Title: Analysis of the stress and deformation states in the vertical flat-jack test

Authors: Corrado Chisari; Lorenzo Macorini; Bassam Izzuddin; Claudio Amadio

Addresses: Department of Civil and Environmental Engineering, Imperial College London, UK ' Department of Civil and Environmental Engineering, Imperial College London, UK ' Department of Civil and Environmental Engineering, Imperial College London, UK ' Department of Engineering and Architecture, University of Trieste, Italy

Abstract: Performing a realistic assessment of unreinforced masonry structures involves designing and executing appropriate experimental tests on masonry components for determining the material model parameters to be used in structural analysis. Considering recent developments in which inverse analysis was used as calibration framework, a vertical flat-jack test is investigated in this paper. Two simplified models are described for the analysis of the stress state in the masonry due to the pressure transferred by the flat-jack. Furthermore, with the aim of designing the sensor setup for the test, a POD analysis on the deformation state of the structure is carried out, highlighting the basic deformation modes which govern the response. The results show that high stresses and local modes can occur in the proximity of the flat-jack, and thus local use of FRP reinforcement is recommended to avoid undesired brittle crack propagation which may prevent accurate calibration of mortar joint mechanical characteristics.

Keywords: stress; deformation; vertical flat-jack; unreinforced masonry; URM; structural assessment; proper orthogonal decomposition; POD; FRP reinforcement; sensor placement; mesoscale modelling; calibration; elastic properties; cohesion; friction coefficient; fracture energy.

DOI: 10.1504/IJMRI.2021.112067

International Journal of Masonry Research and Innovation, 2021 Vol.6 No.1, pp.21 - 44

Received: 07 Feb 2019
Accepted: 01 Aug 2019
Published online: 04 Jan 2021 *

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