This article provides an account tsentrenno and eccentrically compressed reinforced concrete columns of high-strength concrete on the deformed pattern in SP 63.13330.2012. Compares the results of the calculation of the bearing capacity of the columns with the set experimental data. Proposed adjustments in the form of the coefficients in the formulas for the curvature tsentrenno compressed columns j and eccentrically compressed yb.

Keywords: high-strength concrete, physical experiment, prism strength, lateral reinforcement, concrete counters, deformation correction factor

In article the direct connection of a condition of soils and quality of a formed superficial diffusion drain is considered. For minimization of pollution of a superficial drain and ground waters when unloading them in a reservoir it is offered to use coal mining waste as a sorbent of organic and inorganic pollution. Thus, the area of utilization of dump breeds of coal mines for nature protection and soil-improving actions extends.

Keywords: Dump breeds of coal mines; sorbent; minimization of pollution of a superficial drain; the urbanized territories; anthropogenous impact on the soil

2-D and 3-D problems of the elasticity problems for incompressible materials are considered. Solving these problems using the finite-element method results in solving the linear algebraic equations system with sparse matrix. For incompressible materials this system is the system with a saddle point (i.e. the matrix eigen values have different signs). Thus, applying such solving methods as the conjugate gradient method and the generalized minimal residual method is impossible. Uzawa method is suggested to be used for such problems. It is an iterative process, and at each iteration it is necessary to solve the linear algebraic equations system, but this system is without a saddle point. The different variants of Uzawa algorithm are realized within CAE Fidesys software package, and their efficiency is compared in the article.

Keywords: theory of elasticity, incompressible materials, finite-element method, Uzawa algorithm, iteration methods for systems of linear algebraic equations

This paper presents a comparative analysis of the effectiveness of the method Cuthill-McKee algorithm and fill-reducing ordering of a sparse matrix, based on multi-level nested dissection paradigm, developed at the Department of "Computer Science and Engineering," University of Minnesota. For short, we shall call the algorithm Cuthill-McKee CM, and the algorithm of the University of Minnesota — NodeND (Node nested dissection). This article uses a modification of the CM algorithm — RCM (reverse Cuthill-McKee), because in practice the reverse numbering index allows you to get a greater advantage than using a direct algorithm CM. The reason for using these algorithms are high speed computational algorithm, as it is necessary to solve the system proximal to the diagonal, the great acceleration of algorithms for solving FE problems using technology such as CUDA  

Keywords: finite element mesh renumbering methods, three-dimensional mathematical modeling, elasticity theory problems, finite element method, finite element meshes

This paper studies the dependence of the ratio of prismatic strength (Rb) from cube strength (R) for high-strength concrete of classes B70 ... B110. Experiments were carried on the concrete cubes with an edge of 150 mm and prisms with a base 150x150 mm and a height 600 mm. The tendency to reduce the ratio Rb / R with increasing strength of the concrete is founded. A new relationship Rb = f (R) is offered

Keywords: high-strength concrete, physical experiment, prismatic strength, cube strength, the coefficient of the prismatic strength

The paper proposes a new relationship for the analytical description of the diagram «b–b» for high-strength concrete of classes C55/67 ... C90/105. The formula developed on the basis of the accepted in EU relation of Sargin and agrees well with the experimental data. A new relation of the ultimate relative deformation of concrete from the strength is developed

Keywords: high-strength concrete, physical experiment, state diagram of concrete, the stress-strain dependence in concrete, the ultimate relative deformation of concrete

The article discusses issues related to the study of the influence on the deformability of concrete beams of heavy concrete reinforcing steel to replace the carbon fiber arranged in two rows. Found that delamination of the composite beams with reinforcement throughout the range of loads up to 46-54% compared with the reference.

Keywords: concrete, steel, carbon-fiber reinforcement, test samples, strength, steps of loading, deformability, cracking, load level

The article discusses issues related to the strength of the normal sections of reinforced concrete beams in which the steel reinforcement is completely or partially replaced by a carbon fiber rod arranged in two rows. Found that the strength of these beams is only 13% higher than that of the reference.

Keywords: concrete, steel, composite reinforcing, test samples, strength, failure modes, load level

The article presents the results of calculations of reinforced concrete columns of high-strength concrete on the SNiP and SP. Compared the results with experimental data. The proposed adjustment formulas used with correction factors k and w resulting standard deviation of the bearing capacity of the columns from the experimental reduced more than four times.

Keywords: high-strength concrete, physical experiment, the correction factor calculation scheme undeformed

The article presents a brief overview of the results of a study of the compressed elements in our country and abroad, reinforced composite materials. Noted that in Russia this question is poorly understood. Represented a broad research program developed by the Department JBK RSSU aimed to fill these questions.

Keywords: concrete, steel, carbon-fiber reinforcement, test samples, strength, deformability, cracking.

An approach to the calculation of the optimal values ​​of the protective layer of longitudinally reinforced concrete columns, operating at a central compression. Modeling performed using FEM - Ansys package for the design and implementation of spatial models of flat section of the column.

Keywords: reinforced concrete column, longitudinal reinforcement, a protective layer of concrete, finite element method, critical load

On the basis of experimental data on the resistance of reinforced concrete columns eccentric compression was obtained analytical dependence of the limiting compressibility of concrete from the varied factors: the relative eccentricity of the external force eo / h and the reinforcement ratio μ.

Keywords: reinforced concrete column, longitudinal reinforcement, a protective layer of concrete, finite element method, critical load

Information about authors of issue №4 (2013)

Keywords: authors

This paper addresses the testing results of steel rods with grade A500 and A600, which used as a conventional reinforcement. It was investigated the strength properties of carbon and fiberglass sheets with different number of material layers. The results are compared with the data given in the quality certificates.

Keywords: fiberglass, carbon frp sheets, laminates, sheets of carbon and fiberglass, the ultimate load ,strength

The questions related to the study of various varying factors on the strength of normal sections in beams. Here's a program of research by one methodology designed to study the effect of the type and content of steel reinforcement and externally composite on the strength of normal sections that have not previously been investigated.

Keywords: Concrete, reinforced concrete, the percentage of reinforcement, carbon frp sheets, fiberglass, laminates