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The primary structure of the cellular wall of Shanghai Natural History Museum (SNHM) can be defined as a grid structure on a single curved surface (developable), with a cell-like configuration. The shape of the wall (surface) is defined by two free-form curves, which explicate a ruled/lofted surface. The cellular wall is one of the most captivating elements in the SNHM design. Besides its architectural appearance it also has an important function in the structural system to distribute both horizontal and vertical forces. It requires large efforts to create the optimal configuration that meets both its architectural and structural objectives. This includes the structural material of the cellular wall. The objective of this Master’s thesis research is to explore an ‘optimal’ grid structure for the cellular wall. Since the geometry of the wall surface is determined in advance, the design exploration will focus on the grid/pattern generation, and the basic purpose of optimization is to explore a pattern in which elements are tuned up by different design constrains (requirements). The chosen approach is to design the structural cellular wall by parametric CAD modeling via parametric design tools (GenerativeComponents, etc). These parametric associative tools generate the complex geometry by applying rules and capturing relationships among model elements and link the geometrical data to the analytical and drafting software. The typical modeling process and advantages of this approach will be exampled by a case study of Nautilus shell model (Chapter 4.2). Chapter 2-4 will give some background information based on literature study, including the main topics of: SNHM project information and structural optimization proposals, Free-form/Special structural design technologies, and parametric associative design approach. In Chapter 5, the design alternatives will be studied: a design exploration diagram will be draw to clarify the design constrains and their requirements, following the proposal of structural parameters. Various structural materials with construction methods will be compared, and some references study for the structural patterns and grid structures will be recorded. Study of grid structures with basic grid types (rectangular, triangular, hexagonal) will be performed to high-light the structural behaviors and design principles of cell-like grid. In Chapter 6 & 7, cell-like pattern exploration by parametric CAD modeling will be conducted, which includes building parametric CAD models and structural analysis. According to the grid generation technologies (pre-studied in Chapter3), the parametric models will be created in 3 categories: 1- Structured grid models Structured grids have advantages of easy to implement and good efficiency, but various grid sizes can’t be introduced or the grid cells will deform too much. Regular grid will result in un-evenly distributed loads and stresses under the design load cases. 2- Modified structured grid models A- Insert triangular elements, following the stiffness requirement: this method increases the total stiffness and creates moment-free nodes, but at the same time, it's easy to cause stress concentration. B- Locally double-up hexagonal grid, following the strength requirement: The implementation of double-up grid is easier and results in a configuration of fractal geometry (local double rhythm). 3- Unstructured grid models Unstructured grid models are generated via Voronoi Diagram. Some experiments have been done to find efficient methods to generate a point-set (grid points) and generate grid on the wall surface. The ‘attract & repel’ method and UV mapping tool were implemented in this design case. When the local densities of the grid structure are fine tuned up with the imposed load cases (structural requirements), the material will be used in an efficient way, which can be read from the analysis results – better forces distribution and low stress level. The local densities/grid sizes are changed smoothly, which brings nice design aesthetic. [Suggestion] In the modified structured grid models, by locally cutting-out triangles will cause stress concentration, which cannot efficiently increase the total stiffness. A suggested method is to corporate Voronoi diagram with the associated Delaunay triangulation, efficiently getting advantages of the stiff triangle components. Member design Another method is to apply different profiles (crosssections) for individual beam elements according to the structural requirements. Although it will bring extra requirements for construction – carefully coded and stored, this approach provides quite an efficient structure. Chapter 8 concludes the findings of this Master’s thesis research as conclusions and recommendations for further research.

Onderzoek naar de bouwakoestische aspecten van IFD-constructies: - Binnenwanden - Vloerconstructies - Gevelconstructies

Tensairity is a lightweight structural concept, a synergistic combination of an air-beam, cables and struts, which is categorized as a pneumatic structure. The central idea of Tensairity is to use a low pressure of the internal air to stabilize compression elements against buckling. The basic element consists of a simple air-beam (a low pressure inflated tube), a compression element tightly connected to the air-beam and two tension cables having a spiral shape around the tube. Both the cables and the struts play the role of transferring the applied forces over the air inflated beam; the latter stabilizes then the compression element against buckling. This solution increases the load-carrying capacity compared to a traditional simple air-beam. At the same time, the pressure inside the air-tube can be lowered. Tensairity is, due to its characteristics, especially interesting for temporary and architectural applications, like roof structures, (temporary) bridges and tent structures. The applicability of the concept is not restricted to beams. It is also valid for columns or arches. The simplest Tensairity beam has a cylindrical geometry, but many other shapes are possible, too. Cigar-shaped or spindle-shaped beams still have a circular cross section, but are stiffer than the cylindrical structure.

When analyzing three-dimensional problems with nonlinear finite element analysis (NLFEA) often problems are encountered such as bifurcation and divergence of the solution. In particular, cases subjected to tension softening tend to encourage the emergence of multiple equilibrium paths. In order to overcome these problems the Sequentially Linear Analysis (SLA) method has been developed for three-dimensional solid elements. SLA is an alternative for incremental-iterative solution schemes to model the nonlinear fracture behavior of quasi-brittle materials. It is an attractive method since it avoids the well known convergence and bifurcation problems that are often encountered when using incremental-iterative schemes such as Newton-Raphson. SLA uses a series of linear analyses to model the nonlinear behavior of the structure. By directly specifying a damage increment in each linear analysis, extensive iterations within the load or displacement increment can be avoided. The main objective of this research was to see how the Sequentially Linear Analysis approach could be extended to solid elements, so that it could be used for three-dimensional fracture problems as well. Although three-dimensional geometries such as masonry structures have been analyzed before using SLA, it was always restricted to two-dimensional finite elements only (shell elements). Therefore, first a theoretical constitutive model for three-dimensional stress-strain states has been developed that served as the starting point. Implementation in DIANA was the major second step from which the third and last step could be started: the verification on various fictive and real cases. A single element pull test was used to solve programming errors, whereas the notched beam offered the possibility to check how the newly developed SLA-code would perform for larger models. Both cases showed excellent agreement with the experiment. However, most attention was dedicated to the verification and physical interpretation of a real reinforced concrete slab. The results were critically evaluated, interpreted and compared to results from the experiment and the incremental-iterative Newton-Raphson method. It was concluded that the Sequentially Linear Analysis is able to properly capture the quasi-brittle behavior of the reinforced concrete slab. Especially in comparison to the three-dimensional Newton-Raphson results, SLA turned out to be more robust and accurate.

Constructieve veiligheid blijkt de laatste jaren niet vanzelfsprekend en staat daarom erg in de belangstelling. Dit afstudeeronderzoek geeft inzicht in de oorzaken en andere aspecten van constructieve schade. Hiertoe zijn 151 bouwincidenten onderzocht. De bron van het onderzoek zijn vonnissen van arbitrage-instituten.

With an increasing population in the Netherlands, people started to live relatively close to the primary road network. This led to major noise hindrance issues. As a solution it was decided to apply porous asphalt surfaces on the primary road network. These types of surface layers have a relatively open structure compared to traditionally applied dense asphalt mixtures. Application of porous surfaces brings along their first major advantage: noise reduction. A second major advantage of porous asphalt layers is an increased safety during rainfall. Due to its open structure water is stored and moved horizontally within the layer which reduces splash and spray effects and thus increases the visibility of drivers during rainfall. On the other hand the major disadvantage of porous asphalt layers is durability. The decisive factor for the relative short lifetime of porous asphalt is the loss of aggregates from the surface, also known as ravelling. This type of distress leads to a rough surface and decreases the material’s noise reduction potential. Further on the loosened particles cause damage to cars. In the winter ravelling develops at a much higher speed. This results in totally damaged sections as was noticed during the winter of 2009/2010 in the Netherlands. In this research a recently developed Lifetime Optimization Tool for porous asphalt was used to find out why different sections of the primary road network showed this type of excessive damage. Therefore LOT required information about the load, geometry and the response of these failed porous asphalt sections. In this research eight different sections were studied. The required input for LOT was determined directly from these eight sections. The results showed that in the winter the main cause for this increase in damage is caused by the reduced relaxation potential of the mortar of the mixture. Further on the calculated performance of the eight different sections was compared with the observed performance during the winter of 2009/2010 and it was shown that they were in good agreement with each other. From this it was concluded that the Lifetime Optimization Tool is capable of explaining winter damage of porous asphalt concrete

In skew bridges torsion occurs. This leads to a substantial amount of reinforcement stirrups. Minalu already did research to torsion in bridge decks with different types of finite element models. The question when torsion cracks will really occur is still unanswered. This question is the main subject of this research. The focus of the research is on a skew bridge with a skew angle of 45 degrees. In that bridge the largest torsional moments will occur. Beside that also a straight bridge is analysed, the torsional moments in a straight bridge are always lower than in a skew one under the same loading. The loads of Eurocode 1991-2 are used. Two important load configurations governing for torsional moments and shear force are used: a configuration which is used in daily practice at Spanbeton and a configuration developed by Minalu. An attempt is made to model the whole bridge including physically non-linear behaviour with the program ATENA 3D to analyse the torsion effects. With the current state-of-the-art modelling technology that appeared to be impossible. For that reason a simplified model is developed to simulate the stress state and cracking in one ZIP girder. It was concluded that it is important to use more quadratic elements over the thickness of the web to obtain correct torsion shear stresses. From the simplified model it is concluded that, despite some shortcomings, clearly a substantial length at the ends of the girder is uncracked. To be sure that the computer model is correct a calculation of the principal stresses is carried out at the ultimate limit state. The stresses due to prestressing, own weight and the weight of the fresh poured concrete can be calculated by hand. The calculation of the force distribution of the loads on the deck can be carried out using finite element methods. Scia Engineer (orthotropic plate model) and ATENA 3D (volume elements) are used for this calculation. Especially the determination of the torsional moments from ATENA by using an analysis of the rotations is interesting. This calculation results in the torsional moments, bending moments en shear forces acting on the ends of the girder. The main conclusion of this research is that in ultimate limit state no cracking will occur in the end of the considered girder in the skew bridge. This means that only the minimal shear reinforcement must be applied and the full torsional stiffness can be used in finite element calculations. A practical method to check this for other bridges using ZIP-girders is proposed.

The main focus of this research was on the heat flow (density) through a roof in summertime. The effect of different roof toppings and construction types on the heat flow are investigated. Both a field experiment as well as a model were set up, to acquire data and generate results. Central research question was: What difference does roofing material and insulation make on the heat transfer/flow through a roof? With the following sub questions: What is the amount of heat transferred through a roof in summer conditions? How can this heat transfer be modelled? Key parameters that determine the heat flow through a roof are the reflectivity of the roof top, the insulation value and the (thermal) mass of the roof construction. Literature reports that change of the albedo of roofing reduces roof top temperature, inner temperature and energy usage for cooling. The higher the insulation value of the roof, the less reduction in energy demand for cooling when a cool roof is installed. Planted roofs give similar results. The soil and leaf layer function as an extra insulation layer on the roof. Nevertheless, plants cannot replace traditional insulation. A field experiment was performed in the summer 2011 on four locations. On three locations the rooftops were black, while a part was covered with white roofing. The Rc-value and mass of the roofs differs. The last location concerns a green (or planted) roof. The difference in outer surface temperature between black and white roofing was at maximum 25°C, the average on warm summer days was 9°C. The outer surface temperature of the green roof was of the same value as white roofing. The heat flow (qin) through roofs covered with white roofing was lower than in case when black roofing was installed. The size of the difference (Δqin) depends on Rc-value and thermal mass of the roof construction. The peak in qin and Δqin were not measured exactly at the same time, but variance was not more than a hour. Due to insufficient data from the field experiment, the heat flow qin through a green (planted) roof was not determined. A model in CAPSOL is set up in order to gain results of the difference in heat flow through roofs covered with black and white roofing. Model and field experiment outcomes were in good agreement. In the model heat transfer coefficients αe and αi must be defined. It was found that a value of αe between 15-20 W/m2K give good results when compared to the field experiment. For αi a value between 5-9 W/m2K can be chosen, it doesn’t effect the model results of qin. White roofing (a=0,2) lowers the heat flow through a roof. With the model outcomes graphs are generated which give the relation between Rc-value and difference in heat flow (Δqin) between black (a=0,9) and white (a=0,2) roofing. This is executed for light roofs (wooden construction, 20-50 kg/m2) and heavy roofs (concrete construction, 300-400 kg/m2). Thermal mass influences the moment in time of the Δqin. It was found that the peak in Δqin for light roofs with an Rc< 4,5 m2K/W occurs during office hours. In case of a heavy roof the peak Δqin is around midnight. Finally the daily Heat Flow Factor is introduced. It gives the daily difference in heat flow between black and white roofing in percentage of the daily incoming solar radiation. This percentage is translated to values for Δqin on a mean Dutch summer day (Σqsun=7200 Wh/m2)

The increased number of underground infrastructure projects asks for a reliable and efficient assessment of settlement damages to buildings. Currently a three-stage method is in use: the first stage looks into the greenfield deformations, the second stage is a linear elastic 2D method in which greenfield deformations are applied onto a building and the third stage uses finite element methods and 3D models. The goal of this thesis was to improve the second stage by incorporating a non-linear masonry model and a soil-structure interface. A 2D parametric analysis has been performed in which various material and geometrical parameters were varied. The soil model was simplified to a linear-elastic model. The results of the research are twofold. On the one hand there are the results of the parametric analysis showing the effect of incorporating the non-linear masonry model and the soil-structure interface. On the other hand incorporating these two aspects a number of issues came up: the influence of the crack model and convergence criterion, the influence of the building location, the influence of the initial stress and the influence of the participating soil width. For each issue an explanation was sought and the consequences were determined. The results of the parametric analysis showed that including a non-linear material model and a soil-structure interface leads to lower acceptable volume losses. In practice it is generally believed that the current models are already too conservative. The difference between reality and the models must be sought in components that are still missing in the current model.

With the introduction of the Eurocode, different formulas are used for shear tests in concrete structures than the previous Dutch standard.These formulas are often used in new building designs. If the result compared with the Dutch standard is either favorable or unfavorable, the design should be modified. It is interesting to research the impact of new formulas applied to existing structures. In certain situations the structural safety has to be reviewed and the use of Eurocode could apply. This research compares four methods of calculation for the shear test in an existing immersed tunnel. The four methods of calculation are based on the Dutch standard, the Eurocode, the IBBC method and a finite element calculation with the program Atena. In addition also the effects of fire on the shear test are considered. The reference project is the Maastunnel, the oldest immersed tunnel in the Netherlands. To compare the different methods properly a unity check is used. The load on the structure is divided by the maximum load that the structure can bear. The construction is safe when the unity check is less than 1. By the results of the unity check it is possible to draw conclusions about the safety of the construction according to the different methods. The most critical parts of the structure are near the corners in the roof. Three methods meet the requirements of the shear test and therefore show that the construction is safe, only the Eurocode does not. Calculations with Atena shows that the construction has a unity check of 0,4 (safe) and more important, shear failure is not dominant. The shear test for the current immersed Maastunnel results in roughly the same safety features for the current Dutch standards, the IBBC formulation and the finite element method in Atena. The shear test by the new Eurocode shows a clearly lower safety. Main reason is that according to Eurocode, the contribution of the strength of concrete and reinforcing steel should not be added. For the authors of the Eurocode, testing of existing structures was not the starting point. The finite element method shows that the vault function has a major influence on the ultimate failure behavior. If an arch can occur, the shear strength would increase significantly. The shear strength is strongly influenced by the geometry of the corner of the roof. A frequently used general formulation for the shear tests, results in the use of tests which are not designed specifically for the type of construction. This may result in an unnecessarily amount of reserve, while construction is actually stronger than predicted by the test. The influence of fire on the shear test is limited if the structure can deform. Even if splashing of concrete occurs, a vault can add significant strength. It is shown that prevented deformation has a major influence on the shear test. For tunnels a certain degree of foreclosure cannot be neglected. The assumption that the tunnel deformation by fire is completely forbidden, will require too conservative results. It is therefore recommended to examine the foreclosure rate in order to calculate the additional internal forces.

Developments in the Dutch civil sector resulted in a shift of the solution-oriented approach of the market towards a more problem oriented approach. In a problem oriented approach, the principal has to provide the contractor with a larger solution space. This can be achieved by focussing on the definition of the problem instead of the solution. De contractor is responsible for the development of the solution corresponding to the problem. Systems Engineering is a method which makes simplification of the entire project possible by facilitating a structured working method and several instrument. Therefore Systems Engineering is seen as the method that can support this changed approach by making the transfer and further developing of the project more successful. The method finds its origin in the telecom sector and is widely adopted by the aerospace sector. Due to the positive results, the theory is also adopted by the Dutch civil sector.

Currently there are a lot of vacant buildings available. To reuse these buildings, which may or may not have monumental status, the project has to be financially feasible. If a building has good potentials to be reused, the capacity of the structure and the possibilities of adapting the structures needs to be examined to make a project possible This study focuses on how the structural design influence the redesigning for reuse of a monument. As a design case the Flour factory in Leiden has been selected. The old flour factory ‘de Sleutels’, located at the corner of the Oosterkerkstraat and the canal the Zijlsingel in Leiden is a complex of nine different buildings with each different characteristics. The architect Peter Zumthor designed a plan on how to reuse the existing buildings and which interventions should be done to realize this. The problem definition is the following: How can the interventions, as proposed by Peter Zumthor and partner, be integrated in the current structures of the former flour factory ‘meelfabriek de Sleutels’ in Leiden, so that sound safe structures, set out in the Dutch Building Regulations and in the Eurocode-regulations, are created and which adjustments and additions should be made to realize this goal? The methodology generated is applied on this project. First as much as possible data was searched for. This data was, when possible, compared to inspections on the buildings on site to get a realistic overview of the characteristics of the building. Where data was missing assumptions were made (in reality it is recommended to find the missing data by inspections on site) or conclusions were drawn from visible inspections. With this overview it was possible to detect the failures and possibilities of the structures of the buildings. The failures and possibilities resulted in different solutions to realize the proposed architectural interventions in the existing structures. A selection of the best solution was done by testing them on the set preconditions (as set in the architectural analysis, in reality this is done by client, architect, state or municipality and other stakeholders involved). The solution that fits best is selected to develop the final structural design. To adapt the Boiler House to an workshop building the foundation capacity has to be examined further and the possibility to couple the building in South direction to the cleaning building to provide stability. If it is possible the steel should be examined on its yielding strength and a check has to be done if the masonry is still intact and if the bond between steel skeleton and concrete floors still is present, otherwise anchors could be used to solve this problem. To adapt the silos built in 1904 to a hotel the foundation should be reinforced, because it has now only a rest-life of 25 years. The cracks in the roof should be repaired to prevent (further) carbonation and corroding of the steel. To adapt the Mill to an atelier building, sloping columns are added to transfer the overloading forces to the outer dies, with extra capacity, to make the foundation safe. Braces are added in the outer portals and two inner portals to take care of the displacement. The structure should be cleaned from corrosion and protected; a sprinkler installation should diminish the temperature of the structure to provide fire safety. To adapt the Flour Warehouse to a fitness building a steel top is realised with steel-plate concrete floors to make a light structure, to create a safe foundation. Outriggers are placed in the top to take care of the displacement. Where reinforcement is visible the concrete should be repaired to prevent (further) carbonation and corroding of the steel. To adapt the silos built in ’37, ’38 and ’55 to a hotel the concrete has to be repaired where reinforcement is visible to prevent (further) carbonation and corroding of the steel. To adapt the cleaning building to a design office the foundation capacity has to be examined further and the concrete has to be repaired where reinforcement is visible to prevent (further) carbonation and corroding of the steel. To adapt the extension of the Mill to apartments the structure should be cleaned from corrosion and protected. The displacement should be diminished by adding braces or a core. To adapt the Tower of Silos into design and fashion shops the concrete has to be repaired where reinforcement is visible to prevent (further) carbonation and corroding of the steel. The final conclusion: The interventions and additions of the structures of The Mill and the Flour Warehouse are sound safe structures verified according to the Dutch Building Regulations and the Eurocode-regulations. The capacity of the existing structures is used at full extend and simple solutions make additions or adaptions possible. The monumental values are kept intact and the preconditions as set according to the vision of the architect and the client wishes are nearly achieved. Recommendations When an existing structure is adapted to the needs of a renovation project the following recommendations can be done: • Use the methodology as generated in this thesis, based on the ABCD method. When data is thoroughly searched and compared with measurements from inspections on the structures it is possible to find failures and possibilities, which give a good base for the redesign. • When there is a need for adapting the structure search for the extra capacity of a structure and make a solution with this capacity. • From this thesis it appears that buildings build until at least 1947 were not designed on stability and or horizontal displacement, consider this when making a redesign for a structure of the same period.

Transparent building appeals to imagination. The availability of glass in all shapes and sizes is continuously increasing; architects and engineers thankfully make use of the given opportunities. But glass has also some specific disadvantages, as it’s extreme brittleness. Luckily more materials are available that offer the desired transparency; transparent plastics might be a promising addition to the world of transparent building. The transparent plastics that are considered most suitable for building applications are Acrylic (PMMA) and polycarbonate (PC). In this research the behaviour of these transparent plastics is analysed and it is investigated whether and how the materials can be used in building structures, to further explore the dream of completely transparent buildings. Transparent plastics show some, for building materials, unusual characteristics, as thermoplastic and visco-elastic behaviour, special production techniques and a very low ratio between Young’s modulus and strength. This requires a different design approach. A case study is performed to get more feeling for the design with thermoplastics. To be able to use the freedom of shape and to explore the limits of the materials an observation tower is designed. An entirely transparent tower, made completely from transparent plastics. The design demonstrates that it is technically possible to design building structures in acrylic and polycarbonate. Transparent plastics offer promising possibilities for building design but still a lot will have to be investigated further before they can really be used for load bearing structures. For instance the development of standard details, the investigation of fire safety, the buckling behaviour of plastics and the long-term behaviour for a design life over 20 years, which is now the limit by a lack of data,. This will be a trajectory of years but other materials have come that long road before. Once the plastics industry recognises the opportunities of investing in this new product market the development of suitable building products, details and optimal material compositions will certainly progress faster. Transparent plastics will probably never become a threatening substitute for standard glazing applications, but they have the ability to become a worthy colleague to glass in the future and an interesting addition to the world of transparent building.

The main research objective of this study is to gain more insight into the uncertainties that are occurring in maintenance projects. A lot of research has already been performed on the subject of budget overruns in large scale new development infrastructure projects, however, information on budget overruns in maintenance projects is lacking. Uncertainties are an important contribution to the cost increase of (infrastructure) projects. During a project unforeseen events are always occurring. This is taken into account by adding an item ‘unforeseen’ to the cost estimate. The actual occurring unforeseen costs can be split up into three categories: unforeseen costs in the execution phase, contractors bid uncertainty and ‘other unforeseen’ due to, amongst others, further specification of the project. It appears that in new-to-build projects the unforeseen in the execution phase (quantified by additional works) can be as high as 25 to 30 percent of the total project costs. In maintenance projects this is a lot lower: a maximum of five percent. This has to do with the repetitive character of maintenance works, the often limited project size, the possibility for detailed inspections and the fact that the works often take place in already stirred ground. Though, maintenance projects are characterized by a relative large uncertainty between the initiation phase and the start of the execution. This is because in maintenance projects one never starts with a ‘green-field’ situation. In other words, the initial state is often unclear in the early phase of the project, and this is especially the case for unique, technical complex projects, such as control system projects. Because this report was initiated by the Airfield Maintenance Services (AMS) division of Amsterdam Schiphol Airport, applying the information found on the basis of the main research objective is a second goal of this thesis. It is in the ambition of AMS to be reliable and predictable. Not only when it comes to the management of its assets, but also when the financial performances are concerned. Also within the rest of the organization accurate cost estimates are seen as an important means towards more efficient and effective cost control. This enables them to make better informed decisions. Therefore, the second research objective of this study is to improve the early-phase cost estimation process of maintenance projects and to find out whether probabilistic cost analysis techniques could be of value in this process. The scope of this study is limited to the CAPEX projects; the large renovation projects. The current practice in the cost estimation process at SCHIPHOL GROUP is that every year in the first quartile a business plan for the upcoming five years is made based on the company’s strategic goals. The input for this business plan is the budget estimates that are provided by the maintenance managers of AMS. At this moment uniformity is lacking in these estimates. Moreover, when the estimates are made the scope of the project is often still very unclear. Based on this business plan, after further specification, the project budgets are determined in the fourth quartile. The annual budget for the next year is the project budgets combined. From a comparison between the business plan, the annual budget and the actual expenditures in the projects it appeared that the latter are significantly lower. This can be mainly explained by the fact that throughout the year projects have been removed from the business plan scope. However, a statistical analysis of the projects itself shows that on an average the expenditures were 7% higher (with a standard deviation of 34%) than estimated in the business plan. This can be further specified per project type. Because the project budget estimates were made in a later stage, they are more in line with the actual costs. What also showed from this analysis is that smaller projects show a larger variation in the nominal unforeseen than larger projects. This could indicate that in maintenance projects larger projects can be seen as a cluster of smaller projects with relatively little overlap between them, thus acting as a portfolio where overruns in one part of the project are compensated by underruns in another. The cost estimation process can in first instance be improved by creating uniform estimates in combination with a clear definition of the scope. When, next to this, the costs are booked into the accounting software system in a corresponding manner, a database can be built with very usable information. At first this information can be used to gain insight into the size of the cost items. If needed, it will then be able to make decisions accordingly. Further this can be used as a starting point for new estimates, which will make them more reliable. In the second place it is recommended to do the estimate in a probabilistic manner. This means that the total estimated amount is represented by a probability function with an average value and a standard deviation. With this a probability of exceeding the chosen project budget is introduced. In this way one recognizes the uncertainty of an estimate and this information can be used to determine the budget. There are different methods by which a probabilistic cost estimate can be made. In this thesis it is recommended to do this statistically (with the use of historical data) and not Bayesian. This is related to the issue that it appears to be difficult for cost estimators to estimate extreme values, uncertainties and risks. It should be noted that when historical data is not present, the Bayesian method can be used until enough statistical information is gathered. For the determination of the project and the annual budgets the following is proposed. When the annual budget is applied for one can take the uncertainty of the estimates into consideration. This becomes relatively smaller when the projects are bundled in a portfolio and regarded as a whole. The annual budget can be set to a value equal to the sum of the project cost averages plus a value of k times the standard deviation. Subsequently the projects can be given a budget with a probability of exceedance of 0.5 or even higher. Next to this a contingency fund with a size of the earlier mentioned k times σ can be kept at the management level of AMS. If it seems that the projects will be more expensive than the set budget the project manager can request for extra budget from this contingency fund, but only on the basis of solid argumentation. It should be noted that it is not in everyone’s interest to make the estimates more accurate and transparent. Some stakeholders could benefit from a large budget and more freedom when it comes to the allocation of financial resources. This could lead to strategic behavior. Budget slack is an example of this. This means that one applies for a larger budget to make it easier to reach a target. Also there is the MAIMS (money allocated is money spent) principle, which means that one is inclined to fully spent a given budget, even though this is not always necessary for the originally set scope and quality of the project. By using the in this thesis proposed estimation method and budgeting process, these effects can be diminished, by increasing the transparency and starting off with tighter budgets for the projects. Besides, it is regarded in the best interest of the entire organization when transparency and reliability of the estimates is increased, such that more efficient and effective cost control is possible. Finally, the estimation process of Schiphol AMS can be improved by starting the projects more early. When there is already a preliminary design of a project before the budget is set in the final business plan, a part of the uncertainty in the scope and in the further specification can be reduced. Information of the project organization within SCHIPHOL GROUP and the contractor can serve as valuable information here. This does not necessarily have to cost extra money and time, since a part of the engineering of the project that needs to be done anyway is only moved forward in time. On top of that there is added value in the fact that more reliable estimates can be delivered.

Today, timber structures are receiving attention more and more. Because of the increasing interest in sustainable construction as well as for other reasons, building industry in Europe is (re)-discovering multi-storey timber structures for construction of mid-rise buildings. In this master’s thesis, an analytical calculation method and modelling approach are presented, to calculate the timber-frame shear-wall racking stiffness. With the research, a specific gap in engineers knowledge is completed, and a contribution is made to the development of multi-storey timber-frame structures in the Dutch context of building engineering.

Buildings must be designed to meet horizontal deformation and vibration requirements when loaded by a wind force. These requirements can be governing in the design of the load bearing structure of a high-rise building. The structure can be optimized by describing and analyzing its dynamic behaviour. Information on damping is required to accurately describe the structure’s response. Codes provide global information on damping parameters. Since buildings are being built higher and higher, the quest for more accurate information arises. In this study information on 11 Dutch buildings was studied and damping parameters derived from measurements were related to the structural characteristics. Damping ratio expressions were derived. An analytical model of the structure’s dynamic response was developed. Damping was split in four sources to identify the contribution from individual structural aspects. The model was also used to advise on improving the monitoring of buildings in practice.

This project is aiming to reduction of energy demands, and greenhouse gas emissions consequently, by achieving less heating demand and higher thermal comfort for residential buildings. The choice of refurbishment as the best solution for that is investigated. For the needs of the project, a case study was used, carefully chosen to be representative and of common detailing, so the solutions proposed can be implemented to more buildings. The criteria for the refurbishment measures that were investigated were mainly: not extreme costs, comfort for the residents during the construction and the possibility to generalize the solution for more buildings. CAPSOL models were created for the calculation of the heating demand in the exiting situation and the refurbishment solutions. The result of this modeling was that the building has to be fully refurbished in order for it to achieve both high thermal comfort and low heating demand. Passive measures, like second skin façade and closed-off balcony, work better than external insulation, especially if they are south oriented. The greenhouse gas emissions were calculated both form the heating demands and by calculating the embedded energy of the materials used in each refurbishment solution. Again, the passive measures were more efficient because glass and steel are much less environmentally-costly materials than aluminium frames and external insulation. Also, geothermy played an important role in reducing the emissions greatly.

During this MSc thesis it has been carried out an extensive literature review on fire safety engineering, on timber behaviour on fire and on fire safety regulations in different countries. A preliminary design for a high rise cross laminated timber building (CLT) has been carried out in order to obtain a minimum thickness of the structural elements needed for the load bearing structure. This thickness has been verified according to prescriptive fire regulations. Furthermore, fire safety analyses have been performed to evaluate a more realistic fire behaviour of exposed timber structures. The finite element program SAFIR and the fire model OZone have been used in the advance calculations. Finally, it is shown that timber buildings should be designed according to advance fire safety approach and suggestions are given for developing a timber fire model.

Introduction A tensile-compression ring structure is derived from the spoke wheel principle. The general shape of the ground plan of a regular football stadium, which is more oval or rectangular shaped, is in contradiction with the spoke wheel principle. The goal of the thesis is to investigate the use and attractiveness of the spoke wheel principle for football stadia Research The thesis consists of an analysis and design component. The spoke wheel principle for the use for bicycles and for roof structures have been analysed. By designing a roof structure more insight is gained and conclusions can be made regarding the use of the spoke wheel roof structures for football stadia. Analysis The strength and stiffness of the wheel depends on the amount of ring action in the structure. When a tensile load acts on the ring, the ring becomes compressed and ring action arises. This principle can be applied for roof structures. The more ring action can be provided, the more efficient the roof structure will become and more material will be saved. The amount of ring action in a spoke wheel depends on four key factors: strength of the ring, loads, translation and curvature. To come to a design, the influence of different design variables on the key factors have been investigated. Design For the study of the use of the spoke wheel principle for stadia roof structure, two types of roof structures are investigated: Non-pretensioned spokes In a spatial truss system beam action will play an important role in the total stiffness of the roof structure. By directly transporting the loads to the ring elements that possess sufficient curvature, the ring action is used at full extend. The results confirm that the efficiency of the structure increases. By optimizing each single element in the roof structure, using parametric modelling, a lot of material can be saved. Pretensioned spokes A cable structure is not able to provide stiffness by beam action. The stiffness of the roof structure depends on the amount of ring action in the structure. The results showed that the reference stadium possess not enough curvature to provide an efficient spoke wheel roof by means of a cable structure. Further research is needed to use the available ring action at a greater extend for cable roof structures. Conclusion Research showed that a spoke wheel roof structure is an attractive type of structure for stadia use. The amount of curvature in the roof is crucial whether it is possible to come to an efficient structural design. When there is a lack of curvature a spatial truss structure is able to provide extra stiffness to the roof. Cable structures are very dependent from ring action, it is advised to use this type of structure only for roofs that possess curvature in the complete roof. To increase the application of the cable roof structure more research is needed.