Subject. Analysis of applicability and effectiveness of various complexity level models in design of reinforcement of stretch elements by gluing on their surface high-strength fiber reinforced polymers (HSFRP). Research objectives. Determine the necessary level of complexity of the calculation model based on the comparison of calculation results obtained on models of various complexity within the elastic behavior of the reinforced element and analysis of features of its elastoplastic behavior in case of its overload. Materials and methods. Few relatively simple variants of HSFRP-reinforcement structures with application of four Finite Element Method (FEM) simulation models of varying complexity and an analytic approach. Plane and spatial Finite Element (FE) models with PC LIRA (SCAD) and FEMAP (NASTRAN) apply in considered series of numerical experiments. Comparative analysis of results of elastic FEM calculation based on various FE models with the results obtained using analytical expressions. A number of diagrams and tables represent the results of calculations. Nonlinear FEM analysis reveals some features of the reinforced elements response under extreme loads. Results. The effect of various factors on the bonded joint behavior observed, the equations and formulae for the analysis and design are applied, the analytical approach based numerical results well correspond with those obtained using FEM. A number of nonlinear FEM calculations discover some features of elastic-plastic response of joints. Conclusions. All the considered here FE models within the limits of elastic design are quite compatible mutually and with an approximate analytical approach as well. The least time-and effort-expensive for the stage of preliminary assessment of the various parameters effect on the glued joint behavior in the elastic design of the stretched elements reinforcement is an analytical approach allowing instantaneously obtain the resulting main components of stresses and forces in the components of joint to scroll through parameter values. FEM simulation for elastic calculation is expedient for verification of results. The simplified plain FEM simulation seems to be quite reliable here. In inelastic state of the reinforced element material yet, the features of its stress-strain distribution not observable in the elastic stage of its loading and requiring special attention and refined FEM simulation may dominate.

This article discusses the connection of a steel sheet pile to an I-beam by welding to increase the horizontal load-bearing capacity. The connection to the I-beam is checked during an experimental study for axial tension. Deformations at reference and maximum loads, as well as stresses in the weld metal and I-beam metal, are recorded. During the tests, the bearing capacity of the welded joints was confirmed, data on plastic deformations of the sheet pile walls under various loads were obtained.

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This article discusses the connection of a steel sheet pile to an I-beam by welding to increase the horizontal load-bearing capacity. The connection to the I-beam is checked during an experimental study for axial tension. Deformations at reference and maximum loads, as well as stresses in the weld metal and I-beam metal, are recorded. During the tests, the bearing capacity of the welded joints was confirmed, data on plastic deformations of the sheet pile walls under various loads were obtained.

Subject - analysis of applicability and effectiveness of cascade type models in design of strengthening of stretch elements by gluing on their surface fiber reinforced polymers (FRP). Research objectives – cascade method of stretched elements reinforcement with adhesive joints presentation. Materials and methods – few variants of FRP-reinforcement with application of FEM simulation and analytic approach. A number of diagrams and tables represent the results. Results - a highly efficient and cost-effective method of strengthening the stretched elements to increase their bearing capacity reserves, the features of the bonded joint behavior, the equations and formulae for analysis and design. Conclusions - the name “cascade” reflects the features of the proposed strengthening design. The base element relaxation is gradual with each successive element attached. Analytical expressions in a rather general form are obtained and presented to design the cascade strengthening scheme. Design examples concentrate on the analysis of the adhesive joints application to attach FRP elements. The results suggest the effective use of adhesive joints to strengthen rather strong, including steel, stretched elements. The cascade method eliminates the indispensable use of highly expensive high-strength materials, thereby reducing the cost of reinforcement structures.