Periodic Reporting for period 1 - RAMBEA (Realistic Assessment of Historical Masonry Bridges under Extreme Environmental Actions)
Período documentado: 2019-07-03 hasta 2021-07-02
The RAMBEA project has developed an innovative methodology for realistic analyses of historical masonry bridges under extreme environmental actions. It is based upon a two-scale FE description of masonry components of the bridge combined with contact elements to connect masonry arch and external walls to the continuum backfill domain. The developed modelling strategy allows a reliable description of the anisotropic micro-structure of masonry, considering the cohesive and frictional characteristics of the masonry joints, including the degradation of strength and stiffness under cyclic loading. The model enables realistic predictions of complex, three-dimensional cracking patterns while allowing for computational efficiency. Moreover, the RAMBEA project has developed a practical and robust calibration procedure based upon the mesoscale mechanical properties of bricks and masonry joints which can be easily obtained by non-destructive in-situ tests, suitable to be used for historical constructions and cultural heritage assets.
The developed methodology has been applied to real case studies, where the numerical predictions provided by the novel efficient strategy have been compared against available experimental data or the numerical results obtained employing high-fidelity mesoscale descriptions of the analysed bridge structures. The main outcome of RAMBEA is thus an efficient and accurate numerical approach for the structural assessment of historical masonry bridges subjected to complex loading conditions corresponding to extreme natural events.
• Literature review of the effects of extreme environmental actions on masonry bridges; Selection of representative case studies for which experimental tests are available: two multi-ring arches, one single-bay and one double-bay arch-bridge samples and a large viaduct have been selected; Development of detailed mesoscale models of the selected case studies: the models have been modelled in ADAPTIC1 and calibrated based on the available experimental data.
• Review of the main modelling approaches available in the literature for masonry arch bridges including discrete elements and continuous FE models employing damage-plasticity constitutive laws; Development of a new 3D macroscale model, considering the frictional and cohesive characteristics of masonry and cyclic material degradation; Implementation of the new model in ADAPTIC1; Validation of the model against physical tests and mesoscale virtual tests.
• Extensive review and training on non-destructive testing techniques for the geometrical and mechanical characterisation of historical masonry bridges; Development and validation of a model calibration procedure based on mesoscale parameters of bricks and mortar joints, which can be obtained by non-destructive or low-invasive tests.
• Realistic assessment of the selected case studies under vertical static loading and horizontal seismic actions; Execution of in-situ non-destructive experimental tests on the Quebradas viaduct in Portugal; Identification of the model parameters based on the experiments and an advanced optimisation procedure based on genetic algorithms.
• The study results have been published/submitted for publication in journals and presented at various international conferences and seminars.
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1 Izzuddin, B.A. 1991. Nonlinear dynamic analysis of framed structures, Imperial College London (University of London).
The RAMBEA project covered a critical knowledge gap between simplistic limit analysis and FE models and mesoscale approaches, providing researchers and practitioners with an efficient but accurate modelling strategy for masonry bridges allowing for the complex 3D interaction between the different components of masonry bridges under extreme loading. Moreover, the project developed a comprehensive model calibration strategy to obtain the model parameters from non-destructive in-situ tests, suitable for historical masonry bridges belonging the cultural and architectural heritage.
In conclusion, the innovative modeling strategy developed in the RAMBEA project drastically limits the computational cost associated with realistic assessments of large bridges, allowing for a model calibration based on practical in-situ non-destructive tests. It is expected to constitute an essential step towards the widespread use of realistic nonlinear analysis in engineering practice to assess existing and historical masonry arch bridges.