Metal building roof systems with C- or Z-section purlins require restraint to resist lateral forces developed within the roof system under gravity loads. The currently available procedures for predicting these forces have been shown to be inaccurate for sloped roofs and difficult to apply to roof configurations with multiple points of anchorage. A new method has been developed that builds on the previous research and accurately addresses roof slope as well as the use of multiple anchorage devices of finite stiffness. The development of this method relied on a stiffness model, similar to that used by previous researchers, which was updated and calibrated to the results of recently completed tests. The calculation procedure explicitly addresses the location and stiffness of anchorage devices as well as the inherent stiffness of the purlin system to accurately distribute the anchorage forces. / Master of Science

Presently, the industry accepted method for determining the positive moment strength of gravity loaded standing seam metal roof systems is the "Base Test Method". The Base Test Method provides a means for determining the positive moment strength of a multiple span, multiple purlin line standing seam roof system using the results from a set of six single span, simply supported, two-purlin line experimental tests. A set of six base tests must be conducted for each combination of purlin profile, deck panel profile, clip type, and intermediate bracing configuration. The primary objective of this study is to investigate the possibility of eliminating some of the roof system parameters specifically, clip type, purlin flange width, and roof panel thickness. This study used the results from nine series of tests. Each series consists of 11 to 14 gravity loaded base tests. The first three series were used to examine the effects of clip type on the strength of standing seam roof system. The final six series was used to examine the effects of flange width and roof panel thickness. All nine series were constructed using Z-purlin sections with flanges facing the same direction (like orientation). Based on the results of this study, clip type, purlin flange width, and roof panel thickness all have an effect on the strength of standing seam roof systems. Although none of the roof components can be completely eliminated from the required test matrix, by using trend relationships an acceptable test protocol was developed that results in a significant reduction in the number of required base tests. / Master of Science

This project studied the effects of wind tunnel test loads applied to purlins in low rise steel buildings compared to those determined with currently recognized wind loading provisions. The National Institute of Standards and Technology (NIST) database of low-rise building wind tunnel test data, which was collected at the University of Western Ontario (UWO) boundary layer wind tunnel, was used to model a realistic wind load scenario. Pressure coefficient data recorded in the database was applied statically to individual purlins in a typical design for the size of buildings studied. These results were then compared to those obtained using the wind design provisions in ASCE 7-16 Chapter 30 for Components and Cladding. The primary data of interest was shear and moment values along the length of the purlins, which were modeled as continuous beams. Comparisons were made between the resultant shear and moment from both the wind tunnel load and ASCE 7-16 load values at 1-foot increments along the length of the purlin. The results showed that the overall peak values obtained from wind tunnel test loads were 3% to 49% higher than those calculated using ASCE 7-16 for purlins that were on the windward edge of the building. Purlins on the interior of the building varied in whether they exceeded the loads calculated with ASCE 7. Changing the height of the structure and the terrain roughness both increased the number of purlins that were lower than the values provided in ASCE 7-16 in the interior of the structure. / Master of Science / Purlins are roof members used in low rise steel buildings to transmit wind loads applied to the roof of the structure to the frame of the building. This project studied the effects of applying loads to purlins using methods specified by the code compared to those found in a wind tunnel, to look at the similarity of the values and model the actual behavior of the purlins more accurately. For this study, wind tunnel test data obtained from the National Institute of Standards and Technology (NIST) database was applied to the purlins and the shear and moment was calculated. These results were compared to the current code requirements provided in the American Society of Civil Engineers (ASCE) 7 document: Minimum Design Loads and Associated Criteria for Buildings and Other Structures. The results showed that the loads developed in the purlins subjected to wind tunnel test loadings were 3% to 49% higher on the edge of the building than those that had the ASCE 7 design loads applied. More accurately modeling the behavior of the purlins using wind tunnel test data and beam models showed that in locations where the purlins received the maximum wind force, the ASCE 7 requirements for components and cladding tended to be lower than the wind tunnel test data. However, in locations where the purlins were not experiencing the maximum wind force, the ASCE 7 requirements tended to overpredict the loads, based on the use of symmetric high wind areas to design for all wind angles.

The aim the diploma thesis is the design and the assessment of the main structure of the shopping centre in the Hradec Králové. The shape of the construction is the cylindrical hall with dimensions 120 x 32 m. The structure is formed by lattice trusses, solid purlins, columns and composite construction. The model of the structure and some calculations were provided by the program Dlubal RFEM.

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

Supplement No. 1 to Section D3.1 of the 1999 AISI Cold-Form Specification contains the current provisions for predicting required lateral restraint forces in Z-purlin supported, sloped metal roof systems under gravity loads. A proposed prediction equation, relying heavily on engineering principles, has been developed because the current provisions in the specification are empirical and based on statistical analysis. The provisions treat roof slope and system effects incorrectly, which necessitates refinement. Also, an assumed roof panel stiffness value was used for the development of the current design provisions, ignoring the effect that varying stiffness values have on the required restraint forces. To determine the validity of the new restraint force prediction equation, experimental testing was conducted on single span and multiple span metal roof systems. Z-purlins were used extensively with through-fastened and standing seam roof panel. Two, four, and six purlin lines were used for the single span tests while only four purlin lines were used for the multiple span tests. Restraint forces were measured at five restraint locations in each span: support, third-point, midpoint, quarter-point, and third-point plus support. Each restraint configuration was tested at six roof slopes: 0:12, 0.5:12, 1:12, 2:12, 3:12, and 4:12. For each restraint configuration and roof slope, the restraint forces were measured and compared to predicted forces using the proposed design equation. The proposed equation contains the term "δ" which is the resultant eccentricity of the applied gravity load acting on the top flange of a purlin. A value of 1/3 was assumed for d in the development of the proposed equation and many of the test results were in agreement with this value. However, other results were in better agreement with a value of 0 for d and some of the measured forces were between the predicted forces with d = 0 and d = 1/3. No consistent correlation between the results and the proposed prediction equation was found. / Master of Science

Terças de aço formadas a frio são muito utilizadas em sistemas de cobertura e fechamento. Para conferir continuidade entre tramos adjacentes e possibilitar um melhor aproveitamento de material, são empregadas ligações parafusadas por transpasse e com luva. O comportamento estrutural dessas ligações é muito dependente da sua configuração geométrica e do nível de carregamento. Com base em uma série de nove experimentos e análises teóricas, o comportamento estrutural dessas ligações foi investigado no tocante aos esforços resistentes e à rigidez. Observou-se que o modo de falha tem sempre uma componente distorcional significativa e uma resistência menor que a prevista pela metodologia atual de projeto. No caso do momento fletor resistente, a distribuição de tensões de flexão oblíqua é a que melhor se aproxima do comportamento real das terças, sendo possível a partir de uma análise de estabilidade elástica considerando tal comportamento, e, baseado no método da resistência direta e na curva de dimensionamento do modo distorcional, obter uma previsão segura do momento fletor resistente. Além disso, a rigidez da ligação, com relação aos deslocamentos verticais é bastante dependente do tipo de ligação, sendo que as terças com ligações por luva são mais deformáveis que terças sem ligações. Por outro lado, terças com ligações por transpasse são menos deformáveis que terças fisicamente contínuas. As parcelas de rigidez da ligação são apresentadas, e a componente de deformação do furo é a mais significativa. Uma expressão para deduzir a rigidez rotacional da ligação é apresentada, juntamente com um modelo de barras para modelagem da ligação. Os resultados teóricos se ajustam muito bem aos experimentais. Conclui-se em linhas gerais, que as ligações por transpasse podem ser consideradas plenamente satisfatórias do ponto de vista de comportamento estrutural, sendo que terças com essas ligações são mais resistentes e rígidas que terças com continuidade física. O mesmo não ocorre nas terças com ligações por luva, porém, dada a limitação no número de ensaios, tais ligações carecem mais estudos. / Cold-formed steel purlins are widely used in roofs and wall systems. The continuity of long runs of cold-formed steel purlins is guaranteed by sleeve and overlap bolted connections, which allows a better load distribution and material savings. The structural behavior of these connections is highly dependent on their geometric configuration and load level. The strength and stiffness of these connections were determined through a series of nine experiments, numerical and analytical analysis. Results have shown that distortional buckling has a major contribution on the stability analysis of the cold-formed steel purlin. To safely determine the flexural strength of the purlin, one must consider unrestrained bending stress distribution and distortional buckling. The connection type influences the rigidity of the purlin thus the vertical displacement. Purlins with overlapped connections are stiffer than physically continuous ones, although purlins with sleeved connections are not. The bearing deformation at the connection region is responsible for a reduction in the system stiffness. To account for the change in stiffness and determine the vertical displacement, an expression for the bearing stiffness and a beam model are proposed. The results of this model show good agreement with experimental data. The general conclusion of this research is: overlapped bolted connections enhance the structural response of the purlins when compared to physically continuous ones. The same does not hold true for purlins with sleeved connections.

Atualmente, os perfis de chapa dobrada têm encontrado intensa aplicação como elementos estruturais nas construções em aço e como consequência, estão sujeitos aos mais diversos tipos de carregamentos. Este trabalho apresenta os aspectos gerais do dimensionamento de perfis de chapa dobrada submetidos à flexão enquanto utilizados como vigas propriamente dito e, também, enquanto utilizados como terças. Analisam-se seções tipo U, tipo U enrijecido e tipo Z enrijecido. Os ensaios em perfis fletidos foram realizados sobre 3 diferentes condições de carregamento, com dois vãos distintos, em um total de sessenta e quatro perfis ensaiados. Para os perfis conectados às telhas de aço, os ensaios foram realizados em uma \"caixa de sucção\" desenvolvida especificamente para este projeto. Os perfis foram conectados às telhas pela mesa por meio de parafusos auto-brocantes, sendo realizados quinze ensaios. Os resultados dos ensaios são comparados com os resultados teóricos, resultados normatizados e resultados de alguns procedimentos aproximados. / Nowadays, the cold-formed steel members have intense application as structural elements in constructions and, in consequence, they are subjected to several types of loads. This work presents the general aspects of the study of cold-formed steel members subjected to flexion used as beams and, also, as purlins. Sections of type U, type C and type Z are analysed. The tests in beams were carried out under three different conditions of loads, with two distinct spans, in total of sixty four tests. For the purlins connected to roof system, the tests were in a \"suction box\", developed especially for this project. The purlins were connected to the roof system by the flange by using self-drilling screws, being carried out fifteen tests. The results of those tests are compared with the theoretical results, design specification provisions and results of some approximated procedures.

Atualmente, os perfis de chapa dobrada têm encontrado intensa aplicação como elementos estruturais nas construções em aço e como consequência, estão sujeitos aos mais diversos tipos de carregamentos. Este trabalho apresenta os aspectos gerais do dimensionamento de perfis de chapa dobrada submetidos à flexão enquanto utilizados como vigas propriamente dito e, também, enquanto utilizados como terças. Analisam-se seções tipo U, tipo U enrijecido e tipo Z enrijecido. Os ensaios em perfis fletidos foram realizados sobre 3 diferentes condições de carregamento, com dois vãos distintos, em um total de sessenta e quatro perfis ensaiados. Para os perfis conectados às telhas de aço, os ensaios foram realizados em uma \"caixa de sucção\" desenvolvida especificamente para este projeto. Os perfis foram conectados às telhas pela mesa por meio de parafusos auto-brocantes, sendo realizados quinze ensaios. Os resultados dos ensaios são comparados com os resultados teóricos, resultados normatizados e resultados de alguns procedimentos aproximados. / Nowadays, the cold-formed steel members have intense application as structural elements in constructions and, in consequence, they are subjected to several types of loads. This work presents the general aspects of the study of cold-formed steel members subjected to flexion used as beams and, also, as purlins. Sections of type U, type C and type Z are analysed. The tests in beams were carried out under three different conditions of loads, with two distinct spans, in total of sixty four tests. For the purlins connected to roof system, the tests were in a \"suction box\", developed especially for this project. The purlins were connected to the roof system by the flange by using self-drilling screws, being carried out fifteen tests. The results of those tests are compared with the theoretical results, design specification provisions and results of some approximated procedures.

Terças de aço formadas a frio são muito utilizadas em sistemas de cobertura e fechamento. Para conferir continuidade entre tramos adjacentes e possibilitar um melhor aproveitamento de material, são empregadas ligações parafusadas por transpasse e com luva. O comportamento estrutural dessas ligações é muito dependente da sua configuração geométrica e do nível de carregamento. Com base em uma série de nove experimentos e análises teóricas, o comportamento estrutural dessas ligações foi investigado no tocante aos esforços resistentes e à rigidez. Observou-se que o modo de falha tem sempre uma componente distorcional significativa e uma resistência menor que a prevista pela metodologia atual de projeto. No caso do momento fletor resistente, a distribuição de tensões de flexão oblíqua é a que melhor se aproxima do comportamento real das terças, sendo possível a partir de uma análise de estabilidade elástica considerando tal comportamento, e, baseado no método da resistência direta e na curva de dimensionamento do modo distorcional, obter uma previsão segura do momento fletor resistente. Além disso, a rigidez da ligação, com relação aos deslocamentos verticais é bastante dependente do tipo de ligação, sendo que as terças com ligações por luva são mais deformáveis que terças sem ligações. Por outro lado, terças com ligações por transpasse são menos deformáveis que terças fisicamente contínuas. As parcelas de rigidez da ligação são apresentadas, e a componente de deformação do furo é a mais significativa. Uma expressão para deduzir a rigidez rotacional da ligação é apresentada, juntamente com um modelo de barras para modelagem da ligação. Os resultados teóricos se ajustam muito bem aos experimentais. Conclui-se em linhas gerais, que as ligações por transpasse podem ser consideradas plenamente satisfatórias do ponto de vista de comportamento estrutural, sendo que terças com essas ligações são mais resistentes e rígidas que terças com continuidade física. O mesmo não ocorre nas terças com ligações por luva, porém, dada a limitação no número de ensaios, tais ligações carecem mais estudos. / Cold-formed steel purlins are widely used in roofs and wall systems. The continuity of long runs of cold-formed steel purlins is guaranteed by sleeve and overlap bolted connections, which allows a better load distribution and material savings. The structural behavior of these connections is highly dependent on their geometric configuration and load level. The strength and stiffness of these connections were determined through a series of nine experiments, numerical and analytical analysis. Results have shown that distortional buckling has a major contribution on the stability analysis of the cold-formed steel purlin. To safely determine the flexural strength of the purlin, one must consider unrestrained bending stress distribution and distortional buckling. The connection type influences the rigidity of the purlin thus the vertical displacement. Purlins with overlapped connections are stiffer than physically continuous ones, although purlins with sleeved connections are not. The bearing deformation at the connection region is responsible for a reduction in the system stiffness. To account for the change in stiffness and determine the vertical displacement, an expression for the bearing stiffness and a beam model are proposed. The results of this model show good agreement with experimental data. The general conclusion of this research is: overlapped bolted connections enhance the structural response of the purlins when compared to physically continuous ones. The same does not hold true for purlins with sleeved connections.