STRESS-STRAIN STATE OF MASONRY OF CHIMNEY TRUNKS FROM DEAD LOAD, WIND LOAD AND TEMPERATURE EFFECT

Nowadays there are more than 3000 masonry chimneys in Ukraine. The life of most chimneys is more then 20 years, about 20 % of the chimneys are operated for more than 50 years. Inspection of the technical condition of the chimneys, evaluation of their load-carrying capacity and design of recommendations for further work of chimneys is an actual research task. There are no actual normative documents about calculation and design of masonry and reinforced concrete chimneys in Ukraine. In reference literature and normative documents, the design scheme of the chimney trunk is adopted in the form of a cantilever beam. In the calculation it is recommended to take into account the longitudinal-transverse bending from the action of the wind load and its own weight, as well as the roll of the foundation. Strength test of the trunk is performed separately for horizontal sections and for vertical sections. For horizontal sections it is performed for longitudinal force and bending moment from its own weight and wind load, for vertical sections - for temperature forces after the temperature drop along the thickness of the barrel wall. This approach doesn't fully reflect the real work of the masonry, which is in a complicated state of stress. Purpose. To perform a comparative calculation of the various trunks of masonry chimney, analyze the factors affecting the stress-strain state of the masonry trunks. Conclusions. It is proposed carry and calculation of the masonry trunks for the temperature impact in elastic stage with regard to join work masonry and clamping rings, taking into account not only the tangential, but also the longitudinal temperature stresses and analyze the work of the masonry in the plane stress state. Proposed calculation makes it possible to determine the moment of formation of force and temperature cracks in the masonry. It is necessary to clarify the stress-strain state and criteria of the trunks strength of masonry chimney under a two-dimensional stress state with the help of numerical and experimental models.