scholarly journals Modified Dolphin Monitoring Operator for Weight Optimization of Frame Structures

2017 ◽  
Author(s):  
Ali Kaveh ◽  
S. R. Hoseini Vaez ◽  
Pedram Hosseini
Keyword(s):  
Steel Structures ◽  
The Other ◽  
Frame Structures ◽  
Weight Optimization ◽  
Colliding Bodies Optimization ◽  
Suitable Tool ◽  
Enhanced Colliding Bodies Optimization

In this article, a modified dolphin monitoring (MDM) operatoris introduced and used to improve the performance of the collidingbodies optimization (CBO) algorithm for optimal designof steel structures (CBO-MDM). The performance of the CBO,enhanced colliding bodies optimization (ECBO) and CBOMDMare compared through three well-established structuralbenchmarks. The optimized designs obtained by thesealgorithms are compared, and the results show that the performanceof CBO-MDM is superior to those of the other twoalgorithms. The MDM is found to be a suitable tool to enhancethe performance of the CBO algorithm.

Behaviour of steel frames under fire conditions

1999 ◽  
Vol 26 (2) ◽  
pp. 156-167 ◽  
Author(s):  
D I Nwosu ◽  
VKR Kodur
Keyword(s):  
Fire Resistance ◽  
Steel Frames ◽  
Load Ratio ◽  
Steel Structures ◽  
Point Of View ◽  
Frame Structures ◽  
Structural Behaviour ◽  
Analysis And Design ◽  
In Fire ◽  
Fire Conditions

A state-of-the-art review of the behaviour of steel frame structures in fire is presented. Results from different studies indicate that the behaviour of a complete structure is different from that of a single structural member under fire conditions from the point of view of fire resistance. Earlier studies also show that analysis and design of steel structures against fire based on their overall behaviour could lead to a reduction or the elimination of applied fire protection to certain structural members. The effects of continuity, restraint conditions, and load ratio on the fire resistance of frame structures are discussed. The beneficial aspects derived from considering overall structural rather than single-member behaviour in fire are illustrated through the analysis on two one-bay, one-storey, unprotected steel portal frames, a column, and a beam. Also comparison is made between the performance of a beam with different end restraints in fire. Results from the analyses indicate that the fire resistance of a member is increased when it is considered as part of a structure compared with when it is considered as a single member.Key words: steel, frames, fire resistance, buckling, loads, overall structural behaviour.

Optimal design of nonlinear large-scale suspendome using cascade optimization

2017 ◽  
Vol 33 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Ali Kaveh ◽  
Masoud Rezaei ◽  
MR Shiravand
Keyword(s):  
Optimal Design ◽  
Large Scale ◽  
Simple Procedure ◽  
Geometry Optimization ◽  
Steel Structures ◽  
Optimization Method ◽  
Scale Space ◽  
Cross Sectional ◽  
Colliding Bodies Optimization ◽  
Design Variables

Large-scale suspendomes are elegant architectural structures which cover a vast area with no interrupting columns in the middle. These domes have attractive shapes which are also economical. Domes are built in a wide variety of forms. In this article, an algorithm is developed for optimum design of domes considering the topology, geometry, and size of member section using the cascade-enhanced colliding bodies optimization method. In large-scale space steel structures, a large number of design variables are involved. The idea of cascade optimization allows a single optimization problem to be tackled in a number of successive autonomous optimization stages. The variables are the optimum height of crown and tubular sections of these domes, the initial strain, the length of the struts, and the cross-sectional areas of the cables in the tensegrity system of domes. The number of joints in each ring and the number of rings are considered for topology optimization of ribbed and Schwedler domes. Weight of the dome is taken as the objective function for minimization. A simple procedure is defined to determine the configuration of the domes. The design constraints are considered according to the provisions of Load and Resistance Factor Design–American Institute of Steel Constitution. In order to investigate the efficiency of the presented method, a large-scale suspendome with more than 2266 members is investigated. Numerical results show that the utilized method is an efficient tool for optimal design of large-scale domes. Additionally, in this article, a topology and geometry optimization for two common ribbed and Schwedler domes are performed to find their optimum graphs considering various spans.

An enhanced colliding bodies optimization and its application

2019 ◽  
Vol 53 (2) ◽  
pp. 1127-1186
Author(s):  
Debao Chen ◽  
Renquan Lu ◽  
Suwen Li ◽  
Feng Zou ◽  
Yajun Liu
Keyword(s):  
Colliding Bodies Optimization ◽  
Enhanced Colliding Bodies Optimization

Elasto-Plastic Frames

2015 ◽  
pp. 231-275
Keyword(s):  
Shear Walls ◽  
Steel Structures ◽  
Frame Structures ◽  
Numerical Implementation ◽  
Concrete Frames ◽  
Dual Systems ◽  
Reinforced Concrete Frames ◽  
Plastic Analysis ◽  
The Subject ◽  
Wide Beams

The goal of this chapter is to describe how the concepts presented in Chapters 5 and 6 can be included in the mathematical models for the elastic plastic analysis of frame structures. The numerical implementation of such an analysis is described in Chapter 8. The models presented in this chapter cover applications for reinforced concrete frames, shear walls, wide beams, and dual systems, as well as steel structures. Both cases, planar and tridimensional analyses, are considered. However, this chapter does not yet describe the numerical and computational analysis of elasto-plastic structures; this is the subject of the next chapter.

The behaviour, overview of damage and retrofit of steel buildings after the earthquakes of September 1985

1987 ◽  
Vol 20 (1) ◽  
pp. 30-41 ◽  
Author(s):  
Enrique Martinez-Romero
Keyword(s):  
Mexico City ◽  
Seismic Performance ◽  
Seismic Design ◽  
Steel Structures ◽  
The Other ◽  
Design Codes ◽  
Steel Buildings ◽  
Steel Construction ◽  
History Of

A brief introduction on the earthquake history of Mexico is made. A description of the various types of steel structures built in Mexico City is made, including comparisons of the other types of steel construction with more modern practices. Performance of steel buildings in the September 1985 earthquake are discussed and related to the local geotechnical conditions, including foundation behaviour. The evolution of seismic design Codes in Mexico City is presented and the Emergency Provisions recently issued, are discussed. Finally, some ideas of repairing damaged steel structures to improve their seismic performance meeting the higher demands of the reformed Code, are given as a retrofit.

The Second Order Elastic-Plastic Analysis of Plane Steel Frame Structures with Semi-Rigid Connections

2012 ◽  
Vol 166-169 ◽  
pp. 454-458
Author(s):  
Xi Bing Hu ◽  
Peng Zhou
Keyword(s):  
Steel Structures ◽  
Calculation Model ◽  
Second Order ◽  
Frame Structures ◽  
Rigidity Matrix ◽  
Elastic Plastic ◽  
Plastic Analysis ◽  
Steel Frame Structures ◽  
Plane Steel Frame ◽  
Nonlinear Behaviors

Considering the nonlinear behaviors of semi-rigid connections, a new calculation model for the second order elastic-plastic analysis of plane steel structures is presented by replacing the general element with a new one, which has two rotational springs at its ends. Based on the theory of beam-to-column, the element’s rotation-displacement equations are revised, and the second order elastic-plastic rigidity matrix of this kind of structure is derived in this paper. And the second order elastic-plastic program of this kind of structure is worked out. Two steel frames are calculated with this program. The results of calculations show that this model is reliable and fit to the analysis of all plane steel structures.

Seismic response of concentrically braced steel frames

1991 ◽  
Vol 18 (6) ◽  
pp. 1062-1077 ◽  
Author(s):  
Richard G. Redwood ◽  
Feng Lu ◽  
Gilles Bouchard ◽  
Patrick Paultre
Keyword(s):  
Structural Engineering ◽  
Nonlinear Response ◽  
Steel Structures ◽  
Frame Structures ◽  
Braced Frames ◽  
Braced Frame ◽  
Concentrically Braced ◽  
Engineering Steel ◽  
Analysis Design ◽  
Improved Design

Braced frame structures designed according to the 1990 edition of the National Building Code of Canada and the CSA standard for steel structures (CAN/CSA-S16.1-M89) are analyzed under a number of different earthquake motions. The nonlinear response is studied in the light of the design philosophy, and the validity of a number of design assumptions is examined. The study is limited to a group of eight-storey frames, located either in Victoria, British Columbia, or Montreal, Quebec, all with the same bracing configuration. A 20-storey frame in Montreal is also considered. The results suggest a number of areas in which improved design provisions could be made. Key words: analysis, design, structural engineering, steel, earthquakes, braced frames.

scholarly journals Statics and Kinematics in Cyclic Behaviour of Semi-Rigid Steel Structures

2016 ◽  
Vol 6 (2) ◽  
pp. 25-32
Author(s):  
Corina - Ana Moldovan
Keyword(s):  
Constitutive Relation ◽  
Steel Structures ◽  
Numerical Results ◽  
The Other ◽  
Base Shear ◽  
Seismic Behaviour ◽  
End Plate ◽  
Cyclic Behaviour ◽  
Lateral Displacements ◽  
Seismic Forces

Abstract The contribution presents a set of seismic analyses of multi - storey steel structures with semi-rigid beam column connections acted upon by seismic actions. Semi-rigidity of the structures beam to column connections is conferred by two types of beam to column connections: top and seat and web angle (TSW) and end-plate (EP) joints. Computed numerical results are associated to two classes (static and kinematic) of seismic behaviour parameters expressing the two contradictory effects of semi-rigidity. On one hand, the lateral flexibility induces larger lateral displacements while, on the other hand, it attracts smaller base shear seismic forces. Also, the constitutive relation M − θr induced into semi- rigid beam column connections by seismic actions is presented. The results are presented in their numerical form and in a comparative graphical manner allowing for relevant comments and conclusions

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