An investigation into the acceleration response of a damaged beam-type structure to a moving force

Journal of Sound and Vibration

Hester

2013

Self Cite

Publication information Journal of Sound and Vibration, 332 (13): 3201-3217Publisher Elsevier Item record/more information http://hdl.handle.net/10197/6212 Publisher's statementThis is the author's version of a work that was accepted for publication in Journal of Sound and Vibration. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Sound and Vibration (VOL 332, ISSUE 13, (2013) that did not appear in the healthy structure is present in the response of the damaged structure. This paper elucidates from first principles how the acceleration response can be assumed to consist of 'static' and 'dynamic' components, and where the beam has experienced a localised loss in stiffness, an additional 'damage' component. The combination of these components establishes how the damage singularity will appear in the total response.For a given damage severity, the amplitude of the 'damage' component will depend on how close the damage location is to the sensor, and its frequency content will increase with higher velocities of the moving force. The latter has implications for damage detection because if the frequency content of the 'damage' component includes bridge and/or vehicle frequencies, it becomes more difficult to identify damage. The paper illustrates how a thorough understanding of the relationship between the 'static' and 'damage' components contributes *Manuscript Click here to download Manuscript: Manuscript RevC.doc Click here to view linked References 2 to establish if damage has occurred and to provide an estimation of its location and severity.The findings are corroborated using accelerations from a planar finite element simulation model where the effects of force velocity and bridge span are examined.

“…A five-axle articulated vehicle is used with eight independent degrees of freedom: bouncing and pitching motion of the tractor centre of gravity, pitching motion of the semitrailer centre of gravity and vertical hop motions of each axle assembly, as described by Harris et al [12] The model incorporates road irregularities in the form of numerically generated road surface profiles. These 1-dimensional profiles are generated based on the International Standards Organisation's method of representing road surface roughness with a power spectral density function.…”

Section: Description Of the Modelmentioning

confidence: 99%

Characteristic dynamic traffic load effects in bridges

O’Brien

Rattigan

et al. 2009

Engineering Structures

When formulating an approach to assess bridge traffic loading with allowance for Vehicle-Bridge Interaction (VBI), a trade-off is necessary between the limited accuracy and computational demands of numerical models and the limited time periods for which experimental data is available. Numerical modelling can simulate sufficient numbers of loading scenarios to determine characteristic total load effects, including an allowance for VBI. However, simulating VBI for years of traffic is computationally expensive, often excessively so. Furthermore, there are a great many uncertainties associated with numerical models such as the road surface profile and the model parameter values (e.g., spring stiffnesses) for the heavy vehicle fleet. On site measurement of total load effect, including the influence of VBI, overcomes many of these uncertainties as measurements are the result of actual loading scenarios as they occur on the bridge. However, it is often impractical to monitor bridges for extended periods of time which raises questions about the accuracy of calculated characteristic load effects.Soft Load Testing, as opposed to Proof Load or Diagnostic Load Testing, is the direct measurement of load effect in bridges subject to random traffic. This paper considers the influence of measurement period on the accuracy of soft load testing predictions of characteristic load effects, including VBI, for bridges with two lanes of opposing traffic. It concludes that, even for relatively short time periods, the estimates are reasonably accurate and tend to be conservative. Provided the data is representative, Soft Load Testing is shown to be a useful tool for calculating characteristic total load effect.