Kirichenko D. O. Carrying capacity of airfield and road slabs made of fiber concrete.
The dissertation on competition of a scientific degree of the doctor of philosophy on a specialty 192 – Construction and civil engineering. – Odesa State Academy of Civil Engineering and Architecture, Odesa, 2023.
The dissertation study is devoted to the study of the influence of dispersed reinforcement of concrete with steel fiber on the bearing capacity and deformability of airfield and road slabs.
In the introduction, the justification for the choice of the research topic is given, the purpose and tasks of the research, scientific novelty and practical significance of the work are formulated, its general characteristics and connection with scientific programs are presented.
The first section of the thesis presents a detailed review and analysis of the existing normative basis for calculations of road and airfield slabs and publications that reflect the achievements of domestic and foreign scientists regarding the bearing capacity and deformability of airfield and road slabs.
The second section of the work presents the methodology and results of experimental studies of road and airfield slabs.
In accordance with the research program on the strength and crack resistance of road and airfield slabs, two road slabs and two airfield slabs were manufactured by order of the Department of Construction Mechanics at Velikodolynsky Zavod ZBK LLC. Tests of serial plates were preceded by tests of model samples, which became one of the tasks of this work.
A universal stand has been developed for testing models of road and airfield slabs. Computer modeling and finite-element analysis of slabs were performed in two programs - PC LIRA-SAPR and SOFiSTiK. A comparative analysis of the results obtained experimentally, using the finite element method and according to the recommendations of current regulatory documents is given.
The third section of the dissertation is devoted to the calculations of the studied slabs according to normal sections. Theoretical and experimental studies were conducted to determine the bearing capacity. The dimensions of the models of reinforced concrete and steel fiber concrete slabs were 1375x825x65 mm. Both series of slabs were reinforced with a spatial frame, which consisted of two meshes of type Br-1 reinforcement with a diameter of 5 mm.
Reinforced concrete and fiber concrete slabs were considered under two loading schemes ― girder and cantilever.
Models of reinforced concrete slabs were calculated according to the method of L.P. Polyakov, E.F. Lysenko, and L.V. Kuznetsova and according to the method of DSTU B.V.2.6–156:2010 "Concrete and reinforced concrete structures from heavy concrete", models of slabs made of fiber concrete - according to the methodology of DSTU N.B.V.2.6–78:2009 "Instructions for the design and manufacture of steel fiber concrete structures" and according to DSTU–N B V.2.6–218:2016 "Instructions for design and manufacturing structures from dispersed reinforced concrete". For comparison, according to the methodology given in DSTU–NB V.2.6–218:2016, a strength check was also carried out by the diagrammatic method of slab No. 4 made of steel fiber concrete according to bending moments in the cantilever part.
The given values of bending moments for each model of plates, which were obtained theoretically and experimentally, agree well with each other. For reinforced concrete slabs with both load schemes, the deviation is 10%, and for fiber concrete slabs ― 0.4%.
The fourth section of the dissertation presents the calculations of the studied slabs for inclined sections. To carry out calculations of the strength of inclined sections on the effect of transverse forces, models of reinforced concrete slabs were calculated according to the method of L.P. Polyakov, E.F. Lysenko, and L.V. Kuznetsova and according to the method of DSTU B.V.2.6–156: 2010 "Concrete and reinforced concrete structures made of heavy concrete", models of slabs made of fiber concrete - according to the methodology of DSTU N.B.V.2.6–78:2009 "Guidelines for the design and manufacture of steel fiber concrete structures" and according to DSTU–N B V.2.6–218:2016 "Instructions for designing and manufacturing structures from dispersed reinforced concrete". The given values of bending moments for each model of plates, which were obtained theoretically and experimentally, agree well with each other. For reinforced concrete slabs with both load schemes, the deviation is 10%, and for fiber concrete slabs ― 0.4%.
The results obtained in this research work are implemented in the practice of design and operation of buildings, as well as used in the educational process of higher education institutions.
Keywords: road slab, airfield slab, reinforced concrete, fiber concrete, testing, bearing capacity, crack resistance, normal section, inclined section, computer simulation.
