•Target-tracking DIC seismic response monitoring from large-scale bridge shake table test.•Field monitoring and system identification of pedestrian bridge using target-tracking DIC.•3D DIC ...displacement measurements are verified against conventional instrumentation.•DIC-based system ID is verified for two bridges against results from accelerometers.
Our nation’s infrastructure is aging and deteriorating which increases the need for condition assessment and structural health monitoring. For this purpose, there is a growing interest in using non-contact monitoring methods because of the challenges associated with deploying and installing conventional instrumentation. Target-tracking digital image correlation (DIC) is among these methods and is the focus of this paper. Several research activities have been conducted at the University of Nevada, Reno in the field of dynamic monitoring using DIC and presented here. The first part of the paper is concerned with a large-scale laboratory application where target-tracking DIC was utilized to monitor the response of a bridge structure tested under bidirectional earthquake shaking. The 3D dynamic response of the bridge, along with modal properties, i.e. natural frequency, damping ratio, and mode shapes, were measured or determined using both DIC and conventional instrumentation then compared for validation purposes. The second part of the paper presents results from field monitoring of an actual footbridge under pedestrian loading to determine the vibration frequencies of the bridge, and again compare it against results from conventional accelerometers for validation. From both applications, the DIC is demonstrated to successfully capture (1) peak and residual bridge deck rotation and deformation under different earthquake intensity levels and (2) modal properties for system identification. Practical DIC sampling rates were used to accurately monitor and capture the dynamic response of bridges, which shows a high potential for using DIC for larger structural health monitoring applications and future reconnaissance works.
This study focuses on utilizing computer modeling and simulation techniques, specifically the ANSYS software, to analyze the dynamics of bridge structures. The primary objective was to study the ...vibrations of a riverbed metal bridge structure and determine their characteristics. The research involved theoretical dynamic calculations considering the design features of the bridge components and the materials used in their construction. The obtained results enabled the determination of resonance frequencies for the vibration modes. By utilizing the ANSYS software, a three-dimensional virtual model of the bridge structure was created, allowing for a detailed analysis of its dynamic behavior. The first three vibration modes of the riverbed metal bridge structure were calculated, and numerical results were obtained for six modes. The findings of this research have practical significance as they provide informed decision-making support during the construction, maintenance, and modernization of bridge structures. The study of bridge dynamics using advanced technologies contributes to enhancing the safety, reliability, and longevity of these vital infrastructure assets.
•Tuned inerter damper is proposed to control the vibrations of adjacent bridge structures.•The control effectiveness of the proposed damper is compared with the conventional viscous dampers.•Tuned ...inerter damper can achieve the same control effectiveness with smaller damping coefficient than viscous dampers.•Vibration characteristic differences between adjacent bridges influence the control effectiveness.•Increasing the absolute stiffness of a bridge improves the control efficiency.
This paper proposes using a tuned inerter damper (TID) system to mitigate the potential pounding and unseating damages between the adjacent bridge structures under severe earthquakes. The control effectiveness of the proposed method is investigated both in the frequency and time domains. For comparison, the models and responses of the adjacent bridge structures without control and controlled by the traditional viscous dampers that are modelled by a Kelvin system or a Maxwell system are also developed and calculated. The analytical results reveal that the TID system can achieve almost the same or even better control effectiveness compared to the conventional viscous dampers with a much smaller additional damping. The proposed method can provide a good alternative to control the excessive relative motions between the adjacent bridge structures.
•IMTR regularizes noisy influencelines for damage characterization in beams.•TR and IMTR compared and implementedon analytical and experimental data.•IMTR improves performance over TR in cases of ...deep, sharp damage.
Bridge structures decay throughout their lives even under nominal operating conditions. As bridge infrastructure ages and wears naturally or under extreme load, there is a need to monitor and evaluate bridge performance in an efficient way. This paper presents an impairment detection method that assesses the curvature of noisy static deformation influence lines to predict the location and severity of structural damage. In this method, a parametric approximation and two direct regularization methods i.e., Tikhonov Regularization (TR) and the proposed Iterative Multi-parameter Tikhonov Regularization (IMTR), are implemented to reduce the impact of measurement noise on flexural rigidity estimations. While the TR method assumes one regularization parameter for all unknowns of the optimization problem, the IMTR method has individual, iteratively optimized, regularization parameters for each unknown. To evaluate the performance of the presented method, four nominally identical beam structures with four different damage scenarios and multiple levels of measurement noise are studied. Combining the quadratic spline parametric approximation with either direct regularization method produces adequate curvature estimates that are subsequently used to predict the location and severity of damage. In cases of deep, sharp damage, the IMTR method improves the prediction performance by reducing percent error 4–32%, for noise levels ranging from 0% to 5%, when compared to prediction results from the conventional TR. Both regularization methods give comparable results for shallow, wide damage. A laboratory experiment is included that presents the FRE on a statically indeterminate system; both TR and IMTR provide reasonable estimations of the location and severity of damage.
Goals. To carry out experimental studies of enforcing the reinforced concrete bending elements with pre-stressed composite materials. Research Methods. Rectangular reinforced concrete elements ...enforced with polymer composite materials were used as laboratory samples, the measurement was carried out using strain gauges and analog indicators. Research results. A laboratory research program has been developed. The technology for enforcing the reinforced concrete samples by using pre-stressing of fibre-reinforced polymer has been developed. The results of experimental studies regarding the bearing capacity of laboratory reinforced concrete samples enforced with pre-stressed fibre-reinforced polymer are presented. The new enforcement technology was developed. It implies using a device patented by the authors, and the fundamentally new patterns for destruction of samples are presented. The impact of a various strip tension degree (12 kN compared with 6 kN) was analyzed, a difference of 31 % was determined for bearing capacity and 17% for the cracking resistance of reinforced concrete samples. Conclusions. The conducted analysis of the experimental study allows concluding that reinforcement with pre-stressed composite materials (bands) allows increasing the strength of the samples up to 70%, and also increases cracking resistance by 80 %.
Modelling of bridge structures is an important topic due to the increasing need to get accurate information in a visual way. Registration between as-built laser data and global design reference one ...is necessary to guarantee the validity and dependency of the proposed model. This research presents a new registration method based on artificial neural networks (ANN) methodology. A developed software is implemented to apply ANN and to achieve the research objective. A steel structure bridge is chosen for the application of the proposed system. A point cloud laser data (as built) of the bridge is registered to the design model. The results show that the developed registration method is potential and reliable due to the insignificance of the error between both as-built model and the design model. The assumed level of significance is 95% and the error between as-built model and the design model after the registration process is found to be less than 5%. So, one concludes that the developed method can be used as a registration method for the laser scanning bridge structures. Some recommendations are presented to the future study concerned with using deep learning (DL) to apply the registration process to get better results.
Although some studies have been conducted to simulate the dynamic response of bridge piers under barge impact, several essential modeling issues (e.g., reasonably exerting permanent loads and ...simplifying FE models) are not well examined. Hence, high-resolution FE models are meticulously developed in this paper to simulate barge collisions with a typical four-span continuous girder bridge. Numerical results highlight the importance of the gravity load for barge impact-induced responses. A simplified bridge model is proposed to improve computational efficiency. The proposed simplified method is found to be more accurate than that of the one-pier two-span (OPTS) model. Also, it is observed that although the peak impact force increases with impact energy, the impact-induced displacement does not always increase. It is attributed to the fact that the spectral characteristics of the impact force-time history have a significant influence on the impact-induced responses. To improve the impact resistance, three strengthening methods based on ultra-high-performance fiber-reinforced concrete (UHPFRC) are investigated and compared. It is found that strengthening columns with two-end UHPFRC jackets is superior to other strengthening methods when considering cost-benefit ratio. Finally, a multi-objective optimization design procedure is presented for the UHPFRC-strengthened columns.
•Reasonably including the influence of permanent loads is crucial to numerically evaluate barge-impact resistance of bridge piers.•The proposed simplified model retaining the whole girder exhibits better accuracy than the OPTS model.•The responses of bridge piers do not always increase with the impact energy due to the characteristics of barge impact loads.•The strengthened column with two-end UHPFRC jackets is more promising than the other strengthening schemes.•A multi-objective optimization design method is developed for UHPFRC-strengthened columns.
In many instances, the safety of existing structures can no longer be demonstrated by standard code-based assessments. Reasons for this include changes in the code, changes in the demands on the ...structures and deterioration. To address this problem, it is common practice to perform a more detailed assessment utilizing advanced models. In this way, many structures can be shown to comply with safety requirements, even if they cannot be verified by standard assessments. The standard code models are often conservatively biased. This leads to designs which include hidden safety. If the reassessment is performed with more advanced models in lieu of standard models, the hidden safety can vanish. Concurrently, the reduced uncertainty of advanced models may compensate this safety reduction. In this paper we investigate this issue on a hypothetical population of existing bridge structures under traffic. We consider that the standard code model is exchanged by an advanced traffic load simulation.
Traditional material for concrete reinforcement is steel. In recent times, non-metallic fibres have been intensively investigated and some of them used for construction of bridges. FRP composites are ...durable materials which are different from the steel reinforcement for their resistance to the electrochemical corrosion. With respect to steel, different mechanical behavior of non-metallic reinforcement, however, involves some drawbacks - namely the lack of thermal compatibility between concrete and FRP reinforcement. FRP composites belong among anisotropic materials. Their properties depend on the type, volume and alignment of the fibres, the matrix type, form and quality of the construction. The analysis of causes of failures on German bridges shows that reinforcement corrosion initiated by chlorides makes up 2/3 of all the failures recorded in the bridge construction. Corrosion of the reinforcement initiated by chlorides is the main cause of the loss of serviceability of bridge structures. In such an environment, fibre-reinforced polymer (FRP) reinforcement can fully replace the traditional steel reinforcement. The paper presents the mechanical properties and durability of different types of the FRP rebar's and their use in construction of bridges.
Recently, the authors explored the effectiveness of using an inerter-based device to mitigate pounding induced damage between two adjacent bridge structures, and the advantages of this system were ...illustrated by comparing its performances with the conventional viscous dampers. However, the seismic excitations at the supports of the adjacent bridge structures were assumed to be the same in that study, i.e. only uniform ground motion was considered. In reality, ground motions at different locations of a structure are inevitably different, and spatially varying ground motions (SVGMs) can influence the structural seismic responses significantly. Extensive research works have been carried out to investigate the influence of SVGMs on the seismic responses of engineering structures. However, no open literature reported the results when an inerter-based device is involved. In this study, the motion equations of two adjacent bridges coupled by a tuned inerter damper (TID) are firstly derived, and the seismic responses of the adjacent bridges with and without control are calculated. In particular, the parameters that significantly influence SVGMs, i.e. wave passage effect and coherency loss effect, are discussed.
•Equations for adjacent bridges coupled by a TID subjected to SVGMs are derived.•The influences of the key parameters of SVGMs are systematically discussed.•TID decreases the sensitivity of relative displacement to the frequency ratio of adjacent structures.
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