scholarly journals Construction of the interaction curve of concrete-encased composite columns based on the deformation domains of reinforced concrete sections

2015 ◽  
Vol 8 (4) ◽  
pp. 447-466 ◽  
Author(s):  
P. A. S. ROCHA ◽  
K. I. DA SILVA
Keyword(s):  
Reinforced Concrete ◽  
Computer Program ◽  
Axial Force ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Longitudinal Reinforcement ◽  
Limit Values ◽  
Composite Columns ◽  
Interaction Curves ◽  
The Moment

AbstractThis paper proposes a methodology for obtaining the interaction curve for composite steel-concrete sections subject to combined compression and bending based on the deformation domains of reinforced concrete structures defined by ABNT NBR 6118 [1]. For this, were developed expressions for the axial force, the moment and the strains of concrete, longitudinal reinforcement and the elements comprising the metal profile in each deformation domain.Based on these expressions a computer program called MDCOMP (2014) was created. In this study the same limit values of longitudinal reinforcement strain defined by ABNT NBR 6118 [1] were used for the steel profile strains. To verify the numerical implementations performed, the interaction curves and the plastic resistance of the section obtained by MDCOMP program were compared with those determined from the recommendations of Eurocode 4 [2], of ABNT NBR 8800 [3] or literature responses.

scholarly journals CALCULATION SCHEME OF REINFORCED CONCRETE STRUCTURES OF CIRCULAR CROSS-SECTION UNDER BENDING WITH TORSION

2021 ◽  
Vol 17 (3) ◽  
pp. 63-82
Author(s):  
Vladimir Kolchunov ◽  
Sergey Bulkin
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Concrete Structures ◽  
Circular Cross Section ◽  
Shear Stresses ◽  
Reinforced Concrete Structures ◽  
Dowel Action ◽  
The Moment ◽  
External Forces ◽  
Spatial Section

The developed design diagram of the ultimate resistance of reinforced concrete structures in bending with torsion of circular cross-sections most fully reflects the features of their actual exploitation. For a spatial crack of a diagonal large ellipse, sections are taken in the form of a swirling propeller with concave and convex spatial parabolas from the first and second blocks between vertical transverse circular sections from the beginning to the end of the crack. For practical calculations in compressed and tensioned concrete, a polyline section of three sections is considered: two longitudinal trapezoids and the third middle section of the radius curve of a small ellipse close to forty-five degrees. When calculating unknown forces, solutions of the equations of equilibrium and deformations of the sections are made up to the end of the crack passing through the moment points for the resultant moments and the projections of internal and external forces. Shear torsional stresses along the linear longitudinal sections of the trapezoid were presented, as well as normal and shear stresses located on the end cross-sections at a distance x from the support. The height of the compressed area of concrete decreases with an increase in bending moments in the spatial section between the first and third cross-sections. It is found in their relationships and connections. The dowel action of reinforcement is determined using a special model of the second level with discrete constants. The static loading scheme was considered from the standpoint of an additional proportional relationship between the torques along the length of the bar in the spatial section and the first and third transverse sections. For a dangerous spatial crack, when projected onto the horizontal axis, the length C was found from a diagonal large ellipse of a round bar.

scholarly journals Computer-Aided Construction at Designing Reinforced Concrete Columns as Per Ec

2015 ◽  
Vol 20 (1) ◽  
pp. 183-200
Author(s):  
M. Zielińska ◽  
K. Grębowski
Keyword(s):  
Reinforced Concrete ◽  
Computer Program ◽  
Load Capacity ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Methodology And Phenomena ◽  
C Programming ◽  
European Standards ◽  
Buckling Length ◽  
The Impact

Abstract The article presents the authors’ computer program for designing and dimensioning columns in reinforced concrete structures taking into account phenomena affecting their behaviour and information referring to design as per EC. The computer program was developed with the use of C++ programming language. The program guides the user through particular dimensioning stages: from introducing basic data such as dimensions, concrete class, reinforcing steel class and forces affecting the column, through calculating the creep coefficient taking into account the impact of imperfection depending on the support scheme and also the number of mating members at load shit, buckling length, to generating the interaction curve graph. The final result of calculations provides two dependence points calculated as per methods of nominal stiffness and nominal curvature. The location of those points relative to the limit curve determines whether the column load capacity is assured or has been exceeded. The content of the study describes in detail the operation of the computer program and the methodology and phenomena which are indispensable at designing axially and eccentrically the compressed members of reinforced concrete structures as per the European standards.

scholarly journals Collapse rates of reinforced concrete structures during large magnitude earthquakes: case study for Romania

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Florin Pavel
Keyword(s):  
Reinforced Concrete ◽  
Seismic Event ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Large Magnitude ◽  
Rc Structures ◽  
High Rise ◽  
The Moment ◽  
Water Tanks

AbstractThis case study focuses on the evaluation of the collapse rates of various types of reinforced concrete structures (residential and industrial) as observed from the data collected in Romania after the Mw 7.4 Vrancea earthquake of March 4, 1977. The results of the analyses show that the largest collapse rates were attributed to elevated reinforced concrete silos and water tanks. Moreover, the majority of the collapsed elevated reinforced concrete water tanks were full at the moment of the seismic event. Very small collapse rates were observed for high-rise residential RC structures and for the multi-storey industrial RC structures.

scholarly journals CRACK RESISTANCE OF REINFORCED CONCRETED AND REINFORCED RUBBER CONCRETE BEAMS

2020 ◽  
Vol 1 (22) ◽  
Author(s):  
Artem Levchenko ◽  
Aleksei Polikutin ◽  
Dmitry Barabash
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Crack Resistance ◽  
Voltage Drop ◽  
Concrete Structures ◽  
Polymer Concrete ◽  
Reinforced Concrete Structures ◽  
Longitudinal Reinforcement ◽  
Structural Element ◽  
Concrete Body

The issue of the appearance and development of cracks, as well as an increase the cracking moment is of particular importance for bending elements operating under aggressive environmental conditions. In structures without cracks, steel reinforcement operates in fairly favorable conditions. However, when cracks appear in the sections of the structural element, the reinforcing bar is exposed to aggressive environmental influences, the voltage drop across the reinforcement also increases, etc.In reinforced concrete structures, tensile stresses are perceived by reinforcing bars, an increase in the content of longitudinal reinforcement in the section leads to some increase in crack resistance of structures, however, an increase in the percentage of longitudinal reinforcement causes a number of undesirable phenomena such as increased consumption of reinforcement and increased weight of the structure. Also, the introduction of reinforcement into the concrete body does not eliminate such disadvantages of concrete as susceptibility to corrosion, low elasticity, low tensile strength and tensile strength. The use of polymer concrete improves these properties of reinforced concrete structures, while the density of fiber rubcon and rubcon is slightly lower than that of traditional concrete, and, consequently, the weight of structures made of this polymer concrete.

Design of precast reinforced concrete structures of frame buildings: a new set of rules

2019 ◽  
pp. 4-9 ◽  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Building Frames ◽  
Fine Grained ◽  
Rigid Frame ◽  
Floor Slabs ◽  
Frame Buildings ◽  
Spatial System ◽  
Precast Elements

Currently, prefabricated reinforced concrete structures are widely used for the construction of buildings of various functional purposes. In this regard, has been developed SP 356.1325800.2017 "Frame Reinforced Concrete Prefabricated Structures of Multi-Storey Buildings. Design Rules", which establishes requirements for the calculation and design of precast reinforced concrete structures of frame buildings of heavy, fine-grained and lightweight structural concrete for buildings with a height of not more than 75 m. The structure of the set of rules consists of eight sections and one annex. The document reviewed covers the design of multi-story framed beam structural systems, the elements of which are connected in a spatial system with rigid (partially compliant) or hinged joints and concreting of the joints between the surfaces of the abutting precast elements. The classification of structural schemes of building frames, which according to the method of accommodation of horizontal loads are divided into bracing, rigid frame bracing and framework, is presented. The list of structural elements, such as foundations, columns, crossbars, ribbed and hollow floor slabs and coatings, stiffness elements and external enclosing structures is given; detailed instructions for their design are provided. The scope of the developed set of rules includes all natural and climatic zones of the Russian Federation, except seismic areas with 7 or more points, as well as permafrost zones.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

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.

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