Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 6 of 6
Full-Text Articles in Engineering
Structural Analysis And Optimization Of Skyscrapers Connected With Skybridges And Atria, Amy Jean Taylor Mccall
Structural Analysis And Optimization Of Skyscrapers Connected With Skybridges And Atria, Amy Jean Taylor Mccall
Theses and Dissertations
Skybridges and atria between buildings are becoming more and more popular. Most current skybridge connections are either roller or rigid-connections. This dissertation presents an investigation of the structural analysis and optimization of skyscraper systems with hinge-connected skybridges, and compares the results to skyscraper systems with roller-connected skybridges and to skyscraper systems without skybridges altogether. Also presented is an investigation of the structural analysis and optimization of skyscrapers both with and without atria between the buildings. It was assumed that the atria envelope was constructed with cushions made from lightweight, transparent, and flexible Ethylene Tetrafluoroethylene (ETFE). A simplified skyscraper skybridge model …
Accuracy Of A Simplified Analysis Model For Modern Skyscrapers, Jacob Scott Lee
Accuracy Of A Simplified Analysis Model For Modern Skyscrapers, Jacob Scott Lee
Theses and Dissertations
A new simplified skyscraper analysis model (SSAM) was developed and implemented in a spreadsheet to be used for preliminary skyscraper design and teaching purposes. The SSAM predicts linear and nonlinear response to gravity, wind, and seismic loading of "modern" skyscrapers which involve a core, megacolumns, outrigger trusses, belt trusses, and diagonals. The SSAM may be classified as a discrete method that constructs a reduced system stiffness matrix involving selected degrees of freedom (DOF's). The steps in the SSAM consist of: 1) determination of megacolumn areas, 2) construction of stiffness matrix, 3) calculation of lateral forces and displacements, and 4) calculation …
Minimizing Base Column Demands In Multi-Story Buckling Restrained Braced Frames Using Genetic Algorithms, Christopher Hiroshi Yeates
Minimizing Base Column Demands In Multi-Story Buckling Restrained Braced Frames Using Genetic Algorithms, Christopher Hiroshi Yeates
Theses and Dissertations
Most structural optimization procedures focus on minimizing the total volume of steel in an attempt to reduce overall costs. However, many other factors can have an effect on the overall cost of a structure. Base column demands in particular, can affect base plate sizes, anchorage, and foundation design. Researchers have found that present methods for estimating column demands are too conservative. Nonlinear time history analyzes were conducted on buckling-restrained braced frames of six heights. Optimized results were found considering three ductility constraints and two optimization objectives. The two optimization objectives were minimized total brace area and minimized base column demands. …
A Comparison Of Optimized Nonlinear Time History Analysis And The Equivalent Lateral Forces Method For Brace Design, Lukas Balling
A Comparison Of Optimized Nonlinear Time History Analysis And The Equivalent Lateral Forces Method For Brace Design, Lukas Balling
Theses and Dissertations
This thesis presents the development of a design procedure for buckling-restrained braced frames (BRBF's). This procedure uses nonlinear time history analysis and a formal optimization algorithm. The time history analysis includes an elasto-plastic model for the braces. The optimization algorithm is a genetic algorithm. This procedure is referred to throughout the thesis as the "Nonlinear Time History Analysis Procedure with Optimization" (NTHO). Current design specifications for BRBF's are based on inelastic design spectra and approximate formulas for the determination of natural period. These spectra are used to obtain seismic base shear, and the distribution of equivalent lateral forces. Yielding and …
Optimization Of Shape, Size, And Topology Design Variables In Trusses With A Genetic Algorithm, Kevin M. Gillman
Optimization Of Shape, Size, And Topology Design Variables In Trusses With A Genetic Algorithm, Kevin M. Gillman
Theses and Dissertations
Briggs' genetic algorithm was extended in the Gillman algorithm to include shape optimization of trusses. Other contributions include value representation, different member linking, alternate genes, automatic k-factor evaluation for buckling, and the option to prevent overlapping members. The purpose of these contributions was to make optimization using a genetic algorithm more accessible to design engineers. The Gillman algorithm was demonstrated in two original examples as well as an example from a published work. The Gillman algorithm was effective in finding lighter designs.
The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan
The Benefit Of Using Simulation To Improve The Implementation Of Lean Manufacturing Case Study: Quick Changeovers To Allow Level Loading Of The Assembly Line, Jack J. Mcclellan
Theses and Dissertations
In today's competitive manufacturing environment, companies are constantly looking for ways to improve. Because of this, many companies are striving to become "lean" by implementing lean manufacturing, which is a difficult process. To aid in the implementation of lean manufacturing, simulation was used to reduce the trial-and-error period of lean manufacturing and find to optimum approach to implement the lean manufacturing principle. In this research, a case study of implementing level loading of the production schedule for BullFrog International, L.C. will be examined. To make it possible to implement level loading, the thermo-former machine at the beginning of the operations …