scholarly journals Upper Bound Method for Yield Design of Reinforced Concrete Slabs Using Conic Programming and an Adaptive Remeshing Strategy

2019 ◽  
Author(s):  
Hector Andres Tinoco
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Upper Bound ◽  
Limit State ◽  
Standard Form ◽  
Numerical Procedure ◽  
Concrete Slabs ◽  
Flow Rule ◽  
Adaptive Remeshing ◽  
Reinforced Concrete Slabs

This study presents a numerical procedure for the analysis of reinforced concrete slabs (RCS) that obey Nielsen's yield criterion (slabs orthogonally reinforced). An upper bound formulation combined with finite elements was established to solve the kinematic theorem as a conic optimization problem with the aim to determine the maximum bearing capacity of RCS. Discrete Kirchhoff finite elements were implemented and adapted to establish a limit state problem for the yield design. By using Nielsen´s criterion, a kinematic criterion was established applying the flow rule of plasticity. The kinematic criterion was included in the upper bound formulation with the aim to constraint the curvatures of the slab. The upper bound formulation was organized in the standard form of a second order cone programming (SOCP) problem since the kinematic criterion was formulated in conic form. Numerical examples were proposed to test the accuracy of the method including the adaptive remeshing strategy.

OPTIMAL DESIGN OF RIGID PAVEMENT MADE OF PREFABRICATED REINFORCED CONCRETE SLABS BASED ON THE RESULTS OF THE CALCULATION OF THE SHEAR RESISTANCE BY FINITE ELEMENTS METHOD

2018 ◽  
Vol 8 (3) ◽  
pp. 4-7
Author(s):  
Anton O. GLAZACHEV ◽  
Liliya Y. GIMADETDINOVA ◽  
Alexey P. GONCHARUK ◽  
Igor V. NEDOSEKO
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Optimal Design ◽  
Finite Elements ◽  
Shear Resistance ◽  
Numerical Calculations ◽  
Concrete Slabs ◽  
Design Tools ◽  
Rigid Pavement ◽  
Reinforced Concrete Slabs

The article presents a comparative analysis of the results of the calculation of rigid pavement on the shear stability obtained by the classical engineering method and using numerical calculations. The conclusion is made about the possibility of using modern design tools to select the optimal design of rigid pavement.

scholarly journals INVESTIGATION OF THE CARRYING CAPACITY OF REINFORCED CONCRETE SLABS WITH CRACKS AFTER THEIR REINFORCEMENT WITH COMPOSITE FABRICS BY THE FINITE ELEMENT METHOD USING THE PRINS COMPUTER COMPLEX

2019 ◽  
Vol 45 (4) ◽  
pp. 142-152 ◽  
Author(s):  
V. P. Agapov ◽  
K. R. Aydemirov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Elements ◽  
Concrete Slabs ◽  
The Finite Element Method ◽  
Design Scheme ◽  
Reinforced Concrete Slabs ◽  
Composite Fabrics ◽  
Element Method

Objectives. The finite element method for cracked reinforced concrete slabs analysis after they were reinforced with composite fabrics in order to determine the residual safety factor is considered. Method. The method is based on the use of algorithms for calculating of structures with the account of the geometrical and physical nonlinearities, implemented in the PRINS program. These algorithms assume the use of the same calculation scheme in the process of the problem solving. However, the specifics of the assigned problem is that the design sсheme of the structure before the appearance of defects in it and after its amplification with the help of composite materials should change. Result. Taking into account this circumstance, the algorithms of nonlinear calculation of structures under the PRINS program were supplemented with an option that allows changing the parameters of the design scheme in the process of through calculation. To study the bearing capacity of reinforced concrete slabs, multilayer finite elements are used, for each of which a specific package of materials is specified. Modernization of the design scheme in this case comes down to replacing one package of materials with another. An example of calculation of a slab with a crack reinforced with composite fabric is given. Conclusion. It is shown that the use of a tunable design scheme can significantly improve the accuracy of calculations. In this case, the final result depends on what stage of the formation of defects in the slab its strengthening is realized. The special  multilayered finite elements of a quadrangular shape are used in calculations. The elements consist of four simple triangles, for which most of the matrix characteristics are calculated in a closed form. This is especially important when carrying out nonlinear calculations that require repeated computations of these characteristics. 

scholarly journals ALGORITHM FOR DEFORMATION ANALYSIS AND EXPERIMENTAL STUDY OF REINFORCED CONCRETE SLABS WITH UNILATERAL BONDS

2017 ◽  
Vol 21 (2) ◽  
pp. 99-109
Author(s):  
I. N. Serpik ◽  
K. V. Muymarov ◽  
S. N. Shvachko
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Thin Layers ◽  
Secant Method ◽  
Deformation Analysis ◽  
Concrete Slabs ◽  
Transverse Cracks ◽  
Reinforced Concrete Slabs

A computation scheme for the analysis of reinforced concrete slabs using the finite element method providing possibility to consider unilateral connections has been developed. The stress-strain state of a slab is modeled taking into account physically nonlinear behavior of concrete and reinforcement, reinforcement discreteness, formation of transverse cracks in concrete. Kirchhoff hypotheses are considered to be true for a slab as a whole. It is believed that reinforcement out of cracks has a perfect adhesion with concrete. Concrete is represented by a system of thin layers, each of which is in a two-dimensional stress state. Approximation of displacements in this multilayer scheme is performed using triangular plate finite elements. Deformation of the reinforcement is described by means of rods working only in tension or compression. Unilateral connections are the contact finite elements. Concrete strength is evaluated according to Karpenko criterion. Deformation of concrete between cracks is described in accordance with Murashev’s approach.On the basis of the principle of virtual displacements assembling of elements takes place. A secant method case providing the convergence of the iterative process for a complex nonlinear problem of this type is proposed. At the first stage, a step-by-step increase of external forces is provided until the actual level of loading is achieved. Only one iteration of the secant method is performed at each step. Then, the iterative solution of the problem with repeated change of secant modulus is applied. The efficiency of this algorithm is confirmed on the basis of theoretical analysis and experiment for a rectangular in terms of bending reinforced concrete slab with free bearing on three sides, and not fixed on the fourth side. Three slab samples were tested and formation of cracks was monitored, measurement of deformations and displacements were performed

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