SEISMIC FAILURE ANALYSIS OF COMPLEX HERITAGE MASONRY STRUCTURES USING ENERGY OUTPUTS OF FINITE ELEMENT ANALYSIS

Abstract

The present work describes how energy outputs from 2-and 3D nonlinear FE analyses can be used to accurately assess failure conditions produced by seismic action on complex masonry heritage structures. This methodology relies on the analogy between plastic strains development and fracture propagation that is inherent to the concrete damaged plasticity (CDP) macro-model used in Abaqus/CAE Explicit to represent the quasi-brittle behavior of masonry material. Under seismic conditions, deterioration of a structure from static integrity to dynamic failure is precipitated by increasing time dependent loading. Once critical conditions are reached, the structure begins to show signs of local failure and internal energy initially stored as elastic strain energy begins to dissipate through fracture propagation. Dissipation in models with CDP materials produces plastic strain distributions that represent fractures. Thus, plastic dissipation energy will rapidly increase with time as regions of plastic strain propagate throughout the model. Approaching failure this growth becomes asymptotic. Accordingly, the instant at which elastic strain energy stored from loading and plastic dissipation energy generated from plasticstrain-represented fractures are equal can be taken as the time of complete structural failure. The successful application of this energy-based approach to the evaluation of the lateral capacity of heritage masonry monuments is illustrated with three case studies: 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), and. The first two cases are analyzed under dynamic conditions using the present methodology and the third case combines the proposed method together with conventional pushover analysis. The method is verified with other quantitative measures of failure. © 2024, University of Cantabria - Building Technology R&D Group. All rights reserved.