Seismic Failure Analysis of Complex Heritage Masonry Structures Using Energy Outputs of Finite Element Analysis

The structural assessment of masonry construction often requires the use of nonlinear 2- and 3D finite element analysis. This work describes a strategy for using energy outputs from such analyses to accurately assess failure conditions precipitated by increasing lateral load. The methodology relies on the analogy between plastic strains and fracture that is inherent to the concrete damaged plasticity (CDP) macro-model used to represent the quasi-brittle behavior of masonry material. At critical conditions, energy imparted to a structure by loading can no longer be completely stored as elastic strain energy and must be dissipated. This occurs with fractures in masonry, which are represented with plastic strains when using a CDP material. The development of plastic dissipation energy can therefore be used as a measure for understanding the progressive collapse of a structure, as we illustrate with three case studies analyzed using Abaqus/CAE Explicit: the massive, earthen pyramid at Huaca de la Luna (Trujillo, Peru), the Roman pozzolanic concrete vault of Diocletian’s Frigidarium (Rome, Italy), and mixed material triumphal arch of the San Pedro Apóstol Church of Andahuaylillas (Peru). The method is verified with other measures of failure and has particular applicability for seismic analysis of complex masonry and earthen structures.