The response of steel-framed structures to applied loading depends to a large degree on the behaviour of the joints between the columns and beams. Traditionally designers have assumed that these joints act either as 'pinned', with no ability to transmit moments from beam to column, or as 'rigid', providing perfect continuity between the connected members. Advances in analysis, and developments in modem codes of practice, permit designers to account for the real behaviour of steel joints where this is known or can be predicted. Even though experimental studies of joints conducted at many research centres around the world have provided a large bank of test data, the vast number of variables in joints (beam and column sizes, plate thicknesses, bolt sizes and spacing, etc.) often means that data for a specific joint arrangement does not exist. As a result, researchers have turned their attention to ways of predicting the behaviour of such joints. One approach which has gained acceptance is based on the "Component Method" in which overall joint behaviour is assumed to be produced by the responses of its various simpler components. To date, data on the response of joints at elevated temperatures has been gathered from full-scale furnace tests on cruciform arrangements, which have concentrated exclusively on moment-rotation behaviour in the absence of axial thrusts. However, when steel-framed structures are subjected to fire, the behaviour of the joints within the overall frame response is greatly affected by the high axial forces which are created by restraint to the thermal expansion of unprotected beams. If momentrotation- thrust surfaces were to be generated this process would require prohibitive numbers of complex and expensive furnace tests for each joint configuration. The alternative, and more practical, method is to extend the Component Method to the elevated-temperature situation. The basic theme of the Component Method is to consider any joint as an assembly of individual simple components. Each of these components is simply a non-linear spring, possessing its own level of strength and stiffness in tension, compression or shear, and these will degrade as its temperature rises. The main objective of this study was to investigate experimentally and analytically the behaviour of tension and compression zones of end-plate connections at elevated temperatures. A series of experiments has been carried out and a simplified analytical model has been developed, and this has been validated against the tests and against detailed finite element simulations. The simplified model is shown to be very reliable for this very common type of joint, although similar methods will need to be developed for other configurations. The principles of the Component Method can be used directly in either simplified or finite element modelling, without attempting to predict of the overall joint behaviour in fire, to enable semi-rigid behaviour to be taken into account in the analytical fire engineering design of steel-framed and composite buildings.

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Orientador: José Antônio Matthiesen / Banca: Renato Bertolino Junior / Banca: Antonio Alves Dias / Resumo: Atualmente no Brasil, há a necessidade de se construir novas pontes, além da grande demanda por pontes de pequenos e médios vãos em novas regiões agrícolas. Com este propósito, a empresa Galvani propôs um sistema estrutural que será utilizado como estrutura principal de uma ponte de madeira, sendo utilizada madeira de reflorestamento da espécie Eucalipto Citriodora. O sistema estrutural estudado consiste em um pórtico pré-tensionado, com duas peças de madeira roliça com 15 metros de altura interligadas por um nó metálico em seu topo, essas peças terão um travamento horizontal efetuado por uma peça de madeira roliça a três quartos da altura da base do pórtico. Este pórtico será a sustentação principal, por tirantes, de um tabuleiro de uma ponte de 5 metros de largura por 30 metros de comprimento. O estudo necessário foi realizado para que este sistema estrutural atenda a todos os requisitos das normas técnicas da ABNT vigentes no país e que satisfaça a expectativa do seu principal idealizador, o engenheiro civil Rodolfo Galvani Júnior / Abstract: Currently in Brazil it's necessary to build new bridges, because there are a large demand for small and medium bridges in new agricultural areas. For this purpose, the company Galvani proposed a new structural system to be used as the principal structure of a wooden bridge, and is used the reforestation wood of species Eucalyptus citriodora. The structural system consists to apply a displacement at the base of the principal structure and will be analyzed its influence in improving the structural behavior when it is loaded. The principal structure have two pieces of roundwood with 15 meters of height and both are connected with the use of metal profiles, these parts will have a lock on a horizontal piece of roundwood to three quarters of the height of base of the structure. This principal structure is used like a support of a main board of a bridge of 5 meters width by 30 meters in length. The objective of this research is study this new structural scheme complies with the requirements of technical standards ABNT and meets the expectation of engineer civil Rodolfo Galvani Junior / Mestre

Over the last decade it has become increasingly clear that the traditional methods of fire safety design can be unnecessarily conservative and therefore expensive. In 1995 a series of fire tests were carried out at Cardington, UK on a full-scale eight storey steel-concrete composite building. These tests produced an extensive body of data about the response of such structures to fire conditions and it is intended that this data be used to develop a clearer understanding of the structural behaviour involved. This thesis presents a method of analysing the behaviour of structures such as the Cardington frame using the commercial finite element package ABAQUS, with the addition of user defined subroutines; applies the method to two of the Cardington tests and analyses the results. FEAST, a suite of computer programmes that defines the behaviour of shell finite elements using a stress-resultant approach, was programmed for use with ABAQUS. The FEAST suite consists of two main programmes. The first, SRAS, is designed to model the behaviour of orthotropic plate sections at elevated temperatures. The second, FEAI, interfaces with the finite element package ABAQUS and allows realistic models of the behaviour of whole structures in fire conditions to be obtained. Phenomena modelled by FEAST include non-linear thermal gradients, non-linear material behaviour and coupling between membrane and bending forces. FEAST was used to analyse the behaviour of the Cardington Restrained Beam Test and the Cardington Corner Test. In both cases it was possible to produce a comprehensive set of results showing the variation of forces, moments and deflections in the structure under fire conditions. In addition, a number of parametric studies were performed to determine the effect of factors such as slab temperature and coefficient of thermal expansion on the behaviour of the structure. Special attention was given to the role of tensile mebrane action. The results showed that the behaviour of the heated structure was very different to that of an unheated structure. The response of the structure was shown to be very strongly governed by restrained thermal expansion and by thermal gradients. Degradation of material properties were found to have only a secondary effect on the structural behaviour.

In the analyses of steel framed structures it is customary to assume the beam to column connections as either fully rigid which means that all moments are transferred from beam to column with negligible rotation or ideally pinned that resists negligible moment. This assumption is reasonable for some types of connections. However when considering steel connections such as bolted-bolted double web angle connections it can be seen that the behavior of these connections is in between the two extreme cases. Thus a third connection type, namely semi rigid or partially restrained connection, is introduced. However this type of connection exhibits such a nonlinear behavior that modeling this behavior necessities a substantial effort. Moreover to perform a performance based analyses the true behavior of these connections should be incorporated as part of the modeling effort. Several researches dealing with these two topics have been undertaken in literature. Despite these efforts, modeling of the moment rotation behavior of these connections still requires improvement especially under cyclic loading conditions. In addition to this, performing an analysis with existing elements incorporating semi-rigid connections as a spring attached to beam ends is not practical because of the fact that displacement based formulation increases meshing significantly which requires substantial computational power. In this study a hysteretic (quadra-linear) moment rotation model considering pinching, damage and possibility of residual moment capacity is developed. The behavior is calibrated via experimental data available in the literature. Furthermore a force based macro element considering spread inelastic behavior along the element is presented. With this element several connections located anywhere along the beam could be incorporated in the analysis with less degree of freedom with respect to displacement based elements. Moreover the macro element model can be used in conjunction with corotational formulation for the capture of nonlinear geometric effects.

Made available in DSpace on 2014-06-11T19:25:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-05-25Bitstream added on 2014-06-13T20:13:40Z : No. of bitstreams: 1 manera_rs_me_ilha.pdf: 1781622 bytes, checksum: df51260a9abc905f915b3ff67132b0bb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Atualmente no Brasil, há a necessidade de se construir novas pontes, além da grande demanda por pontes de pequenos e médios vãos em novas regiões agrícolas. Com este propósito, a empresa Galvani propôs um sistema estrutural que será utilizado como estrutura principal de uma ponte de madeira, sendo utilizada madeira de reflorestamento da espécie Eucalipto Citriodora. O sistema estrutural estudado consiste em um pórtico pré-tensionado, com duas peças de madeira roliça com 15 metros de altura interligadas por um nó metálico em seu topo, essas peças terão um travamento horizontal efetuado por uma peça de madeira roliça a três quartos da altura da base do pórtico. Este pórtico será a sustentação principal, por tirantes, de um tabuleiro de uma ponte de 5 metros de largura por 30 metros de comprimento. O estudo necessário foi realizado para que este sistema estrutural atenda a todos os requisitos das normas técnicas da ABNT vigentes no país e que satisfaça a expectativa do seu principal idealizador, o engenheiro civil Rodolfo Galvani Júnior / Currently in Brazil it's necessary to build new bridges, because there are a large demand for small and medium bridges in new agricultural areas. For this purpose, the company Galvani proposed a new structural system to be used as the principal structure of a wooden bridge, and is used the reforestation wood of species Eucalyptus citriodora. The structural system consists to apply a displacement at the base of the principal structure and will be analyzed its influence in improving the structural behavior when it is loaded. The principal structure have two pieces of roundwood with 15 meters of height and both are connected with the use of metal profiles, these parts will have a lock on a horizontal piece of roundwood to three quarters of the height of base of the structure. This principal structure is used like a support of a main board of a bridge of 5 meters width by 30 meters in length. The objective of this research is study this new structural scheme complies with the requirements of technical standards ABNT and meets the expectation of engineer civil Rodolfo Galvani Junior

In this study, methods for the geometric nonlinear analysis and the material nonlinear analysis of plane frames subjected to elevated temperatures are presented. The method of analysis is based on a Eulerian (co-rotational) formulation, which was developed initially for static loads, and is extended herein to include geometric and material nonlinearities. Local element force-deformation relationships are derived using the beam-column theory, taking into consideration the effect of curvature due to temperature gradient across the element cross-section. The changes in element chord lengths due to thermal axial strain and bowing due to the temperature gradient are also taken into account. This "beam-column" approach, using stability and bowing functions, requires significantly fewer elements per member (i.e. beam/column) for the analysis of a framed structure than the "finite-element" approach. A computational technique, utilizing Newton-Raphson iterations, is developed to determine the nonlinear response of structures. The inclusion of the reduction factors for the coefficient of thermal expansion, modulus of elasticity and yield strength is introduced and implemented with the use of temperature-dependent formulas. A comparison of the AISC reduction factor equations to the Eurocode reduction factor equations were found to be in close agreement. Numerical solutions derived from geometric and material analyses are presented for a number of benchmark structures to demonstrate the feasibility of the proposed method of analysis. The solutions generated for the geometrical analysis of a cantilever beam and an axially restrained column yield results that were close in proximity to the exact, theoretical solution. The geometric nonlinear analysis of the one-story frame exhibited typical behavior that was relatively close to the experimental results, thereby indicating that the proposed method is accurate. The feasibility of extending the method of analysis to include the effects of material nonlinearity is also explored, and some preliminary results are presented for an experimentally tested simply supported beam and the aforementioned one-story frame. The solutions generated for these structures indicate that the present analysis accurately predicts the deflections at lower temperatures but overestimates the failure temperature and final deflection. This may be in part due to a post-buckling reaction after the first plastic hinge is formed. Additional research is, therefore, needed before this method can be used to analyze the materially nonlinear response of structures.

The amount of total and relative sway of a framed or a composite (frame-shear wall) building is of utmost importance in assessing the seismic resistance of the building. Therefore, the design engineer must calculate the sway profile of the building several times during the design process. However, it is not a simple task to calculate the sway of a three-dimensional structure. Of course, computer programs can do the job, but developing the three-dimensional model becomes necessary, which is obviously tedious and time consuming. An easy to apply analytical method is developed, which enables the determination of sway profiles of framed and composite buildings subject to seismic loading. Various framed and composite three-dimensional buildings subject to lateral seismic loads are solved by SAP2000 and the proposed analytical method. The sway profiles are compared and found to be in very good agreement. In most cases, the amount of error involved is less than 5 %. The analytical method is applied to determine sway magnitudes at any desired elevation of the building, the relative sway between two consecutive floors, the slope at any desired point along the height and the curvature distribution of the building from foundation to roof level. After sway and sway-related properties are known, the requirements of the Turkish Earthquake Code can be evaluated and / or checked. By using the analytical method, the amount of shear walls necessary to satisfy Turkish Earthquake Code requirements are determined. Thus, a vital design question has been answered, which up till present time, could only be met by rough empirical guidelines. A mathematical derivation is presented to satisfy the strength requirement of a three-dimensional composite building subject to seismic loading. Thus, the occurrence of shear failure before moment failure in the building is securely avoided. A design procedure is developed to satisfy the stiffness requirement of composite buildings subject to lateral seismic loading. Some useful tools, such as executable user-friendly programs written by using &ldquo / Borland Delphi&rdquo / , have been developed to make the analysis and design easy for the engineer. A method is also developed to satisfy the ductility requirement of composite buildings subject to lateral seismic loading based on a plastic analysis. The commonly accepted sway ductility of &amp / #956 / &amp / #916 / =5 has been used and successful seismic energy dissipation is thus obtained.

The Canterbury Earthquakes of 2010-2011, in particular the 4th September 2010 Darfield earthquake and the 22nd February 2011 Christchurch earthquake, produced severe and widespread liquefaction in Christchurch and surrounding areas. The scale of the liquefaction was unprecedented, and caused extensive damage to a variety of man-made structures, including residential houses. Around 20,000 residential houses suffered serious damage as a direct result of the effects of liquefaction, and this resulted in approximately 7000 houses in the worst-hit areas being abandoned. Despite the good performance of light timber-framed houses under the inertial loads of the earthquake, these structures could not withstand the large loads and deformations associated with liquefaction, resulting in significant damage. The key structural component of houses subjected to liquefaction effects was found to be their foundations, as these are in direct contact with the ground. The performance of house foundations directly influenced the performance of the structure as a whole. Because of this, and due to the lack of research in this area, it was decided to investigate the performance of houses and in particular their foundations when subjected to the effects of liquefaction. The data from the inspections of approximately 500 houses conducted by a University of Canterbury summer research team following the 4th September 2010 earthquake in the worst-hit areas of Christchurch were analysed to determine the general performance of residential houses when subjected to high liquefaction loads. This was followed by the detailed inspection of around 170 houses with four different foundation types common to Christchurch and New Zealand: Concrete perimeter with short piers constructed to NZS3604, concrete slab-on-grade also to NZS3604, RibRaft slabs designed by Firth Industries and driven pile foundations. With a focus on foundations, floor levels and slopes were measured, and the damage to all areas of the house and property were recorded. Seven invasive inspections were also conducted on houses being demolished, to examine in more detail the deformation modes and the causes of damage in severely affected houses. The simplified modelling of concrete perimeter sections subjected to a variety of liquefaction-related scenarios was also performed, to examine the comparative performance of foundations built in different periods, and the loads generated under various bearing loss and lateral spreading cases. It was found that the level of foundation damage is directly related to the level of liquefaction experienced, and that foundation damage and liquefaction severity in turn influence the performance of the superstructure. Concrete perimeter foundations were found to have performed most poorly, suffering high local floor slopes and being likely to require foundation repairs even when liquefaction was low enough that no surface ejecta was seen. This was due to their weak, flexible foundation structure, which cannot withstand liquefaction loads without deforming. The vulnerability of concrete perimeter foundations was confirmed through modelling. Slab-on-grade foundations performed better, and were unlikely to require repairs at low levels of liquefaction. Ribraft and piled foundations performed the best, with repairs unlikely up to moderate levels of liquefaction. However, all foundation types were susceptible to significant damage at higher levels of liquefaction, with maximum differential settlements of 474mm, 202mm, 182mm and 250mm found for concrete perimeter, slab-on-grade, ribraft and piled foundations respectively when subjected to significant lateral spreading, the most severe loading scenario caused by liquefaction. It was found through the analysis of the data that the type of exterior wall cladding, either heavy or light, and the number of storeys, did not affect the performance of foundations. This was also shown through modelling for concrete perimeter foundations, and is due to the increased foundation strengths provided for heavily cladded and two-storey houses. Heavy roof claddings were found to increase the demands on foundations, worsening their performance. Pre-1930 concrete perimeter foundations were also found to be very vulnerable to damage under liquefaction loads, due to their weak and brittle construction.