Stress and strain studies of historical masonry

Introduction . Brick masonry of historical buildings has a number of features compared to masonry made of contemporary materials. This applies to both strength and strain characteristics. Incorrectly assessed strain of masonry walls, pillars, etc. can lead to a faulty estimate of the magnitude of forces redistributed between them. Aim . To obtain experimental data on the strength and strain of masonry made of historical brick, including that constructed with lime mortar; to use the obtained results for strength and strain studies of masonry reinforced by mortar injection, including in combination with indirect reinforcement, in areas with repairs during the restoration of historical masonry with contemporary one, as well as in locations of combined action of backfill and facing layers. Materials and methods. Compression tests are carried out on historical brick samples in the form of pillars and walls with mortars of various strengths, including lime mortar. Samples with the inner layer (backfill) different in strength and strain from the facing layers are additionally tested for local compression and central compression with a uniformly distributed load. Results . The main strength and strain characteristics of masonry made of historical brick, including those with lime mortar, are obtained. The research results are used in the development of regulatory documents on masonry structures, as well as recommendations and projects for strengthening the masonry structures of historical buildings. Conclusions . The elastic characteristics of masonry with lime and complex lime-admixed mortars are below the standard values. The transverse expansion coefficients of masonry (Poisson’s ratio) for various vertical stresses were obtained to be included in regulatory documents. The compressive strength of the masonry significantly exceeds the values specified in the standards, which is largely due to the quality of performed work as well as specifics of historical bricks masonry.