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Using steel jackets around reinforced concrete columns is a widespread technique for static and seismic retrofitting applications. The dimensionless interaction diagrams for reinforced concrete columns strengthened with steel angles are not attempted yet. Thus, this paper presents the formulation of dimensionless interaction diagrams for reinforced concrete columns strengthened with steel angles and strips. The axial loads and uniaxial bending moments are calculated using the plastic stress distribution method, and then the dimensionless interaction diagrams are generated. These diagrams enable analysis (estimation of the column load carrying capacity) and design (required amount of steel reinforcement) of such columns. Numerous examples are given to explain the Use of the new proposed diagrams. These examples have shown that the new proposed charts are straightforward in structural analysis and design applications. [ABSTRACT FROM AUTHOR]

The drawing method of diagrams "bending moment – curvature" that describe the cross-section stress-strain state of the reinforced concrete elements with consideration of an axial force is proposed in the article. Diagrams "bending moment – curvature" at different values of an axial force are shown. It is seen from the diagrams that compressive axial force increases the crack resistance of the cross-section but leads to the brittle destruction. The maximum bearing capacity of the cross-section is reached with application of the reduced axial force αN=0,4. Results of the reinforced concrete frame analysis with the usage of diagrams "bending moment – curvature" drawn with and without consideration of axial forces are compared with the results of the experimental research. Mistake does not exceed 1-2%. [ABSTRACT FROM AUTHOR]

The article presents a method for calculating reinforced concrete floors using an approximation in the form of a cross-rod system. It is shown that the appearance of cracks in the concrete changes the bending and torsional stiffness of the floor elements. However, almost all software solutions for structural analysis account only for the change in the bending stiffness of the rod elements, as a result of the formation of cracks. The torsional stiffness, on the other hand, remains the same and does not change during the iterative calculations. As a result of this lack of consideration, the forces in complex statically indeterminate systems are obtained with errors. To eliminate this drawback, it is proposed to account for the change in the torsional stiffness of the rods as a result of cracking. Formulas are provided to account for the change in bending and torsional stiffnesses, due to the formation of cracks, as part of the iterative calculations of floors and cross-rod systems. It is shown that after calculating the cross-rod system, it is easy to account for the forces in a solid slab. The formulas for the transition from the bending and torsion of the rod system, to the bending and torsion of a solid slab are provided. A method for determining the reactions in the supports of the elements that are used in the calculation of rod systems, by the displacements method is provided, taking into account the variable stiffness along the length of each element. This, as a result, increases the accuracy of the forces being determined. Using a reinforced concrete cross-rod system with plan dimensions of 6000x6000 mm, as an example, it is shown that when the change in the torsional stiffness of the rods, due to the formation of cracks is accounted for, the torsional moments in the rods can vary by more than 260%, compared to the calculation without taking into account the change in torsional stiffness. Bending moments differ up to 20%. These results show that when designing statically indeterminate reinforced concrete systems, it is important to account for the variation in the torsional stiffness of the elements, as a result of concrete cracking. [ABSTRACT FROM AUTHOR]

The paper deals with dynamic response of cylindrical steel reinforced concrete tank subjected to earthquake loading. When a tank containing liquid vibrates, the fluid filling exerts additional hydrodynamic pressure together with hydrostatic pressure on solid domain of the tank. Dynamic analysis of a liquid–filled tank can be done using the concept of generalized single – degree – of freedom (SDOF) systems representing impulsive and convective modes of vibration of the tank – liquid system. The dynamic response of cylindrical tank subjected to earthquake loading are total base shears, total bending moment and total overturning moment. [ABSTRACT FROM AUTHOR]

The aim of this research work is to study the most important parameters that affect the loading capacity and behavior of elliptical ring reinforced concrete beams with (L) section. Twenty specimens were modelled using ETABS Software to study the effect of changing the length of the major axis (while keeping the ratio of the major to minor axis equal to 0.64), width, height, thickness, and loading type. The maximum values of negative bending and torsional moments in addition to midspan deflection increase by 1.24-8.24%, 1.33-11.43%, and 32.5-131%, respectively when the major axis of beam increases by 20-60%. Whereas, major axis increase leads to decrease the maximum positive bending moments and load capacity by 5.91-4.45% and 26.5-52.9%, respectively. That happens due to the extending of span length that happened because of major axis increase. When the beam height increases by 25-75%, the maximum positive and negative bending moments (M+ve) and (M-ve), torsional moments and load capacity increase by 33.92-102.4%, 33.92-100%, 29.84-89.74% and 38.8-116.6%, respectively. While this increase in height leads to maximum deflection decrease by 5-8.4%. That happens because the beam sectional area increases due to increasing beam height. M+ve and M-ve, load capacity and midspan deflection decrease by 0.33-7.9%, 1.61-1.1%, 4-20%, and 11-30%, respectively when beam width increases by 46.6-140%. While this increase in width leads to torsional moment to increase by 2.15-0.87%. The sectional area of beam increases because of width increase, i.e., additional strength capacity. When thickness of beam increases by 100-500%, M+ve, M-ve, load capacity and maximum deflection decrease by 4.25-18.8%, 2.3-16.2%, 7.4-37% and 19.8-67%, respectively, whereas the torsional moments increase by 1.42-0.12%. Finally, torsional moments increase by 0.68-1.49 %, respectively due to testing through partial or full uniform load by 20-100% length of span. [ABSTRACT FROM AUTHOR]

The current work presents a study on strength and behavior of reinforced concrete T-section elliptical ring deep beams through the finite element technique. The parameters that were taken into consideration are diagonal axis (major axis) with the same major axis to minor axis ratio, height, flange thickness, web thickness, and compressive strength of concrete. It is found that the maximum values of positive bending moment (Mmax+ve), maximum negative bending moments (Mmax-ve), maximum torsional moments (Mmaxtor) and deflection increase by about 0.12-0.77%, 1.86-4.9%, 1.9-3.77% and 22.7-77.9%, respectively when the beam diagonal axis increases by 16-50%. Mmax+ve, Mmax-ve, Mmaxtor and load capacity increase by about 68.43-135.3%, 71.13-142%, 61.89-123.8%and 71-142%, respectively when the beam height increases by 50-100%. While the increase in height leads to decrease in the maximum deflection by about 4.62-5.33%. Mmax+ve, Mmax-ve, load capacity and max deflection decrease by about 0.38-4.04%, 1.135-6.25%, 1.51-6.06%, 13.5-30.9%, respectively when the flange thickness increases by 100-200%. While the increase in flange thickness leads to increase in the Mmaxtor by about 0.57-0.42%. Mmax+ve, Mmax-ve, Mmaxtor, load capacity and max deflection increase by about 210.4-446.8%, 156.63-374.9%, 216.5-494%, 215.4-469.2% and 82.4-129.8%, respectively, when concrete web thickness increases by 50-100%. Mmax+ve, Mmax-ve, Mmaxtor, load capacity and max deflection increase by about 15.69-42.49%, 15.78-41.62%,15.81-41.7%, 16.92-44.61% and -0.37-0.37%, respectively, when concrete compressive strength increases by 33.33-100%. [ABSTRACT FROM AUTHOR]

Bar elements pretensioned by unbonded steel reinforcement placed in narrow ducts are considered in this paper. Such elements find one of their main applications in the field of post-tensioned reinforced concrete. One of the main features of the post-tensioned concrete beams is an interaction between pretensioned strand and rest of the construction body which appears like a distributed balancing load. Increasing of the beam deflection leads to tensioning force change in its strands. This affects to the balancing load that in turn differs the subsequent deflection increasing. Analysis of influence of changing balancing load to equilibrium of cross sections of simply supported post-tensioned reinforced concrete beam has been made in the proposed article by methods of applied mechanics of materials. It is shown that increasing deflection of the beam and corresponding growth of balancing load are compensated by bending moment caused by eccentrical compression of the beam. [ABSTRACT FROM AUTHOR]

In this paper, the application of light gauge steel to composite plate structures was studied experimentally. The light gauge steel section was intended to replace reinforcing bars on the reinforced concrete structures. Observations were conducted for 6 specimens. They were 3 specimens of conventional reinforced concrete structures and the other 3 specimens of composite light gauge steel and concrete ones. All of the specimens had a typical dimension of 300 mm width with 3 variations of the section depths: 80, 100, and 120 mm. The specimens were positioned on the simple supports with a 2000 mm effective span length. Two-point loads loading scheme was subjected to the specimen. The load increased monotonically until the ultimate condition was obtained. The delayed first crack was found on the composite specimens, while on the reinforced concrete, it occurred at the earlier stage of loading. Different types of ultimate conditions were found: compression failure on the uppermost fiber of composite specimen, crack on the pure bending moment and shear spans. As expected, the ultimate load increased linearly as the plate depth increased. Effect of different cross-sectional areas and material's grade between reinforcing bars and the light gauge steel section was considered to obtain equivalent the ultimate load from two different types of the specimens. [ABSTRACT FROM AUTHOR]

The purpose of this study is to compare the strength, crack resistance and deformation of T-section beams made of reinforced concrete, rubber concrete and fiber rubber concrete. Rubber concrete (or abbreviated rubcon) is a highly effective composite polymer concrete based on liquid rubber, which has favorable physical and mechanical characteristics, as well as almost universal chemical resistance to aggressive media. This article presents the results of testing prototypes of T-beams using the following procedure. The beams were tested for bending by two forces applied in thirds of the span, increasing until failure. As longitudinal reinforcement, rods of class A500C were used. As transverse - Bp500, 5 mm in diameter, with a pitch of 50 mm. Fiber reinforcement is represented by steel fibers (ratio of diameter to fiber length 1/100), located randomly throughout the volume of the experimental beams. The section of the beams is assigned taking into account the requirements of SP 63.13330.2018 "Concrete and reinforced concrete structures": length - 1400 mm; web height - 95 mm; web width - 60 mm; flange height - 25 mm; flange width - 240 mm. It was found that the value of the destructive experimental bending moment in reinforced concrete beams is 1.20 times less than in rubcon and fiber rubcon beams. It was revealed that the most effective use of the strength of a normal section before reaching the maximum allowable deflection is observed in a rubcon beam (BKT240x95x25-2x10). [ABSTRACT FROM AUTHOR]

This paper displays the horizontal curvature (circular curvature) effect on deep beams using finite element analysis. Thirty-five reinforced concretes horizontally arched deep beams were analyzed. The parameters that were taken into consideration in the current work are the curvature angle (α) and beam height (H) while keeping one constant value for the beam length (L), i.e., different length to depth ratios (L/H). It is found that for L/H=2; the load capacity decreases by about 38-73% and 16-67%, respectively, when changing α from ∞ (straight beam) to 180 degrees, while torsional moments increase by about 74-174%. Negative bending moments decrease by about 13-56% when changing α from 30 to 180 degrees. The deflection decreases by about 0.1-1.8% when changing α from ∞ to 90 degrees. For L/H=2.5; The load capacity decreases by about 36-73% and 15-67%, respectively, when changing α from ∞ to 180 degrees, while torsional moments increase by about 73-168%. Negative bending moments decrease by about 14-57% when increasing α from 30 to 180 degrees. Decreasing deflection by about 4.1-5.9% when increasing α from 60 to 90 degrees. For L/H=3; load capacity decreases by about 34-73% and 14-68%, respectively, when changing α from 0 to 180 degrees, while torsional moments increase by about 71-161%. Negative bending moments decrease by about 15-58% when increasing α from 30 to 180 degrees. The deflection decreases by about 6-9.7% when increasing curvature angle from 60 to 90 degrees. For L/H=3.5; the load capacity decreases by about 34-73% and 14-69%, respectively, when changing α from 0 to 180 degrees, while torsional moments increase by about 70-156%. Negative bending moments decrease by about 15-59% when changing α from 30 to 180 degrees. Midspan deflection decreases by about 4.6-14.7% when changing α from 60 to 120 degrees. Finally, it is found that for L/H=4; The load capacity decreases by about 33-74% and 14-69%, respectively, when changing α from 0 to 180 degrees, while torsional moments increase by about 69-150%. Negative bending moments decrease by about 16-60% when changing α from 30 to 180 degrees. Changing α from 60 to 120 degrees leads to decrease deflection by about 9.1-19.4%. [ABSTRACT FROM AUTHOR]

The current work presents a parametric study for twenty-five reinforced concrete overhang curved deep beams using finite element analysis. The parameters that were taken into consideration are radius, height, width, compressive strength of concrete and number of supports. It is found that the max positive moments increase by about 2.8-4.4% when decreasing the radius of beam by about 16-33%. The max negative bending moment, max torsional moments and max deflection decrease by about 1.9-12.4%, 0.4-8.9% and 30-87%, respectively, when beam radius decreases by 16-66%, whereas load capacity increases by about 23-195%. The max positive bending moment, max negative bending moment, torsional moment and load capacity increase by about 32-128%, 30-124%, 31-125% and 31-127% respectively, when the beam height increases by 12.5-100%, while deflection decrease by about 9-18%. The max positive bending moment, max negative bending moment, torsional moment, load capacity and max deflection increase by about 32-147%, 29-134%, 30-138%, 32-146% and 1.2-4.9%, respectively when beam width increases by 12.5-50%. The max positive bending moment, max negative bending moment, torsional moment, load capacity and max deflection increase by about 17-70%, 15-61%, 15-63%, 17-69% and 0.1-0.4%, respectively, when concrete compressive strength increase by 33-166%. Finally, it is found that the max positive bending moment increases by about 32% when increasing number of supports by 33%. Max negative bending moment and capacity of load increase by about 17-60% and 106-763%, respectively, when number of supports increases by 33-133%. Torsional moment and max deflection decrease by about 0.8-16% and 29-78%, respectively when number of supports increases by 33-133%. [ABSTRACT FROM AUTHOR]

Multi story Reinforced concrete cement Structure exposed to hazardous earthquakes. It was discovered that main reason behind failure of RC building is irregular distribution of mass, stiffness and strength or because of irregular geometrical arrangements. In reality, many existing structures contain irregularity because of useful and stylish prerequisites. However, past earthquake records show the poor seismic behaviour of this structure. The contextual analysis right now stresses onauxiliary conduct of multi-story working for various arrangement shapes like rectangular shape, H, U, L and plus shape. Demonstrating of 12-stories reinforced concrete frame structure is done on the ETABS programming for analysis. Post analysis of the structure of bending moments, maximum storey displacement and maximum shear force are computed and then compared for all the analysis result cases. For analysis of the structure response spectrum analysis is used. [ABSTRACT FROM AUTHOR]

The contemporary situation shows that the influence of soil structural interface (SSI) might be adverse to the seismic reaction of structure and abandoning soil structural interface in the analysis may lead to a risky strategy. Although this, the customary design procedure usually involves a postulation of the fixed condition at the base of foundation avoiding the flexibility of the base of the structure, the contractibility of soil mass and as a result, the effects of foundation settlement on additional rearrange of bending moment and shear force demands. The effects of SSI are examined for G+15 story vertical irregularity high-rise RC building resting on a raft foundation. Two methods are used to evaluate the target MRF RC building: Equivalent Static Load Method (ESLM), Response Spectrum Method (RCM). To acquire the statistical result by using SSI modal situation are those consistent to fixed-base support condition and the ultimate response of story shear, story displacement, and story drift are analyzed. [ABSTRACT FROM AUTHOR]