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Andrea Dallasta - One of the best experts on this subject based on the ideXlab platform.

  • influence of model parameter uncertainty on seismic transverse response and vulnerability of steel concrete Composite Bridges with dual load path
    Journal of Structural Engineering-asce, 2012
    Co-Authors: Enrico Tubaldi, Michele Barbato, Andrea Dallasta
    Abstract:

    This paper uses a fully probabilistic approach to investigate the seismic response of multispan continuous Bridges with dissipative piers and a steel-concrete Composite (SCC) deck, the motion of which is transversally restrained at the abutments. This bridge typology is characterized by complex dual load path behavior in the transverse direction, with multiple failure modes involving both the deck and the piers. Proper assessment of the seismic vulnerability of these structural systems must rigorously take into account all pertinent sources of uncertainty, including uncertainties in both the seismic input (record-to-record variability) and the properties defining the structural model (model parameters). Model parameter uncertainty affects not only the structural capacity, but also the seismic response of a structural system. However, most of the procedures for seismic vulnerability assessment focus on the variability of the response resulting solely from seismic input uncertainty. These procedures either neglect model parameter uncertainty effects or incorporate these effects only in a simplified way. A computationally expensive but rigorous procedure is introduced in this work to include the effects of model parameter uncertainty on the seismic response and vulnerability assessment of SCC Bridges with dual load path. Monte Carlo simulation with Latin hypercube sampling, in conjunction with probabilistic moment-curvature analysis, is used to build probabilistic finite-element models of the Bridges under study. Extended incremental dynamic analysis is used to propagate all pertinent sources of uncertainty to the seismic demand. The proposed pro- cedure is then applied to the assessment of three benchmark Bridges exhibiting different seismic behavior and dominant failure modes. Comparison of the response variability induced by seismic input uncertainty and the response variability induced by model parameter un- certainty highlights the importance of accounting for the latter when evaluating the safety of the typology of Bridges considered in this study. DOI: 10.1061/(ASCE)ST.1943-541X.0000456. © 2012 American Society of Civil Engineers. CE Database subject headings: Steel; Concrete; Composite Bridges; Finite element method; Seismic effects; Dynamic analysis; Earthquake engineering; Load factors; Uncertainty principles.

  • transverse seismic response of continuous steel concrete Composite Bridges exhibiting dual load path
    Earthquakes and Structures, 2010
    Co-Authors: Enrico Tubaldi, Michele Barbato, Andrea Dallasta
    Abstract:

    Multi-span steel-concrete Composite (SCC) Bridges are very sensitive to earthquake loading. Extensive damage may occur not only in the substructures (piers), which are expected to yield, but also in the other components (e.g., deck, abutments) involved in carrying the seismic loads. Current seismic codes allow the design of regular Bridges by means of linear elastic analysis based on inelastic design spectra. In Bridges with superstructure transverse motion restrained at the abutments, a dual load path behavior is observed. The sequential yielding of the piers can lead to a substantial change in the stiffness distribution. Thus, force distributions and displacement demand can significantly differ from linear elastic analysis predictions. The objectives of this study are assessing the influence of piers-deck stiffness ratio and of soilstructure interaction effects on the seismic behavior of continuous SCC Bridges with dual load path, and evaluating the suitability of linear elastic analysis in predicting the actual seismic behavior of these Bridges. Parametric analysis results are presented and discussed for a common bridge typology. The response dependence on the parameters is studied by nonlinear multi-record incremental dynamic analysis (IDA). Comparisons are made with linear time history analysis results. The results presented suggest that simplified linear elastic analysis based on inelastic design spectra could produce very inaccurate estimates of the structural behavior of SCC Bridges with dual load path.

Michele Barbato - One of the best experts on this subject based on the ideXlab platform.

  • influence of model parameter uncertainty on seismic transverse response and vulnerability of steel concrete Composite Bridges with dual load path
    Journal of Structural Engineering-asce, 2012
    Co-Authors: Enrico Tubaldi, Michele Barbato, Andrea Dallasta
    Abstract:

    This paper uses a fully probabilistic approach to investigate the seismic response of multispan continuous Bridges with dissipative piers and a steel-concrete Composite (SCC) deck, the motion of which is transversally restrained at the abutments. This bridge typology is characterized by complex dual load path behavior in the transverse direction, with multiple failure modes involving both the deck and the piers. Proper assessment of the seismic vulnerability of these structural systems must rigorously take into account all pertinent sources of uncertainty, including uncertainties in both the seismic input (record-to-record variability) and the properties defining the structural model (model parameters). Model parameter uncertainty affects not only the structural capacity, but also the seismic response of a structural system. However, most of the procedures for seismic vulnerability assessment focus on the variability of the response resulting solely from seismic input uncertainty. These procedures either neglect model parameter uncertainty effects or incorporate these effects only in a simplified way. A computationally expensive but rigorous procedure is introduced in this work to include the effects of model parameter uncertainty on the seismic response and vulnerability assessment of SCC Bridges with dual load path. Monte Carlo simulation with Latin hypercube sampling, in conjunction with probabilistic moment-curvature analysis, is used to build probabilistic finite-element models of the Bridges under study. Extended incremental dynamic analysis is used to propagate all pertinent sources of uncertainty to the seismic demand. The proposed pro- cedure is then applied to the assessment of three benchmark Bridges exhibiting different seismic behavior and dominant failure modes. Comparison of the response variability induced by seismic input uncertainty and the response variability induced by model parameter un- certainty highlights the importance of accounting for the latter when evaluating the safety of the typology of Bridges considered in this study. DOI: 10.1061/(ASCE)ST.1943-541X.0000456. © 2012 American Society of Civil Engineers. CE Database subject headings: Steel; Concrete; Composite Bridges; Finite element method; Seismic effects; Dynamic analysis; Earthquake engineering; Load factors; Uncertainty principles.

  • transverse seismic response of continuous steel concrete Composite Bridges exhibiting dual load path
    Earthquakes and Structures, 2010
    Co-Authors: Enrico Tubaldi, Michele Barbato, Andrea Dallasta
    Abstract:

    Multi-span steel-concrete Composite (SCC) Bridges are very sensitive to earthquake loading. Extensive damage may occur not only in the substructures (piers), which are expected to yield, but also in the other components (e.g., deck, abutments) involved in carrying the seismic loads. Current seismic codes allow the design of regular Bridges by means of linear elastic analysis based on inelastic design spectra. In Bridges with superstructure transverse motion restrained at the abutments, a dual load path behavior is observed. The sequential yielding of the piers can lead to a substantial change in the stiffness distribution. Thus, force distributions and displacement demand can significantly differ from linear elastic analysis predictions. The objectives of this study are assessing the influence of piers-deck stiffness ratio and of soilstructure interaction effects on the seismic behavior of continuous SCC Bridges with dual load path, and evaluating the suitability of linear elastic analysis in predicting the actual seismic behavior of these Bridges. Parametric analysis results are presented and discussed for a common bridge typology. The response dependence on the parameters is studied by nonlinear multi-record incremental dynamic analysis (IDA). Comparisons are made with linear time history analysis results. The results presented suggest that simplified linear elastic analysis based on inelastic design spectra could produce very inaccurate estimates of the structural behavior of SCC Bridges with dual load path.

Oneil Han - One of the best experts on this subject based on the ideXlab platform.

  • analysis of the shear behavior of stubby y type perfobond rib shear connectors for a Composite frame structure
    Materials, 2017
    Co-Authors: Sang Hyo Kim, Kun Soo Kim, Dohoon Lee, Jun Seung Park, Oneil Han
    Abstract:

    Shear connectors are used in steel beam–concrete slabs of Composite frame and bridge structures to transfer shear force according to design loads. The existing Y-type perfobond rib shear connectors are designed for girder slabs of Composite Bridges. Therefore, the rib and transverse rebars of the conventional Y-type perfobond rib shear connectors are extremely large for the Composite frames of building structures. Thus, this paper proposes stubby Y-type perfobond rib shear connectors, redefining the existing connectors, for Composite frames of building structures; these were used to perform push-out tests. These shear connectors have relatively small ribs compared to the conventional Y-type perfobond rib shear connectors. To confirm the shear resistance of these stubby shear connectors, we performed an experiment by using transverse rebars D13 and D16. The results indicate that these shear connectors have suitable shear strength and ductility for application in Composite frame structures. The shear strengths obtained using D13 and D16 were not significantly different. However, the ductility of the shear connectors with D16 was 45.1% higher than that of the shear connectors with D13.

Aristidis Iliopoulos - One of the best experts on this subject based on the ideXlab platform.

  • design of steel concrete Composite Bridges to eurocodes
    2013
    Co-Authors: Ioannis Vayas, Aristidis Iliopoulos
    Abstract:

    The conceptual and detailed design of Composite Bridges in accordance with Eurocodes, the suite of European Standards covering structural design of all civil engineering works, including Bridges, is covered in this book. Included in the codes are prescriptive normative rules regarding safety factors, loads and their combinations, material properties, required verifications and analysis methods; bridge design is strongly based on these codes, as well as other issues that are included. The design for a majority of Composite bridge superstructures is addressed in this book, and readers are guided through the selection of appropriate structural bridge systems. Software supported analysis models are proposed, required verifications for sections and members at ultimate and serviceability limit states are outlined, including fatigue and plate buckling, as well as deck and bearings seismic design. The main types of common Composite Bridges are presented, structural forms and systems are discussed, erection methods and preliminary design aids are described. Railway bridge information is provided, but road Bridges through the design examples are the focal point. Fatigue analysis and design, fatigue load models, detail categories, and fatigue verifications for structural steel, reinforcement, concrete, and shear connectors are presented. With an emphasis on reinforced elastomeric bearings, structural bearings and dampers are also covered. This book is useful for bridge designers, structural engineering students, or for those needing to convert from other codes to Eurocodes, such as practicing engineers.

  • three dimensional modeling for steel concrete Composite Bridges using systems of bar elements modeling of skewed Bridges
    International Journal of Steel Structures, 2011
    Co-Authors: Ioannis Vayas, Theodoros Adamakos, Aristidis Iliopoulos
    Abstract:

    A new improved way for modeling steel Composite straight Bridges has been presented (Vayas, 2009; Vayas, 2010). The proposed model is based on the representation of steel I-girders through the use of equivalent trusses. The concrete slab is suitably represented by a set of bar elements. Diaphragms and stiffeners may also be taken into account. In contrast to the grillage model, which is usually used for the analysis of Bridges, the recommended three dimensional model allows for a more reliable prediction of deformations and internal forces. This paper discusses the extension of the model to skewed Composite Bridges. The presence of skew makes the analysis complicated and for this reason the grillage analysis is not always recommended. Phenomena like differential deflections of the main girders during concreting and lateral displacements of the flanges can be adequately predicted using the proposed model. The new way for modeling Composite Bridges, using a spatial system of beam-like structural elements, can also be used for stability analysis of skewed Bridges. Worked examples are provided to illustrate the set up procedure of the proposed modeling and to compare the different ways of analysis.

  • modeling of curved Composite i girder Bridges using spatial systems of beam elements
    Journal of Constructional Steel Research, 2011
    Co-Authors: Theodoros Adamakos, Ioannis Vayas, Stelios Petridis, Aristidis Iliopoulos
    Abstract:

    Abstract A new way of modeling steel Composite Bridges has been presented by Vayas et al. (in press, 2010)  3. , 4. . The proposed model is based on the representation of steel I-girders by equivalent trusses. The concrete slab is suitably represented by a set of bar elements, and the bearings by appropriate springs. Diaphragms and stiffeners may also be taken into account. In comparison to the grillage model, which is usually used for the analysis of Bridges, the proposed three-dimensional model allows a more reliable prediction of deformations, internal forces, and stresses. Curved Bridges display unique behavior characteristics, and for this reason a grillage analysis is not always suitable. The new way of modeling Composite Bridges, using a spatial system of beam-like structural elements, is applied in this paper for the modeling of curved Composite Bridges. Worked examples are provided to illustrate the set-up procedure of the proposed modeling and to compare its results with those of corresponding finite element models.

  • spatial systems for modelling steel concrete Composite Bridges comparison of grillage systems and fe models
    Steel Construction, 2010
    Co-Authors: Ioannis Vayas, Theodoros Adamakos, Aristidis Iliopoulos
    Abstract:

    Plane grillages and finite element models are widely used for the design of Bridges. In a grillage idealization the entire superstructure of the bridge is suitably represented by different sets of bar elements. On the other hand, the finite element method makes use of plane and solid elements for the three-dimensional representation of the structure. Although these models are generally accepted as sufficiently accurate, they are associated with some drawbacks. To overcome the difficulties of plane grillage and finite element analyses, a new way of modelling steel Composite Bridges is presented in this paper. The proposed model is based on the simulation of steel I-girders through the use of equivalent trusses. The concrete slab is represented by a set of bar elements and the bearings by the use of appropriate springs. Diaphragms and stiffeners may also be taken into account. This new way of modelling Composite Bridges using a spatial system of beam-like structural elements allows deformations and internal forces to be predicted reliably, and can be used for dynamic and stability analysis. Worked examples are also provided to illus trate the setup procedure for 3D modelling and to compare the different analysis methods. The work presented in this paper is part of a research project investigating the modelling of steel and Composite Bridges which is being carried out at the National Technical University of Athens.

G. De Roeck - One of the best experts on this subject based on the ideXlab platform.

  • damage detection of shear connectors in Composite Bridges
    Structural Health Monitoring-an International Journal, 2009
    Co-Authors: G. De Roeck
    Abstract:

    Headed shear studs are commonly used to resist longitudinal shear forces in Composite railway Bridges. Due to the growth of traffic and increase in train speed, these studs are subjected to high-cycle fatigue loading which may lead to damage, thus affecting the integrity between the steel girder and the concrete slab. Therefore, it is necessary to find a corresponding nondestructive damage detection method. Within the frame of this paper, the occurrence of damage in shear studs is studied by numerical analysis. In the numerical model of a real Composite bridge, headed shear studs are represented by spring elements. A damage indicator based on the local modal curvature and the wavelet transform modulus maxima is proposed for stud damage identification. The efficiency of the damage indicator is investigated by means of numerical simulations where different levels of damage are introduced to the stud by decreasing the spring stiffness. It is verified that the proposed damage index can be used to locate and t...