scholarly journals Reinforcement of Flexural Members with Basalt Fiber Mortar

Fibers ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 26
Author(s):  
Dmitry Kurlapov ◽  
Sergey Klyuev ◽  
Yury Biryukov ◽  
Nikolai Vatin ◽  
Dmitry Biryukov ◽  
...  

Reconstruction of buildings and structures is becoming one of the main directions in the field of construction, and the design and production of works during reconstruction are significantly different from the ones of new buildings and structures. After carrying out a number of studies on the inspection of the technical condition of buildings in order to determine the effect of defects on the bearing capacity, the criteria for assessing the state of floor slab structures were identified. Conclusions on the state and further work of elements of reinforced concrete structures are considered. The authors achieve the aim of reinforcing flexural elements of reinforced concrete structures with fiber-reinforced mortar, which is especially important for floor elements with increased operational requirements. A technique for constructing a reinforcement layer using fiber-reinforced mortar from coarse basalt fiber has been developed. The parameters of basalt fiber in the reinforcement layer are substantiated. A method for solving problems of the operation of multilayer coatings under the influence of operational loads is used, in which the model prerequisites for describing the operation of layers are simplified, where the bearing layers are represented by classical Kirchhoff-Love plates. When solving problems, the maximum possible number of design features of flexural members is taken into account, in combination with appropriate experimental studies, the method allows us to consider all the variety of structures for reinforcing coatings and meet the needs of their practical application.

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.


2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.


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