Treillis (assemblage)

Un treillis, ou système triangulé, est un assemblage de barres verticales, horizontales et diagonales formant des triangles, de sorte que chaque barre subisse un effort acceptable, et que la déformation de l'ensemble soit modérée. Cette structure est devenue courante en construction à partir de la révolution industrielle, pour des ponts, fuselages d'avion En effet, un tel assemblage allie résistance, rigidité et légèreté, et permet d'utiliser des éléments normalisés (barres) ; par ailleurs, le treillis peut éventuellement être préassemblé. Lorsqu'un treillis est soumis à un effort, certaines parties de l'assemblage sont mises en compression et d'autres parties en tension. Par exemple, dans le cas d'un pont en treillis, les poutres supérieures sont comprimées, les poutres inférieures sont tendues, et les pièces en diagonale évitent le vrillage des poutres principales. Les axes des barres concourent en nœuds ; ce sont les points d'assemblage des barres. D'un point de vue mécaniqu

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ME-104: Introduction to structural mechanics

The student will acquire the basis for the analysis of static structures and deformation of simple structural elements. The focus is given to problem-solving skills in the context of engineering design.

CIVIL-124: Statics I

Développer une compréhension des modèles statiques. Étude du jeu des forces dans les constructions isostatiques.

CIVIL-235: Design of steel structures

Ce cours permet de maitriser les aspects fondamentaux et pratiques du dimensionnement des structures en acier. Il traite des poutres, des poteaux, des assemblages, des cadres, des systèmes porteurs et des problèmes de stabilité.

A novel optimization approach for minimum cost design of trusses

Abhinav Gupta

This paper describes new optimization strategies that offer significant improvements in performance over existing methods for bridge-truss design. In this study, a real-world cost function that consists of costs on the weight of the truss and the number of products in the design is considered. We propose a new sizing approach that involves two algorithms applied in sequence -(1) a novel approach to generate a "good" initial solution and (2) a local search that attempts to generate the optimal solution by starting with the final solution from the previous algorithm. A clustering technique, which identifies members that are likely to have the same product type, is used with cost functions that consider a cost on the number of products. The proposed approach gives solutions that are much lower in cost compared to those generated in a comprehensive study of the same problem using genetic algorithms (GA). Also, the number of evaluations needed to arrive at the optimal solution is an order of magnitude lower than that needed in GAs. Since existing optimization techniques use cost functions like those of minimum-weight truss problems to illustrate their performance, the proposed approach is also applied to the same examples in order to compare its relative performance. The proposed approach is shown to generate solutions of not only better quality but also much more efficiently. To highlight the use of this sizing approach in a broader optimization framework, a simple geometry optimization algorithm that uses the sizing approach is presented. This algorithm is also shown to provide solutions better than the existing results in literature. (c) 2007 Elsevier Ltd. All rights reserved.

2007

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Experimental investigation into the shear resistance of a reinforced UHPFRC web element

Eugen Brühwiler, Rita Galrito, Talayeh Noshiravani, Karl Telleen

Ultra-high performance fiber reinforced concrete (UHPFRC) can be implemented in combination with steel reinforcing bars to enhance the performance of UHPFRC elements subject to shear stresses. This paper presents an experimental investigation into the behavior of a UHPFRC web element in shear. Two I-shaped beams are constructed out of UHPFRC, with longitudinal reinforcing bars in the tension flange. One of the beams includes transverse bars in the web; the other contains no transverse bars. When loaded to failure in a three-point bending test, the specimen with transverse bars exhibits greater shear strength than the specimen without transverse bars. The observed strengths of both specimens show good agreement with a proposed expression for estimating the shear strength of UHPFRC elements. The proposed expression is based on a truss model for shear resistance, and it treats UHPFRC fibers as reinforcement with a variable angle of inclination, bridging shear cracks at an angle perpendicular to the length of the crack.

fib PhD Symposium2010

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Design and control of a prototype structure that adapts to loading through large shape changes

Arka Prabhata Reksowardojo, Gennaro Senatore, Ian Smith, Apoorv Srivastava

This paper reports on experimental testing that was carried out on a prototype adaptive structure designed to counteract the effect of loading through controlled large shape changes. The prototype is 6.6 m truss equipped with 12 linear actuators which has been designed through a method that combines geometry optimization and non-linear shape control. The structure is designed to adapt into target shapes that are optimal under each load case. Shape adaptation is achieved through controlled length changes of linear actuators that strategically replace some of the structure elements. The actuator placement is optimized to control the structure into the required target shapes. This way, material utilization is maximized and thus material energy embodied is reduced. Experimental testing is carried out to verify numerical findings and investigate the feasibility of the design method. The applied load is inferred through a classification model based on supervised learning. A control algorithm based on a linear-sequential form of geometry optimization is proposed. Experimental results show that this method successfully allows for real-time shape adaptation to achieve stress homogenization under various loading conditions. Copyright (C) 2020 The Authors.

ELSEVIER2020

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Ingénierie des structures

L'ingénierie des structures est un domaine de l'ingénierie et plus particulièrement du génie civil, traitant de la stabilité des constructions (conception et de l'analyse des structures). Une struct

Poutre (construction)

right|thumb|Poutres et solives dans une maison polonaise Une poutre est à l'origine un bois de brin, de manière préférentielle du chêne, équarri à la scie de long ou à la hache (cognée, herminette et

I-beam

I-beam is a generic lay term for a variety of structural members with an or -shaped cross-section. Technical terms for similar items include H-beam (for universal column, UC), w-beam (for "wide flan