| 1. |
- Albright, Ann, et al.
(författare)
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Dynamic soil-structure interaction of a single-span railway bridge, forced vibration testing and simulation
- 2023
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; , s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- High-speed railway is expanding drastically in Sweden, necessitating new technology, and improve-ments of existing structures. End-shield bridges are a common and under-tested bridge type inSweden. Their dynamic performance is significantly impacted by their boundary conditions due to thesoil–structure interaction (SSI) and their large masses cantilevering beyond the footings. A specificend-shield bridge was tested under low (5 kN) and high (20kN) amplitude-forced hydraulic excitationfor a wide range of frequencies. Several train passages for typical passenger trains,‘X62’, were meas-ured with the same experimental setup. The results were analysed to isolate the significant modes ofthe system and the natural frequencies. A full 3D numerical model was calibrated and updated inAbaqus, along with a brief sensitivity study to determine the most influential parameters. Finally, theresponse to passing trains and Eurocode design HSLM trains was calculated. The experimental studyshowed that higher loading amplitudes resulted in higher damping and lower natural frequencies. Thenumerical analysis showed that for this bridge type the SSI cannot be neglected and can be success-fully introduced in the model.
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| 2. |
- Bagge, Niklas, 1987-, et al.
(författare)
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A multi-level strategy for successively improved structural analysis of existing concrete bridges: examination using a prestressed concrete bridge tested to failure
- 2019
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 15:1, s. 27-53
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a multi-level strategy with increased complexity through four levels of structural analysis of concrete bridges. The concept was developed to provide a procedure that supports enhanced assessments with better understanding of the structure and more precise predictions of the load-carrying capacity. In order to demonstrate and examine the multi-level strategy, a continuous multi-span prestressed concrete girder bridge, tested until shear failure, was investigated. Calculations of the load-carrying capacity at the initial level of the multi-level strategy consistently resulted in underestimated capacities, with the predicted load ranging from 25% to 78% of the tested failure load, depending on the local resistance model applied. The initial assessment was also associated with issues of localising the shear failure accurately and, consequently, refined structural analysis at an enhanced level was recommended. Enhanced assessment using nonlinear finite element (FE) analysis precisely reproduced the behaviour observed in the experimental test, capturing the actual failure mechanism and the load-carrying capacity with less than 4% deviation to the test. Thus, the enhanced level of assessment, using the proposed multi-level strategy, can be considered to be accurate, but the study also shows the importance of using guidelines for nonlinear FE analysis and bridge-specific information.
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| 3. |
- Bagge, Niklas, 1987-, et al.
(författare)
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Failure tests on concrete bridges : Have we learnt the lessons?
- 2018
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Ingår i: Structure and Infrastructure Engineering. - : Taylor & Francis. - 1573-2479 .- 1744-8980. ; 14:3, s. 292-319
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Tidskriftsartikel (refereegranskat)abstract
- Full-scale failure tests of bridges are important for improving understanding of bridges’ behaviour and refining assessment methods. However, such experiments are challenging, often expensive, and thus rare. This paper provides a review of failure tests on concrete bridges, focusing on lessons from them. In total, 40 tests to failure of 30 bridges have been identified. These include various types of bridges, with reinforced concrete or prestressed concrete superstructures, composed of slabs, girders and combinations thereof. Generally, the tests indicated that theoretical calculations of the load-carrying capacity based on methods traditionally used for design and assessment provide conservative estimates. It can also be concluded that almost a third of the experiments resulted in unexpected types of failures, mainly shear instead of flexure. In addition, differences between theoretical and tested capacities are often apparently due to inaccurate representation of geometry, boundary conditions and materials
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| 4. |
- Bayoglu Flener, Esra, et al.
(författare)
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Field testing of a long-span arch steel culvert during backfilling and in service
- 2005
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 1:3, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents the first part of the in-situ measurements and data analyses for the tests conducted during backfilling and during service of a long-span corrugated steel culvert railway bridge over Skivarpsan, Rydsgard, Sweden. Static and dynamic tests were carried out measuring strains and displacements. Temperature readings were taken along with the measurements. Comparisons of moments during compaction showed that there is good agreement between test results and theoretical values. The theoretical calculation of the rise of the crown during compaction and the crown moments due to live load seem to be conservative, while the theoretical axial forces agree reasonably with the measured axial forces.
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| 5. |
- Bennitz, Anders, et al.
(författare)
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CFRP strengthening of a railway concrete trough bridge : a case study
- 2012
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 8:9, s. 801-816
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an upgrading and monitoring of a Swedish concrete railway bridge. The methods used for the upgrading as well as for the monitoring are innovative and new. Carbon fibre tubes are inserted in holes in the bridge deck, drilled in the transverse direction of the slab at a location ca. 40 mm from the top. Carbon fibre NSMR bars are bonded in transverse grooves in the soffit of the slab. Both methods are intended to increase the transverse bending moment capacity of the troughs' bottom slab in the ultimate limit state. Monitoring is performed to verify the effectiveness of the strengthening and to understand the behaviour of the bridge. However, for obvious reasons, monitoring is only carried out in the SLS (service limit state). Even though only marginal effects of strengthening could be recorded in the SLS, both the strengthening and monitoring were considered successful at a cost of approximately 8% of the total cost of a new bridge replacement.
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| 6. |
- Blazkova, S, et al.
(författare)
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Uncertainty in flood estimation
- 2009
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 5:4, s. 325-332
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this contribution is to form a clear picture of uncertainties we encounter in flood estimation, including both real-time flood forecasting and simulation for flood risk estimation. In simulation, we prefer the thesis of equifinality to obtain global optima. Many models producing acceptable simulations can be considered as multiple working hypotheses about the system process representations. Some of those hypotheses might later be confirmed or rejected, given additional data. In GLUE (Generalized Likelihood Uncertainty Estimation) the parameter sets are sampled randomly from physically reasonable ranges, often using uniform sampling where there is no strong information about prior expectations of parameter values. The parameter sets are then used to generate different realizations of the model outputs, which are then evaluated using some criteria (measures of likelihood) to provide a weight associated with each parameter set. Likelihood here is used in a much broader sense than in statistical inference. If some limits of effective observation error can be specified prior to running any simulations, models predicting outside of those limits can then be rejected as non-behavioural. Thus, any model evaluation of this type needs to take account of the multiple sources of model error more explicitly. This, however, is difficult for realistic cases. The procedure for the GLUE methodology is illustrated in examples. Usability for practical problems is suggested and future development is outlined.
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| 7. |
- Blomfors, Mattias, 1990, et al.
(författare)
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Incorporation of pre-existing longitudinal cracks in finite element analyses of corroded reinforced concrete beams failing in anchorage
- 2020
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; In press, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Transportation infrastructure is of fundamental importance and must be regularly assessed to ensure its safety and serviceability. The assessment of ageing reinforced concrete bridge stock may need to consider corrosion and cracks, as the likelihood of deterioration increases with age. This work accordingly investigates the incorporation of pre-existing anchorage zone corrosion cracks into the finite element modelling of reinforced concrete beam structural behaviour. Three methods of accounting for cracks were applied: (1) modifying the bond stress–slip relation, (2) weakening elements at the position of the crack, and (3) weakened discrete crack elements. The results show that modifying the bond stress–slip relation results in accurate predictions of the ultimate capacity when one-dimensional reinforcement bars are used in the model. Weakening elements at the position of the crack provides reasonable results when the anchorage is modelled with three-dimensional reinforcement bars and a frictional bond model. The implementation of discrete cracks was found to be unsuitable for the studied load situation, as compressive stresses formed perpendicular to the crack. It was concluded that the capacity of the studied case could be well estimated based on visual measurements, without knowledge of the exact corrosion level.
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| 8. |
- Bornet, Lucie, et al.
(författare)
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Influence of the ballasted track on the dynamic properties of a truss railway bridge
- 2015
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 11:6, s. 796-803
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Tidskriftsartikel (refereegranskat)abstract
- This article presents numerical and experimental analyses of a steel truss railway bridge. The main interest of this work is that dynamic experiments have been performed before and after the ballasted track was placed on the bridge. Consequently, it has been possible to quantify the effect of the ballast and the rails on the dynamic properties of the bridge. For that, two finite element models, with and without the ballasted track, have been implemented and calibrated using the experimental results. It appears that the ballast gives an additional stiffness of about 25-30% for the lowest three eigenmodes. This additional stiffness can be only partly explained by the stiffness of the ballast. In fact, it seems that this additional stiffness is also due to a change of the support conditions.
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| 9. |
- Butt, Ali Azhar, 1984-, et al.
(författare)
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Assessment of the attributes based life cycle assessment framework for road projects
- 2015
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Ingår i: Structure and Infrastructure Engineering. - : Taylor & Francis. - 1573-2479 .- 1744-8980.
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Tidskriftsartikel (refereegranskat)abstract
- Number of life cycle assessment (LCA) tools has been suggested for pavements. However, very few have been adopted by the road authorities. Key reasons for this lack of implementation have been the tendency for very broad LCA analyses that include system boundaries considerably beyond the more natural system boundaries associated with road design, construction and maintenance as well as the lack of available LCA tools that have attributes that reflect key road properties. In this paper, a new attributesbased pavement LCA framework is evaluated for use on real road materials. Aggregates from two different sources and the effect of using a warm mix asphalt additive (WMAA) in asphalt mixtures were investigated in the laboratory. Different pavement design alternatives were generated using the laboratory data and analyzed using the road LCA framework. Asphalt production and material transportation were found to be the most energy consuming processes. The results presented showed that having actual pavement material properties as the key attributes in LCA enables a pavement focused assessment of environmental impacts associated with different design options and, LCA can help in decision support by evaluating environmental impacts of different design alternatives in a project planning/design stage.
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| 10. |
- Cantero, Daniel, et al.
(författare)
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Train–track–bridge modelling and review of parameters
- 2016
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Ingår i: Structure and Infrastructure Engineering. - : Taylor & Francis Group. - 1573-2479 .- 1744-8980. ; 12:9, s. 1051-1064
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Tidskriftsartikel (refereegranskat)abstract
- This study gathers all necessary information to construct a model to calculate the coupled dynamic response of train–track–bridge systems. Each component of the model is presented in detail together with a review of possible sources for the parameter values, including a collection of vehicle models, a variety of track configurations and general railway bridge properties. Descriptions of the most important track irregularity representations are also included. The presented model is implemented in MATLAB and validated against a commercially available finite element package for a range of speeds, paying particular attention to a resonant speed. Finally, the potential of the described model is illustrated with two numerical studies that address interesting aspects of train and bridge dynamic responses. In particular, the effect of the presence of a vehicle on the bridge’s fundamental frequency is studied, as well as the influence of the wavelength of the rail irregularities on the dynamic effects of the bridge and the vehicle.
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