Damage Detection of Masonry Structures Under Shaking Table Tests Through Relative Displacements by 3d Optical Markers

Abstract

Large-scale seismic experimental facilities play a relevant role and provide essential contribution to the performance-based earthquake engineering. In such a context, recent advances in experimental data acquisition methodologies in large laboratories can open new perspective to the evaluation of structural performance of tested mockups under seismic load. In particular, the application of 3D motion capture systems to shaking table testing provides a unique tool for recording relative displacements of a large number of measurement points. The analysis of 3D relative displacements during dynamic tests allows to evaluate the structure deformations and to monitor the cracks formation and evolution, which can lead to the formulation of damage indices. Also, the failure mechanism could be easily visualized and analyzed by monitoring the cumulative relative displacements between markers. In addition, in-plane and out-of-plane deformations of walls could be monitored during each seismic test, providing accurate information on the torsional and bending effects. A case study is presented about a full-scale model of a masonry cross vault of the mosque of Dey, Algiers, tested at the ENEA Casaccia shaking table. The cross vault was subjected to a seismic sequence based on the 21-May-2003 earthquake recorded at Keddara station. The results obtained through the processing of the data from 67 markers located on the vault showed the potentialities of the methodology.

Numerical Investigation on the Seismic Response of a Masonry Cross Vault Based on the Discrete Macro-Element Method

“…The failure of these structural typologies is mainly associated with the in-plane shear distortions or the lack of lateral instability due to relative displacements [1,2] To better understand the behavior of these elements, experimental and numerical research has been carried out considering different loading and boundary conditions. For instance, laboratory testing focused on assessing the response of these elements due to vertical loadings such as imposed differential displacements or concentrated loads [3][4][5][6][7] and shaking table tests [8][9][10] have been performed in the last decades. On the other hand, the numerical investigations associated with masonry cross vaults involved applying nonlinear analyses based on different approaches, such as the Finite Element Method [11][12][13][14][15] or the Discrete Element Method [16][17][18].…”