CALCULATION OF FLEXIBLE CONCRETE BEAMS WITH BASALT REINFORCEMENT

Аннотация

INTRODUCTION concrete, the distance between the element In construction practice, using mirror composite reinforcements, conducting research in the supports and the amount of the load. directions of increasing the fire resistance and elasticity module of concrete, and improving the At small values of the loads in the loading stages, stress-deformation state, strength, and crack Q=0.2-0.3Qult, the deflections of the sample beams resistance properties of bending elements has become one of the urgent tasks. According to the did not become large (f≤0.4mm ) and they study and analysis of scientific research works, the increased almost linearly. With the increase of the operation of flexural concrete structures equipped with basalt reinforcements under the influence of load on the steps, the graph showed a curved forces in the conditions of our republic has not yet character, and in cases where the load values are been sufficiently studied. Q≥0.4Qult, a sharp increase in coolness is observed. Basalt reinforcements produced in the Republic of Uzbekistan are the most optimal option for At values of Q>0.6Kult, the thicknesses increased conducting research on normal heavy concretes, which are used in the construction practice in the sharply and their amount increased to 2.4-3.0mm. largest volume and in all types of construction In this case, it is possible to observe the high objects. deformability of baalt reinforcements. The main part. The coolness of flexural concrete beams with basalt reinforcement depends on the It was observed that before the occurrence of reinforcement of the beam, the strength of the boundary conditions in the beams, the deflections https://www.theamericanjournals.com/index.php/tajet 84 THE USA JOURNALS THE AMERICAN JOURNAL OF ENGINEERING AND TECHNOLOGY (ISSN – 2689-0984) VOLUME 06 ISSUE08 in them reach f=3.4-4.0mm. 1 1 1 = ( ) +( ) (2) 𝑟 𝑟 1 𝑟 2 Before limit states occur in flexural concrete - for sections with cracks in the extension zone elements with basalt reinforcement, together with 1 1 1 1 their strength, uniformity is required. In addition to = ( ) −( ) +( ) (3) 𝑟 𝑟 1 𝑟 2 𝑟 3 the calculation of stability conditions, they must Here: also be calculated for coolness. 1 1 ( ) ,( ) - curvatures resulting from the Determining the calculated stiffness in the sample 𝑟 1 𝑟 2 beams was carried out in the following order (1). continuous action of short-term loads and temporary long-term loads, respectively. Calculation of elements of constructions according 1 to coolness is carried out based on the following ( ) − curvature resulting from the non- 𝑟 1 condition: continuous effect of all loads, which are calculated 𝑓 ≤ 𝑓 (1) according to deformations; 𝑢𝑙𝑡 where: f is the cooling of the element due to 1 ( ) − curvature resulting from the non- 𝑟 2 external load; f_ult is the limiting coolness allowed permanent effects of permanent and temporary in the element. long-term loads; The stiffness of constructions is determined 1 ( ) − curvature resulting from the continued according to the general rules of construction 𝑟 3 mechanics, depending on the bending, sliding and effect of permanent and temporary long-term axial deformation characteristics (curvature, loads. angles, displacement, etc.) of its sections along the The curvature 1/r caused by the corresponding length of the element. loads is determined by the following formula: For flexural elements with a constant cross-section 1 𝑀 = , (4) 𝑟 𝐷 along the length of the element without cracks, the where: M is the bending moment caused by the deflections are determined based on the general external load (taking into account the moment rules of construction mechanics using the unity of created by the longitudinal force N), this moment is the cross-sections. created with respect to the axis normal to the plane The full curvature of bending elements is of action, and the given cross section of the element determined by the following formulas: passes through the center of gravity; - for sections without cracks in the extension zone: D is the bending stiffness of the given cross-section https://www.theamericanjournals.com/index.php/tajet 85 THE USA JOURNALS THE AMERICAN JOURNAL OF ENGINEERING AND TECHNOLOGY (ISSN – 2689-0984) VOLUME 06 ISSUE08 of the element, its value is determined according to where: I is the moment of inertia of the cross- the following formula: section of the concrete section with respect to the center of gravity of the element; I_f-the moment of 𝐷 =𝐸 ∙𝐼 , (5) 𝑏1 𝑟𝑒𝑑 inertia of the surface of the cross-section of the where: E_b1 is the deformation modulus of cross-section of the stretched armature relative to compressed concrete, this modulus is determined the center of gravity of the element; depending on the duration of the impact of loads 𝛼 is the coefficient of bringing reinforcement to and the presence or absence of cracks; I_red is the 𝑓 concrete, moment of inertia of the given cross-section relative to the center of gravity of th