scholarly journals OPTIMIZATION OF TREE STRUCTURES WITH HALF-DRAWER GRIDS

2020 ◽  
pp. 39-50
Author(s):  
А. С. Марутян
Keyword(s):  
Bearing Capacity ◽  
Communication Systems ◽  
Truss Structure ◽  
Truss Structures ◽  
Technical Solution ◽  
Rectangular Section ◽  
Tree Structures ◽  
Load Bearing ◽  
Different Shapes ◽  
Necessary And Sufficient

Приведено новое техническое решение в виде дополнительных стержней I-образной, Y-образной, Ψ-образной формы в полураскосных решетках для стержневых (ферменных) конструкций. Показана эффективность их применения в фермах, у которых грузовыми являются не только верхние (сжатые) пояса, но также и нижние (растянутые). Повышена степень унификации ферменной конструкции из гнутосварных профилей (профильных труб) прямоугольного сечения за счет повторного использования в верхнем поясе расчетного сечения, принятого для нижнего пояса. При этом ресурсы несущей способности разнятся между ними в пределах 3-4-процентного порога, что обеспечивает необходимую и достаточную равнопрочность обоих поясов при их унификации. Соединительные узлы верхнего пояса с дополнительными полураскосами разных очертаний позволяют опереть на них определенное количество прогонов с уменьшенными размерами грузовых площадей. Увеличение общего количества прогонов приводит к их облегчению, что представляет собой весьма важный фактор для несущих конструкций, рассчитанных на особые нагрузки и воздействия, а также для объектов повышенной ответственности. Выявлена перспективность применения нового технического решения в составе несущих и связевых систем различных зданий и сооружений. A new technical solution is presented in the form of additional I-shaped, Y-shaped, Ψ-shaped rods in half-diagonal lattices for rod (truss) structures. The effectiveness of their use in farms is shown, in which not only the upper (compressed) belts, but also the lower (extended) ones, are cargo. The degree of unification of the truss structure from bent welded profiles (profile pipes) of a rectangular section due to the reuse in the upper zone of the design section adopted for the lower belt is increased. At the same time, the resources of the bearing capacity differ between them within a 3… 4 percent threshold, which ensures the necessary and sufficient equal strength of both zones when unifying them. The connecting nodes of the upper belt with additional half-braces of different shapes allow to support a certain number of runs with reduced sizes of cargo areas. An increase in the total number of runs leads to their facilitation, which is a very important factor for load-bearing structures designed for special loads and impacts, as well as for objects of increased responsibility. The prospects of applying a new technical solution as a part of the bearing and communication systems of various buildings and structures are revealed.

OPTIMIZATION OF TRUSS STRUCTURES OF THE STANDART SERIES WITH CROSS GRIDS

2021 ◽  
pp. 70-81
Author(s):  
А.С. Марутян
Keyword(s):  
Comparative Analysis ◽  
Optimal Design ◽  
Bearing Capacity ◽  
Communication Systems ◽  
Truss Structures ◽  
Technical Solution ◽  
Equal Strength ◽  
Necessary And Sufficient ◽  
Patent Examination

Представлено конструктивно-компоновочное решение стержней Y-образных и Ψ-образных очертаний в фермах с перекрестной решеткой или фермах с перекрестной решеткой и полустойками (полуподвесками), техническая новизна которого подтверждена результатами патентной экспертизы. Универсальность этого решения для ферменных конструкций обеспечивает ту эффективность, с какой оно применимо к грузовым верхним поясам, грузовым нижним поясам или грузовым верхним и нижним поясам одной и той же решетки. Повышена степень унификации типовой фермы из прокатных профилей за счет использования в верхнем поясе расчетных сечений, принятых для нижнего пояса. При этом ресурсы несущей способности разнятся между ними не более чем на полтора процента, что обеспечивает необходимую и достаточную равнопрочность обоих поясов для их более рациональной унификации. Выполнен сравнительный анализ основных результатов решения вариантного и оптимального проектирования ферменных конструкций применительно к решеткам с двойными системами полураскосов и решеткам с одинарными системами раскосов. Выявлена перспективность применения нового технического решения в составе несущих и связевых систем различных зданий и сооружений. The structural and layout solution of rods of Y-shaped and Ψ-shaped outlines in trusses with a cross lattice or trusses with a cross lattice and half-posts (half-suspensions) is presented, the technical novelty of which is confirmed by the results of patent examination. The versatility of this truss solution is as effective as it is for load tops, load bottoms, or load tops and bottoms of the same grid. The degree of unification of a typical truss of rolled sections has been increased due to the use of design sections in the upper belt adopted for the lower belt. At the same time, the resources of the bearing capacity differ between them by no more than one and a half percent, which ensures the necessary and sufficient equal strength of both belts for their more rational unification. A comparative analysis of the main results of the solution of the variant and optimal design of truss structures as applied to gratings with double systems of half-braces and gratings with single systems of braces is carried out. The prospect of using a new technical solution in the composition of bearing and communication systems of various buildings and structures has been revealed.

OPTIMIZATION OF TREE STRUCTURES WITH RHOMBIC GRIDS

2021 ◽  
pp. 54-68
Author(s):  
А.С. Марутян
Keyword(s):  
Cross Sections ◽  
Communication Systems ◽  
Technical Solution ◽  
Building Structures ◽  
Tree Structures ◽  
Different Shapes ◽  
Support Conditions ◽  
Necessary And Sufficient ◽  
Patent Examination ◽  
Rhombic Lattice

Представлено конструктивно-компоновочное решение стержней Y-образных и Ψ-образных очертаний в фермах с ромбической решеткой или фермах с ромбической решеткой и полустойками (полуподвесками), техническая новизна которого подтверждена результатами патентной экспертизы. Универсальность этого решения для ферменных конструкций обеспечивает ту эффективность, с какой оно применимо к грузовым верхним поясам, грузовым нижним поясам или грузовым верхним и нижним поясам одной и той же решетки. Повышена степень унификации фермы из прямоугольных гнутосварных профилей (профильных труб) за счет использования в верхнем поясе форм и наружных габаритов поперечных сечений, принятых для нижнего пояса. При этом ресурсы несущей способности разнятся между ними в пределах однопроцентного порога, что обеспечивает необходимую и достаточную равнопрочность обоих поясов для их более рациональной унификации. Узловые соединения стержней разных очертаний с верхними поясами позволяют оптимизировать опорные условия настилов и прогонов с уменьшением размеров их грузовых площадей. Возрастание общего количества прогонов приводит к снижению их суммарной массы и массы кровельного ограждения, что весьма актуально для вариантного и оптимального проектирования строительных конструкций с учетом риска лавинообразного обрушения. Выявлена перспективность применения нового технического решения в составе несущих и связевых систем различных зданий и сооружений. The structural and layout solution of rods of Y-shaped and Ψ-shaped outlines in trusses with a rhombic lattice or trusses with a rhombic lattice and half-posts (half-suspensions) is presented, the technical novelty of which is confirmed by the results of patent examination. The versatility of this truss solution is as effective as it is for load tops, load bottoms, or load tops and bottoms of the same grid. The degree of unification of the truss of rectangular bent-welded profiles (shaped pipes) has been increased due to the use in the upper chord of the forms and outer dimensions of the cross-sections adopted for the lower chord. At the same time, the resources of the bearing capacity differ between them within a one- percent threshold, which ensures the necessary and sufficient equal strength of both belts for their more rational unification. Nodal connections of rods of different shapes with the upper chords allow to optimize the support conditions of decks and purlins with a decrease in the size of their cargo areas. An increase in the total number of runs leads to a decrease in their total mass and the mass of the roofing, which is very important for the variant and optimal design of building structures, taking into account the risk of an avalanche collapse. The prospect of using a new technical solution in the composition of bearing and communication systems of various buildings and structures has been revealed.

FINITE ELEMENT ANALYSES ON CORRODED PONY TRUSS BRIDGE FOR REASONABLE MAINTENANCE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Risa Fujinaga ◽  
Tatsumasa Kaita ◽  
Ryoko Koyama ◽  
Tsutomu Imai ◽  
Katashi Fujii
Keyword(s):  
Bearing Capacity ◽  
Ultimate Load ◽  
Plane Deformation ◽  
Element Model ◽  
Truss Structures ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Out Of Plane ◽  
Pony Truss Bridge ◽  
Truss Bridge

The load bearing capacity of an existing corroded pony truss bridge, which is used for 100 years was estimated from FEM results for whole bridge model. The beam element model is to clarify that the influence of the residual out-of-plane deformation in main truss structures on the load bearing capacity from the viewpoint of whole bridge. Also, shell element model is to clarify that the influence of severe corrosion damages occurred in many structural members on the load bearing capacity as whole bridge. On the other hand, the influence of assumed support conditions in analytical models were discussed from the analytical results of both type of models, because it will be thought that the performance of shoes deteriorates gradually by long in-service period. The ultimate load bearing capacity was estimated by the critical live load magnification. From the analytical results, the residual out-of-plane deformation of main truss structures in this bridge had little influence on the ultimate load bearing capacity. Also, the ultimate load bearing capacity may decrease up to 20% due to aging deterioration of shoes including corrosion damages. In bridge maintenance, it should be paid attention on local severe corrosion damages on the structural member, which may occur higher secondary stress.

J1810105 Evaluation Method of Residual Load Bearing Capacity for Escalator Truss Structure under Compressive Load Condition

2014 ◽  
Vol 2014 (0) ◽  
pp. _J1810105--_J1810105-
Author(s):  
Keisuke MORI ◽  
Yutaka HASHIOKA ◽  
Masahiko NAWATA ◽  
Takanori YOKOI ◽  
Kazutoshi AKAZAWA
Keyword(s):  
Bearing Capacity ◽  
Evaluation Method ◽  
Compressive Load ◽  
Load Condition ◽  
Truss Structure ◽  
Load Bearing Capacity ◽  
Load Bearing

OPTIMIZATION OF TRUSS STRUCTURES WITH CHORDS OF STEP-VARIABLE CROSSSECTIONS MADE OF RECTANGULAR PIPES

2021 ◽  
Vol 295 (2) ◽  
pp. 53-61
Author(s):  
A.S. Marutyan ◽  
Keyword(s):  
Cross Sections ◽  
Welded Joints ◽  
Optimization Problems ◽  
Truss Structures ◽  
Technical Solution ◽  
Variable Cross ◽  
Load Bearing ◽  
Strength Tests ◽  
The Difference

The article describes the regularity of the optimization calculation of unification zones in relation to beam chords of step-variable cross-sections with the determination of their design coefficients. The rationality of the formation of these chords in truss structures made of rectangular pipes is shown due to the difference not in the heights of the sections, but in their thicknesses with welded joints on the longitudinal slits.The engineering method for calculating such joints, as well as their load-bearing capacity, has been tested by tensile strength tests of the samples.The universality of the technical solution of welded joints with slits ensures their use in structures made of tubular and rolled profiles, and it preserves the accepted layout of standardized trusses with assemblies and flanged connections. The significant reduction in structural material (steel) in standardized trusses made of bent-welded profiles was revealed when chords of uniform cross-sections were replaced with chords of step-variable cross-sections. The article also gives the comparative calculation of the design coefficients and the averaged coefficients of chord elements use when the lengths of the unification zones and the belt panels coincide. Sufficient correctness of the approximate calculation method for solving optimization problems and variant design of load-bearing structures is confirmed.

scholarly journals Inherent Adaptive Structures Using Nature-Inspired Compound Elements

2020 ◽  
Vol 6 ◽  
Author(s):  
Mohammad Reza Chenaghlou ◽  
Mohammad Kheirollahi ◽  
Karim Abedi ◽  
Ahmad Akbari ◽  
Aydin Fathpour
Keyword(s):  
Bearing Capacity ◽  
Steel Tube ◽  
Truss Structures ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Load Bearing ◽  
Natural Systems ◽  
Long Span ◽  
Steel Core ◽  
Bamboo Stem

Biomimicry studies have attracted significant attention in research and practice, leading to effective engineering solutions to develop new types of structures inspired by natural systems. The objective of this study is to employ natural structures' inherent adaptivity under changing loading conditions. Three new types of compound elements are proposed that are able to improve the structure load-bearing capacity through passive inherent adaptivity. A self-centering system, inspired by the human spine, which comprises a column pre-stressed through cables, is employed as a kinematic isolator. A similar self-centering system is applied to increase the load-bearing capacity of unreinforced masonry columns. An axially loaded element, inspired by the bamboo stem, which comprises a steel core reinforced by a series of cylindrical plates that are encased in a steel tube, is employed to control the onset of instability in long-span truss structures. Application to typical frame, masonry, and truss structures is investigated through finite element analysis. Results show that the proposed compound elements are effective to increase the structure load-bearing capacity and to reduce the response under seismic excitation owning to their inherent adaptive features.

Studies of Anti-Disaster Ability of the Plate Truss Structure

2013 ◽  
Vol 438-439 ◽  
pp. 1892-1894
Author(s):  
Jiao Wei Feng ◽  
Jun Yan Lu ◽  
Jin Dong Ma
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Truss Structure ◽  
Local Damage ◽  
Vertical Load ◽  
Grid Structure ◽  
Load Bearing Capacity ◽  
Positive Role ◽  
Load Bearing

The grid structure often overall failed dut to local damage under the disaster load. In order to avoid the situation, the load cases of the plate truss structure under vertical load are analyzed in this paper. Taking the measure of strengthening the important bars, the ultimate bearing capacity of the structure is improved significantly. The improved load bearing capacity plays a positive role in resisting exceeding loads. Anti-disaster ability of the structure is improved.

scholarly journals On Adjusting the Load Bearing Capacity of Decisive Members to Reliability Classes of Statically Determinate Complex Structures

2013 ◽  
Vol 59 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Z. Kowal
Keyword(s):  
Bearing Capacity ◽  
Complex Structures ◽  
Tabular Form ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Structure Reliability ◽  
Necessary And Sufficient

Abstract The paper provides a solution to the problem of dimensioning decisive bars on the basis of the conditions of meeting the recommended reliability classes [9] of statically determinate structures composed of n members. A theorem was formulated: if a statically determinate structure composed of n decisive members is to attain the reliability greater than, or equal to, the recommended reliability p = 1- q, it is necessary and sufficient that the damage frequency sum qi of decisive members is smaller than the admissible damage frequency q of the structure: Σqi < q. On the basis of this theorem, s coefficients that recommend increase of the load bearing capacity of the decisive bars in a statically determinate structure constructed in order to meet the recommended class [9] of the structure reliability, are estimated and presented in a tabular form.

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