Nonlinear Dynamic Analysis of a Masonry Arch Bridge Accounting for Damage Evolution

Abstract

This study investigates the nonlinear dynamic response of the masonry bridge ‘Ponte delle Torri’ in Spoleto, aiming at assessing the seismic performance of the structure and evaluating the occurring damaging mechanisms. A 3D Finite Element (FE) macromechanical procedure implemented in the FE program FEAP is adopted to model the bridge. To reproduce the typical nonlinear microcracking process evolving in masonry material when subjected to external loads, an isotropic damage model is used. This is based on a scalar damage variable introduced in the stress-strain constitutive law and equally degrading all the components of the elastic constitutive operator. A nonlocal integral definition of the damage associated variable, that is the equivalent strain measure governing its evolution, is adopted to overcome the mesh dependency problems of the FE solution typically occurring in the presence of strain softening behavior. Based on the results of a recent study by some of the authors, a single equivalent pier is analyzed, whose geometry and boundary conditions are selected so that its response can provide useful information on the out-of-plane dynamic behavior of the overall bridge. To perform the seismic assessment, a set of recorded accelerograms is properly selected to simulate the seismic history of the Spoleto site. The nonlinear dynamic response of the structure is evaluated and monitored in terms of top displacement time history, evolution of the global damage index, and distribution of the damage variable. First, a set of analyses is performed by imposing the selected ground motions one by one on the initial undamaged configuration for the structure with the aim of emphasizing the damaging effects on its dynamic response. Then, the accelerograms are arranged in sequence to reproduce the seismic history of the site and analyze the influence of accumulated damage on the dynamic amplification of the response. A critical comparison of the bridge response to the sequence of accelerograms and the single records is made, and the interaction between the damaged structure dynamic response and the signal characteristic is highlighted, as well.

Finite Element Modeling of an Italian Masonry Arch Bridge Detecting Damage Under Seismic Excitations

“…Masonry material response is described by the constitutive law with damage proposed in Addessi and Sacco 2016 [4]. This phenomenological law has already been applied in FE analyses of masonry bridges, within a macromechanical approach, as reported in [6,11] where the response of the monumental bridge of Spoleto, in Italy, has been extensively investigated under seismic actions focusing on its damage scenarios. The adopted isotropic law models the damage evolution due to microfracture process related to prevalent tensile states in masonry.…”

“…(4)where is the current damage value evaluated in the basis of the nonlocal equivalent strain measure and several mechanical parameters, for which a more detailed description is reported in [4,11,12]: (5) Damage formulation is also based on the assumption of thermodynamic irreversibility, for which , and the maximum damage state is reached for a value of the scalar variable D equal to 1.…”

The Effects of River Torrents and Debris on Historic Masonry Vaulted Arch Bridges

“…The main focus is on horizontal actions due to seismic phenomena. The dynamic response of the Ponte delle Torri Viaduct and the damage caused by the recent earthquake were investigated in [6]. Cyclic push-over analysis with the effect of natural seismic spectra was carried out in [7].…”

Seismic Vulnerability Assessment of Multi-arch Gallery Masonry Bridges Adopting Different Seismic Analysis Procedures

“…The investigation showed that the bridge has generated high tensile stress at the spandrel walls which causes the failure of the bridge. Addessi et al (Addessi et al 2021) investigated the bridge response to the sequence of the accelerogram as well as for single record. The study found that the relationship between the damage index and control node displacement is noteworthy and provides the significant information regarding the performance of the bridge.…”