Relative displacements of 3D optical markers for deformations and crack monitoring of a masonry structure under shaking table tests

Abstract

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 of the tested structure. The analysis of 3D relative displacements during dynamic tests allows us to evaluate the structure deformations and to monitor the cracks formation and evolution. The present paper focuses on the processing and analysis of 3D motion capture data to extract accurate displacements between markers positioned on a full-scale model of a masonry cross vault representing a vault of the mosque of Dey, Algiers, tested at the ENEA Casaccia Research Centre. The management and processing of the data acquired through 67 markers located on the vault are described, showing the potentialities of the methodology. Moreover, the possible formulation of damage indices based on the structure deformations and cracks aperture detected from markers relative displacements (MRDs) was explored. In particular, cracks could be counted and classifi ed as a function of the detected apertures, following damage thresholds indicated in the Italian regulations. Moreover, the failure mechanism could be easily visualized and analysed by monitoring the cumulative MRDs. 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.

Stochastic simulation of earthquake ground motions for the seismic assessment of monumental masonry structures: Source‐based vs site‐based approaches

“…One should note that maximum base shear and maximum control-points displacement comparisons might be performed even if the structure under investigation does not present damage, whereas the damage pattern becomes relevant only when non-linearities are experienced. Different approaches to quantify the damage on masonry structures have been proposed in the literature [54][55][56] ; however, no studies assess the similarities in terms of damage semiotics, giving them an integral score. To this end, a methodology involving the Hausdorff distance score method 57 has been integrated with concepts arising from (i) the structural damage occurring in masonry structures and (ii) engineering-based knowledge from several post-earthquake field observations of the authors of this paper.…”

“…Different approaches to quantify the damage on masonry structures have been proposed in the literature 54–56 ; however, no studies assess the similarities in terms of damage semiotics, giving them an integral score. To this end, a methodology involving the Hausdorff distance score method 57 has been integrated with concepts arising from (i) the structural damage occurring in masonry structures and (ii) engineering‐based knowledge from several post‐earthquake field observations of the authors of this paper.…”

Damage detection via modal analysis of masonry structures using shaking table tests

“…Two 2-storey URM and CM building models, with dimensions of 3.00 × 3.50 m in plan and a height of 2.20 m for each storey, were tested on the 3D shaking table at the ENEA laboratory in Rome. 63,64 Figure 1A reports a general view of the two building models right after the construction phase. The layout of the models was inspired by a typical masonry building as storey height, wall thickness and openings are concerned, while the plan dimensions were designed accounting for the shaking table features.…”

“…Two 2‐storey URM and CM building models, with dimensions of 3.00 3.50 m in plan and a height of 2.20 m for each storey, were tested on the 3D shaking table at the ENEA laboratory in Rome 63,64 . Figure 1A reports a general view of the two building models right after the construction phase.…”

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

“…More structural details on the Mosque of Dey can be found in [15][16]. The structural properties and characteristics of the tested mock-up are described in detailed in [17]. The mock-up was initially tested with two steel longitudinal bars linking transversal walls, functioning as tie-rods.…”