When a ship-owner orders a vessel from a shipyard, a contract is written to confirm and guarantee the agreement for both parts. An important requirement of the contract is the vessel's speed at a given engine power, RPM and draught, in "ideal" conditions (i.e. calm, infinitely deep and current free water, with smooth hull and propeller surfaces at with no wind and zero drift and rudder angle). The speed capacity of the recently built ship is measured carrying out a speed trial. It is rarely possible to perform the trial under ideal, contractual conditions, and the speed will normally be reduced by environmental factors. Whenever the test is carried out in conditions deviating from those contractually specified, the speed must be corrected for, to best coincide with the contractual stipulations. These corrections can be of significant magnitude and are of great economic importance. Penalties of considerable size are given to shipyards that fail to deliver in accordance with the contract. There are various standards published providing guidelines regarding the execution of speed trials, the measurements that are to be performed during the trials and corrections for environmental factors that are to be made in retrospect. ISO (2002), Perdon (2002), Bose (2005) and B. Henk (2006) were chosen for evaluation and comparison in this thesis. The recommendations of the standards are occasionally disagreeing.The main resistance contribution is claimed to be wind and wave (Bose (2005) and B. Henk (2006)). B. Henk (2006)) states; "these corrections (small displacement deviations, shallow water, and salinity deviations) are relatively small compared to wind and wave directions". Reinertsen (2011) suspects that the added wave resistances calculated by the Hyundai shipyard are too large. This assumption is based on Haugan (2011)'s (employee of KGJS) mean wave load calculations that generally gave results 30 % lower than those found by Hyundai. An unrealistically large correction factor for wave resistance is most definitely advantageous for the shipyard. This will give a higher calculated contractual speed, and the shipyard is consequently more likely to meet the contractual requirements. The Hyundai shipyard's correction procedures were evaluated based on the relevant standards. The shipyard neglects all resistance components, but the added resistance due to wind and waves (they also correct for large discrepancies between the trim/draught obtained at speed trial and that contractually stipulated. This is however not relevant for tankers, as these generally are capable of achieving design draught at the sea trial). This is consistent with the recommendations of Perdon (2002) and B. Henk (2006). The shipyard does not have the speed trials conducted in head - or following waves, nor head - or following wind. B. Henk (2006) and Perdon (2002) underline the importance of executing the speed trials in head - or following waves. Perdon (2002) argues; "in the case when the waves do not come from the bow or the stern the correction methods are not sufficiently reliable and the effects of steering and drift on the ship's performance may be underestimated". ISO (2002) recommends performing the trials in head and following wind (note that there usually is a correlation between true wind - and wave direction).The Hyundai shipyard assumes that the wave direction with respect to the ship's centerline equals the relative wind angle. This conflicts with the recommendations of the standards. They advise to obtain the wave direction by visual observations or instruments such as buoys or sea wave analysis radars. Furthermore, Hyundai's assumption is highly illogical from a scientific standpoint. In this thesis, the added wave resistance (due to diffraction) was computed by a handful of methods proposed in the literature. The computed values obtained in this report were all substantially larger than those found by Hyundai. This denies Reinertsen (2011)'s suspicion of Hyundai's correction factors for wave resistance being unrealistically high. B. Henk (2006) emphasizes the importance of accounting for the location of the anemometer in the computations of added resistance due to wind. This is not done by the shipyard. B. Henk (2006) proposes a formula for correction of improper placements of the anemometer. In this thesis, the added wind resistance was calculated, including this correction. The added resistance found was 28 % smaller than the value obtained by Hyundai. This is relevant as the wind tends to be a key resistance contribution.Finally, the Energy Efficiency Design Index (EEDI) has been described. The EEDI estimates a ship's CO2 emission per ton-mile of goods transported; put differently, the vessel's impact on the environment in relation to its benefit for society. The EEDI is to be implemented for all new ships, 1st of January 2013. The value of this index will be determined based on results from speed trials.

The number of collisions between ships and icebergs are increasing in correlation with the increase of the number of ships sailing in Arctic areas. Due to the exploitation of gas fields in Arctic areas, the LNG shipping in these areas is expected to increase. The consequences of an iceberg impact can be critical for ship structure, the crew and the cargo, and it is important to be able to predict the result of such a scenario.Different relevant impact scenarios have been discussed, and it has been concluded that the most critical scenario for a spherical type LNG carrier is an impact at the bow shoulder where the distance between the outer hull and the cargo tanks is at its shortest. Based on this study, a bow shoulder impact has been chosen as the scenario investigated in the thesis.To investigate the influence of the surrounding water, an ALE-model representing this was therefore supposed to be modelled in LS-DYNA. After several unsuccessful tests this work was postponed to further work, but a detailed description of the ALE-modelling and the different options tested has been carried out.A detailed FE model of the bow shoulder section of an ice strengthened spherical type LNG carrier has been carried out. The mesh in this section has been modelled sufficiently fine to capture the governing deformation mechanisms and the total number of elements in the model are therefore large. This will lead to increased computation time, but this is acceptable based on the accuracy of the results obtained. In addition to the local bow shoulder model, a FE model of a global 125 000 dwt. LNG tanker has been established. The outer shell and coarse geometry has been provided by Ph.D. candidate Martin Storheim, and the detailed bow shoulder model has been included in this global model. The global model is meshed with large rectangular four-node elements, and transitions to the detailed model have been created. Properties have been added to the global model in terms of getting a model which represents the real ship to the best extent possible.The steel material model used is developed by Hagbart Alsos and includes a RTCL fracture criterion. The ice material model is developed by Zhenhui Liu and is modelled to represent a physical approach to the crushing of the ice. The aluminium material is based on studies performed by Moss Maritime and simple power law calculations.The added mass and weight of the LNG cargo has been included as increased density in the outer hull below the water line and in the tank shells respectively. The aim of the simulations has been to investigate similarities and differences in different collision approaches. Three different approaches have therefore been simulated for two different impact angles. For the local model, two simplified approaches have been simulated:•A prescribed displacement has been applied to the iceberg. This is the most common approach in collision simulations due to lower requirements to computer performance.•An initial velocity has been given to the iceberg. This approach requires more computer resources, but will probably yield less conservative results.Pinned boundary conditions have been applied to the bow shoulder model for all the local analyses. In addition to the local analyses, a full global analysis has been performed for the two different impact angles. In these simulations no boundary conditions have been applied to any of the colliding bodies, and initial velocity is given to the ship structure. The mass of the iceberg is approximately 2500 tons and for the global analyses no velocity of the iceberg has been assumed.The results obtained from these simulations have shown that both of the local simulations tends to over-estimate the indentations. The prescribed displacement analyses yields over-conservative results for long duration simulations, but at large impact angles the results obtained are reasonable for longer simulated time than for small impact angles. The initial velocity method yields more reasonable results, and this approach is therefore better to apply when the damage from a collision scenario is estimated by simplified methods.To investigate the effect of the iceberg size, two simulations including an iceberg of approximately 19 000 tons have been carried out. These simulations have shown that the damage in such collision is significantly larger than for the small iceberg. It has also been seen that there is less difference between the simplified approach and the full analysis for the large iceberg than for the small iceberg approaches. This is remarkable, since the boundary conditions have been assumed to give larger contribution to the result for the large iceberg.Unreasonable large accelerations have been found in collision simulations described in different papers. To investigate this in the simulations performed in this thesis, the accelerations and motions have been observed in different spots which is not directly impacted by the collision. No extreme values of either accelerations or motions have been found, and it is concluded that this is not a problem for the collision scenario simulated in this thesis.

The calculation of ice-induced loads on ships is still mainly based on empirical models. In order to gain a better physical understanding of the loading on ice-going vessels, Det Norske Veritas launched an <i>ice load monitoring<i> project involving full scale trials with the coastguard vessel KV Svalbard during the winters 2006, 2007 and 2011. The results from the full scale measurements conducted with KV Svalbard has been topic of several earlier master's thesis at NTNU,The master thesis consists of four parts. The first part is a literature review of the mechanical and physical properties of sea ice.The second part is a review of the rule sets developed by DNV and the IACS regarding vessels operating in ice infested waters. Both design principles and numerical values have been evaluated. The main difference between the designs principles used, is that IACS base their rules on a plastic method of approach, while DNV uses an elastic method. Despite the difference in the design principles, when comparing their numerical values turned out to be quite similar. The DNV rules are in general most conservative for the smaller vessels and the IACS rules the most conservative for large vessels. The third part consists of a finite element study of a part of the bow on KV Svalbard. A systematic load scheme is used, consisting of 102 load cases. For each of the stress factors there where made graphs that showed the stress at the sensor location when moving the patch load. The sensor mounted on the frame were able to measure load that was within the frame loading area and sensor mounted on the stringer could measure stress for all of the load cases in the horizontal directions. One of the explanations for this is that the stringer transfers stress from the load patch area that could be measured by the sensors.The last part consists of a comparison between measurements from the full scale trials and the results from the 102 load cases. This comparison is done through a weighted summation method where 5 different load cases are combined to represent the measured result, and a load factor is calculated for each load case for its contribution of the measured results. The stress component used in this comparison is the shear stress tau xy The load cases were tested against the 11 measurements from the full scale trials. There were in total 11 load cases that gave positive factors for all of the 11 measurements at the same time. A figure was made to show which load cases were likely to contribute in the solution of the load cases. Load cases inside the frame loading area have the largest load factors for the solution of measurements.This load decision scheme is very sensitive to the selection of load cases and boundary conditions. A change of the boundary conditions for the model was tried out for 7 load cases, and with changed boundary conditions, only 5 gave positive load factors.The results of this thesis shows that is possible to find many solution to the measured result by combining many load case, but is it not possible to decide <i>the<i> solution.

The exible pipelines has been widely used by the oil and gas industry the lastdecades and this trend is expected to continue as the operating depths are increasedfurther. For deep water applications the radial and lateral buckling modes can becritical. Many studies has been carried out using nite element models to studythese failure modes.In this thesis a nite element model is created with the aim to recreate resultsobtained in a recently published article by Vaz and Rizzo. The model is built upusing pipe, beam, contact and spring elements to represent the complex behaviourof the cross section. The loading is carried out by rst applying the dry mass, thenthe external pressure and nally end compression.When comparing buckling loads generated in this thesis by the ones in thearticle by Vaz and Rizzo the observation made is that the buckling loads from thisthesis are signicantly higher. When comparing only the inclination of the endshortening versus buckling load curves it was seen that the curves from article hada only slightly larger inclination than the results from the analyses in this thesis.This indicates that there is a small dierence in the stiness used. By modifyingthe stiness it should be possible to get the same inclination of the curve.Analyses were also carried out on how the slip distance aects the bucklingloads. By increasing the slip distance by 50% and 100% it was observed thatthe buckling loads were reduced drastically. In the article by Vaz and Rizzo noinformation is given on the slip distance. By tuning the slip distance and stinessof the springs it should therefore by possible to obtain the exact same results as inthe article. This clearly illustrates the importance of stating all assumptions andinput parameters when describing models used for analysis.

An explosion on a typical offshore installation is a critical, however rare accidental event which may result in damage and loss of property, and in the worse case loss of lives. Top-side sections on an offshore installation which are exposed to an explosion blast should be designed to withstand such an event in a way that further escalation of the damage on personnel or property is avoided. There is however limited information on the modeling and analysis procedures for dealing with such events, and most classification rules on this subject give limited information and guidelines on the practical implementation of such effects for general analysis purposes. This thesis has been an investigation on these matters.The basis of this Master thesis has been on a pipe rack structure from one of Aker Solutions' top-side projects. It has been assumed that this structure is exposed to an accidental hydrocarbon explosion, and the resulting structural response has been investigated. A parameter study has been performed by varying blast load levels and durations. The effects due to the weight of the piping on the structure have also been studied. The main task of this thesis has been to compare simplified, static analysis models against dynamic analysis models as to calculate dynamic amplification factors (DAF), the purpose of this is to better understand the dynamic behavior of the structure due to the blast loading. The intention is that the dynamic amplification factors are to be used further by the engineers at Aker Solutions for dimensioning and designing of similar structures.Results showed that the blast loads as used in the analyses did not cause any structural responses within the material's plastic range. Further on, it was found that the magnitude of dynamic amplification is depending on both the blast duration emph{and} the weight of the pipes on the pipe rack. Typical results indicated that this dynamic amplification was reduced with increased blast duration.

Due to a rising interest in oil exploration in Arctic areas several new platform designs have been introduced to combat the problems with level ice loads. This has led to research into ice strengthening and how this affects the open water behaviour. One of the new designs, called the Total Buoy, has a slanted hull in the waterline intended to deflect level ice down and around the structure, but this hull design introduces a geometrical non-linearity. This non-linearity causes problems in the design of these types of structures, because most hydrodynamic program cannot handle the rapid change of geometry in the waterline. This has inspired several attempts to write a simple numerical model to handle the calculation, and avoid costly model tests in the pre-design.A large part of this thesis presents the theory and methods used in the development of this new numerical model. This is meant to document the thought process in a way which can allow others to continue the development. The numerical model was developed to calculate motion results from regular waves in the three symmetric motions; Surge, Heave and Pitch. In addition to this a very simple ice calculation was included as a starting point for further development.As part of this work on a new numerical model a parallel study of an alternative commercial program was done. This is to test the usability of an (expensive) commercial program in relation to this non-linear problem. The DNV program Wasim was selected for this purpose, and the modelling has also been documented and the input files are included in the electronic appendix.After documenting the basis of the numerical model and Wasim model it was necessary to do a comprehensive comparison study of the models. To help with the comparison Force Technology allowed the use of model tests results which were performed on the Total Buoy concept in 2006. The comparisons showed that while the numerical model was showing some large responses around the heave natural period in both heave and pitch the results were in general close to the model tests. The Wasim model did not show the same correlation in surge and pitch, but the heave results were shown to be close, but the use of the Wasim program is believed to be unwise on this type of problem.Finally, an assessment of the Total Buoy's open water and level ice behaviour was done. This assessment showed that the Total buoy would most likely have problems with large pitch motions. This was shown to be true in both the Norwegian Sea and the Eastern Barents Sea, the Norwegian Sea was found to be a unlikely deployment area due to the lack of level ice. The pitch motion was so large that it would make year round human habitation impossible, and it was advised that the buoy should not be used for this purpose, and only in the eastern Barents Sea. Finally, it was found that the ice theory which was applied for the ice calculation could not give a true assessment of the level ice capabilities of the buoy, and the lack of other alternative solutions made the assessment impossible.

As modern bridge design continuously aims for longer and slender bridges, it is necessary to be able to determine aerodynamic properties of such structures with a highdegree of accuracy. The horizontal degree of freedom has traditionally been considered uninteresting, and aerodynamic properties have been determined by section model tests involving a vertical and a torsional degree of freedom only. However, for very long bridges, horizontal motion may prove to be important.This thesis has focused on an experimental setup based on the traditional suspension rig, but in addition to vertical and torsional motion, it also allows horizontal motion. A prototype intended for still air experiments has been designed, built and tested.Introducing a third degree of freedom renders the stiffness of the system non-linear with respect to motion of the section model. To better understand the model’s behaviour in the rig, a FE-model and an analytical stiffness model have been developed.Two types of system identification methods were utilised to determine the dynamic properties of the prototype. The Covariance Block Hankel Matrix (CBHM) method have over the years been used to determine aerodynamic properties of several well-known bridges, e.g. the Hardanger Bridge, while Subspace State Space System Identification (N4SID) methods is a newer family of methods well known for their robustness, accuracy and ease to use.It turns out that the N4SID method used in this thesis produces far better damping estimates than the CBHM method.The proposed experimental setup seems promising for further research and development, although it has several drawbacks and limitations.

Tradisjonelle arbeidsformer i dagens byggebransje vier lite oppmerksomhet til forvaltning, drift og vedlkehold (FDV) av bygninger. BIM, bygningsinformasjonsmodellering, kan bidra til en ny digital arbeidsprosess, hvor FDV står i sentrum. Resultatet av en slik prosess er en modell, en database, hvor all informasjon om et bygg ligger lagret.LYDIA er FDV-programvare, utviklet og levert av Lydia AS. De ønsker å videreutvikle LYDIA i retning BIM, og se på hvordan sammenhengen BIM-LYDIA kan utføres i praksis. Lydia AS opplever i dag størst utfordringer ved import av informasjon til LYDIA-databasen. Kundene samler manuelt inn store mengder informasjon til databasen. Erfaringer viser at endel kunder strever med å forstå bruksnytten av LYDIA.Systemarkitekturen presentert i oppgaven løser Lydia AS sine forutsetninger for overgangen BIM-LYDIA. Funksjonaliteten i LYDIA er opprettholdt. buildingSMART sitt standardiserte filformat, IFC, er brukt som utgangspunkt for overføring av informasjon. Løsningen er realiserbar innen andre kvartal 2014. Modellen forenkler dagens importarbeid. Lydia AS sine kunder slipper manuell dataregistrering som øker risikoen for feil. Ved import direkte fra BIM forenkler man prosessen med å hente informasjon til LYDIA-databasen. Modellen bygger likevel ikke oppunder en ny samarbeidsprosess. Digitale arbeidsformer kan endre de tradisjonelle arbeidsformene i byggebransjen. Utgangspunktet for slike arbeidsprosesser er større tillit og mer fokus på samskaping. Lydia AS må selv tenke gjennom hvilken retning de ønsker å ta for fremtidige LYDIA.

<p>In this investigation strength and structural behaviour of prestressed concrete is studied with one full scale test of one flat slab, 16000 mm x 19000 mm, and three slabs on ground each 4000 mm x 4000 mm with thickness 150 mm. The flat slab was constructed and tested in Aalesund. This slab has nine circular columns as support, each with diameter 450 mm. Thickness of this test slab was 230 mm and there were two spans in each direction, 2 x 9000 mm in x-direction and 2 x 7500 mm in y-direction from centre to centre column. The slab was reinforced with twenty tendons in the middle column strip in y-direction and eight tendons in both outer column strips. In x-direction tendons were distributed with 340 mm distance. There were also ordinary reinforcement bars in the slab. Strain gauges were welded to this reinforcement, which together with the deflection measurements gives a good indication of deformation and strains in the structure.</p><p>At a live load of 6.5 kN/m² shear failure around the central column occurred: The shear capacity calculated after NS 3473 and EuroCode2 was passed with 58 and 69 %, respectively. Time dependent and non-linear FE analyses were performed with the program system DIANA. Although calculated and measured results partly agree well, the test show that this type of structure is complicated to analyse by non-linear FEM.</p><p>Prestressed slabs on ground have no tradition in Norway. In this test one reinforced and two prestressed slabs on ground were tested and compared to give a basis for a better solution for slabs on ground. This test was done in the laboratory at Norwegian University of Science and Technology in Trondheim. The first slab is reinforced with 8 mm bars in both directions distributed at a distance of 150 mm in top and bottom. Slab two and three are prestressed with 100 mm² tendons located in the middle of slab thickness, and distributed at a distance of 630 mm in slab two and 930 mm in slab three. Strain gauges were glued to the reinforcement in slab one and at top and bottom surface of all three slabs. In slab two and three there were four load cells on the tendons.</p><p>Each slab were loaded with three different load cases, in the centre of slab, at the edge and finally in the corner. This test shows that stiffness of sub-base is one of the most important parameters when calculating slabs on ground. Deflection and crack load level depends of this parameter. Since the finish of slabs on ground is important, it can be more interesting to find the load level when cracks start, than deflection for the slab. It is shown in this test that crack load level was higher in prestressed slabs than in reinforced slab. There was no crack in the top surface with load in the centre, but strain gauges in the bottom surface indicate that crack starts at a load of 28 kN in the reinforced slab, and 45 kN in the prestressed slabs. Load at the edge give a crack load of 30 kN in reinforced slab, 45 kN and 60 kN in prestressed slabs. The last load case gives crack load of 30 kN in reinforced slab, 107 kN and 75 kN in prestressed slabs. As for the flat slab, FE analyses were performed for all of the three slabs on ground, and analyses shows that a good understanding of parameters like stiffness of sub-base and tension softening model, is needed for correct result of the analyses.</p>

<p>Exploration for oil and gas is moving towards deeper waters. Steel has been the most common riser material. Related to deep water concepts titanium has become an alternative to steel for these applications.</p><p>Several codes exist today for predicting collapse loads for marine pipes. However, the capacity formulas are developed for steel. If the formulas are applied directly to titanium several parameter uncertainties will be unknown. Ideally, extensive model testing of titanium pipes is required. This thesis discusses and investigates utilisation of experimental material test data and a supplementary numerical approach based on finite element analysis. The relationship between material model parameters as input to the analysis and the collapse capacity is investigated by performing a series of nonlinear FEM analyses.</p><p>Statistical models for the input material model parameters are established based on tests on small specimens cut from titanium pipes. These models are subsequently combined with results from the FEM analyses by application of response surface methods. As output from the analysis, the probability distributions of the pipe capacity with respect to local buckling/collapse are obtained.</p><p>Finally, the data from the nonlinear finite element analyses are compared to a relevant design code. Suggestions for a possible basis for design formulas to check for the local collapse capacity of deep water titanium risers are provided.</p>