The temperature block length for the wet facing masonry under freezing

Introduction. The outer layer of exterior walls is the facing masonry, experiencing a complex stress-strain state when taking its own weight, climatic loads, and exposures (wind pressure, humidity, and air temperature). An analysis of available research results, as well as the requirements of regulatory documents showed that no consideration is given to the temperature deformations of wet masonry when freezing. In this regard, the studies were conducted to assess the impact of this effect on the stress-strain state of the facing masonry.

Aim. To obtain a universal dependence of the temperature block length of the facing masonry, including its freezing.

Materials and methods. The study is applied to the facing masonry (facing layer) of multilayer exterior walls of buildings, modeled in the LIRA-CAD software package, which implements the finite element method in the form of displacement method. The research results of the work of M.A. Mury "Temperature deformations of wet brickwork" (2008) are used here.

Results. An empirical dependence of the temperature block length of the facing masonry for exterior multilayer walls is obtained based on the analysis of the thermal stress state of the masonry resulting from numerical calculation. A logically justified structural solution of the facing masonry unit with antifriction interface with the floor slab is proposed.

Conclusions. According to the results, the length of the masonry temperature block is not only affected by the temperature difference and the stiffness of the supporting structure, but also by the humidity conditions of its operation. When the humidity of the masonry increases from 6 to 12 %, the design length of the temperature block significantly decreases. The lengths of temperature blocks, set according to existing methods (including methods of design standards), have an overestimated value, and thus the durability of facing masonry is essentially reduced, or even destructed in a number of cases.

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