Nebojša Mojsilović

Strength of Masonry Subjected to Combined Actions

A sandwich model is presented to predict the strength of masonry wall elements subjected to combined in-plane forces and moments. The validity of the model is demonstrated by comparisons with eighteen large-scale tests on clay brick and calcium-silicate block walls. While the experimental verification has been limited to clay brick and calcium-silicate block masonry the sandwich model is also applicable to concrete block masonry.

Deformation capacity of unreinforced masonry walls subjected to in-plane loading: a state-of-the-art review

A research project on the deformation capacity of unreinforced masonry structures is underway at the Institute of Structural Engineering of ETH Zurich. The development of the basic building blocks for the displacement-based design of unreinforced masonry structures is the objective of the present research project, which should be seen as a first step in an initiative to investigate the limits of the deformation capacity of unreinforced masonry walls. This paper presents a summary review of previous experimental and analytical studies on the deformation capacity of unreinforced masonry walls subjected to in-plane loading. This review is the first phase of the aforementioned research program. A summary of 71 shear tests on unreinforced masonry walls is presented in the form of a database, along with the statistical analysis and discussion of the tests results. Furthermore, three different computational approaches for structural masonry, i.e. micro-modelling, macro-modelling and macro-element discretization, are discussed, and a review of macro-elements for the in-plane response of unreinforced masonry walls is presented. The reviewed models are discussed and a set of conclusions is given. Special attention is devoted to the deformation capacity parameter throughout the paper. Finally, the paper shows the limitations of our current state of knowledge of the deformation capacity of structural masonry.

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

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 objects 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.

Simulation of boundary conditions for testing of masonry shear walls

This paper is focused on the simulation of the fixed-ends boundary conditions in shear testing of unreinforced masonry walls. Two different approaches to simulate the fixed-ends boundary conditions, i.e. the static and kinematic approaches, are introduced, and their validity is discussed with the help of our own recent experimental data. It is shown that the static approach can result in unrealistic boundary conditions, and it is not a proper way to simulate the fixed-ends boundary conditions.

I-Shaped Unreinforced Masonry Wallettes with a Soft-Layer Bed Joint: Behavior under Static-Cyclic Shear

AbstractIn order to extend the latest findings on the in-plane shear behavior of rectangular unreinforced masonry (URM) wallettes with soft-layer bed joints and gain insight into the possible influ...