No abstract

A suspension bridge is the most suitable type for a long-span bridge due to rational use of structural materials. Increased deformability, which is conditioned by the appearance of the elastic and kinematic displacements, is the major disadvantage of suspension bridges. The problem of increased kinematic displacements under the action of symmetrical and non-symmetrical load can be solved by the prestressing. A prestressed suspension bridge with span of 200 m was considered as an object of investigations. The cable truss with the cross web was considered as the main load carrying structure of prestressed suspension bridges and was compared with the single cable. The considered prestressed suspension bridge was investigated by the FEM program ANSYS 12 and by the small scale physical model. Rational, from the point of view of minimal vertical kinematic displacements, main load-carrying structure of prestressed suspension bridge was developed. The obtained results shows, that usage of cable truss with the cross web as the main load carrying structures of prestressed suspension bridge in comparison with the single cable, reduces vertical displacements upwards by 63.1%, downwards by 1.8% and total displacements by 29.6% under the action of worth situated load.

High-strength hybrid composite cables with large specific strength on the basis of such materials as carbon fibre reinforced plastics (CFRP), glass fibre reinforced plastics (GFRP) and Vectran, are widely used in constructional practice. But using a steel component enables to increase small relative elongation, decrease brittleness and expand area of application of high-strength hybrid composite cables. Steel was investigated in combination with such materials as CFRP, GFRP, and Vectran. The behaviour of hybrid composite cable was investigated analytically and by experiment. Hybrid composite cables with the increased specific strength were considered as materials of several cable groups for a prestressed saddle-shaped cable roof with dimensions 50×50 m. The opportunity to decrease the displacements of composite saddle-shaped cable roof by using cable trusses, made from the hybrid composite cable with the increased specific strength was investigated. Rational geometric characteristics of the cable truss were determined by the numerical experiment. It was shown that using hybrid composite cable enables to increase its specific strength up to 2.4 times. Rational components for composite cable with an increased specific strength were chosen by the numerical experiment.

Abstract. An option for reducing material consumption in bent construction is flat plate replacement with a curved or saddle shaped plate (shell). This option applies to plywood sheet, provided that the curved or saddle shaped plates are made in widely used multilevel plywood presses with parallel shelves using layers with an appropriate physical properties, geometric dimensions and orientation, creating a structurally asymmetrical sheet, relative to mid-surface. Improved currently used method for calculation of curvature with taking into account curvature interaction effect and elastic characteristic change in moisture changing process. Compared results obtained by improved method and finite element method. Using improved method calculated values of curvature for a sheet with different geometrical properties and moisture conditions.

This paper discusses an optimized structural plate of plywood composite that consists of top and bottom plywood flanges and a core of plywood ribs. The objective function is structure's weight. Typical constrains – maximal stress criteria and maximal deformation criteria – are used. The optimization is done by Genetic Algorithm (GA), and optimization results are used to train Feed-Forward Artificial Neural Network. The numerical simulation of plywood structure is done by using classical linear Kirchoff–Love theory of multilayer plate and Finite Element Method. As a result, an effective optimization methodology for plywood composite material is proposed. The most rational (according to strength-stiffness criteria) plywood composite macrostructure is obtained for some typical cases.