The objective of this study is to examine the effect of rotational restraints on thermal post-buckling response of sway columns using geometrically nonlinear analysis. The present design approach considers columns to have failed once they buckle. However, the columns under fire load are found to exhibit significant post-buckling strength which could be utilized for more economical design. The past researchers on the nonlinear thermal analysis used isolated columns with idealized support conditions which mean the columns are assumed to be free or fully restrained in the rotation, lateral and, axial directions. However, that is seldom the case in real structures and the restraint at an end of the column depends upon the members connected at that joint. The restraint provided to the column by the members connected at the joint will be in between the free case and fully restrained case. This study incorporates the variation in rotational restraint due to changes in the properties of members connected at the ends of the column. The columns are assumed to be fully restrained in the axial direction. Since the study is being carried out on sway columns, the restraint in the lateral direction is zero.

<p> A research programme is presented to more fully understand the behaviour of Round Hollow Structural Sections subjected to inelastic strain reversals. An attempt is made to establish a preliminary guideline for choosing a reasonable value for the slenderness ratio (D/t) that qualifies the Round HSS for cyclic loading. </p> <p> An experimental programme on nine sections was performed to evaluate the loss in load capacity due to inelastic cyclic loading and to construct the load-deflection hysteresis loops. </p> <p> Three different limiting cyclic deflections were imposed to the smallest D/t section and a comparison was made between the performance of the tube in each case. </p> <p> Prasad's computer program was used to select the strain value at which local buckling will appear and to calculate the half buckle wave-length. The results were compared to the experimental results obtained by the author. </p> <p> A comparison is made between two Round HSS having different diameters and thicknesses but the same D/t ratio. </p> <p> A comparison is made between the behaviour of Round HSS and Square HSS subjected to the same cyclic loading programme. </p> <p> An attempt is made to suggest a reasonable curve relating the number of cycles to failure and the D/t ratio. </p> / Thesis / Master of Engineering (ME)

This paper presents the experimental results and observation of elliptical concrete filled tube (CFT) columns subjected to axial compressive load. A total of twenty-six elliptical CFT specimens including both stub and slender composite columns are tested to failure to investigate the axial compressive behaviour. Various column lengths, sectional sizes and infill concrete strength are used to quantify the influence of member geometry and constituent material properties on the structural behaviour of elliptical CFT columns. As there is no design guidance currently available in any Code of Practice, this study provides a review of the current design rules for concrete filled circular hollow sections in Eurocode 4 (EC4). New equations based on the Eurocode 4 provisions for concrete filled circular hollow sections were proposed and used to predict the capacities of elliptical CFT columns.

Feasible span-to-depth ratios for many modern bridge systems have been identified and documented in literature. No such parameters have been adequately identified in terms of proportioning bridge piers. This thesis includes a study of 22 existing reinforced concrete highway bridges and their respective pier systems to determine the state-of-the-art in design. The effect of different geometric and material parameters such as concrete strength, reinforcement ratio and slenderness ratio on the structural behavior of individual piers and multiple pier systems was examined. Approximate methods, which may be used for the purposes of preliminary design are discussed and reviewed. Serviceability and ultimate limit states design aids that can be used to identify appropriate preliminary cross-sectional pier dimensions and reinforcement ratios for individual piers given various slenderness ratios were developed. The structural behavior as well as an approach to the preliminary design of multiple pier bridge systems is presented.

Feasible span-to-depth ratios for many modern bridge systems have been identified and documented in literature. No such parameters have been adequately identified in terms of proportioning bridge piers. This thesis includes a study of 22 existing reinforced concrete highway bridges and their respective pier systems to determine the state-of-the-art in design. The effect of different geometric and material parameters such as concrete strength, reinforcement ratio and slenderness ratio on the structural behavior of individual piers and multiple pier systems was examined. Approximate methods, which may be used for the purposes of preliminary design are discussed and reviewed. Serviceability and ultimate limit states design aids that can be used to identify appropriate preliminary cross-sectional pier dimensions and reinforcement ratios for individual piers given various slenderness ratios were developed. The structural behavior as well as an approach to the preliminary design of multiple pier bridge systems is presented.

The purpose of this study is to explore haw thinning planning standards agree with standards of estimation. Study was carried out in Kretinga forest enterprise Grūšlaukė forestry. Study of ratio of stands medial diameter and medial high was carried out in 11 – 60 years old pure spruce. The main purpose of thinning is to increase total productivity of forest stands and to form desirable structure and closeness of stands. It is important that all kinds of forest thinning concern biodiversity, increase resistance to wind and snow damage of forest stands, improve the quality of growing timber. Forests thinning use that timber part which rots in forests and gives no profit. To reach all these purpose forests thinning must be planned. Planning standard must be definite as it possible. It is important that these standards be suit with forests thinning normative. It was estimated that both standards has different rates and they are not matched. Thinning is planning by thickness of stands, but they are estimating by the number of trees in one hectare of stands. It was estimated that the ratio of forest stands medial diameter and medial high can be used in thinning planning. In pure spruce stands thinning must planned until ratio of medial diameter and medial high reach value: 0,8 in 11 – 20 years old stands; 0,9 in 21 – 40 years old stands; 1,0 in 41 – 60 years old stands.

Made available in DSpace on 2014-07-29T15:03:35Z (GMT). No. of bitstreams: 1 pre-textuais Rodrigo Fernandes.pdf: 349523 bytes, checksum: 27a5e6d7df167303c662872391301d36 (MD5) Previous issue date: 2007-10-01 / This work contains a theoretical analysis of the behavior of plate girders. A plate girder has been calculated based on the criteria of the American standard Manual of Steel Construction Load and Resistance Factor Design (AISC, 1994), and checked by the Brazilian standard NBR 8800: Projeto e execução de estruturas de aço de edifícios (método dos estados limites) (ABNT, 1986), the revision project of the Brazilian standard Projeto de Revisão da NBR 8800: Projeto e execução de estruturas de aço e de estruturas mistas aço-concreto de edifícios (ABNT, 2003), the revision project of the Brazilian standard Projeto de Revisão da NBR 8800: Projeto de estruturas de aço e de estruturas mistas de aço e concreto de edifícios (ABNT, 2007) and the European standard Eurocode 3: Design of steel structures Part 1.1: General rules and rules for buildings (CEN, 1992). PFEIL (1989) has calculated a plate girder by using the Brazilian standard NBR 8800/86. The calculated dimension have been checked by the mentioned standards. NARAYANAN (1992 apud OWENS, KNOWLES E DOWLING, 1992) has dimensioned a plate girder by using the British standard BS 5950: Structural use of steelwork in building. Part 1: Code of practice for design in simple and continuous construction: hot rolled sections (BSI, 1990), which has also been checked by the mentioned standards. Furthermore, theoretical analyses related to the calculus of plate girders presented by many authors have been considered. The main goal is to assess the criteria utilized by the standards for the calculus of plate girders. From the obtained results, for the checked girders, by the standards and related theories, a comparative analysis among the utilized criteria by the standards has been made. The reached conclusion is that the Brazilian standard and its revision projects has identical criteria compared to the American standard for the calculus of plate girders. The European standard presents slightly different criteria compared to the American standard; however, both provide close results one compared to another. The theories utilized have also provided close results from those obtained by the standards. / Neste trabalho é feita uma análise teórica sobre o comportamento de vigas esbeltas. Uma viga esbelta foi dimensionada com base nos critérios da norma americana Manual of Steel Construction Load and Resistance Factor Design (AISC, 1994), e depois verificada pela norma brasileira NBR 8800: Projeto e execução de estruturas de aço de edifícios (método dos estados limites) (ABNT, 1986), pelo projeto de revisão da norma brasileira Projeto de Revisão da NBR 8800: Projeto e execução de estruturas de aço e de estruturas mistas aço-concreto de edifícios (ABNT, 2003), pelo projeto de revisão da norma brasileira Projeto de Revisão da NBR 8800: Projeto de estruturas de aço e de estruturas mistas de aço e concreto de edifícios (ABNT, 2007) e pela norma européia Eurocode 3: Design of steel structures Part 1.1: General rules and rules for buildings (CEN, 1992). PFEIL (1989) dimensionou uma viga esbelta utilizando a norma brasileira NBR 8800/86. As dimensões calculadas foram verificadas pelas normas citadas. NARAYANAN (1992 apud OWENS, KNOWLES E DOWLING, 1992) dimensionou uma viga esbelta utilizando a norma britânica BS 5950: Structural use of steelwork in building. Part 1: Code of practice for design in simple and continuous construction: hot rolled sections (BSI, 1990), a qual foi também verificada pelas normas citadas. Também foram consideradas análises teóricas relativas ao cálculo de vigas esbeltas apresentadas por diversos autores. O objetivo principal é avaliar os critérios utilizados pelas normas para o cálculo de vigas esbeltas. A partir dos resultados obtidos, para as vigas analisadas, pelas normas e pelas teorias existentes, foi feita uma análise comparativa entre os critérios utilizados pelas normas. A conclusão a que se pôde chegar é que a norma brasileira e seus projetos de revisão apresentam critérios idênticos aos da norma americana para o cálculo de vigas esbeltas. A norma européia apresenta critérios um pouco diferenciados dos critérios da norma americana, mas fornecem resultados aproximados entre si. As teorias utilizadas também forneceram resultados aproximados dos resultados obtidos pelas normas.