A discrete approach for modelling backfill material in masonry arch bridges

Abstract

Masonry arch bridges form a significant portion of the European transport infrastructure network. Many of these bridges are relatively old but still in service. Increasing vehicle loads and speeds have highlighted the need for reliable estimates of their service condition. Past research demonstrated that load-carrying capacity of a masonry arch bridge is a function of the soil response. However, today, the approaches used for the simulation of soil in masonry arch bridges are over-simplistic and most of them do not take into account the soil-structure interaction phenomena. This paper presents a novel modelling approach, based on the discrete element method, for the simulation of backfill material in masonry arch bridges. According to the method, bricks in the barrel vault are simulated as an assembly of distinct blocks separated by zero thickness interfaces at each mortar joint. Backfill is represented as an assemblage of densely packed discrete irregular deformable particles, here called "inner-backfill particles". A series of computational models were developed and their results are compared against fullscale experimental test results. A good agreement between the experimental and the numerical results was obtained which demonstrates the huge potential of this novel modelling approach. One of the major advantages of the proposed approach is its ability to simulate the initiation and propagation of cracking in the backfill and arch ring with the application of the external load. It is envisaged that the current modelling approach can be used by bridge assessment engineers for understanding soil pressures and load distribution on the backfill and arch ring and thus develop serviceability criteria for masonry arch bridges of their care.

DECM: A Discrete Element for Multiscale Modeling of Composite Materials Using the Cell Method

“…The first possibility is a micro-modeling approach and consists in modeling a masonry element by means of distinct blocks and joints, represented by face-to-face contacts through assigned contact points. The blocks can be rigid or, in more refined analyses, deformable [37][38][39]. In the second case, the DEM model solves the problem in large displacements for the joints and small deformations for the blocks.…”

Numerical Analysis of an FRP-Strengthened Masonry Arch Bridge

“…The FEM calibration carried out in the previous section is extended to the case of the well-known Prestwood bridge, for which experimental data from a destructive test is available (see Figure 7A). First, using the ultimate experimental load and previous numerical analyzes developed by other authors (Cavicchi and Gambarotta, 2005;Sarhosis et al, 2019) a FEM of the original structure, was performed. Subsequently, a second model, in which a layer of FRP is applied at the arch intrados, was developed using the analysis strategy and the bond-slip law previously calibrated.…”

“…With this need in mind, in recent years, different calculation methods and guidelines (e.g., UIC guideline) 1 for the evaluation of the ultimate (ULS) and serviceability limit states (SLS) of masonry bridges have been developed. Among the available methods for the structural analysis of masonry bridges, it is possible to find: simplified methods (Zhang et al, 2018), numerical method for assess the seismic capacity (Pelà et al, 2013;Zampieri et al, 2014Zampieri et al, , 2015aSarhosis et al, 2016;Mahmoudi Moazam et al, 2018;Marefat et al, 2019), methods based on the limit analysis (Basilio et al, 2014;Chiozzi et al, 2017;Bertolesi et al, 2018), analysis strategies able to take into account the settlement of the supports (Galassi et al, 2018a,b;Zampieri et al, 2018aZampieri et al, ,b, 2019 or geometry uncertainties (Cavalagli et al, 2017), macro-element models (Cannizzaro et al, 2018;D'Altri et al, 2019), and methods based on finite element modeling (FEM) (Brencich and Sabia, 2008;Costa et al, 2016;Scozzese et al, 2019), discrete element modeling (DEM) (Sarhosis et al, 2016(Sarhosis et al, , 2019Forgács et al, 2017Forgács et al, , 2018Stockdale et al, 2019) or a combination of both (Milani and Lourenço, 2012).…”

“…The model considers the bond-slip law at the FRP-masonry interface provided by the CNR-DT 200 R1/2013 2 and a non-linear stress-strain behavior for the masonry. Then, the model is extended for the case of the single-span Prestwood bridge, tested to collapse more than 30 years ago (Page, 1987;Cavicchi and Gambarotta, 2005, 2006Sarhosis et al, 2019). Available experimental data from the original test and the results of the numerical models of the laboratory tested arches are used to predict the increase in strength provided by a hypothetical intervention of this structure by means of FRP.…”

DECM: A Discrete Element for Multiscale Modeling of Composite Materials Using the Cell Method

“…The first possibility is a micro-modeling approach and consists in modeling a masonry element by means of distinct blocks and joints, represented by face-to-face contacts through assigned contact points. The blocks can be rigid or, in more refined analyses, deformable [32][33][34]. In the second case, the DEM model solves the problem in large displacements for the joints and small deformations for the blocks.…”