Diss. Luleå : Luleå tekniska universitet, 2007. / Härtill 5 uppsatser.

Licentiatavhandling Luleå : Luleå tekniska universitet, 2008. / Härtill 5 appendix.

Licentiatavhandling Lund: Lunds tekniska högskola, 2002.

<p>The thesis deals with the deformation problem of segmental, cast-in-place concrete cantilever bridges. This type of bridge has shown some propensity to develop larger deflections than those were predicted in the design calculation. Excessive deflections may lead to deterioration of aesthetics, serviceability problems and eventually early reconstruction of the bridge. Also in the construction stages the deflections have to be properly compensated to achieve the smooth camber in the completed bridge deck.</p><p>Deformation prediction in concrete cantilever bridges is not as reliable as it would be necessary due to several factors. The high degree of uncertainty in creep and shrinkage prediction in concrete constitutes the major difficulty. Other factors are the complex segmental construction procedure and the sensitivity of the deformations to variations in the construction schedule, the uncertainty in estimating the frictional loss of prestress and relaxation in the prestressing tendons and uncertainty in estimating model parameters such as temperature and relative humidity.</p><p>The doctoral study was initiated with the objective to improve deformation prediction in segmentally cast concrete cantilever bridges and to establish guidelines for deformation analysis based on advanced numerical methods.</p><p>A database on observed deformations in three modern long span concrete cantilever bridges in Norway has been established. Two of the bridges were partly constructed from lightweight aggregate concrete. The deformations have been monitored since the construction stages up to the present time. The measurements cover the construction stages and the service life of 14, 8 and 3 years, respectively for the three bridges. The measured deformations are deflections in the superstructure and in one of the bridges, also strain measurements in the piers and the superstructure.</p><p>A sophisticated numerical model was created for deformation analysis. The numerical model realistically simulates the segmental construction procedure and the entire life span of the bridge. The effects of the segmental construction method, temporarily supports and constraints and changes in the structure system during construction are taken into account. The model considers the different concrete age from segment to segment, the sequential application of permanent loads and prestressing and the effect of temporary loads. The prestressing tendons are individually modelled with their true profile taking into account the variation of the effective prestressing force along the length of the tendon and with time.</p><p>The finite element model consists of beam elements which are based on an advanced beam element formulation. The beam model was verified against a robust two-and-a-half dimensional shell model concerning its general performance and some specific issues. The comparison confirmed the accuracy of the beam model. Existing experimental data on creep and shrinkage in lightweight aggregate concrete and high strength concrete were evaluated in comparison with theoretical models. The main focus was on the CEB-FIP Model Code 1990 and its subsequent extensions. The findings were considered in the numerical studies.</p><p>Deformations of the three bridges were computed. The CEB-FIP Model Code 1990 material model was used for concrete for the most part. The elastic moduli were taken from test results where they were available. The creep coefficient and the shrinkage strain of the lightweight aggregate concrete were assumed equal to those of normal density concrete of the same strength. The agreement between the calculated and the measured deformations were satisfactory in view of the large uncertainty involved in theoretical prediction. While moderate differences were observed in most cases, no clear overall tendency toward underor overestimation was found. In subsequent numerical studies, the sensitivity of the deformations to variations in various model parameters was investigated. The B3 model was compared to the CEB-FIP Model Code 1990 in the analysis of one of the bridges, where the latter model showed somewhat better agreement with the measurements.</p><p>The last part of the work concerned a robust probabilistic analysis which was based on a Monte Carlo simulation. The objective of the probabilistic analysis was to estimate the statistical properties of the deformation responses. With the distribution function of a given deformation response being known, the confidence limit for the deformation can be determined. It is recommended to design the bridge for the long-time deflection which represents a certain confidence limit (e.g. the 95 % confidence limit) of the response rather than its mean. Such way the risk that the bridge will suffer intolerable deflection over its life span can be minimised.</p>

<p>Situations involving impact, i.e. the collision between two or more solids, were at one time primarily of concern to the military. Nowadays, as safety is highlighted within most branches of industry, the field of impact dynamics covers a wide range of situations and is of interest to engineers from a large number of different disciplines. This is in particular true for the oil, transport, space, military, nuclear and metal forming industry. </p><p>This thesis describes an experimental and numerical investigation on the ballistic penetration and perforation of Weldox 460F steel plates, and consists of eight independently published parts that are linked together through a synopsis. The thesis was generated from a project in progress on the behaviour of structural components subjected to impact loading conditions. </p>

Situations involving impact, i.e. the collision between two or more solids, were at one time primarily of concern to the military. Nowadays, as safety is highlighted within most branches of industry, the field of impact dynamics covers a wide range of situations and is of interest to engineers from a large number of different disciplines. This is in particular true for the oil, transport, space, military, nuclear and metal forming industry. This thesis describes an experimental and numerical investigation on the ballistic penetration and perforation of Weldox 460F steel plates, and consists of eight independently published parts that are linked together through a synopsis. The thesis was generated from a project in progress on the behaviour of structural components subjected to impact loading conditions.

The thesis deals with the deformation problem of segmental, cast-in-place concrete cantilever bridges. This type of bridge has shown some propensity to develop larger deflections than those were predicted in the design calculation. Excessive deflections may lead to deterioration of aesthetics, serviceability problems and eventually early reconstruction of the bridge. Also in the construction stages the deflections have to be properly compensated to achieve the smooth camber in the completed bridge deck. Deformation prediction in concrete cantilever bridges is not as reliable as it would be necessary due to several factors. The high degree of uncertainty in creep and shrinkage prediction in concrete constitutes the major difficulty. Other factors are the complex segmental construction procedure and the sensitivity of the deformations to variations in the construction schedule, the uncertainty in estimating the frictional loss of prestress and relaxation in the prestressing tendons and uncertainty in estimating model parameters such as temperature and relative humidity. The doctoral study was initiated with the objective to improve deformation prediction in segmentally cast concrete cantilever bridges and to establish guidelines for deformation analysis based on advanced numerical methods. A database on observed deformations in three modern long span concrete cantilever bridges in Norway has been established. Two of the bridges were partly constructed from lightweight aggregate concrete. The deformations have been monitored since the construction stages up to the present time. The measurements cover the construction stages and the service life of 14, 8 and 3 years, respectively for the three bridges. The measured deformations are deflections in the superstructure and in one of the bridges, also strain measurements in the piers and the superstructure. A sophisticated numerical model was created for deformation analysis. The numerical model realistically simulates the segmental construction procedure and the entire life span of the bridge. The effects of the segmental construction method, temporarily supports and constraints and changes in the structure system during construction are taken into account. The model considers the different concrete age from segment to segment, the sequential application of permanent loads and prestressing and the effect of temporary loads. The prestressing tendons are individually modelled with their true profile taking into account the variation of the effective prestressing force along the length of the tendon and with time. The finite element model consists of beam elements which are based on an advanced beam element formulation. The beam model was verified against a robust two-and-a-half dimensional shell model concerning its general performance and some specific issues. The comparison confirmed the accuracy of the beam model. Existing experimental data on creep and shrinkage in lightweight aggregate concrete and high strength concrete were evaluated in comparison with theoretical models. The main focus was on the CEB-FIP Model Code 1990 and its subsequent extensions. The findings were considered in the numerical studies. Deformations of the three bridges were computed. The CEB-FIP Model Code 1990 material model was used for concrete for the most part. The elastic moduli were taken from test results where they were available. The creep coefficient and the shrinkage strain of the lightweight aggregate concrete were assumed equal to those of normal density concrete of the same strength. The agreement between the calculated and the measured deformations were satisfactory in view of the large uncertainty involved in theoretical prediction. While moderate differences were observed in most cases, no clear overall tendency toward underor overestimation was found. In subsequent numerical studies, the sensitivity of the deformations to variations in various model parameters was investigated. The B3 model was compared to the CEB-FIP Model Code 1990 in the analysis of one of the bridges, where the latter model showed somewhat better agreement with the measurements. The last part of the work concerned a robust probabilistic analysis which was based on a Monte Carlo simulation. The objective of the probabilistic analysis was to estimate the statistical properties of the deformation responses. With the distribution function of a given deformation response being known, the confidence limit for the deformation can be determined. It is recommended to design the bridge for the long-time deflection which represents a certain confidence limit (e.g. the 95 % confidence limit) of the response rather than its mean. Such way the risk that the bridge will suffer intolerable deflection over its life span can be minimised.

The present study deals with full- and model scale study of wind effects on a medium-rise building in a built up area. Most low-rise building experiments have been based on an isolated building placed in a relatively uniform terrain. Similarly, the very tall buildings often extend out from their environment in a similar fashion. However, buildings are constructed in various shapes and placed in different types of terrain and topography. Therefore, despite a number of studies made in the past, there are still problems that remain unsolved. As the majority of office- and residential buildings in populated areas fall in the intermediate height category, it should be of interest to examine the wind effects acting upon such a building, as well as its dynamic response. For this purpose, an experimental program was initiated utilising a combination of full-scale measurements and wind tunnel studies, where the fluctuating wind actions are evaluated from recorded simultaneous point pressure fluctuations. Recent improvements in experimental techniques and data handling enable a more detailed information gathering that should eventually lead to an improved understanding of the pressure field around buildings. The investigation studies, experimentally, the wind induced dynamic loading and response of a multi-story building of intermediate height. The presented work evolves on one hand around experimental data acquisition in both full- and model scale, whereas on the other it evolves around basic data reduction, understanding and interpretation of the acquired data. The objective of the study is, in a way, to attempt to provide a sound wind loading chain a la Davenport [29], in the form of data that would facilitate the study of the links connecting the main parameters i.e. Wind – Load – Response. This entails the definition of the relevant wind parameters, the description of the aerodynamic loading process, such as the time-dependent variations of pressure fluctuations on the building surface, and an investigation of the wind induced response of a medium-rise building. Information on the study-building and the experimental setup and procedures is given, for both full-scale and model scale. The full-scale and model scale data are systematically compared through the evaluation of descriptive parameters of both wind turbulence and surface pressures. In general, the evaluated full-scale parameters are found to be in qualitatively good agreement with the model scale parameters. However, the investigation revealed some characteristic differences between full-scale and model scale behaviour. These differences are largely related to the fact that significant variability is found to be inherent in the fullscale data, whereas considerably less variability seems to be associated with the wind tunnel data.

<p>In the year 2010 a transition will take place here in Sweden from the present rules how to dimension buildings in to the common rules with have been developed in Europe, the Eurocodes. Eurocode is the term for a collection standard that contains calculation rules in how to dimension constructions and buildings. They are developed by the European standardize committee.</p><p>The purpose with this examination work is to get an insight of what changes this will contribute to, and how it will affect the dimensioning. Are there going to be any differences in the dimension you finally chose?</p><p>To investigate these possible differences two constructions will be calculated first in the present Swedish rules, and then in the coming eurocodes.</p><p>One of these two constructions will be build completely in steel, while the other will be build completely in concrete. The steel building will have a beam and a column dimensioned, the concrete building will likewise have a beam and a column dimensioned. To reach as equivalent comparison as possible will the same load, geometry and circumstance prevail for both standards. Limitation has been done to only dimensioning the beam and the column who is most charged.      </p><p>After we performed the calculations we could make the conclusion that dimensioning with Eurocode a higher efficiency was received, a 10 % higher efficiency on the materials. The strength of the material is with calculations with Eurocode higher, and so are the loads. One of the reasons for this is that the securityclass is added to the loads in Eurocodes and are drawn off from the strength of the materials in BKR.         </p> / <p>År 2010 kommer en övergång att ske i Sverige från de nuvarande reglerna att dimensionera bärverk enligt BBK till de gemensamma reglerna som tagits fram i Europa de så kallade Eurocodes. Eurokoder är benämningen på en samling standarder som innehåller beräkningsregler för dimensionering av bärverk till byggnader och anläggningar. De tas fram av den europeiska standardiseringskommittén.</p><p>Syftet med examensarbetet är att skapa en överblick om vilka förändringar detta kommer att leda till och hur detta kommer att påverka dimensionering av bärverk samt om det kommer att bli några skillnader i vilken dimension man slutligen väljer.</p><p>För att komma fram till skillnaderna mellan de två olika standarderna så kommer två byggnader att dimensioneras, Byggnaderna kommer först att dimensioneras enligt de nuvarande reglerna enligt BBK, därefter så kommer samma beräkningar göras enligt de nya reglerna enligt eurocodes.</p><p>Byggnaderna som kommer att dimensioneras kommer att bestå av två material antingen bestående av stål eller betong. Byggnaden bestående av stål kommer att ha balk och pelare i stål och den andra byggnaden kommer att ha en pelare och balk bestående av betong. För att få en så likvärdig jämförelse som möjligt mellan de två olika standarderna så kommer samma typ av laster och förhållanden att verka på elementen. Begräsningar har gjorts att bara dimensionera den mest belastade balken respektive pelaren.</p><p>Efter att vi utfört beräkningarna drog vi slutsatsen att vid dimensionering enligt Eurocode erhålls en 10 % högre utnyttjandegrad av materialet än vi dimensionering enligt BKR.   Generellt vid beräkningarna så blir hållfasthetsvärdena större för Eurocode, kompenserande blir då också lasten större. En anledning till detta är att säkerhetsfaktorn läggs på lasten i Eurocode och reducerar kapaciteten i materialet för BKR.</p> / Beräkningsanalyser

<p><strong>Abstract</strong><p>The tests work is about the subject "synergism of steel and concrete."</p><p>The construction sector is in a strong competition and the different companies in the Prefab</p><p>Market has ever tried to develop new design solutions that are efficient and environmentallyfriendly.</p><p>The purpose of this report is to highlight different aspects of interaction and size up a columndimension and to examine its efficiency and load capacity as Eurocode 3 and Eurocode 4. A sizing chart that describes the relationship between the torque and normal force shouldalso be made of the interaction .</p></p><p> </p>