The objective of this study was to develop design equations that predict lateral restraint forces in two commonly used Z-purlin supported roof systems. These are quarter point bracing and third point plus support bracing. To that end, a stiffness model used in the past has been reintroduced. This model has been modified slightly to better represent roof system behavior. The updated stiffness model was then used to estimate lateral restraint forces for a number of roof systems with a varying cross sectional dimensions of the purlin, number of purlin lines, number of spans, and span length. A regression analysis was then performed on the data to obtain empirical design equations similar to those found in the 1996 Edition of the American Iron and Steel Institute's Specification for the Design of Cold-Formed Steel Members, Section D.3.2.1. <i>Vita removed April 4, 2011. GMc</i> / Master of Science

Made available in DSpace on 2016-12-08T17:19:30Z (GMT). No. of bitstreams: 1 Capa.pdf: 170642 bytes, checksum: b2fceb213a41d92382392df8b6c975b5 (MD5) Previous issue date: 2007-07-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo principal deste trabalho foi desenvolver um elemento finito singular O para determinar o fator de intensidade de tensão K1 com precisão. Este elemento singular e o elemento Quarter-pojnt são utilizados para duas aplicações bastante comuns: uma placa com trinca central com carregamento de tração e uma viga com trinca lateral e ao carregamento de flexão. Neste trabalho são mostrados em detalhes as malhas as nas analises e os métodos da Extrapolação e da Tangente para o deslocamento e tensão empregados para o cálculo do Fator de Intensidade de Tensão K1. Os resultados de métodos foram comparados com os resultados analíticos para o fator de intensidade de tensão K1. Os melhores resultados encontrados para K1 foram obtidos com o a Extrapolação de deslocamento e com o elemento finito singular apresentado neste trabalho.

This study focuses on assessing the accuracy of the Euler-Bernoulli beam theory as computational bases to calculate strain and deflection of composite sandwich beam subjected to three-point and four-point bending. Two groups of composite sandwich beams tests results will be used for comparison purposes. Mechanical properties for the laminated skin are provided by researchers from University of Mississippi (Ellen Lackey et al., 2000). Mechanical properties for the balsa wood core are provided by Alcan Baltek Corporation. Appropriate material properties and test geometries are then used in the Euler-Bernoulli-based algorithm in order to generate analytical data for comparison to experimental data provided by researchers from University of New Orleans (UNO, 2005). The resulting single material cross section is then analyzed in the traditional manner using the Euler-Bernoulli beam theory. In general, the Euler-Bernoulli beam theory provides an appropriate analytical approach in predicting flexural behavior of composite sandwich beams.