Structural Optimization using the Principle of Virtual Work and an Analytical Study on Metal Buildings

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Virginia Tech

A tool for analyzing and understanding the behavior of structural systems based on the principle of virtual work was developed by Dr. Finley Charney in the early 1990s. The program was called DISPAR, which stands for DISplacement PARticipation factors, and was written to work in accordance with SAP90 and ETABS. This program became outdated once newer versions of SAP90 and ETABS were released. Starting with version 11 of SAP2000, Computers and Structures released an Open Application Programming Interface (OAPI) which allowed programmers efficient access to the information in SAP2000. With this release came the motivation to update the program DISPAR to work with SAP2000 version 11 and other versions to follow. This thesis provides an overview of how the new version of DISPAR was programmed using VB.Net and OpenGL.

This thesis starts off with an in depth discussion and literature review on the development of the principle of virtual work. The literature review covers how virtual work can be used as a tool to understand structural behavior as well as optimize structural performance.

The updated version of DISPAR (DISPAR for SAP2000) was then used to analyze the behavior of metal building frames under various loadings. The focus of this study was to determine the effect modeling the column base connection as partially rigid has on wind drift in metal building frames. Before beginning the study, a literature review was conducted on the rotation stiffness provided by typical column base connections. The information obtain in the literature review was then used to create a finite element model of a typical column base connection in a metal building. Once the finite element model was completed, DISPAR for SAP2000 was used to conduct a study on the sensitivity of the rotational stiffness of the column base connection.

column base connection, structural optimization, virtual work