Improving analytical models for shear design and evaluation of reinforced concrete structures

2010 ◽  
pp. 77-92 ◽  
Author(s):  
Michael P. Collins
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Analytical Models ◽  
Reinforced Concrete Structures ◽  
Shear Design

Nonliear Analysis of Reinforced Concrete Structures Considering Plastic Deformation

2015 ◽  
Vol 802 ◽  
pp. 231-236
Author(s):  
Mirzakhid Khamitovich Miralimov
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Computational Method ◽  
Analytical Models ◽  
Reinforced Concrete Structures ◽  
Strain Diagram ◽  
Stress Strain ◽  
Plastic Properties ◽  
Nonlinear Properties ◽  
Limiting Condition

Analytical models and the basic preconditions for analysis of concrete and reinforced concrete structures should be established based on actual plastic properties of concrete and reinforcement, as well as consideration of presence of cracks in the concrete. It is known that the relationship between stress and strain in reinforced concrete is significantly different in the stage of work with cracks and without them. Development of computational method opens wide prospects in this direction. In this work the calculation of strength and definition of forces in constructive elements of structure from operational loadings are made on the basis of the finite element method. Analysis is carried out with the use of quadrangular isoparametric and beam elements by the method of level-by-level plasticization. Analytical model contains the nonlinear properties of concrete and reinforcement. Method and algorithm of calculation have been developed taking into account of real stress-strain diagrams from experiment. Method and algorithm of calculation of reinforced concrete designs include the limiting condition of deformation on the basis of known stress-strain diagram both for reinforcement and concrete. An example of analysis involving a tunnel structure for an underground station to determine internal forces using the proposed method was shown.

Nonlinear Vibration Characteristics of Fatigue Damaged Reinforced Concrete Structures

2005 ◽  
Vol 297-300 ◽  
pp. 2592-2597
Author(s):  
Jin Ho Kim
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Concrete Structures ◽  
Analytical Models ◽  
Fatigue Properties ◽  
Reinforced Concrete Structures ◽  
Isolation System ◽  
Discrete Crack ◽  
Isolation Systems

In this paper, nonlinear vibration techniques were applied to investigate stages of progressive damage in three vibration isolation systems induced by dynamic loadings. Analytical models for reinforced concrete structures of three isolation systems were developed based on FEM with discrete crack concept. Vibration response spectra and the spectra of forces transmitted through the isolators were computed with respect to stationary dynamic loads. In addition, fatigue properties of concrete structures were examined for given materials’ properties and given geometries. The results indicated that the proposed isolation system 3 can improve fatigue resistance by extending fatigue life and changing the failure mode from shear to flexure.

scholarly journals Probabilistic corrosion time initiation modelling in reinforced concrete structures using the BEM

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Giovanni Pais Pellizzer ◽  
Edson Denner Leonel
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Analytical Models ◽  
Mechanical Degradation ◽  
Reinforced Concrete Structures ◽  
Structural Durability ◽  
Probabilistic Values ◽  
Propagation Period ◽  
Corrosion Time

Abstract The reinforcement’s depassivation in reinforced concrete structures occurs when the chloride concentration at the reinforcement’s interface reaches the threshold content. The depassivation phenomenon starts the propagation period, in which huge mechanical degradation processes are triggered. Moreover, it is well established that the propagation period is considerably shorter than the initiation period. Therefore, the accurate prediction of the corrosion time initiation is a major issue in structural durability domain. This study presents a transient formulation based on the Boundary Element Method (BEM) for the corrosion time initiation assessment. The diffusion fields evaluated by the BEM are utilized into a probabilistic framework, which enables the assessment of probabilistic values for corrosion time initiation. Therefore, the formulation handles properly the uncertainties in this problem, which is largely subjected to randomness. Three applications are presented. The robustness and accuracy of the proposed approach over classical analytical models are highlighted.

scholarly journals Temperature action in analysis of thermal stressed state of massive concrete and reinforced concrete structures

2018 ◽  
Vol 245 ◽  
pp. 03016 ◽  
Author(s):  
Aleksandra Makeeva ◽  
Aleksandra Amelina ◽  
Kirill Semenov ◽  
Yuriy Barabanshchikov
Keyword(s):  
Reinforced Concrete ◽  
Stressed State ◽  
Diurnal Temperature Range ◽  
Thermal Stresses ◽  
Concrete Structures ◽  
Analytical Models ◽  
Reinforced Concrete Structures ◽  
Construction Period ◽  
Massive Concrete ◽  
Temperature Action

The work is dedicated to research of the thermal stresses state of massive concrete and reinforced concrete structures in construction period. The article examines the results of the analysis of the thermal stress state, which occurs in massive concrete ground slab with thickness of 1 m. The study was conducted with using analytical models, which include the factor of diurnal temperature range in comparison with simplified methods. Authors established that solving the problem of thermal stressed state of the massive foundation slabs in the building period without taking into account the influence temperature changing during the month might not cause to significant deviation of the real diagram of the thermal stresses and elongation deformations in the structures body: error is less than 0.5%.

scholarly journals Influence of the stiffness of beam-column connections on the structural analysis of reinforced concrete buildings

2018 ◽  
Vol 11 (4) ◽  
pp. 834-855
Author(s):  
J. B. SANTOS ◽  
T. J. DA SILVA ◽  
G. M. S. ALVA
Keyword(s):  
Reinforced Concrete ◽  
Structural Analysis ◽  
Concrete Structures ◽  
Bending Moment ◽  
Analytical Models ◽  
Reinforced Concrete Structures ◽  
Overall Stability ◽  
Partial Transfer ◽  
Structural Calculation ◽  
Real Behavior

Abstract Conventional structural analysis of buildings in reinforced concrete is performed considering beam-column connections as rigid. However, experimental results prove the existence of relative rotations in beam-column connections of reinforced concrete structures, showing the partial transfer of bending moment. In this study the influence of the stiffness of beam-column connections on the global stability and in the column bending moments of buildings in reinforced concrete was investigated. A building was designed with rigid connections and deformable connections to identify the importance of considering the influence of the stiffness of the beam-column connections in the overall stability of monolithic and in the redistribution efforts in reinforced concrete structures. In order to determine the stiffness rotation of deformable connections, two analytical models available in literature were used, and a comparison between the results obtained by each analytical model was also performed. Based on the results, it is concluded that neglecting the influence of the stiffness of the beam-column connections on the analysis of monolithic reinforced concrete structures may result in different solutions compared to the real behavior of the structure. The stiffness values obtained with the analytical models usually differ from the condition of rigid connections, suggesting an adjustment on the standard consideration of rigid connections adopted by the computer programs of structural calculation.

Experimental Investigation of Corrosion-Induced Cover Cracking in Reinforced Concrete Structures

2011 ◽  
Vol 197-198 ◽  
pp. 1690-1693
Author(s):  
Chun Hua Lu ◽  
Wei Liang Jin ◽  
Jiang Hong Mao
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Test ◽  
Concrete Structures ◽  
Concrete Cover ◽  
Corrosion Products ◽  
Analytical Models ◽  
Reinforced Concrete Structures ◽  
Accelerated Corrosion ◽  
Cover Cracking ◽  
Accelerated Corrosion Test

Concrete cover cracking induced by reinforcement corrosion is an important problem in reinforced concrete structures. Several existing analytical models for cracking time are discussed, and it is found that the penetration of corrosion products into corrosion cracks is neglected in these models. Based on our study, a theoretical model that takes the ingress of rust into cracks into account is proposed to predict the cracking time. In order to analyze the amount of corrosion products deposited in cracks, an accelerated corrosion test was performed. Based on the experimental results, the parameter k, which deal with the ingress of corrosion products into cracks, is calibrated to be 0.1~0.3 for accelerated corrosion test. By comparing the predictions with the test results, it is found that the proposed model has high accuracy in analyzing the cracking time and that the mean absolute error between predictions and observations is about 9.4%.

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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