1 

Slender box girders and/or less stirrups by applying HSC or HSFRC
By making use of HSC the box girders of Spanbeton are designed more slender. Use was made of additional prestressing and additional stirrups. Steel fibers were used to increase the ductility of the HSC.
Besides the ductility, the steel fibers were used to increase the shear capacity of the concrete. Due to this increase, less stirrups were needed.

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2 

Application of FRC/ECC in integral bridges
The focus of this study is to research if ecc/frc is applicable for integral bridges. Integral bridge are bridges without or partly without intermediaries. A bridge normally consist of a substructure, superstructure and intermediaries. The superstructure comprises the bridge deck and the substructure consist of the abutments, piers and the foundation. The intermediaries are expansion joints and bearings which enables the bridge to deform and/ or to transfer the deformation and loading from the superstructure to the substructure. With or without intermediaries leads to different structural systems. A bridge with these intermediaries is called a ‘conventional bridge’ and a bridge without these intermediaries is called a ‘fully integral bridge’. There are also structural systems in between a conventional bridge and a fully integral bridge. (see chapter 1)
Integral bridges have been built in the United States, Canada, Australia and several countries in Europe. The choice for an integral bridge over a conventional bridge depends strongly on the length of the bridge, the bridge location, the climate and the requirements of the bridge and the road. In some states of the U.S., integral bridges are preferred over conventional bridges. Hence, more than 1000 integral bridges have been built in the U.S. including the longest steel and concrete integral bridges. Some states in the U.S. prefer integral bridges over conventional bridges, because in their experience the elimination of expansion joints and bearings leads to a more durable structure and less maintenance. The maximum bridge length is disputed by the State engineers. Normally the allowable length is between 60 and 180 meter depending on the state limitations. (See section 3.1)
Integral bridges are not used as a common practice in the Netherlands. The preferred structural system is a conventional bridge. The integral bridges that have been built, seem to be a choice of the designer. Most of the integral bridge that have been built, are single span bridges. (See section 3.1)
All construction elements of an integral bridge are monolithically connected. This results in one integral system where there is interaction between the sub and superstructure and between the bridge and the embankment soil. This is an important difference compared to a conventional bridge, where the sub and superstructure function more like single structural systems. The structural system of an integral bridge can be schematized as a portal frame. In this case the beam of the portal frame is the superstructure and the columns comprise the substructure. In a portal frame, deformation in the beam will cause deformation in the columns. The deformation that occurs in the bridge deck of the integral bridge is caused by loading, temperature influences and timerelated material effects. These loads and effects will cause the following rotations and displacements in the structure (see section 3.2):
Vertical displacement and rotation (weight of the bridge, asphalt, traffic)
 Rotation (temperature gradient daily cycle)
 Contraction (shrinkage, creep, elastic shortening prestressing)
 Expansion (temperature yearly cycle)
An integral bridge is a durable structure due to the absence of expansion joints and bearings. However, without expansion joints and bearings the bridge deforms into the soil due to the deformation of the bridge deck. The deformation of the bridge deck is caused by the temperature influences and timerelated material effects. The timerelated material effects are shrinkage, creep and elastic shortening in case of a prestressed concrete element. These effects are responsible for deformation of the bridge deck in time. The temperature influences lead to a cyclic behaviour. This behaviour could be divided in two cycles, namely a yearly and a daily cycle. Both cycles causes cyclic deformation of the bridge deck. This deformation of the bridge deck is only possible if the bridge is able to deform into the soil. This may imply certain problems, because the soil is not rheological. These problems are (See also section 0 and chapter 4):
 Settlement of the soil close to the abutment ‘bump in the road’
 Asphalt/pavement problem
 Foundation/piles
 Early age cracking
 Wing walls
 Cracking of the abutment stem or the bridge deck at the abutment
The major goal of this thesis is to investigate if the application of frc/ ecc in the connection of integral bridge has advantages. Fibre reinforced cementitious composites could be distinguished from conventional concrete due to the application of fibres. The application of fibres leads to some interesting properties, for example a higher strength, more ductility, more toughness, durability, higher stiffness and thermal resistance. FRC composites could be distinguished in ‘hardening and ‘softening’. An FRC composite has ‘hardening’ when the structural strength is equal to or greater than the cracking strength. This means that after the first ‘crack’ the tensile strength of the FRC composite is still increasing. This hardening can also occur under bending, and then the FRC composite is called ‘deflectionhardening’. When this hardening occurs under tension then the FRC composite is called ‘strainhardening’. An FRC composites has ‘strainsoftening’, when the tensile strength declines after the first crack. (see chapter 6)
There is chosen to apply the FRC composites in the connection. A major motivation is to reduce reinforcement in the connection between the sub and superstructure. This is firstly investigated by constructing strutandtiemodels (STM) and stringpanel model (SPM). The STM and SPM showed that influence of foundation pile on the connection is decisive. Two mechanisms could describe for the structural behaviour of the foundation pile in the connection. The first mechanism is the transfer of forces and moments by friction between the foundation pile and the surrounded concrete (Figure 74A) and the second mechanism is the transfer of forces and moments by a coupling force (Figure 74b). Both mechanisms are analysed by using the STM and SPM. This provided a good image of the flow of the forces and stresses in the connection. (See chapter 7 and appendix A)
The 2D FEM is developed on basis of the results of the STM and the SPM and the building project ‘bridge Schokkeringweg’. The forces, the moment, the boundary conditions and the dimensions are based on the calculations of the ‘bridge Schokkeringweg’. The research focuses on the two mechanisms. Therefore, friction and cohesion between the foundation pile and the surrounded concrete and the horizontal reinforcement in this area are taken as variables. The results show that the strength of the connection depends mostly on the horizontal reinforcement and cohesion and friction have almost no influence. (More about the conclusions, see section 8.6)
The next step was to investigate the effect of the FRC composites on the 2D FEM. The FRC composites used in this research are classified on basis of tensile strength, strain and ‘hardening or softening’. For this research, a 2D FEM with and without horizontal reinforcement in the area of the foundation pile is used. The results show that FRC composites leads to an improvement of the rotational stiffness of the connection and for 2D FEM without horizontal reinforcement also to a higher structural strength of the connection. However, the improvements are minor and therefore it is advised to not apply FRC composites in integral bridges. (see section 9.4)

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3 

Is project success a coincidence or can it be enforced? A comparative study on the critical success factors of the Stadsbrug Nijmegen project and similar civil engineering projects in the Netherlands

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4 

Virtual design and construction in the AEC industry

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5 

Issue dynamics in the execution phase of large airport terminal adaptation projects

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6 

Contract management in DBFM(O) projects

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7 

Organizational Barriers for adopting project alliancing: An investigation in the Dutch public infrastructure procurement organizations.

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8 

Towards a risk management framework for construction projects: Analyzing the risk procedures in construction projects, and developing a risk management framework for EPC and EPCm projects at Tebodin

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9 

Embracing change: The road to improvement?

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10 

Regional approach to infrastructure provision

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11 

Interproject learning of innovations: A study in learning of innovations from project to project at Rijkswaterstaat

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12 

Application of Ultra High Performace Fibre Reinforced Concrete in the Building Engineering
Material properties of concrete have developed rapidly in the past fifteen years. With the advent of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) a new material has emerged which is; much stronger, stiffer and durable than conventional concrete. Nonetheless despite these promising developments and due the high material costs UHPFRC is only rarely applied in small niche markets.
The objective of this thesis is to derive an innovative and distinctive design which makes best advantage of the characteristic properties of UHPFRC.

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13 

3D Finite element analysis of a scaled trapezoidal 3story reinforced concrete structure on a shaking table
This master thesis is about finite element analyses of a 3D model of a 1/4th scaled trapezoidal 3story reinforced concrete mockup on a shaking table which is part of Smart 2013 international benchmark. The idea of this benchmark is to asses and predict the dynamic behavior of the reinforced concrete mockup with respect to seismic loading using finite element method software. In this master thesis, the finite element method software Diana is used to asses and predict the dynamic behavior of the scaled mockup with respect to seismic loading.

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14 

Solar updraft tower  structural optimisation under dynamic wind action
As fossil fuel reserves are rapidly being depleted, sustainable alternatives have to be found to fulfil the world's energy demand. Numerous concepts have been proposed to generate electricity by harnessing renewable energy sources such as solar or wind power. One of these concepts is the the socalled solar updraft tower (SUT). The SUT consists of three elements: a solar air collector, wind turbines and a chimney. The taller the chimney, the larger the stack effect and thus the more energy which can be generated by the turbines. The proposed concepts for this chimney schematise it as a reinforced concrete cylindrical shell, with the bottom half shaped like a hyperboloid and the top half as a flared cylinder, outfitted with ten stiffening rings evenly distributed over the height. Chimneys as tall as 1500m have been proposed, and, previous research shows that these tall structures have very low eigenfrequencies which come very close to the peak of the wind power spectrum. This makes them extremely vulnerable to resonance induced by storm actions.
Two types of resonance can be distinguished in these structures; alongwind resonance, and acrosswind resonance. Alongwind resonance is caused by turbulence in alongwind gusts. The second type, acrosswind resonance, is caused by the alternating shedding of vortices. This leads to pulsating excitation forces in the acrosswind direction, and, if the frequency of the vortex shedding is the same as one of the eigenfrequencies of the chimney, resonance will occur.
In this thesis, a finite element model is created based on a preexisting design. This socalled base model is then analysed to determine which key problem areas could benefit from improvement. The analyses show that especially the first two eigenfrequencies are critical for alongwind resonance as well as acrosswind resonance. These eigenfrequencies are seen as two individual problem areas as improvements to one eigenfrequency not necessarily guarantee improvements to the second eigenfrequency. Furthermore, tension on the windward side leads to cracks in the stiffening rings which negatively influence the eigenfrequencies and thus the dynamic response. The last area which could benefit from optimisation is the cost of the chimney; an optimal solution does not use more material than necessary.
A design tool called SUMAT (Solar Updraft Modal Analysis Tool) is created which enables the user to analyse multiple chimney configurations at once, subsequently being able to compare their results. Various sensitivity analyses are carried out to determine the influence of geometric and material parameters on the four key problem areas of the chimney. A multiobjective optimisation process is followed to optimise each of the key problem areas, ie. objective functions, by hand. The first step in optimising the structure is to subdivide the parameters which were researched into four categories, depending on their usefulness. The second step consists of gradually introducing these parameter changes into the base model.
The optimisation process revealed that the objective functions can be maximised as follows: increasing the moment of inertia of the rings by changing their aspect ratio ensures that the chimney is fully loaded in compression. An increase in the throat height further improves the reduction of tension on the windward side and the first eigenfrequency. A reduction in wall thickness at the top of the chimney improves the first eigenfrequency while also reducing material use. Lastly, it appears that the stiffening rings at the bottom serve little to no purpose. Removing them leads to a reduction in material use while some of the material gained can be used to increase the dimensions of the top rings, consequently improving the second eigenfrequency and reducing tension.
More thorough analyses revealed that the optimisation process has indeed led to an overall improved structure when compared to the original base model. While alongwind resonance does not pose as great a threat as was initially assumed, due to the influence of aerodynamic admittance, the results do show that the improved eigenfrequencies led to a smaller increase in deflection as a result of dynamic wind action. Vortex shedding also no longer poses a threat as the improved second eigenfrequency resulted in critical wind speeds which are much larger than could ever occur at the chosen reference location. Future optimisations should therefore focus more heavily on the second eigenfrequency than on the first, assuming that the accompanying mode shapes stay the same.

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15 

Numerical Analysis of Stability of Steel Columns With Thermal Gradients
This thesis studies the buckling behavior of Ishaped steel columns under the effect of thermal gradients. The mechanical properties of steel decay signicantly with increasing temperature. Therefore, in case of a re, the buckling resistance of steel columns is considerably reduced due to the decrease in the modulus of elasticity and yield strength. Furthermore, in a realistic re scenario, temperature gradients develop throughout the crosssection and throughout the column's length. However, the design guidelines in Eurocode 199312, as well as in other leading construction codes, specify that in the case of a nonuniform temperature distribution the column's buckling resistance must be determined by considering a uniform temperature distribution considering the maximum temperature in the crosssection. The objective of this thesis is to assess the reliability of the provisions given by the Eurocode for elevated temperature design in the presence of temperature gradients. A series of finite element models were created for five different crosssections and analyzed at room temperature, uniform elevated temperature and nonuniform temperature along the crosssection. From the uniform elevated temperature analysis, a buckling curve for elevated temperature was derived. The finite element analysis results for the models under the effect of temperature gradients showed better agreement with this FEMderived buckling curve than with the Eurocode provisions, which were shown to be overconservative for the case of a temperature gradient along the column's weak axis. The FEM results were also compared to the results obtained with the American and Australian building codes….

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16 

Dynamic Analysis on Failure Modes of Tub Mounted Cranes
The trend in Offshore Engineering is towards exploring in deeper waters and more harsh environments. As a consequence, topsides become larger and heavier. In order to keep up with the demand for more lifting capacity, Heerema announced a New Semisubmersible Crane Vessel (NSCV). This vessel will contain two 10 000mt Tub Mounted Cranes (TMC), which will be constructed by Huisman. In order to ensure safety, some level of redundancy has been implemented in the crane’s hoisting systems. However, it was found that there was insufficient knowledge about the consequences of a wire failure in one of the hoisting systems.
In this thesis three possible failure cases were investigated: boom hoist cable failure, main hoist cable failure and a drop of the load. In addition, this thesis also looks at possible ways to reduce the dynamic effects of a wire failure.
Lagrange’s equations were used to derive the equations of motion of the crane and the main hoist lower block. Using these equations of motion a dynamic model was created in MATLAB, using an Ordinary Differential Equation (ODE)solver to solve the equations of motion. For all three cases animations were created in order to provide a visual validation of the models. Additional validation was performed by a comparison with results obtained using simpler models with only one or two degree(s) of freedom.
Parameter studies were performed on all three cases and different scenarios that could occur. For the boom hoist failure case the conclusion is drawn that none of the investigated parameters have a significant influence on the dynamic overshoot that occurs when one of the two wires fails. The overshoot is governed by the inertia of the load and boom.
This is not the case for main hoist failure, where the geometry of the main hoist block had a large influence on the resulting force in the wire. Other parameters that influenced the results of the analysis were the initial length of the main hoist system and the stiffness of the rigging between the hook and the load. With the current design the risk exists that when wire failure happens, the other wires will not be able to cope with the dynamic overshoot and the system will fail. However, it is unlikely that wire failure will happen due to overload in the normal operating case, as a safety factor of three is applied.
The third case, a drop of the load, proved to be the least severe case for the wires. Stress waves were witnessed in the results; however the effect of these were not significant. Even with the effects of stress waves taken into account the force in the wires remained below the initial value with the load still suspended from the crane. Further research on this case should focus on the bending of the boom.
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￼Lastly, the influence of implementing a shock absorber in either the boom or the main hoist system was analyzed. For the boom hoist system the improvements were minimal, and the constant interaction of a damping system is undesired, which leads to the conclusion that it has no further potential. Implementing a shock absorber in the main hoist system resembles much of a Passive Heave Compensator (PHC) and could potentially improve the system. However, current PHC’s do not have the right parameters to have a significant influence. The main reason for this is that the influence of the compensator is divided over many falls, which suppresses the influence.
Further research on this subject should focus on the behavior of the sheaves and falls in the system for two reasons: first, for determining the time it takes for a failing wire to unreeve and lose its carrying capacity; second, in order to determine the effects of the reeving in a system with a shock absorber.

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17 

The Structural Feasibility of 3Dprinting houses using printable polymers
At this point in time, 3Dprinting techniques in general, but especially applied for the building industry, still are in a phase of early experiments. One of the experimental attempts is to print a fullscale, threestory high, house in Amsterdam, using an up scaled version of a FDMprinter that is able to print blocks of 1.8 x 1.8 x 3.0 meters using printable polymers. This thesis report focuses on answering the initial structural question that appears around this project, which is a research to the behavior of the currently applied printing material. The outcome of this research will be used to give recommendations for the structural design of printable geometries. The material research emphasis on obtaining the material properties that are most essential to be known for this particular printing material and the application of the material within this particular building project. These basically are the mechanical (strength) properties of the material and its thermal behavior. Since the FDMprinter lays down the material layer by layer, the hypothesis was that the material would show anisotropic behavior. Therefore the strength properties are researched in different orientations relative to the direction of the printed lines. Furthermore, it was expected that the strength properties would differ for the horizontal plane and vertical plane in which there can be printed, as the resolutions in both planes differ as well.
As a part of this research, there is experimented with two innovative production methods for creating test specimens of complex forms, which are direct 3Dprinting and lasercutting of test specimens. It turns out that direct 3Dprinting of test specimens can be a good and quick method for producing complex test specimens, in case the resolution of the applied 3Dprinter is accurate enough. For the applied printer within this case study project, it turns out that laser cutting test specimens is the best option, as it leads to a higher dimensional accuracy and a more uniform specimen thickness. For the vertical printing plane, the material indeed shows clear anisotropic behavior, as the tensile, shear and flexural strength values and the failure modes parallel and perpendicular to the printing direction differ significantly. Material that is printed within the horizontal printing plane shows more isotropic behavior than material that is printed in the vertical plane, due to more and better adhesive connections between the different layers. For the compressive strength it holds that not much difference is noticed between the different orientations, especially because the tested samples are composed of multiple printed layers in both the horizontal and vertical plane. This result leads to an important recommendation to compose printable buildingblocks out of 3Delements instead of only 2Dplate elements, which so far has been the case. This actually leads to a stronger, more isotropic, more homogeneous and therefore better predictable material behavior. Throughout the research this recommendation is further confirmed by outcomes of the absorption test, geometry tests and insulation requirements. The absorption test shows that the material becomes watertight in case multiple printing layers are applied in the horizontal direction. The performed bending and pressure tests on printed geometries demonstrate that geometries, which are build up by a single layer, fail due to local effects: they either fail on local buckling or local bending of an individual member of the geometry or they fail at the location of local inaccuracies, which often occur within printed geometries. The stress level at which these failure modes take place can be significantly increased by composing individual geometry members out of multiple printed layers. Finally, to meet the requirements for heat and sound insulation, a certain wall and floor thickness is required which only can be achieved by printing multiple layers within the horizontal printing direction.
The performed temperaturestrength test and DSCtest show that current thermal behavior of the material is the most important point of concern regarding the applied printing material. The material is applied in the rubber phase, it softens at 60 degrees Celsius and already at a surface temperature of 40 degrees Celsius, the material has lost already about 70% of the material strength it has at room temperature. It is obvious that further research on the improvement of the temperature behavior of the building material is essential to make printable polymers suitable for structural applications. Also the comparison with general structural materials and polymers applied in the construction practice, confirms that the printing material in its current form, is not structurally applicable. Furthermore, the comparison shows that the stiffness of the material needs to be improved, as the Young’s Modulus is relatively low. Although the essence of further research should lie on the improvement of the printing material, it still can be valuable to continue the structural design process parallel to the material development. Based on the performed material research, recommendations are given for design improvements. These recommendations can be used as a starting point for a possible future study to the structural design of printable geometries, chambers and complete houses.

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18 

Humaninduced vibrations on footbridges: A probabilitybased approach of the vibration serviceability of footbridges under vertical pedestrian loading
In structural design there is a tendency towards more slender and challenging architectural structures. Footbridges become more slender with an increasing high ratio live load to dead weight. A consequence of this increased slenderness of footbridges in an increased susceptibility to humaninduced vibrations. The evaluation of the serviceability of footbridges therefore becomes more important.
The first aim of this study was to provide a good basis and overview of the critical aspects in the evaluation of humaninduced vibrations in footbridges. From a literature study, the discussions with engineering companies and an impact study it became clear that there are four critical aspects particularly relevant for further study at the moment: vandal loading, structural damping,additional mass and damping by pedestrians and probability of occurrence of accelerations and the consequences for comfort of the pedestrians.
The second part of this study was focused on the question whether a probabilitybased approach can demonstrate that the Eurocode is conservative in the evaluation of humaninduced vibrations in footbridges. Hereto, a probabilitybased analysis has been performed for the vibration serviceability of footbridges and implemented in a case study with three simply supported footbridges. Instead of looking at the maximum acceleration that is expected for the bridge deck, the accelerations which individual pedestrians experience when crossing the bridge have been investigated. Four scenarios have been compared to the approach prescribed by the Eurocode. The pedestrian loading has been modeled based on two assumptions for the scenarios: scenarios based on densities of the pedestrian ﬂow and scenarios based on group formation.
The conducted research based on assumptions for the pedestrian trafﬁc and a ﬁxed criterion for human comfort, has given valuable insight in the use of a more realistic evaluation of humaninduced vibrations in footbridges. This insight has been obtained for the incoming pedestrian trafﬁc and the exposure to vibrations for individual pedestrians. The adopted probabilitybased approach contributes to demonstrate potential conservatism in the Eurocode regarding the evaluation of humaninduced vibrations in footbridges.

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19 

Prefab vs. InSitu Concrete Viaducts

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20 

The effect of discrete reinforcement on the load‐bearing behavior of a spindle‐shaped Tensairity beam
Tensairity is a lightweight structural concept, a synergistic combination of an airbeam, 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 airbeam (a low pressure inflated tube), a compression element tightly connected
to the airbeam 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 loadcarrying capacity
compared to a traditional simple airbeam. At the same time, the pressure inside the airtube 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. Cigarshaped or spindleshaped
beams still have a circular cross section, but are stiffer than the cylindrical structure.

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