Masonry walls subjected to in-plane cyclic loading: application of digital image correlation for deformation field measurement

Abstract

Within a research project on the deformation capacity of in-plane loaded unreinforced masonry structures, 10 tests were performed on full-scale large walls subjected to in-plane static-cyclic loading. During testing, the measurements included all applied forces together with an overall and a local picture of the deformation state of the specimens. To achieve this, in addition to the traditional hard-wired instruments, i.e., LVDTs and potentiometers, an in-house developed 2D digital image correlation (DIC) measurement system was applied. DIC is a cutting-edge, non-contact, optical measurement technique that provides the complete deformation field by comparing the digital images of the test object's surface before and after the deformation. This paper reports on the applied measurement procedure, discusses important DIC issues and the applicability of DIC for deformation field measurements when testing large masonry walls at full scale. The obtained results proved that in-house developed DIC system based on conventional DSLR cameras can be considered as an effective system to measure the complete deformation field with high level of accuracy and spatial resolution even in the case of large specimens and complicated deformation fields.