The aim of this thesis was to study the load bearing capacity of anchor plates, used for anchorage to concrete located at nuclear facilities. Two different type of anchor plates were examined, which together constitute the majority of the anchor plates used at Forsmark nuclear facility in Sweden. The first is a cast-in-place anchor plate with headed studs and the second is a post-installed anchor plate which uses sleevetype expansion anchors. Hence, anchors with both a mechanical or a frictional interlock to the concrete were examined. The main analysis tool was the finite element method, through the use of the two commercially available software packages ABAQUS and ADINA and their non-linear material models for concrete and steel. As a first step, the numerical methods were verified against experimental results from the literature. However, these only concern single anchors. The results from the verifications were then used to build the finite element models of the anchor plates. These were then subjected to different load combinations with the purpose to find the ultimate load capacity. Failure loads from the finite element analyses were then compared to the corresponding loads calculated according to the new European technical specification SIS-CEN/TS 1992-4 (2009). Most of the failure loads from the numerical analyses were higher than the loads obtained from the technical specification, although in some cases the numerical results were lower than the technical specification value. However, many conservative assumptions regarding the finite element models were made, hence there might still be an overcapacity present. All analyses that underestimate the failure load were limited to large and slender anchor plates, which exhibit an extensive bending of the steel plate. The bending of the steel plate induce shear forces on the anchors, which leads to a lower tensile capacity. In design codes, which assume rigid steel plates, this phenomenon is neglected. The failure loads from all different load combinations analysed were then used to develop failure envelopes as a demonstration of a useful technique, which can be utilised in the design process of complex load cases.

The objective of this research is to create a computationally efficient seismic analysis framework for cold-formed steel (CFS) framed-buildings supported by hysteretic nonlinear models for CFS members and screw-fastened connections. Design of CFS structures subjected to lateral seismic forces traditionally relies on the strength of subassemblies subjected to lateral loading of systems, such as strapped/sheathed shear walls and diaphragms, to provide adequate protection against collapse. Enabling performance-based seismic design of CFS buildings requires computationally efficient and accurate modeling tools that predict the nonlinear cyclic behavior of CFS buildings, the individual CFS components and connections. Such models should capture the energy dissipation and damage due to buckling and cross-sectional deformations in thin-walled CFS components subjected to cyclic loads such as those induced by earthquakes. Likewise, models for screw-fastened CFS connections should capture the energy dissipation and damage due to tilting, bearing, or screw shear when subjected to cyclic loading. In this dissertation, an analysis framework for CFS structures that captures the nonlinear cyclic behavior of critical components including axial members, flexural members, and screw fastened connections is presented. A modeling approach to simulate thin-walled behavior in CFS members is introduced where parameters were developed using results from an experimental program that investigated the cyclic behavior and energy dissipation in CFS axial members and flexural members. Energy dissipation and cyclic behavior of CFS members were characterized for members experiencing global, distortional and local buckling. Cyclic behavior and energy dissipation in thin steel plates and members was further investigated through finite element analysis in ABAQUS to provide a strategy for modeling steel columns cyclic behavior including local buckling. Model parameters were developed as generalized functions of the hysteretic energy dissipated and slenderness. The capabilities of the analysis framework are demonstrated through simulations of CFS wood sheathed shear wall cyclic responses validated with experimental results from full scale shear wall tests. / Ph. D.

Made available in DSpace on 2014-07-29T15:03:33Z (GMT). No. of bitstreams: 1 Dissertacao Emmele G Fontenelle.pdf: 3889725 bytes, checksum: 2db009d8581a8358994f13fbf37f6062 (MD5) Previous issue date: 2011-06-27 / Fastenings inserted in concrete are used in order to allow the introduction of these components in concrete structures, enabling the structural link between metal structures and concrete foundation and between prefabricated components and fixing reinforcement elements. This work will study specifically an anchoring system pre-installed (cast-in-place anchor), consisting of single head studs with square head and subjected to tensile force. Assays were performed in 30 headed studs, using self-compacting concrete with compressive strength in the C-30 class. The main variables are the presence and rate of reinforcement, the arrangement of reinforcement in the blocks, and the influence of both the flexural reinforcement (longitudinal and transverse) and the shear reinforcement (hairpins) on the load capacity of the anchorage. The experimental results were compared with five methods of design found in the literature and show that the flexural einforcement has no effect in increasing the load capacity of the anchorage. The use of a shear reinforcement together with the flexural reinforcement can increase the capacity of the anchor up to 64%. Increasing the distance of the hairpins in relation to the head stud reduces the ultimate load achieved by the anchoring system while the increase in diameter and / or in the number of layers of hairpins can increase the ultimate load. / Pinos de ancoragem inseridos em concreto são empregados com a finalidade de permitir a fixação de elementos para a introdução de solicitações nas estruturas de concreto, viabilizando as ligações estruturais entre estruturas metálicas e a fundação de concreto, entre componentes pré-fabricados e na fixação de elementos de reforço. Neste trabalho será abordado e estudado especificamente um sistema de ancoragem pré-instalado, composto por pino de ancoragem único com cabeça quadrada e submetido à força de tração. Foram realizados ensaios em 30 pinos, utilizando-se concreto auto-adensável com resistência à compressão na classe C-30, tendo como principais variáveis a presença e taxa de armadura, e disposição da armadura nos blocos, analisadas tanto na armadura de flexão (longitudinal e transversal) quanto na armadura de cisalhamento (grampos). Os resultados experimentais foram comparados com cinco métodos de cálculo da literatura e mostram que a armadura de flexão não influencia no aumento da capacidade de carga do pino de ancoragem. A utilização de uma armadura de cisalhamento juntamente com a armadura de flexão pode aumentar a capacidade de carga do pino em até 64%. O afastamento dos grampos em relação ao pino diminui a carga última atingida pelo pino de ancoragem, enquanto o aumento do diâmetro e/ou o aumento do número de camadas dos grampos pode aumentar a carga última.

El transporte terrestre de tipo urbano es uno de los medios viales más importantes y más utilizados en el Perú y en el mundo, en el cual se llega a invertir hasta más de la cuarta parte de tiempo diario en trasladarse en el pavimento o veredas. Actualmente, esta infraestructura vial, es el lugar donde nuestras vidas se encuentran más vulnerables y expuestas a diversos tipos accidentes de tránsito. Estos accidentes se han convertido en un peligro inminente para cualquier individuo, desde un pequeño escolar peatón hasta un experimentado conductor profesional. Es muy probable ser víctimas de un accidente de grado leve o haber presenciado un desafortunado accidente fatal, que comúnmente se visualiza a diario en los noticieros, lo cual carga de preocupación o amargura por las malas condiciones que se encuentra nuestra infraestructura vial. Por esta razón, existe la necesidad de implementar una metodología que identifique masivamente los puntos de siniestros viales por exceso de velocidad, debido a que estas incidencias viales se han convertido en una de las principales causas de personas lisiadas, discapacitadas y fallecidas por accidentes de tránsito. Por lo anterior, esta investigación tiene como objetivo la aplicación del sistema LIDAR (Light Detection and Ranging) para la identificación espacial de puntos de siniestros viales; y el sistema de estoperoles inteligentes para la reducción del exceso de velocidad en el viaducto de la Av. Angamos Este, que verifica el cumplimiento de la normativa vigente y su aplicación según la velocidad de diseño de la vía de interés. / Urban land transport is one of the most important and most used road means in Peru and in the world, in which up to a quarter of the daily time is spent traveling on the pavement or sidewalks. Currently, this road infrastructure is the place where our lives are most vulnerable and exposed to various types of traffic accidents. These accidents have become an imminent danger for any individual, from a small pedestrian schoolboy to an experienced professional driver. It is very likely to be victims of a minor accident or to have witnessed an unfortunate fatal accident, which is commonly seen daily in the news, which carries concern or bitterness due to the poor condition of our road infrastructure. For this reason, there is a need to implement a methodology that massively identifies the points of road accidents due to speeding, because these road incidents have become one of the main causes of disabled, disabled and deceased people due to traffic accidents. Therefore, this research aims to apply the LIDAR system (Light Detection and Ranging) for the spatial identification of road accident points; and the intelligent studs system to reduce excess speed on the Av. Angamos Este viaduct, which verifies compliance with current regulations and their application according to the design speed of the road of interest. / Tesis

The shear capacity of headed studs in precast concrete hollow-core slab construction has been determined experimentally in 12 full-scale push-off tests. The tests were used to study the effects of the size of the gap between the ends of the precast slabs, and the amount of tie steel placed transversely across the joint, and the strength of concrete infill. Under certain situations the capacity of the stud is reduced compared with that in a solid reinforced concrete slab. Maximum resistances are compared with the predictions of BS 5950 and EC4, and a reduction formula for the precast effect is derived.

This study consists of three self-standing parts, each dealing with a different aspect of design of composite steel-concrete flexural members. The first part deals with a new type of shear connection in composite joists. Composite steel-concrete flexural members have increasingly become popular in design and construction of floor systems, structural frames, and bridges. A particularly popular system features composite trusses (joists) that can span large lengths and provide empty web space for installation of typical utility conduits. One of the prominent problems with respect to composite joists has been the installation of welded shear connection due to demanding welding requirements and the need for significant welding equipment at the job site. This part of the study presents a new type of shear connection developed at Virginia Tech— standoff screws. Results of experimental and analytical research are presented, as well as the development of a recommended design methodology. The second part deals with reliability of composite beams. Constant research advances in the field of composite steel-concrete beam design have resulted in numerous enhancements and changes to the American design practice, embodied in the composite construction provisions of the AISC Specification (AISC 1999). Results of a comprehensive reliability study of composite beams are presented. The study considers specification changes since the original reliability study by Galambos et al. (1976), considers a larger database of experimental data, and analyses recent proposals for changes in design of shear connection. Comparison of three different design methods is presented based on a study of 15,064 composite beam cases. A method to consider effect of degree of shear connection on strength reduction factor is proposed. Finally, while basic analysis theories between the two are similar, requirements for determining the strength of composite beams in Eurocode 4 (CEN 1992) and 1999 AISC Specification (AISC 1999) differ in many respects. This is particularly true when considering the design of shear connections. This part of the dissertation explores those differences through a comparative step-by-step discussion of major design aspects, and accompanying numerical example. Several shortcomings of 1999 AISC Specification are identified and adjustments proposed. / Ph. D.

L'utilisation des composites dans la construction des bâtiments ou des ouvrages d'art est de plus en plus importante car ces matériaux présentent des atouts indiscutables comme un très bon rapport performance / poids ou une facilité de mise en oeuvre. Cependant, leur essor est ralenti par certaines faiblesses dont l'une des plus importantes est leur souplesse qui induit des déplacements élevés et des risques d'instabilités importants qui ne permettent pas d'exploiter tout le potentiel de ces matériaux. Dans le cas d'éléments de structure fléchis, une des solutions consiste à associer les profilés composites à une dalle en béton armé. La connexion est établie par des butées mécaniques, par collage, ou l'association des deux. L'objectif général de ce travail est d'étudier le comportement des structures mixtes GFRP-Béton fléchies sous chargement statique instantané : Cette étude comporte un volet expérimental lourd et un volet de modélisation numérique. Elle a été abordée à 3 échelles : matériaux, interface, et structure. Trois modes de connexion ont été exploités. Sur le plan expérimental, nous avons d'abord caractérisé tous les matériaux utilisés : composite, béton, adhésif, acier des armatures et des connecteurs. Puis, la caractérisation à l'échelle de l'interface a été effectuée par l'essai push-out dans différentes configurations (7 séries d'essais au total). Enfin, le comportement à l'échelle d'éléments de structure a été étudié sur des mono-poutres pour des portées allant de 2 m à 4.8 m, sur des poutres composites seules ou sur des poutres mixtes (10 poutres au total). Une passerelle bi-poutre de 4.8 m de portée a également été testée dans la même configuration et jusqu'à la ruine. La modélisation du comportement de ces poutres hybrides a été effectuée selon 2 cas théoriques. Elles ont d'abord été modélisées dans le cadre de la théorie des poutres multicouches, dans le domaine élastique et à l'approche de la ruine. Selon le mode de connexion, le glissement à l'interface est pris en compte ou négligé. Ces poutres ont également été modélisées par la MEF en utilisant des éléments volumiques et en considérant une connexion parfaite. Les résultats d'essais montrent le comportement correspondant à chaque mode de connexion : la connexion par butées mécaniques simples est à ce jour celle qui s'avère la plus efficace. Les écarts modèle / calculs restent acceptables sauf à proximité de l'interface où les déformations peuvent être affectées par la fissuration du béton qui reste difficile à prédire de façon précise. La simulation numérique donne des valeurs très proches de la réalité et répond aux questions posées lors de l'expérience / Advanced composites are increasingly used in construction thanks to their indisputable advantages such as high strength to weight ratio and ease of implementation. However, their growth is hindered by a main weak point: low stiffness. Advanced composites risk instabilities under high loads which make it not possible to exploit their full potential. Considering flexural elements, one of the solutions proposed consists in associating the composite profiles with a reinforced concrete slab. The connection of both materials is either established by bolting, bonding or a combination of both techniques.In this study, 3 different connection modes were tested on structural elements with different spans. Previously, to characterize the mechanical behavior of the interface, 35 push out specimens having bolted or bonded connections were prepared and tested. In addition, all materials used were characterized.A composite beam (Pu1) and 8 hybrid beams (PB1-PB8) were tested under 3 points bending up to failure. The results are exploited to construct and test a hybrid footbridge. 7 push out series were tested and digital image correlation was used to analyze the behavior at the interface and measure the displacement fields to determine the slip. Concrete, GFRP, bolts, the adhesive and the concrete reinforcing steel bars were all characterized.The experimental data obtained from the tests is compared to calculation results obtained by a multi-layer beam model within service limit states and at ultimate ones. Besides, a 3D finite element model was developed to provide more accurate results.The results allow distinguishing 3 behavior modes relative to the 3 connection types: the connection by mechanical studs proves to be the most efficient so far. The measurements are also compared to the results obtained by a multi-layer beam model. The differences are acceptable except in the vicinity of the interface where the deformations can be affected by the cracking of the concrete which remains difficult to predict precisely. The 3D simulations present with an excellent agreement the experiments and explain some observations obtained

This thesis aims to design a bearing composite steel structure for five-storey administration building with ground plan dimensions 35,00 x 50,00 m. Designed building has L-shaped plan, flat roof and attic all the way around. The largest part of the plan area occupies office zone with dimensions of 48,60 x 18,90 m. Contiguous zone communication and sanitation has dimensions of 13,50 x 15,90 m. Floor height is designed 3,60 m, the total height of the building is 18,70 m. Composite steel floor structure consists of transverse primary beams and hinge-connected secondary beams. Integrated formwork (trapezoidal sheet) has ribs oriented perpendicular to the secondary beams. Coupling is bidirectional. Construction will be done in two variants. Variant No.1 assumes primary and secondary beams (at the columns) hinge-connected with columns. In variant No.2 will be frame connection between primary beams and columns and together they will create 2D transverse frames with hinge-connected secondary beams. The supporting structure of the roof is designed similarly to ceiling, but reinforced concrete slab will be replaced with bracing in the roof plane and self-bearing rib sandwich panels. Vertical sheathing of the building provide sandwich panels and strip windows. The type of steel is S355. The building is designed for the site Hradec Králové. Standards and documents used in design of the bearing structure are included in the list of sources. The result of this work is a static analysis with an assessment of all elements of the selected (best) variant of the structure, drawing documentation and technical report.

To save energy it’s popular to build houses with low energy loss. In these houses the walls are keeping a lower temperature in the external side which leads to a higher relative humidity. In addition more material, such as wood studs, are used which means that there is more moisture to dry. More moisture in combination with higher relative humidity may pose a higher risk of microbial growth. The purpose of this study was to investigate what is a reasonable moisture content in wood studs in four different well-insulated exterior walls. It has also been investigated how moisture rearrangements effect the exterior walls. The software Wufi2D, which does moisture-simulations, was used to collect data. The results have been analyzed in Wufi Bio which showed that the moisture content should be somewhere between 12.5 to 18.5%, depending on how the wall is built. The conclusions are that windbreaks vapor resistivity is essential for what is a reasonable built in moisture content in the wood studs. Depending on the materials that are used, it´s important to consider how much moisture the wall construction contains.

In many types of sports, on-screen graphics such as an reconstructed ball trajectory, can be displayed for spectators or players in order to increase understanding. One sub-problem of trajectory reconstruction is tracking of ball positions, which is a difficult problem due to the fast and often complex ball movement. Historically, physics based techniques have been used to track ball positions, but this thesis investigates using a recurrent neural network design, in the application of tracking bouncing golf balls. The network is trained and tested on synthetically created golf ball shots, created to imitate balls shot out from a golf driving range. It is found that the trained network succeeds in tracking golf balls during bounce and roll, with an error rate of under 11 %. / Grafik visad på en skärm, så som en rekonstruerad bollbana, kan användas i många typer av sporter för att öka en åskådares eller spelares förståelse. För att lyckas rekonstruera bollbanor behöver man först lösa delproblemet att följa en bolls positioner. Följning av bollpositioner är ett svårt problem på grund av den snabba och ofta komplexa bollrörelsen. Tidigare har fysikbaserade tekniker använts för att följa bollpositioner, men i den här uppsatsen undersöks en metod baserad på återkopplande neurala nätverk, för att följa en studsande golfbolls bana. Nätverket tränas och testas på syntetiskt skapade golfslag, där bollbanorna är skapade för att imitera golfslag från en driving range. Efter träning lyckades nätverket följa golfbollar under studs och rull med ett fel på under 11 %.