Approximately half of all framework collapses occur during concrete placement. Researchers who have measured the actual loads in formwork shores consistently found that they differ from those predicted. There is some evidence that current methods tend towards underestimation. In Australia the current practice for designing steel formwork shores is set out in Australian Standard AS 3610-1990 Formwork for Concrete. It was the first national standard to be published in limit states format and departed from previous practice introducing new methods for the design of formwork shores. Prompted by doubt cast on current practice and the absence of hard basis for the methods set out in AS 3610, the aim of the research is to develop new more reliable rules for the design of steel formwork shores. This is achieved using first-order probabilistic techniques to compare the reliability of new and reused shores designed in accordance with AS 3610 with current international permissible stress and limit states methods form British, American, Israeli and draft European formwork Standards / Master of Engineering (Hons)

No description available.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 32-33). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 32-33). Also available on the World Wide Web.

Columns are critical elements of any structure and their failure can lead to the catastrophic consequences of progressive failure. In structural design, procedures to design structures to resist conventional loads are well established. But design for accidental loading conditions is increasingly requested by clients and occupants in modern engineering designs. Among many accidental causes that induce column failure, impact (e.g. vehicular impact, ship impact, crane impact, impact by flying debris after an explosion) has rarely been considered in the modern engineering designs of civil engineering structures such as buildings and bridges. Therefore, most of the design requirements for structural members under vehicle impact as suggested by the current standards and codes such as Eurocode 1 are based on simple equations or procedures that make gross assumptions and they may be highly inaccurate. This research aims to develop more accurate methods of assessing steel column behaviour under vehicle impact.The first main objective of this study is to numerically simulate the dynamic impact response of axially loaded steel columns under vehicle impact, including the prediction of failure modes, using the finite element method. To achieve this goal, a numerical model has been proposed and validated to simulate the behaviour and failure modes of axially loaded steel columns under rigid body impact using the commercial finite element code ABAQUS/Explicit. Afterwards, an extensive parametric study was conducted to provide a comprehensive database of results covering different impact masses, impact velocities and impact locations in addition to different column boundary conditions, axial load ratios and section sizes. The parametric study results show that global buckling is the predominant failure mode of axially unrestrained compressed steel columns under transverse impact. The parametric study results have also revealed that column failure was mainly dependent on the value of the kinetic energy of impact. The parametric study has also shown that strain rate has a minor effect on the behaviour and failure of steel columns under low to medium velocity impact. The parametric study results have been used to develop an understanding of the detailed behaviour of steel columns under transverse impact in order to inform the assumptions of the proposed analytical method.To account for the effect of vehicle impact on the behaviour of steel columns, a simplified numerical vehicle model was developed and validated in this study using a spring mass system. In this spring mass system, the spring represents the stiffness characteristics of the vehicle. The vehicle stiffness characteristics can be assumed to be bilinear, with the first part representing the vehicle deformation behaviour up to the engine box and the second part representing the stiffness of the engine box, which is almost rigid. The second main objective of this research is to develop a simplified analytical approach that can be used to predict the critical velocity of impact on steel columns. The proposed method utilizes the energy balance principle with a quasi-static approximation of the steel column response and assumes global plastic buckling as the main failure mode of the impacted column. The validation results show very good agreement between the analytical method results and the ABAQUS simulation results with the analytical results tending to be on the safe side. A detailed assessment of the design requirements suggested by Eurocode 1, regarding the design of steel columns to resist vehicle impact, has shown that the equivalent static design force approach can be used in the design of moderately sized columns that are typically used in low multi-storey buildings (less than 10 storeys). For bigger columns, it is unsafe to use the Eurocode 1 equivalent static forces. It is acceptable to use a dynamic impulse in a dynamic analysis to represent the dynamic action of vehicle impact on columns, but it is important that both the column and vehicle stiffness values should be included when calculating the equivalent impulse force – time relationship. It is also necessary to consider the two stage behaviour of the impacting vehicle, before and after the column is in contact with the vehicle engine. A method has been developed to implement these changes.

"As jurisdictions throughout the world progress toward performance based building codes, it is important that the proper tools be made available to the engineering profession in order that they may take full advantage of these new codes. There is currently a large body of work written on the subject of performance based or engineered structural fire safety. Unfortunately, most of this information is scattered throughout technical journals from different countries and organizations, and not easily accessible to the practicing engineer. Under the current prescriptive code regime there is generally no requirement to undertake an engineering approach to structural fire safety, since the required fire resistance ratings are prescribed and the fire resistance ratings of materials/assemblies are determined through standard tests. However, these methods have been shown to be both unnecessary and expensive in some cases. A method will be developed that can be used to determine required fire resistance ratings for fire exposed structural steel based on a realistic engineering approach. A procedure is summarized for calculating time-temperature curves from a real fire in a typical compartment. With this time-temperature relationship a realistic time to failure for structural steel members can be determined. The method is summarized. Comments regarding important considerations and a worked example are provided to demonstrate the utility of the method."

A three-phase numerical study was undertaken to address some design issues related with special truss moment frames (STMFs). In the first phase, the design approaches for distribution of shear strength among stories were examined. Multistory STMFs sized based on elastic and inelastic behavior were evaluated from a performance point of view. A set of time history analysis was conducted to investigate performance parameters such as the interstory drift ratio and the plastic rotation at chord member ends. The results of the analysis reveal that the maximum interstory drifts are not significantly influenced by the adopted design philosophy while considerable differences are observed for plastic rotations. In the second phase, the expected shear strength at vierendeel openings was studied through three dimensional finite element modeling. The results from finite element analysis reveal that the expected shear strength formulation presented in the AISC Seismic Provisions for Structural Steel Buildings is overly conservative. Based on the analysis results, an expected shear strength formula was developed and is presented herein. In the third phase, the effects of the load share and slenderness of X-diagonals in the special segment on the performance of the system were evaluated. Lateral drift, curvature at chord member ends, axial strain at X-diagonals and base shear were the investigated parameters obtained from a set of time history analysis. The results illustrate that as the load share of X-diagonals increases, the deformations decreases. Moreover, the slenderness of X-diagonals is not significantly effective on the system performance.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 180-185). Also available in electronic format on the Internet.

Thesis (M.S.)--University of North Texas, Dec., 2008. / Title from title page display. Includes bibliographical references.

Orientadores: Francisco Borges Filho, Silvia Aparecida Mikami Gonçalves Pina / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-14T19:39:19Z (GMT). No. of bitstreams: 1 Borsato_KarenTostes_M.pdf: 36279316 bytes, checksum: 0ec83c2265143394abddde3b4095bc42 (MD5) Previous issue date: 2009 / Resumo: As soluções adotadas durante a concepção arquitetônica têm amplas repercussões em todo o processo de projeto e a falta de conhecimento dos princípios determinantes na concepção da estrutura metálica pelo arquiteto é um dos fatores que influencia a pouca utilização deste material. O domínio sobre as especificidades da produção arquitetônica em aço é imprescindível para o correto processo de projeto e garante subsídios para projetistas, que deveriam ser iniciados na formação do arquiteto. Para tanto, o objetivo dessa dissertação é entender como ocorre a integração da arquitetura no processo de projeto e evidenciar quais são os requisitos e peculiaridades da arquitetura em aço. A pesquisa aborda a integração da arquitetura e a concepção do projeto a partir de uma revisão bibliográfica com temas correlatos e um estudo de campo que contribuiu para viabilizar o projeto em aço. A partir dessa revisão, analisou-se arquitetos selecionados de acordo com o envolvimento na produção em aço de modo a demonstrar a metodologia de projeto de cada profissional, possibilitando a posterior análise e comparação de similaridades e divergências. A partir da metodologia dos casos estudados, este trabalho colaborou com o aprimoramento de idéias e descobertas por parte dos profissionais de arquitetura das características e propriedades do aço, permitindo um entendimento da condução do processo de projeto em torno das diretrizes e premissas que garantem a integração das estruturas metálicas na concepção do projeto arquitetônico. Nesse contexto, o produto desta pesquisa envolveu o aumento das inter-relações entre arquitetos e processos de projeto que incluem com sucesso o uso da estrutura metálica. / Abstract: The used solutions during the architectural conception have wide repercutions in the whole design process and the architect's lack of knowledge regarding the principles for defining the steel structure's design is one of the factors influencing the non-use of this material. The know how of steel production's peculiarities is required for a correct design process and garantees a support for architects and engineers which should be acomplished in their graduation. Thus, the purpose of this research is to understand how the design process integrates with arquitecture and also to put in evidence the steel architectures requirements and peculiarities. From this review, previously selected architects were analyzed to show the design process of each of these professionals alowing later analysis and comparison of their similarities and differences. Thus, based on studied cases' methodology this work collaborated with architects' improvement of ideas and discoveries concerning steel's characteristics and properties, allowing the understanding of design's practice in steel construction from a survey around the guidelines that ensure steel structures and architectural projects design integration. / Mestrado / Arquitetura e Construção / Mestre em Engenharia Civil