Вплив високої температури на міцність сталебетонних колон квадратного поперечного перерізу з фібробетонним ядром

Abstract

UA: У статті запропоновано методику розрахунку сталебетонних колон на термосиловий вплив, в яких в якості ядра використовується базальтова та сталева фібра. Виходячи з умов однакової несучої здатності проведено розрахунки на термосиловий вплив колон з різною товщиною сталевої оболонки. Виконано дослідження колони з поперечним перерізом 100х100х3 з різними видами ядра від температури.

EN: The article proposes a methodology for calculating steel concrete columns for thermal force effects, in which basalt and steel fibre are used as a core. For this purpose, it is necessary to determine the prismatic stresses of fibrereinforced concrete with steel and basalt fibres, considering the temperature effect. A column with a transverse dimension of 100x100x3 mm with a core of ordinary concrete 500 mm long and a bearing capacity of 505 kN was selected as a control sample. Based on the conditions of the same bearing capacity, calculations were made for the thermal force effect of columns with different thicknesses of steel shells with cores of concrete with steel and basalt fibres. Graphs of the bearing capacity of a fibre-reinforced concrete column with a core of basalt concrete and steel concrete were constructed as a function of temperature. The graphs show that the characteristic decrease in the bearing capacity of the column at t=100℃, which occurs due to the evaporation of free water from concrete, is absent if the column core is made of concrete with the addition of fibre. This applies to both basalt fibre and steel fibre. At a temperature of t = 100℃, the bearing capacity of columns with the same shell thickness with the addition of basalt fibre is 7.8% higher, and with the addition of steel fibre by 5.8%, respectively, compared to a column with a core without fibre. A column with a cross-section of 100x100x3 with different types of cores was studied as a function of temperature. At a temperature of t=400℃, the column with a basalt concrete core has a bearing capacity 6.5% higher than that with steel fibre, and 13% higher than that without fibre addition. A column with steel fibre in the core has a bearing capacity 6.2% higher than a column without fibre. With a further increase in temperature, the bearing capacity of the columns with different types of fibres begins to converge. This is due to the significant heating of the steel shell and, as a result, a decrease in the strength of the metal.