Experimental and Numerical Mechanical Characterization of Unreinforced and Reinforced Masonry Elements with Weak Air Lime Mortar Joints

Abstract

This paper deals with the results of an experimental and numerical campaign aimed at characterizing the mechanical response of masonry components and panels made of limestone units kept together by weak air lime mortar joints. The selected air lime mortar, typical of ancient masonry buildings but difficult to be built-up artificially, was specifically prepared for the experimental analyses, with the aim of obtaining a laboratory compression strength of 0.25–0.50 MPa. In the first part of the paper, the performed tests concerning the strength of the units (mean compression strength of 80 MPa) and of the mortar (mean compression strength after 28 days of 0.30 MPa), are described for different curing periods. Moreover, tests of masonry triplets in shear (shear strength of 0.11 MPa for null axial forces) are shown and used in order to establish the main parameters of the Mohr–Coulomb failure criterium. Then, the calibration of a continuous numerical micro-model implemented in Kratos Multiphysics is presented. The model is used for reproducing the behavior of an unreinforced panel in shear made of the studied masonry and to appraise the effectiveness of a FRCM- (Fiber Reinforced Cementitious Matrix) based reinforcement intervention applied. The obtained results proved that FRCM allows to increase the strength of the considered masonry type by about eight times and the ductility by about thirteen times.

Shaking Table Test of a Full Scale Three-Leaf Masonry Wall

“…Preliminary tests were carried out at the SCAM (Sperimentazione, Controllo, Analisi e Modelli) laboratory of the University "G. d'Annunzio" of Chieti-Pescara, Italy to mechanically characterize the materials of the wall components [40]. Preliminary tests were carried out because the wall materials were sourced in Italy -although the tested wall was eventually built at the EQUALS laboratory in Bristol.…”

“…Table 7 shows the main mechanical parameters used in the model. The above data was inferred from static tests carried out in the SCAM laboratory of the Department of Engineering and Geology of the University of Chieti-Pescara [40]. The mechanical parameters for stone, mortar joints and filling material (FM) were used to define the damagemechanism behaviour of the constitutive law DamageTC3D [35], with two failure criteria for tension and compression, while the timber beams and the concrete slab were modelled as linear elastic isotropic materials.…”

Comparative analysis of two strengthening solutions for the structural rehabilitation of a historical masonry building

“…At the same time, numerical analyses of masonry structures are a complex problem, due to the special mechanical characteristics of the masonry. Being a laborious process, as it is presented in literature [6][7][8][9][10][11][12][13] and not accessible to all engineers, the regulations provide analytical instruments utilized to assess the seismic vulnerability of the buildings. Moreover, they give recommendations to improve the structural behaviour of the masonry building including numerous types of strengthening solutions, e.g.…”

Study on the Mechanical Properties of Two General-Purpose Cement–Lime Mortars Prepared Based on Air Lime

“…Comparisons of the performance of pure aerial lime masonry in standard and non-standardized tests have also been performed in Pelà et al [ 45 , 46 ], for deepening the knowledge of the behavior of historical masonry structures. Brando et al [ 47 ] proposed a multi-scale approach for a finite element method (FEM) numerical model of historical masonry based on air lime. This approach involves the customized preparation of an air lime mortar based on previous chemical analysis and the validation of a continuous numerical FEM model by means of tests conducted on a limited amount of masonry triplets, assembled with bricks and the previous mortar.…”