CRACK RESISTANCE OF PRESTRESSED REINFORCED CONCRETE FRAME STRUCTURE SYSTEMS UNDER SPECIAL IMPACT

2021 ◽  
Vol 95 (3) ◽  
pp. 15-26
Author(s):  
V.I. KOLCHUNOV ◽  
◽  
К.YU. KUZNETSOVA ◽  
S.S. FEDOROV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Concrete Strength ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Concrete Element ◽  
Concrete Body ◽  
High Strength Fiber

A variant of the crack resistance criterion and the strength criterion of plane-stressed structures made of high-strength fiber-reinforced concrete, fiber-reinforced concrete is proposed. The criteria are based on the theory of plasticity of concrete and reinforced concrete G.A. Genieva. In general, the condition for crack resistance of a plane-stressed fiber-reinforced concrete element is presented in the form of an ellipse with jumps on the coordinate axes of the main reduced stresses. The strength condition of a fiber-reinforced concrete element is described by a complex figure that takes into account cracking in the element under a plane stress state. The characteristic points on the coordinate axes are calculated from the physical and mechanical characteristics of concrete strength, obtained as a result of testing high-strength fiber-reinforced concrete for uniaxial compression and uniaxial tension with “dissolved” fiber in the concrete body and reinforcement reduced to concrete. The results of a comparative analysis of the criteria for crack resistance and strength of high-strength concrete and high-strength fiber-reinforced concrete are given, depending on the percentage of fiber in the concrete body and the type of fiber used. The proposed analytical dependences can be used to analyze the crack resistance and strength of plane-stressed reinforced concrete beams-walls reinforced with fiber, corner zones of shallow shells and other plane-stressed structures made of high-strength fiber-reinforced concrete and fiber-reinforced concrete.

scholarly journals Results of experimental studies of high-strength fiber reinforced concrete beams with round cross-sections under combined bending and torsion

2020 ◽  
Vol 16 (4) ◽  
pp. 290-297
Author(s):  
Vladimir I. Travush ◽  
Nikolay I. Karpenko ◽  
Vladimir I. Kolchunov ◽  
Semen S. Kaprielov ◽  
Alexey I. Demyanov ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Concrete Beams ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Fiber Reinforced ◽  
High Strength Fiber ◽  
Round Cross

The aim of the work - experimental investigation on crack propagation and deformation in high-strength fiber reinforced concrete beams with round cross-sections under combined bending and torsion for the development of practical methods of crack resistance, deformation and strength analysis of such structures, and also for the accumulation of new experimental data on resistance under combined loading. Method is experimental-theoretical. Results. Deflection plots and force-deformation relationships for high-strength fiber reinforced concrete beams with round cross-sections under combined bending and torsion are determined experimentally. Principal deformations in terms of elongation and compression of concrete for the experimental beam structures with high torsion to bending moment ratio are determined. It is established that for high-strength fiber reinforced concrete structures of circular cross-section, generally, development of one-two discrete cracks is observed, therefore the circular shape of the cross-section slightly reduces the concentration defined by the material structure of high-strength concrete. On the basis of the conducted investigation on high-strength fiber reinforced concrete structures with circular sections, new experimental data on the combined stress-strain state in the studied areas of resistance is obtained, such as: values of generalized cracking, and failure, load, its level relative to the ultimate load; distance between the cracks at different stages of crack propagation; crack widths at principal reinforcement axis level, at a double diameter distance from the principal rebar axes and also along the entire crack profile at various stages of loading; coordinates of nonplanar crack formations; patterns of crack formation, development and opening in reinforced concrete structures under combined bending and torsion.

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