The article discusses the stress-strain state of fiber concrete sewer pipes manufactured by the method of dry vibrocompression. The use of large-diameter underground pipes has increased the number of accidents from soil settlement and seismic impact. The main purpose of this work is to study the effect of the transverse component of the seismic load on underground fiber-reinforced concrete pipes. The change in the stress-strain state was carried out using the Plaxis 2D, Plaxis 3D and SAP2000 programs and was confirmed in experimental tests. Calculation was made in the conditions of plane deformation. In the calculation 15 nodal elements were used. In the study of the effective stresses arising in the pipe the weight of backfill over the pipe, loads from a roadbed and dynamic loads from transport were considered together with the seismic influence. Stresses were calculated separately for the case of a reinforced concrete and fiber concrete pipe with a steel and polypropylene fiber. At the test site of the Research Institute of Building Materials laboratory tests of fiber-reinforced concrete samples for compression, bending, crack resistance, tension and splitting were carried out. The main objective of researches is determination of the optimum quantity of a fiber in a pipe and the necessary design mechanical characteristics of a fiber concrete. The elasticity modulus, Poisson's ratio and the tension loadings were defined. When testing steel fibers of 3D and polypropylene fibers were used. The test results of fiber concrete pipes with various content of steel fiber (20, 30 and 40 kg/m³) showed that 30 kg of fiber per one cubic meter of concrete can be considered optimal for the structure.
Anahtar Kelimeler: Fiber Concrete, Pipe, Stress, Strength, Tension
|
