Reinforced Concrete Box Girder Bridges Research Articles

Fatigue assessment of bridges using interacting filtering approach with sub-structured predictor model based on current health

Fatigue estimation for critical structures necessitates comprehensive monitoring, which, in turn, requires dense instrumentation and models that heavily rely on computational resource models that heavily rely on computational resources. However, the fatigue vulnerability of different segments within the infrastructure can be considered to adopt a cost-effective substructure-based monitoring approach, minimizing the need for extensive instrumentation or complex models. However, estimating or instrumenting the substructure boundary adds to the complexity. In addition, conventional fatigue estimation approaches often assume constant structural health, disregarding the unknown current health status of aging structures. To overcome this limitation, a novel substructure-based fatigue life estimation approach is developed, incorporating an interacting ensemble-particle filter that considers the current health status while remaining robust against boundary forces. Numerical experiments validate the proposed approach on a simulated reinforced concrete box girder bridge, utilizing a 3D beam model that accounts for dynamic interaction with vehicles. A parametric analysis investigates the relationships between fatigue damage and factors such as surface roughness, vehicle speed, vehicle weight, and vehicle category, aiming to identify dominant stimuli. The results demonstrate an accurate estimation of health parameters and remaining useful life (RUL). Furthermore, a novel decomposed approach for RUL estimation is developed, enabling the mapping of traffic information to fatigue damage without requiring costly simulations. A case study highlights the practical applicability of the approach, focusing on a reinforced concrete box girder bridge in Himachal Pradesh, India.

UAV photogrammetry and laser scanning of bridges: a new methodology and its application to a case study

The state of preservation of infrastructures, such as bridges and viaducts, plays a crucial role in the economic development of a country. To this aim, a multi-level knowledge-based approach providing guidance on several aspects included in the management of large bridge inventories is utterly needed. In particular, the knowledge of bridge geometry, construction details, and structural defectiveness is of pivotal importance. Accordingly, methodologies to achieve the systematic collection of this information should be investigated and tested in practical applications. This paper presents a new methodology for surveying reinforced concrete box girder bridges using UAV photogrammetry and laser scanning. The proposed methodology is based on the adoption of predefined trajectories to accelerate surveying procedures and achieve high-quality results. The use of UAV photogrammetry allows for capturing high-resolution images of the entire structure, structural flaws included, while laser scanning provides measurements of geometric details. By integrating the data acquired, an accurate 3D digital twin of the bridge can be obtained, and its structural defects can be assessed. A comparison between the employed technologies is also proposed. Although UAV photogrammetry is slightly less precise than laser scanning in detecting geometries and construction details, it offers a more cost-effective and faster alternative to traditional laser scanning, primarily due to its accessibility in the field, without compromising the quality and reliability of the collected data. The proposed methodology has been applied on a case study reinforced concrete box girder bridge located in central Italy. The obtained results highlight the effectiveness of the proposed approach for the systematic collection of essential data for the knowledge of the assets and suggest that UAV photogrammetry can almost replace traditional laser scanning of bridges within the structural risk assessment process.

Time-Dependent Reliability Analysis for Deflection of a Reinforced Concrete Box Girder Bridge

Prior to casting of concrete, proper supervision and attention to camber provision in bridge construction are required. It is also critical to use an appropriate quality control manual, pay due attention to reinforcement bar placement, and have a high level of formwork design before construction begins. If these issues are not properly addressed, performance of structures will be affected. In this research, performance of a 40.5m box-girder reinforced concrete bridge which was constructed without having proper camber is studied. As camber was the most important issue of the bridge under investigation, the impact on strength and serviceability requirements is compared to the standard. A dynamic load test with an Arduino type accelerometer is performed to assess the bridge's current condition in relation to the serviceability limit requirement. The deterioration of reinforced concrete (RC) sections due to reinforcement corrosion, creep, and an increase in load intensity, as well as the corresponding statistical distributions are considered to estimate the long-term effect of bridge deflection. The time-variant analysis results show that a linear decrease in deflection reliability indices with the bridge's expected service life of 58 years and strengthening it increased to 85 years.

Widening method for prestressed box concrete segmental bridges in Vietnam

This paper discusses how a two-lane prestressed box concrete bridge can be designed and constructed so that it can be widened easily into a three- or four-lane bridge in the future. The methods presented are the strutted box widening method (SBWM), which applies to concrete box girder bridges, and the strutted girder widening method (SGWM), which applies to precast concrete girder bridges. The finite element method (FEA) was used in this study to perform the tensile stress and deflection state of the girder in two cases non, and the use of SBWM with 03 different distances of strut: 2m, 3m, and 4m, respectively. The results showed that the SBWM with 4m of strut decreased by 2,9 times in the transverse tensile stress; the deflection is reduced by 2,98 times. This study contributes to the widening method of the reinforced concrete box girder bridge in the future.

Computation of design forces and deflection in skew-curved box-girder bridges

The analysis of simply supported single-cell skew-curved reinforced concrete (RC) box-girder bridges is carried out using a finite element based CsiBridge software. The behaviour of skew-curved box-girder bridges can not be anticipated simply by superimposing the individual effects of skewness and curvature, so it becomes important to examine the behaviour of such bridges considering the combined effects of skewness and curvature. A comprehensive parametric study is performed wherein the combined influence of the skew and curve angles is considered to determine the maximum bending moment, maximum shear force, maximum torsional moment and maximum vertical deflection of the bridge girders. The skew angle is varied from 0o to 60o at an interval of 10o, and the curve angle is varied from 0o to 60o at an interval of 12o. The scantly available literature on such bridges focuses mainly on the analysis of skew-curved bridges under dead and point loads. But, the effects of actual loadings may be different, thus, it is considered in the present study. It is found that the performance of these bridges having more curvature can be improved by introducing the skewness. Finally, several equations are deduced in the non-dimensional form for estimating the forces and deflection in the girders of simply supported skew-curved RC box-girder bridges, based upon the results of the straight one. The developed equations may be helpful to the designers in proportioning, analysing, and designing such bridges, as the correlation coefficient is about 0.99.

Parametric study on skew-curved RC box-girder bridges

This paper deals with the study of a single-cell reinforced concrete (RC) skew-curved box-girder bridge under both dead and IRC live loads using the finite element method. An existing model is considered to validate the present results. A convergence study is carried out to decide the optimum mesh size. An exhaustive parametric study is carried out in which the effect of skewness and curvature on the maximum bending moment, shear force, torsional moment and vertical deflection in both the girders of a single-cell RC skew-curved box-girder bridge is investigated and the results are presented in comparison to a straight bridge. The curve angle varies from 0° to 60° at an interval of 12° and the skew angle varies from 0° to 60° at an interval of 10°. The highly skew-curved bridge is found to be more beneficial than the curved bridge because the bending moment and deflection are less in the skew-curved bridge than that in the curved bridge. The present study may be useful to the engineers in designing the skew-curved RC box-girder bridges.

Fragility Assessment for Horizontally Curved Reinforced Concrete Box Girder Bridges Using As-built Data

Damage to one or multiple components of a bridge could result in various conditions, extended from a cosmetically repairable damage to jeopardizing life safety of the users. Fragility curves are beneficial in seismic risk assessment. Due to the limitations of the transformation network, aesthetic considerations, etc., a bridge might be skewed or curved which makes the problem more complex. Fragility assessment of bridges utilizing dynamic analysis seems to be inevitable in reducing damage levels in future earthquakes. In this study, the effectiveness of adopting fragility curves in performance evaluation and risk assessment of bridges is investigated. It is done by considering a highway curved bridge with eleven piers. FEM model is developed using OpenSees platform. Time history dynamic analysis is used to obtain the displacements and forces as demands of each bridge component. Eventually, fragility curves are developed for four damage states. Pier fragility curves of this bridge depict a very appropriate behavior under various levels of excitation which could be related to the appropriate distance of the stirrups. Prevalent mode of the bridge causes torsion in the first bay of the bridge. In the other two bays, only longitudinal transfer of the deck was observed. Bearing fragility curves of the bridge depict fair results in the transverse direction due to the presence of the shear keys as opposed to the longitudinal direction.

Numerical and Experimental Modeling of the Static Response of Simply Supported Thin-Walled Box Girder Bridges

This paper presents numerical and experimental modeling of the static response of simply supported thin-walled reinforced concrete box girder bridges. The work is executed to verify the validity of software developed by the authors for the finite strip analysis of continuous thin-walled box girder bridges and also to observe the effect of flange width on the static response of these type of structural elements under service load from experimental and numerical studies. The laboratory load/deformation relationship is presented in the form of deflection ratios that is displayed alongside the finite strip analysis results of the same loading condition. The results obtained from the laboratory experiment and the software showed very good agreement and are, averagely, 21.5% and 19.5% higher than that of the beam theory solution respectively. Verification of the software with published solutions is also conducted. The results from the developed software showed very good agreement with literature in terms of deflection and stress distributions. These results suggest that the effect of shear deformation, which is more significant on deflection than on stresses, increases with increase in flange width and that the developed software is capable of capturing the general behavior of thin-walled box girder bridges. http://dx.doi.org/10.4314/njt.v34i4. 4

Vibration Characteristics of Kömürhan Highway Bridge Constructed with Balanced Cantilever Method

Komurhan Highway Bridge is a reinforced concrete box girder bridge located on the 51st km of Elazig–Malatya Highway over the Firat River. Because of the fact that the Komurhan Bridge is the only bridge in this part of Firat, it has major logistical importance. So, this paper aims to determine dynamic characteristics such as natural frequencies, mode shapes, and damping ratios of the bridge using experimental measurements and finite-element analyses to evaluate current behavior. The experimental measurements are carried out by ambient vibration tests under traffic loads. Due to the expansion joint in the middle of the bridge, special measurement points are selected and experimental test setups are constituted. Vibration data are gathered from the both box girder and bridge deck. Measurement time, frequency span, and effective mode number are determined by considering similar studies and literature. The peak picking method in the frequency domain is used for the output-only modal identification. An analytic...

Periodic monitoring of physical property changes in a concrete box-girder bridge

The objective of this paper is to quantitatively evaluate the rate of possible structural property changes of a reinforced concrete box girder bridge over a 2-year period using a system identification technique. The structural condition of the concrete box-girder bridge is monitored four times from December 1997 to October 1999 and the physical property changes are estimated using the frequency-based system identification technique. Modal parameters (resonant frequencies and modal amplitudes) for the bridge are extracted from the measured frequency response functions. The validation of the system identification scheme is demonstrated through a numerical study using the finite element model of the same bridge structure.

Cracking in a Curved, Reinforced Concrete Box Girder Bridge

A study to monitor a multi-span reinforced concrete bridge was recently completed. The bridge is curved, with a non-prismatic three-cell box cross section. Extensive field testing was performed to evaluate the causes and effects of large shear cracks. Evaluation of the test results has shown that the distribution of strains in the bridge is significantly different from those assumed in design. This paper reports on the use of finite element analysis to assist in the evaluation of the behavior. Of prime interest has been the identification of the sources of the discrepancy between the test data and the design. This work shows that it is necessary to include concrete softening due to both shear and flexural cracking. The finite element model has also been used to demonstrate that the cracks were primarily the result of temperature differentials arising from the position of the sun during the normal daily cycle.

Nonlinear behaviour and failure analysis of multicell reinforced concrete box girder bridges

A numerical method of analysis is developed to trace the nonlinear response of multicell reinforced concrete (RC) box girder bridges under stepwise increasing static loads. The nonlinearities considered are material nonlinearities inherent in reinforced concrete structural members, such as cracking of the concrete and yielding of the reinforcement due to flexure, shear, and torsion. The analytical model, based on a three-dimensional grillage, is developed for multicellular structures of arbitrary plan geometry and constant height. The analytical method can trace the complex nonlinear behaviour of the bridge beyond the working stress range up to ultimate failure and collapse of the structure. Collapse mechanisms and failure loads can both be determined. The proposed analytical scheme, which is based on a mixed model formulation, is demonstrated and tested on two numerical examples. The results are compared with experimental results obtained from large-scale tests on RC box girder bridge models and indicate excellent agreement. The behaviour of these bridge models under increasing overloads is discussed. Key words: box girder bridges, bridge design, multicell structures, reinforced concrete, analytical model, nonlinear analysis, mixed model, ultimate strength, failure modes.

Nonlinear analysis of multi-cell reinforced concrete box girder bridges

A numerical method of analysis is developed to determine the nonlinear response, collapse mechanisms and ultimate failure loads of multi-cell RC (reinforced concrete) box girder bridges under stepwise increasing static loads. Nonlinearities considered are material nonlinearities inherent in RC members such as cracking of the concrete, yielding of the reinforcement and formation of plastic hinges due to shear and flexure. The analytical model, based on a three-dimensional grillage, is developed for multicellular structures of arbitrary plan geometry and constant height. Realistic but simple assumptions for the interaction of internal forces due to flexure, shear and torsion in the cellular structure, as well as idealized trilinear force-deformation characteristics for the individual members comprising the grillage, result in a very economical nonlinear analytical model. The proposed analytical scheme, which is based on a mixed model formulation at the element level, is demonstrated and tested on a series of numerical examples and the analytical results indicate good agreement with experimental results obtained from large scale model tests on RC box girder bridges.