INVESTIGATION OF THE INFLUENCE OF AN INTERMEDIATE HINGE SUPPORT IN THE PROBLEM OF BENDING OF AN ELASTICALLY RESTRAINED ORTHOTROPIC BEAM

In this paper, based on the refined theory of orthotropic plates of variable thickness, a system of differential equations is obtained for solving the problem of bending of an elastically restrained beam with an intermediate condition. The beam thickness is constant and is subject to a uniformly distributed load. The effects of transverse shear are also taken into account. Passing to dimensionless quantities, an analytical closed solution is obtained. The question of the influence of changing the place of application of the intermediate condition on the solution is discussed. Depending on the location of the hinge bearing, the question of optimality was posed and resolved according to the principle of minimum maximum deflection. The results are presented in both tabular and graphical form. Based on the results obtained, appropriate conclusions are drawn.

Effect of Support Conditions on Performance of Continuous Reinforced Concrete Deep Beams

While continuous reinforced concrete deep beams with fixed and hinged support conditions are every so often found in structures, little research has focused on their performance. This, in part, can be attributed to the demanding nature of ensuring fixed supports in experimentally testing such members. Nonetheless, conducting numerical analysis in comparison with experimental study has been a typical technique for producing a reliable numerical model as an alternative to destructive tests. This paper is aimed at numerically investigating the impact of different support conditions in the performance of two-span continuous reinforced concrete deep beams. A numerical model of three experimentally tested beams with two exterior rollers and interior hinge support conditions was generated. Good comparison, with an acceptable variation between numerical and experimental results, was achieved by tuning a few parameters in the numerical model, including element type, mesh size, and material constitutive relations. The refined numerical model was used as an alternative to destructive tests to conduct a parametric study to further investigate the impact of different sets of support conditions in the performance of two-span continuous reinforced concrete deep beams. This study highlights the potentially serious consequences of the support conditions in the performance of such deep beams.

Simulation of forced oscillations of an open shell with a small attached mass, with a hinge support, by the method of Pade approximation

В работе приводится уточненная математическая модель вынужденных колебаний разомкнутой оболочки с малой присоединенной массой при шарнирном опирании. Шарнирное опирание рассмотрено как наиболее часто используемое. Уравнения составлены в линейной постановке, решались асимптотическими методами, с помощью аппроксимации Паде. Проведены экспериментальные исследования, для этого изготовлены испытательный стенд, образцы, разработана программа экспериментов. Выполненное сравнение теоретических и экспериментальных данных составляет менее 5%, что говорит о высокой надежности уточненной математической модели. Полученные зависимости частоты колебаний оболочки и параметра волнообразования позволяют производить расчеты разомкнутый тонкостенных цилиндрических оболочек при параметре волнообразования больше 0,3, при проектировании таких конструкций. The paper presents a refined mathematical model of forced oscillations of an open shell with a small attached mass at a hinge support. Hinge support is considered as the most frequently used. The equations are composed in a linear formulation, solved by asymptotic methods, using Pade approximations. Experimental studies were carried out, a test stand and samples were made for this purpose, and a program of experiments was developed. Comparison of theoretical and experimental data it is less than 5%, which indicates a high reliability of the refined mathematical model. The obtained dependences of the shell oscillation frequency and the wave formation parameter make it possible to calculate the open-ended thin-walled cylindrical shells with a wave formation parameter greater than 0.3, when designing such structures.

Modular frame trusses of buildings

The paper describes space-planning and structural concept in source-efficient buildings that provides multiple functions of the rooms and large-span space.The main load-bearing structures of two adjacent storeys are metal trusses with parallel chords between which (between top and bottom chords) intermediate storeys are designed and the space between trusses is occupied by the free plan storeys. Bottom and top chords of the truss resist together with floor structure forming two-storey steel-reinforced concrete unit. To calculate value of deformation capacity for nodal connection a numerical experiment focused on modelling a part of building from solid finite elements has been performed. The results of performed analysis are the average values of stiffness of nodal interface of solid floor slab on corrugated deck and truss chords for finite elements KE 55 of typical layout (of flat finite elements). The obtained average values of stiffness were introduced into structural design of flat finite elements. Taking into account flexibility of floor slab that supported by middle trusses for the given structural concept leads to decreased span bending moments and increased support bending moments by 25% compared with hinge support of floor.

Analytical Method of Determining Folded Depressed Shells’ Free Oscillation Frequency

The paper shows a conclusion and a solution of principal resolving equations of the motion of linear and geometrically non-linear theories of thin depressed shells with median surface breaks. A formula has been obtained for determining the shell’s free bending harmonic oscillation frequency in case of a hinge support on rigid diaphragms. Charts are supplied showing the dependence of free oscillation frequency on the change of different factors. A conclusion has been drawn concerning the analytical method efficiency.

The Response of the Bi-Directional Beam String Structure under Vertical Seismic Considering Supporting Frame

This paper using time time-procedure analysis method to analyze seismic response on a 80 m × 80 m bidirectional beam string structure model. Under vertical seismic action, we respectively compared to the seismic performance under the structure have or no supporting frame and have the same supporting frame but different support conditions. Under vertical seismic action, the axial force of brace is almost the same considering or unconsidering the supporting frame, while the upper beam vertical displacement is increased and the surrounding of the roof even increased several times considering supporting frame; the boundary conditions for the sliding hinge support bidirectional beam string structure which under vertical seismic ( middle seismic ) action the brace axial force and winding beam vertical displacement are nearly same with the fixed hinged support, while the horizontal displacement of the winding beam is larger than the fixed hinged support; the change of support conditions affect the order of the various modes of the structure but no affect the structural vibration modes.

Calculation Model on Single Layer Lattice Shell Static and Dynamic Impact Analysis

Take single layer lattice shell hinge support model, elastic supporting model and whole structure model as object of study, systematic study the working performance of the lattice shell roof structure under different calculation model. Comparison and analysis of various calculation model of static and dynamic, aiming at the lower adopt concrete structure upper span space structure of this kind of composite structure, using different material combination structure damping ratio of practical calculation formula, separately calculated hinge support model and the whole structure model of dynamic response, results show that consider composite structure damping ratio and the whole structure modeling of the calculation model more accord with engineering practice.