Evaluation of technical condition and influence of fire impact on carrier reinforced concrete structures
Journal Title: Вісник Одеської державної академії будівництва та архітектури - Year 2018, Vol 1, Issue 72
Abstract
Constructions made of reinforced concrete under the condition of high-temperature heating change their operational properties. To estimate the thermal effect, the degree of blackness of the surface of the material, which ranges from 0 for transparent and white surfaces, to 1 for a completely black surface, was used. Other factors that affect the load bearing capacity of the constructions in the fire are the heating conditions. The strength of concrete on the compression of reinforced concrete bearing structures was determined by the method of elastic rebound using a scroll meter. The designs in the viewing area are partially soaked, partially repainted. The crane-beam and its hanging paths of rolled twisted-pair, deformed under the influence of high temperature, are not dismantled. The degree of damage to structures from fire depends not only on the temperature, but also on the time of combustion. Constructions were heated to high temperatures. Comparison of the strength of concrete columns on compression in the fire zone with control test constructions outside the zone of fires showed a decrease of 1,5-2,5 times, concrete rafters in 1,3-1,6 times. During the inspection in the building structures of the building a number of damage was detected: – the columns were under the influence of four-side heating. When tightening the protective layer of concrete did not have good adhesion to the core of the intersection, dull sound and split, which indicates that the concrete has warmed to a temperature of 500-5500S. These injuries indicate the «brittle» nature of the destruction of concrete columns, in which it is impossible to guarantee their integrity during the strengthening. Technical condition of columns – «emergency»; – the brick wall is inside – the masonry is stratified, with small blows hammered fly plates. Due to the fact that the brickwork can withstand the impact of fire only once, the wall has lost its fire properties and are subject to dismantling and replacement. Technical condition – «emergency»; – rectangular and substandard farms – were under the influence of triple heating. The main influence of the temperature was felt by the supporting parts, where the main fire zone was located. The bearing capacity of the farms was partially preserved, as they did not collapse. However, the full load from the crane-beam to the cargo to the farms after the fire was applied. A record of forest felling in the area of 0,001-0,03 m2 at a depth of 10-20 mm, which is the result of explosive destruction of concrete and a reliable sign of fragile destruction of concrete. The technical condition of the farm covers – «emergency». When installing hanging cranes, it is impossible to guarantee the integrity of structures, reinforced concrete columns, trusses and internal brick walls of the surveyed object.
Authors and Affiliations
I. V. Klymenko, A. Y. Gilodo, A. N. , Arsiriy
Keywords
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