Energy Model in Calculating the Strength Characteristics of the Reinforced Concrete Components

2018 ◽  
Vol 931 ◽  
pp. 36-41 ◽  
Author(s):  
Valery A. Eryshev
Keyword(s):  
Reinforced Concrete ◽  
Variable Parameter ◽  
Concrete Specimen ◽  
Balance Equations ◽  
Safe Operation ◽  
Deformation Method ◽  
Stress Diagram ◽  
Deformation Mechanics ◽  
Limit Stress ◽  
Flat Section

The article proposes applying energy from law deformation mechanics of the rigid body to deformation method for calculating the strength of reinforced concrete constructions with the use of diagrams illustrating the deformation of concrete and reinforcement. In terms of the energy theory of strength, concrete and rebar accumulate potential energy in the section of the construction component under stress; based on the contours of the diagram used in calculation it is possible to distinguish a stress diagram for concrete of the compressed zone. The value of the strains is equivalent to the force used for the deformation of the concrete specimen under stress (prism-or cylinder-shaped); the force is equal to the area used in the calculation of the normable diagram. The resolving balance equations are deduced with the use of the flat section hypothesis. The conditions of the stress balance in the section of the construction component are tested with the method of the successive approximation. The variable parameter of approximation is the construction component bending. General deformations (deflections) of the construction components are significantly higher than their limit stress values permitted for safe operation.

scholarly journals Forming Limit Stress Diagram Prediction of Pure Titanium Sheet Based on GTN Model

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1783 ◽  
Author(s):  
Tao Huang ◽  
Mei Zhan ◽  
Kun Wang ◽  
Fuxiao Chen ◽  
Junqing Guo ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Pure Titanium ◽  
Void Volume Fraction ◽  
Void Volume ◽  
Forming Limit ◽  
Stress And Strain ◽  
Gtn Model ◽  
Stress Diagram ◽  
Limit Stress ◽  
Hemispherical Punch

In this paper, the initial values of damage parameters in the Gurson–Tvergaard–Needleman (GTN) model are determined by a microscopic test combined with empirical formulas, and the final accurate values are determined by finite element reverse calibration. The original void volume fraction (f0), the volume fraction of potential nucleated voids (fN), the critical void volume fraction (fc), the void volume fraction at the final failure (fF) of material are assigned as 0.006, 0.001, 0.03, 0.06 according to the simulation results, respectively. The hemispherical punch stretching test of commercially pure titanium (TA1) sheet is simulated by a plastic constitutive formula derived from the GTN model. The stress and strain are obtained at the last loading step before crack. The forming limit diagram (FLD) and the forming limit stress diagram (FLSD) of the TA1 sheet under plastic forming conditions are plotted, which are in good agreement with the FLD obtained by the hemispherical punch stretching test and the FLSD obtained by the conversion between stress and strain during the sheet forming process. The results show that the GTN model determined by the finite element reverse calibration method can be used to predict the forming limit of the TA1 sheet metal.

scholarly journals Increment of Steel Tonnage for Reinforced Concrete School Building Considering Seismic Design

2019 ◽  
Vol 8 (3S3) ◽  
pp. 351-355
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Soil Type ◽  
Research Work ◽  
Variable Parameter ◽  
Peninsular Malaysia ◽  
School Building ◽  
Ground Acceleration ◽  
Seismic Fault ◽  
Moderate Earthquake

A series of Indonesian earthquakes, especially from Sumatra caused vibration on buildings in Peninsular Malaysia like Kuala Lumpur and Penang Island. In East Malaysia, Sabah state has been classified as a region with active local seismic fault. A moderate earthquake with Mw6.1 was occurred in Ranau on 5th June 2015 and caused damage on buildings either the structural or non-structural members. Hence, the implementation of seismic design on new buildings is important to ensure public safety. However, such action has its own pro and contra especially when dealing with cost. Therefore, current research work presents the influence of seismic design consideration on the increment of cost for steel reinforcement. For that purpose, a four storey reinforced concrete school building was generated and used as basic model for analysis, design, and taking off. Two level of seismicity representing by the reference peak ground acceleration, αgR equal to 0.07g and 0.10g has been taken into account in the structural analysis and seismic design process. Besides, three soil type namely as soil type A, soil type C, and soil type E also has been considered as variable parameter. Based on result, total steel tonnage in beams for models considering seismic design increases around 14% to 119% higher than the model without seismic design. For columns, the increment is around 13% to 155%. Generally, total cost of steel used as for concrete reinforcement of the whole structure increases around 13% to 131% depending on the level of seismicity and soil type.

Numerical Simulation of 3-D Failure Process of Reinforced Concrete Specimen under Uniaxial Tension

2007 ◽  
Vol 353-358 ◽  
pp. 949-952 ◽  
Author(s):  
Juan Xia Zhang ◽  
Chun An Tang ◽  
Xiu Yan Zhou ◽  
Xing Jie Hui ◽  
Zheng Zhao Liang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Reinforced Concrete ◽  
Uniaxial Tension ◽  
Process Analysis ◽  
Failure Process ◽  
Plain Concrete ◽  
Concrete Specimen ◽  
Numerical Code ◽  
Concrete Prism

The periodically distributed fracture spacing phenomenon exists in the failure process of the reinforced concrete prism under uniaxial tension. In this paper, A numerical code RFPA3D (3D Realistic Failure Process Analysis) is used to simulate the three-dimensional failure process of plain concrete prism specimen and reinforced concrete prism specimen under uniaxial tension. The reinforced concrete is represented by a set of elements with same size and different mechanical properties. They are uniform cubic elements and their mechanical properties, including elastic modulus and peak strength, are distributed through the specimens according to a certain statistical distribution. The elastic modulus and other mechanical properties are weakened gradually when the stresses in the elements meet the specific failure criterion. The displacement-controlled loading scheme is used to simulate the complete failure process of reinforced concrete. The analyses focus on the failure mechanisms of the concrete and reinforcement. The complete process of the fracture for the plain concrete prism and the fracture initiation, infilling and saturation of the reinforced concrete prism is reproduced. It agrees well with the theoretical analysis. Through 3D numerical tests for the specimen, it can be investigated the interaction between the reinforcement and concrete mechanical properties in meso-level and the numerical code is proved to be an effective way to help thoroughly understand the rule of the reinforcement and concrete and also help the design of the structural concrete components and systems.

scholarly journals DUCTILITY OF REINFORCED CONCRETE SUB FRAME FOR INDUSTRIALIZED BUILDING SYSTEM

2019 ◽  
Vol 81 (2) ◽  
Author(s):  
Ahmed Sabah Aljawadi ◽  
Abdul Kadir Marsono ◽  
Che Ros Ismail
Keyword(s):  
Reinforced Concrete ◽  
Earthquake Engineering ◽  
Precast Concrete ◽  
Accurate Determination ◽  
Concrete Specimen ◽  
Reinforced Concrete Beams ◽  
Test Scheme ◽  
Conventional Concrete ◽  
Frame System ◽  
Building System

An accurate determination of industrialized building system (IBS) frames ductility under alternating lateral loads is the key issue of this study. The performance features of IBS H frame assembly subjected to cyclic lateral pushover test with six attached IBS components are reported. A test scheme of nonlinear elastic sub-frame system is proposed to build an IBS structural building system. This system complies with the requirements of strength and ductility governed by European Codes 2 and 8. The three models are a conventional reinforced concrete H frame system CRCH (Model 1), IBS with steel conventional links as reinforcements IBSHN (Model 2), and special spiral links concrete IBSHS (Model 3). Each model is scaled to 1:5. All models are laboratory examined under cyclic lateral pushover test to failure, where the IBS connections are considered as hybrid partial rigid linking beams to columns. The beam ends are connected to column boxes via a U shaped steel plate. The experimental results of the IBS specimens are compared with the conventional reinforced concrete connection of similar shapes and size in the form of H sub-frame mechanism tested under the same condition. The models are subjected to cyclic lateral load controlled applied at the beam-column connection. The performance evaluation of IBS connections is made via load displacement hysteresis, ultimate and collapse parameter, ductility index, and surface cracks appearances. The conventional concrete specimen is obviously found to display better strength compared to IBS. Conversely, the ductility of IBS H frame specimen with spiral shear links and conventional closed loop links exhibits superior features compared to the conventional concrete specimen which is beneficial to earthquake engineering. It is demonstrated that the performance of the precast concrete structure is highly dependent on the ductile capacity of connectors to each of the IBS component. This is significant especially at the joints such as the beam-to-column connections. Our systematic methods on ductility characterizations of reinforced concrete beams may contribute toward the development of IBS in resisting earthquakes.

scholarly journals Improving the efficiency of power boilers by cooling the flue gases to the lowest possible temperature under the conditions of safe operation of reinforced concrete and brick chimneys of power plants

2018 ◽  
Vol 245 ◽  
pp. 07014 ◽  
Author(s):  
Evgeny Ibragimov ◽  
Sergei Cherkasov
Keyword(s):  
Reinforced Concrete ◽  
Power Plant ◽  
Flue Gas ◽  
Power Plants ◽  
Thermal Power ◽  
Operating Mode ◽  
Flue Gases ◽  
Technical Solution ◽  
Gas Temperature ◽  
Safe Operation

The article presents data on the calculated values of improving the efficiency of fuel use at the thermal power plant as a result of the introduction of a technical solution for cooling the flue gases of boilers to the lowest possible temperature under the conditions of safe operation of reinforced concrete and brick chimneys with a constant value of the flue gas temperature, when changing the operating mode of the boiler.

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