Abstract

A review of methods applicable to the study of masonry historical construction, encompassing both classical and advanced ones, is presented. Firstly, the paper offers a discussion on the main challenges posed by historical structures and the desirable conditions that approaches oriented to the modeling and analysis of this type of structures should accomplish. Secondly, the main available methods which are actually used for study masonry historical structures are referred to and discussed.

The main available strategies, including limit analysis, simplified methods, FEM macro- or micro-modeling and discrete element methods (DEM) are considered with regard to their realism, computer efficiency, data availability and real applicability to large structures. A set of final considerations are offered on the real possibility of carrying out realistic analysis of complex historic masonry structures. In spite of the modern developments, the study of historical buildings is still facing significant difficulties linked to computational effort, possibility of input data acquisition and limited realism of methods.

Abstract

The degree of similarity between damage patterns often correlates with the likelihood of having similar damage causes. Therefore, deciding whether crack patterns are similar is one of the key steps in assessing the conditions of masonry structures. To our knowledge, no literature has been published regarding masonry crack pattern similarity measures that would correlate well with assessment by structural engineers. Hence, currently, similarity assessments are solely performed by experts and require considerable time and effort. Moreover, it is expensive, limited by the availability of experts, and yields only qualitative answers. In this work, we propose an automated approach that has the potential to overcome the above shortcomings and perform comparably with experts. At its core is a deep neural network embedding that can be used to calculate a numerical distance between crack patterns on comparable façades. The embedding is obtained from fitting a deep neural network to perform a classification task; i.e., to predict the crack pattern archetype label from a crack pattern image. The network is fitted to synthetic crack patterns simulated using a statistics-based approach proposed in this work. The simulation process can account for important crack pattern characteristics such as crack location, orientation, and length. The embedding transforms a crack pattern (raster image) into a 64-dimensional real-valued vector space where the closeness between two vectors is calculated as the cosine of their angle. The proposed approach is tested on 2D façades with and without openings, and with synthetic crack patterns that consist of a single crack and multiple cracks.

Abstract

The brick and tile of the existing masonry structures are precious, so it is not feasible that the components are used as the dismantling unit for maintenance and reinforcement. The homogenization method is an ef ective multi-scale calculation method, which can be used to establish the analysis model of masonry on the mesoscopic-level. The plane tessellation deconstruction method of masonry structure is proposed, exploring the internal tessellation laws of masonry under dif erent bricklaying methods, and the theoretical system of periodic plane segmentation of masonry is established. Based on regular tessellation theory, the plane segmentation of masonry structures under three kinds of bricklaying methods is periodically carried out through rectangular unit lattice. Deconstructing the smallest element of the tessellation form, the boundary condition of equivalent volume element (RVE) is derived. On the premise of selecting reasonable material parameters, RVE models under three kinds of bricklaying methods are built by finite element software ABAQUS, and the equivalent parameters are obtained to realize the simulation analysis of masonry structure based on micro-mechanics. The results show that the strength of running bonding RVE is higher than that of the other two kinds, and the strength of header bonding RVE is the lowest. The finite element results are compared with the compressive strength results of the specimens under three kinds of bricklaying methods in the existing tests. The results are in good agreement, which shows that the compressive capacity of masonry structures with homogenization simulation under three kinds of bricklaying methods is reliable while homogenization reflects the mechanical characteristics of masonry structure as a whole. The rigid homogenization method based on regular tessellation theory takes brick by brick as components to be dismantled and replaced in the ancient architecture, which opens a new way for the fine analysis of masonry structure. The rigid homogenization method maximizes the protection of the ancient masonry structure, which is of great significance for the protection of human cultural heritage.

Abstract

Masonry arch bridges are found in large numbers on the rail networks of Europe and other parts of the world. However, the mode of response of masonry arch structures subjected to railway loading is little understood. To address this, an experimental study involving large-scale physical models of backfilled masonry arch bridges subjected to railway loading conditions has recently been conducted. This has explored the influence of the rail track bed system on bridge behaviour and on load carrying capacity. Tests indicate that the track bed system fundamentally alters the mode of response of the bridge system, and significantly increases load carrying capacity. Using the same test facility, load tests have also been used to explore and characterise the behaviour and performance of damaged arch bridges, with the test results obtained suggesting that although there is likely to be a reduction in overall capacity, even a significantly damaged arch bridge can still perform adequately under loading. This has important implications for bridge owners and assessment engineers."br/"\\ud "br/"\\ud "strong"Keywords:"/strong" masonry arch bridges, physical modelling, cyclic loading, rail track system, backfill. Document type: Article