In this research an effort is made to contribute to the goals of the Betonakkoord. This is done by optimising the design of big and bulky structures consisting out of a lot of concrete, namely lock heads. Lock heads are part of the navigation lock. The main research question answered in this thesis is phrased as follows: How can the design of lock heads be optimised to increase the sustainability?
Different alternatives have been generated to try to increase the sustainability. Each alternative has been compared to the lock head in Empel to test their feasibility. The following alternatives are considered: Inhomogeneous cross section, Prestressing and Hollow sections. From the alternative study it becomes clear that none of the alternatives are effective. The alternatives show no significant decrease in cost and MKI. Therefore, the alternatives are neglected in the remainder of the research. Based on this conclusion the following question arises: Is it possible to increase the sustainability of a lock head design based on commonly used design rules? In the next step of the research a parametric model is developed in order to answer this question. The parametric model design is based on the rules prescribed by the 'Handboek voor het ontwerpen van Schutsluizen' and the 'Richtlijnen Vaarwegen 2017'. The parametric model takes into account two types of gates, being a single leaf gate and a mitre gate. Again, the lock head in Empel has been used to validate the parametric model. From the parametric model it follows that in general a mitre gate is more cost effective and sustainable than a single leaf gate. This is because a mitre gate is generally shorter than a single leaf gate, so less materials are used and the construction pit can be smaller. Furthermore, the parametric model shows that the global stability check horizontal bearing capacity is a key parameter in the design of a lock head. To account for the horizontal bearing capacity the length and the weight of the lock head are important factors. The next step is to compare the lock head designs from the parametric model with the lock head design in Empel. The lock head design in Empel deviates from the rules prescribed by the 'Handboek voor het ontwerpen van Schutsluizen'. By deviating from the rules a more cost effective and sustainable design is acquired than both the designs from the parametric model. The lock head in Empel is shorter and lighter than the lock head designs from the parametric model. This is due to the fact that the lock head in Empel derives its horizontal bearing capacity from the lock chamber. In order to design a more cost effective and sustainable lock head it is advised to incorporate the lock chamber in the stability calculations. Hereby a shorter lock head can be achieved.

Structures may be subjected to both mechanical loads and imposed deformation. On one hand, the mechanical loads include, for example, the self-weight of the construction work, the action from normal use by person, furniture and movable objects, vehicles, snow, wind, execution, etc. On the other hand, when the deformation of a structure is restrained, imposed deformation occurs. The sources of deformation can be various, not only environmental conditions, such as temperature and humidity changes, but also chemical or physical actions, such as sulphate ingress or creep. If the shortening of a structure is restrained, the structure will be subjected to imposed deformation which results in tensile stress. Since the tensile strength of concrete is relatively low, concrete structures, such as tunnels, bridges and pavement roads, always suffer a high risk of cracking. Even if the concrete structure is prestressed, the tensile stress resulting from imposed deformation would consume the compressive stress in concrete and raise the risk of cracking. If the crack width exceeds the limit, leakage, corrosion and even structural failure may happen. According to the schematized 푁 - 휀 diagram of reinforced concrete, the development of cracking caused by imposed deformation and mechanical load are different. Suppose the cracking is caused by imposed deformation, there is a developing stage for cracking. It means the cracks caused by imposed deformation could be either fully or not fully developed. However, suppose the cracking is caused by mechanical loads, the cracks could only be fully developed. The stiffness of fully or not fully cracked members are different. The stress resulting from imposed deformation in a structure is related to the stiffness of the structure. Therefore, cracking has significant impact on the magnitude of stress resulting from imposed deformation. Therefore, when a structure is subjected to imposed deformation and mechanical load together, it is necessary to take the impact of cracking into account during structure design. The combination of imposed deformation and mechanic loads is referred to as combined actions. It is common to use FEM software to analyze the stress resulting from the combined actions during structure design when cracking has to be taken into account. However, FEM analysis only is not enough. It is also necessary to check the results calculated by FEM software to avoid mistakes, for example a wrong input.
There is a project called 'Approach Ring South, Groningen'. In the project, widened deck KW03.01 is subjected to a combination of imposed deformation and prestressing force. FEM software called SCIA is used to calculate the prestress consumption in the widened deck KW03.01. According to the data file of the project, 41% in maximum of the compressive stress resulting from prestressing is consumed when the structure is subjected to combined actions, which is much more than the engineering experience. As a result, a simple approach is required to check whether the prestress consumption in widened deck KW03.01 suits the expectation or not, where the prestress consumption is calculated by FEM software.

Due to the alteration in height, the centroidal axis of a non-prismatic beam has a non-linear layout when compared to a prismatic beam. Therefore, in case of a non-prismatic beam, the vertical cross-section cut, on which analysis from the codes are performed, is no longer perpendicular to the centroidal axis, unlike prismatic beam. Moreover, due to the geometry, these beams are prone to shear failure which is mainly due to the vertical component of the inclined cross-section forces. The main focus of this study is to compare the cross-section results obtained on inclined and vertical cut and also to validate the inclusion of the vertical component of the inclined forces in the shear capacity equation.
Different approaches are proposed to calculate the cross-section results on an inclined cut, with the internal forces in the global (horizontal and vertical direction) as well as in the local direction (perpendicular and parallel direction of the cut). From the procedure it was seen that in a prismatic beam, subjected to four point bending test, the cross-section results remains the same irrespective of how the analysis is performed. However, in case of non-prismatic beams, the bending moment resistance obtained on an inclined cut, which is perpendicular to the centroidal axis with the forces in local direction, is greater than that obtained on a vertical cut. Therefore to be conservative it is recommended to perform cross-section analysis on a vertical cut in a non-prismatic beam.
A procedure to calculate the shear capacity of non-prismatic beam is determined in this study. First, the shear resistance contributed by concrete and stirrups are calculated at the assumed critical section. Then the inclined internal forces are determined for each load case and the capacity of the beam is either reduced or increased by the vertical component. This capacity is compared with the applied loading and is checked for failure. Since the shear capacity is influenced by the applied loading, failure of the beam is defined as the load for which the determined capacity is lower than the applied loading. The results obtained from this procedure are in good agreement with the limited experimental data available. Therefore, it can be concluded that the vertical component of the inclined cross-section forces should be considered in the shear capacity equation.
Finally non-prismatic bridge deck is also studied and different errors that engineers make in practice is further analyzed. Due to the non-linear layout of centroidal axis, engineers find it difficult to perform analysis on non-prismatic beams. Therefore, the cross-section of the deck is modified, such that the centroidal axis remains linear. The results determined on a modified deck is equal to that obtained on the original model. Another error engineers make is ignoring the inclination of internal forces, which leads to underestimation of the capacity. This study shows that the vertical component of the inclined cross-section forces, which is considered in the shear capacity, should be determined based on the bending moment obtained for the load combination where applied shear force is governing.

Study of interface behavior has been the primary area of focus for researchers in the field of concrete science and technology. This interface between two concrete elements becomes important for prefabricated systems, combination of precast and in-situ concrete elements, combinations of concrete cast at different times, repairs of existing concrete structures, strengthening of a structural element such as beam or slab and so on. In this research an attempt is made to check if the interface behavior is reliably predicted using finite element analysis in ATENA with the help of standard elements available in the software. Validation of the numerical results is performed by simulating an experimental bond test and structural test and conclusions are drawn based on the response of these numerical models.

Strength of the interface is mainly governed by the roughness of the adjacent surfaces. In the literature study, a chronological overview of the development of shear models is presented that make use of these roughness parameters in calculating shear capacity of the interface. A finite element analysis is performed using standard elements available in ATENA. ATENA interface material model (ATENA IMM), present in the software uses 2D line interface elements having zero thickness to model an interface. Roughness parameters assigned to this model are based on the guidelines proposed in different design codes. Many parameters need to be defined in this interface that are difficult to measure accurately from experiments. For this, a 5 mm thick artificial interface layer is created by using 2D linear quadrilateral material elements. This technique is named as artificial interface model (ArtIM) that uses physical material properties to define the interface. Since, cohesion and friction coefficient parameters cannot be specifically defined in ArtIM unlike in ATENA IMM, an explicit roughness is incorporated by designing the interface layer in a wave pattern with certain wavelength and amplitude depending on the different surface roughness classes as defined in the Model Code 2010.

A check is performed for the assigned input parameters for the two interface modelling techniques, by simulating bond tests (direct tension test and shear load test) on a small scale composite concrete specimen. Furthermore, validation of the two interface modelling techniques is carried out by comparing the numerical results to experimental findings for a bond test performed by T. Paulay, R. Park and M. H. Phillips [1] and for a structural test case of the Eindhoven airport car park garage failure [2], [3]. ATENA IMM rightly predicts the initial response of the interface but does not comply with the experimental results once the interface fails. With the use of ArtIM, an overestimation of the shear strength is exhibited and the conventional ratio of 2 between the shear and tensile strength [4], [5] cannot be obtained. Moreover, once the material in the interface layer fails, a brittle behavior is exhibited pertaining to the concrete properties assigned to the interface material layer.

Different reinforcement modelling techniques are studied using ATENA IMM with a very low bond strength (no bond condition). The default 1-D reinforcement (RF) bar element when modelled perpendicular to the interface does not reliably predict the response of loading. Hence, other RF modelling techniques are discussed among which, 1-D RF bar elements modelled in cross pattern reliably predict the initial stiffness of the RF bars. The inclination of the RF bars was tested for different angles to comply with the experimental results. However, further research is required to calculate appropriate inclination of the RF bars. In this case the optimum angle between the cross RF bars and interface is around 80°.

In the structural test, interface behavior is investigated for a specimen with (fully reinforced) and without (partially reinforced) shear reinforcement in the flexural span. ATENA IMM safely predicts the bond strength in case of both, partially reinforced and fully reinforced models. However, by using ArtIM, an overestimation of the interface strength is observed. The important aspect in the structural model is the shear strength of the interface and since, while using an artificial material element for the interface the shear strength obtained is almost 40% higher than the experimental results, the ultimate load carrying capacity of the whole model increases manifold.

After investigating the two interface modelling techniques, on bond level and structural level, it can be concluded that, the ATENA interface material model (IMM) as well as the artificial interface model (ArtIM) do not predict the interface behavior reliably. However, by using ATENA IMM a conservative response is obtained as opposed to the ArtIM which overestimates the shear capacity of the interface.

In August of 2013 Elon Musk published his paper ’Hyperloop Alpha’, in which he describes an alternative transportation system for the to be built railway connection between Los Angeles and San Francisco. The Hyperloop system that Musk describes relies on partial vacuum tubes through which vehicles can travel at speeds up to 1000 km/h with great efficiency. An innovative breakthrough in the transportation sector if it can be made into a reality. Therefore his company SpaceX organised a contest to which many teams applied to built a concept vehicle to be used in the tubes. In 2017 a team of students from TU Delft won the overall prize for the best design and afterwards the team leaders founded Hardt to develop their ideas and make Hyperloop into a reality. BAM Infraconsult supports Hardt and together they develop the Hyperloop and its tube infrastructure. Currently the preliminary design for the tubes is made in steel and no alternatives have been considered. This research focusses on an alternative tube design in concrete. The tube has to not only satisfy the strict requirements that apply to the Hyperloop technology in general, but it also has to adhere to the specific design philosophy of the Hardt vehicle concept. A concept in which the vehicle is suspended from tracks on the ceiling of the tube by a series of magnets. The report is based on the following research question: Is a concrete design a feasible alternative for the design of airtight Hyperloop tubes compared to the considered steel tubes? To answer this question two philosophies are considered and researched into depth. Firstly a design in prefabricated normal strength concrete is analysed, making use of prestressing and conventional reinforcement, following the requirements set in the Eurocode. Secondly an innovative ultra high performance steel fibre reinforced concrete (UHPFRC) design is considered. Again prestressing is applied, however conventional reinforcement is not present in this design as it relies on steel fibres and prestressing alone. This design is modelled according to the French UHPFRC guidelines. A requirement for the design is that the inner diameter of the tubes is equal to 3.6 m and that the tubes span 30 m between pylons. The design methodology is based on a variable thickness of the tubes in order to find the optimal concrete structure that satisfies all requirements. Checks are made for multiple failure modes after which the governing minimum thickness is derived. Other than proving to be structurally sound according to the Eurocode, the tube also has to abide to a strict deflection limitation under dynamic loading conditions. In order to research this criterion the tube design is validated using finite element modelling. Here a combination of different parameters related to the concrete material characteristics and the dimensions of the tube is researched by means of a sensitivity analysis. Using the dynamic amplification factor specified by Hardt, the maximum deflections of the tube are checked and the parameters that have the greatest influence on the deflection are discussed. The obtained results are compared to the steel tube. Furthermore the possibilities for the construction of a concrete tube are considered, including a recommendation for the connections between tube sections. Moreover the transportation of the tubes to the building site and final assembly are taken into account. After all factors are considered a cost estimation is made for the design of the concrete tubes and compared to the cost estimation of the initial steel design of the tubes. This cost estimation does not only consider the material and production costs of the tubes, but also takes into account transportation, assembly, maintenance and site costs plus an allowance for risks and profit. It is concluded that a design in normal strength concrete is possible, but not practical. Its dimensions make the production and assembly very difficult. However a design in UHPFRC is feasible, as its required dimensions are considerably better. Furthermore it satisfies all structural requirements without the use of conventional reinforcement and even the strict deflection criterion at dynamic loading conditions can be achieved. Moreover the design in UHPFRC is a competitive alternative to the steel design, as it has a higher score when all criteria are considered.

To realise more sustainable industrial ground floors the implementation of alkali-activated concrete is considered for jointless elastically supported ground floors. Such floors are realised with large areas without dilations, the shrinkage reduction is therefore restrained causing cracks to arise at the top surface of the floor. The control of cracking is the governing design aspect for jointless ground floor and is done by a top reinforcement mesh combined with the addition of steel fibres in the concrete mixture. Alkali-activated concrete is a concrete realised without cement and has a reduced CO2 footprint, it can show some beneficial material properties, making it a potential concrete for a more sustainable floor. A parametric study is done and an optimised floor realised in alkali-activated concrete is considered. Crack-width calculations of increased accuracy are performed via bond-slip calculations. These are performed analytically and by finite element analysis done with DIANA. Comparisons show that the so called direct method and DIANA underestimate the crack-widths relative to the more accurate analytically computed results. Additionally, it is found that the improved bond strength of alkali-activated concrete results in smaller crack-widths. It follows that with alkali-activated concrete a jointless floor can be realised in a thinner cross-section and with less steel necessary to control the crack-widths. As a result alkali-activated concrete is suitable to construct more sustainable jointless ground floors.

This thesis focusses on the application of vertical profiled mortar connections in precast concrete shear walls that are built up with a stacked element configuration. The goal of the project is to develop a practical modelling approach in order to be able to apply the connections in a FEM model for structural analyses. For this purpose several research aspects concerning the behaviour of the connection were analysed.

Engineering firm Pieters Bouwtechniek Delft has designed many cantilevering elements in Compact Reinforced Composite over the past years. This material, often abbreviated as CRC, is an UHPFRC developed by Hi-Con Denmark and the material distinguishes itself from other concretes as it incorporates large volumes of steel fibres and reinforcement steel. As a result it is a ductile concrete type with outstanding crack controlling properties. One of the challenges met during designing with CRC is the fact that the Eurocode does not implement the improved properties of the material, such as the improved post-cracking response which is a result of the addition of fibres. This results in designs often requiring stirrups in order to comply with the Eurocode with regard to the shear capacity and the prevention of brittle failure.An example case where this problem was faced, is in the design of the landing platform in a staircase for the Raqtan project, engineered by Pieters Bouwtechniek. This design consist of a cantilevered platform, connected to a wall via a console. The Eurocode requires the addition of stirrups, while it is expected that these stirrups are not required in order to provide a sufficiently safe design. Therefore the following question was raised: Were stirrups required in the console in the design of the Raqtan landing platform in order to obtain a level of safety as required by the Eurocode? This report researched the structural response of the element without the application of stirrups in order to answer this question and determine whether the safety standards as stated in the Eurocode are met. The design without the stirrups is validated in three ways. The first method is by application of multiple design standards which incorporate a contribution by the fibres, such as the Model Code 2010 and the renewed French annex to the Eurocode. Most codes did not validate the design and predicted shear failure before the design load was reached. The French annex did validate the application of the design without stirrups. This is a result of the underlying principles used for this approach: the French guideline bases the tensile behaviour of the UHPFRC on the uni-axial tensile curve, while the other guidelines are based on the flexural tensile curve.The second validation method was through the Finite Element Method. Multiple tensile models were validated against previous experiments and were then used to determine the structural response and ultimate capacity of the Raqtan element. The models failed in bending at a capacity above the design load, thus validating the design. After the results were analytically validated, a variation study was performed on the influence of certain model properties on the structural response. The variations, such as the boundary conditions and mesh configuration, did not significantly influence the ultimate capacity. This analysis validated the application of the design without stirrups. The third and last validation was performed by testing multiple elements in the lab to find the actual capacity. Both elements without and with stirrups were tested to compare the resulting change in structural response. Some elements were reinforced to increase the bending capacity by at least 50%, as the FE models predicted failure in bending even when mean material properties were applied. The reinforced elements did not fail in shear as well, which demonstrated that the bending moment capacity was not only governing, but also significantly lower than the shear capacity. The derived design values for the ultimate load resulted in sufficient capacity for the element to resist the design loads.Combining the performed validations, it is concluded that the element's shear capacity was not governing for the ultimate resistance as it was at least 50% higher than the found the bending moment capacity. This bending moment capacity was sufficient according to all applied codes. When this capacity is taken as the total capacity of the element, it can be stated that the element complies with the codes and therefore provides a level of safety as required by the Eurocode.

Shear cracking in slender reinforced concrete beams with thin webs can result in significant shear crack width and deflection which is usually ignored in practice due to lack of availability of the engineering models in design codes. This can lead to unconservative predictions of the crack width and total deflection in the SLS (Serviceability Limit State). The large crack widths can cause problems related to durability, aesthetic appeal, maintainability and fluid tightness of the structure. An inspection in 2001 reveals extensive shear cracks in Grondal and Alvik bridges in Sweden. The problem is so severe that the bridges are temporarily closed. Later, the investigations reveal that although the bridges are designed according to Swedish codes, the provided shear reinforcement is insufficient for crack width control under service loads on the bridge. Therefore, it becomes imperative to evaluate the available crack width models and develop robust models for shear crack width prediction. A literature review of the available models for shear crack width is performed to identify the crucial parameters influencing shear crack width. Shear crack width is influenced by several parameters, but the most critical parameters are shear crack spacing, shear stirrup strain, principle strain in the cracked concrete and diagonal compression strut angle. Thereafter, various models available to evaluate these parameters are reviewed to understand their applicability and limitations.
This is followed by a study for the analysis of performance of the models with respect to the experimental observations. Based on the limited experimental dataset, it is found that the Zakaria et al. (2011) shear crack spacing model, and the fib MC 2010 (Model Code 2010) crack spacing model (for members with orthogonal reinforcement) provide a conservative estimate for the shear crack spacing in RC (reinforced concrete) beams. The predictions from the current EC2 crack spacing model are slightly unconservative. All the three crack spacing models take into account the influence of bond transfer length on the stress distribution in concrete and reinforcement. It is also found that the SMCFT (Simplified Modified Compression Field Theory), CFT (Compression Field Theory) and CCC (Compression Chord Capacity) model provide estimates for the shear crack angle with small deviations from the experimentally observed values. However, all these three models predict flatter (smaller) mean shear crack angles as compared to the experimentally observed values. The SMCFT and CFT determine the diagonal compression strut angle with a consideration of deformations of reinforcement (transverse and longitudinal) and diagonally cracked concrete. On the other hand, the CCC model predicts the diagonal shear crack angle based on the assumption that the horizontal projection of the first branch of flexural-shear crack is equal to 0.85d where d is the effective depth to the longitudinal tensile reinforcement. According to comparison with the experimental observations referred in this study, the CCC model provides a conservative estimate for the concrete contribution to shear resistance which is required to evaluate the shear stirrup strains. Using concrete contribution to shear resistance from this model, an engineering strategy to estimate the concrete contribution to shear resistance at service loads is proposed. Thereafter, five different models for mean shear crack width (the first three models with two variants each) and four different models for shear deflection are proposed. The comparison of the predictions from the mean shear crack width models with the experimental data reveals that a conservative estimate for the shear crack width can be made by equating shear crack width as the product of mean principle tensile strain in the cracked concrete and the shear crack spacing (ModelIIIB, Model-IV and Model-V). It is observed that the assumption of zero concrete contribution to shear resistance (shear-force transfer) at service loads (in B variants of Models-I, II and III) result in relatively higher predicted mean shear crack widths (as compared to the corresponding A variants) and therefore, more conservative estimates. Moreover, the assumption of mean shear crack angle equal to 45 degrees also leads to relatively more conservative estimates of mean shear crack width. Model-IV and Model-V seem to outperform other mean shear crack width models considering mean and consistency of the models together as a metric. The mean and SD of the predictions from Model-IV are 0.85 and 0.30 for the original formulation of the model. However, with the assumption of mean shear crack angle equal to 45 degrees, the mean and SD values are observed to be 0.37 and 0.13 respectively. It is found that a conservative estimate for shear deflection can be obtained by assuming a linear shear force versus deflection response for a slender reinforced concrete beam (Model-I). The ratio of the experimentally observed to predict shear deflection for Model-I is 0.85 with a SD (Standard Deviation) of 0.31. The proposed Models-IIIB, IV and V (in their original formulation) and Models- IB, IIA, IIB, IIIA, IIIB and IV (with an assumption of mean shear crack angle equal to 45 degrees) for the shear crack width and Model-I for shear deflection provide a conservative estimate for the range of experimental beam specimen data covered in this MSc thesis. These models (especially Model-IV for mean shear crack width and Model-I for shear deflection) seem to be potentially useful engineering models for use in engineering practice to evaluate mean shear crack width and shear deflection for slender beams with thin webs (for example slender webs of bridge girders). However, the models require further validation with an experimental study to assess and establish suitability for wider application in design practice.

This research focuses on the structural behaviour of an elastic supported reinforced concrete slab. Over the years, there is a tendency to realise industrial floors with large joint-spacings. The downside of a slab on grade with a large joint-spacing is that the risk of (uncontrolled) cracking due to a shrinkage load is higher, which often results in durability issues. In practice, the slabs on grade are generally designed and constructed based on experience by specialised floor companies and often with less than the theoretical minimum required reinforcement. This research aims to close the gap between theory and practice and to gain insight into the structural behaviour. Moreover, reducing the number of damages in slabs on grade. In the first part of this thesis, the stress development and crack risk in a restrained concrete slab on grade exposed to shrinkage is analysed. The restrained shrinkage stress in the concrete member is mainly influenced by the time-dependent properties of concrete and the degree of restraint of the slab. The most relevant degree of restraint for a jointless slab is by soil friction and depends on the slab length, soil properties and the vertical load like self-weight. From the sensitivity analysis in this research, it is shown that the middle section is fully restrained for slab lengths or joint spacings of 40 to 80 meters long for practical ranged values. The relaxation effect in concrete, based on the creep behaviour, reduces the restrained shrinkage stress over time. Stress reductions of 40% to 70% were found for practical values in the analysis after one year of shrinkage loading. The crack risk in indoor slabs on grade is the highest between two and twelve months after casting according to the findings in practice and this thesis. The early-age crack risk is relatively low for an indoor slab on grade compared to a concrete pavement because of the significant less influences of the environment. The crack risk can be reduced by composing a concrete mixture with a low relaxation coefficient, low concrete shrinkage, low Young's modulus, a high concrete cracking stress capacity and by reducing the degree of restraint of the slab. Secondly, the cracking behaviour of a fully restrained concrete tensile member with only reinforcement near the surface is analysed with analytical models and a finite element model. For modelling cracking in a restrained member initiated by an imposed deformation in the finite element model, the random field application is required. The random field application generates the spatial variation of the tensile strength of the concrete material. The random field simulates weak zones in the concrete member where crack localisation will be initiated. The downside of the random field application is that the crack pattern in the model is predetermined. The cracking behaviour is analysed for a shrinkage load, a point load and for both loads combined. In all the analyses, it is found that cracking in a slab on grade always results in a not fully developed crack pattern. A not fully developed crack pattern is characterised by the forming of additional cracks instead of widening of the existing cracks when the load increases. When cracking due to a shrinkage load in fully restrained members occurs, the imposed load decreases, which reduces the tensile force in the uncracked zone. Force reductions up to 73% were calculated after cracking in a five-meter long restrained slab. For an eccentrically top reinforced member, the first crack occurs at the bottom fibre and is uncontrolled. The tensile force in the reinforcement, in combination with the eccentrical position, induces a negative bending moment in the uncracked zone of the slab on grade. In combination with the restrained shrinkage load, this results in an axial tensile force and a negative bending moment in the uncracked zone after cracking. Over time, the shrinkage load increases and a flexural crack can be initiated at the slab surface. A point load induces a positive bending moment at the position of the load and a smaller negative bending moment next to the point load. After cracking due to the point load, an axial compressive force and an increased negative bending moment are present in the uncracked zones next to the point load. The sensitivity analysis on the behaviour by the point load showed that the principal stresses in the slab could be reduced by increasing the subgrade modulus, the slab height or by lowering the concrete stiffness of the slab. The load combination analysis showed that an axial tensile force and a negative bending moment are present in the uncracked zones. It is found that a higher point load only increased the slab deflection and the number of flexural surface cracks and not the crack width. However, a higher shrinkage strain load did slightly increased the maximum crack width but mainly increased the number of cracks. Therefore, it is concluded that the slab on grade remains in the cracking phase for the combined loading situation. Both in this research and the literature, it is stated that crack width calculations of a restrained concrete slab imposed by a shrinkage load results only in indicative values. The analysis of the cracking behaviour showed that cracking at the surface is induced by an axial tensile force in combination with a negative bending moment. Therefore, estimation of the crack width can best be performed with the CUR-65 model based on an enhanced cracking bending moment of the slab on grade. Because accurate crack width calculations are not possible, recommendations are made on how to reduce the crack widths in a jointless slab on grade. A slender slab with a low concrete tensile strength is advised to reduce the internal cracking force and bending moment. Also, it is found that a lower shrinkage load leads to a smaller crack width. Therefore, a shrinkage reducing concrete mixture is advised. Moreover, high bonding properties between the reinforcement and concrete reduce the crack width, which can be realised with reinforcement with a small diameter and mesh-size. Finally, reinforcement is the most effective in controlling surface cracks when placed in the top fibre of the slab. It is concluded that for a slab on grade, replacing the conventional reinforcement with steel fibre reinforcement does not reduce the required amount of reinforcement for controlling surface cracks.

This Master Thesis is about the comparison of the effective concrete tension zone height determined with either finite element models using DIANA or Eurocode 2 and Jones method. The effective reinforcement ratio is an important parameter for the determination of the crack width and is depending on the effective concrete tension zone height. Therefore a better understanding of the effective concrete tension zone height can be beneficial for the determination of the crack width. Especially for structures with multiple layers of reinforcement. The finite element models have been used to check whether the assumptions made in Eurocode 2 and Jones method are correct for the determination of the effective concrete tension zone height.

Tourism is one of the main sources of income of Jamaica. . However, at the moment the beaches are retreating. An example is the erosion of Hellshire Beach, showing a retreat of ten meters in only seven years. To preserve the beaches effectively, a new concept is requested. The main requirements of the system are wave attenuation and the marine life enhancement.

The literature study showed, a variety of coastal management techniques exist. However, none of those solutions are capable of attenuating waves and enhancing marine life in an effective way. Ranking criteria are given and the following concept groups are generated: boulders, gabions, marine blocks, big (open) blocks and 'lego' (interlocking) blocks. The Multi-Criteria Analysis shows that the big (open) blocks are the most viable and two concepts are designed within this concept group: a triangular and a hexagonal block structure.

In the hydrodynamic and wave models (Delft3D), a study is performed to find the relation between breakwater dimensions and wave attenuation. Also, three different conditions are modelled: daily conditions, hurricane conditions, and one-year storm conditions at the Hip-Strip in Montego Bay. Using the results from the hurricane model, the flow- and wave forces are calculated using the Morison equations for lift and drag. Three lay-outs for submerged breakwaters are tested in the model. This led to the final lay-out which is a combination of the three tested breakwaters.

Following the Delft3D models, a structural analysis is done with the flow- and wave forces from the Morison equation. The structural analysis focuses on the sliding and uplift of the submerged breakwater. The hexagonal structure shows a better stability than the triangular blocks in hurricane conditions and therefore chosen as the final concept. A sensitivity analysis is performed with regard to the friction coefficient, the force-time profile and the placement errors. The placement errors turn out to be crucial and a connection between the top block and the base is needed to retain stability.

The final dimensions (l x w x h) of the hexagonal blocks are 3 x 0.75 x 0.93 meter. The blocks can be made from a low strength class concrete and reinforcement is needed to provide strength during lifting. To enhance the marine life enhancement properties, fish condos of 4" and 6" are provided, the surface is made more permeable and the pH of the concrete is altered by curing.

The structure shows great future potential and can be built soon. It is a state of the art structure, the stability is high, it enhances the marine life, the final dimensions will precisely agree with the drawings and there is no need for a nearby quarry. However, to all this benefits, there is also a drawback; the cost. The cost is a multiple of the conventional armour stones. Recommendations are given to bring expenses down. Placement in shallow water is preferred and replacing steel reinforcement by fibre reinforcement is worth investigating. Those recommendations will decrease the cost and will increase the viability of the Honeycomb block concept.

This thesis focuses on the dynamic analysis of liquid storage tanks subjected to seismic excitation with its primary aim being the development of a semi-analytical model able to predict this dynamic response accurately. In engineering practice, there are two primary methods to solve this problem. Numerical models based primarily on the finite element (FE) method, can treat the dynamics of the tank-liquid system with high accuracy. However, this comes at the cost of low computational speed; these models are slow and sophisticated finite element packages are required that can deal with both the structure and the liquid with equal rigor. On the other hand, analytical methods exist to solve the tank-liquid interaction problem. The latter, although computationally fast, lack of accuracy and can treat only the most simplistic configurations regarding the structural type. In this thesis, we aim to develop a semi-analytical model that combines the strong elements of both approaches, i.e. it is computationally fast and accurate.

In the first part of the thesis, a two-dimensional case is analyzed in which the tank is composed out of three beams representing the plate and the wall of the tank, while the liquid is assumed two-dimensional. With this model, the semi-analytical solution method is established. The method is very straightforward and is based on the principle of dynamic sub-structuring which is valid for linear systems. The response of the structure, i.e., the three interconnected beams, is expressed in terms of the in-vacuo beam modes; a modal basis that is convenient since different modes are orthogonal to each other. The liquid motion is expressed as a superposition of two or three potentials each of which, in turn, is also shown in terms of modes. By representing the response of each sub-structure in terms of an orthonormal set of modes, the behavior of the system is spatially fixed, and the remaining unknowns are only the modal coefficients representing the multipliers of the various modal shapes. The latter is obtained by enforcing displacement compatibility conditions at the liquid-tank interface and by satisfying the forced equations of motion of the structure. The results of the adopted solution approach are compared against known results in the literature for validation purposes.

With the developed three-dimensional model a parametric study is conducted in order to determine the influence of tanks dimensions, soil flexibility and wave speed on the structural response. Results are compared with others available in the literature in order to validate the model. The present model can be easily extended to include more complicated structures, e.g. horizontal tanks and tanks of different geometry. Finally, the model can be amended by a more accurate representation of the soil in terms of a three-dimensional layered continuum by merely adding an extra sub-structure to the system (the layered soil) while keeping the same solution approach.

Zeeland, located in the south west of The Netherlands, has suffered major casualties and damage due to the flood in 1953. After the disaster, the Dutch Government appointed the so-called Deltacomittee, provided with the task of advising on the execution of the Deltaplan. As part of the Deltaplan, North Sea estuaries has been closed off from the North Sea in order to provide sufficient safety against flooding in the future.
The 11000 hectare Lake Grevelingen was one of the closed off North Sea estuaries. Two dams and two islands enclose the lake and prevent fresh water flowing in. Characteristic of former estuaries are deep gullies that remain intact as any kind of sediment transport is prevented. Contact with the North Sea is prevented due to the construction of the Brouwersdam, the western border of Lake Grevelingen. Direct after finishing the construction works of the Brouwersdam, Lake Grevelingen showed reducing oxygen gradients and thus a decreasing water quality, especially at the deep gullies. The construction of a stop lock, the Brouwerssluice, was conducted to prevent the further decrease of the oxygen gradient.
Today, more than 40 years after finalizing the Brouwerssluice, the low oxygen gradient tends to rise to shallower areas and reaches critical values. Measures, such as a water inlet system are due to be constructed.
Introducing a tidal range of 50 cm has shown to be a valid solution to overcome the decreasing water quality. The tidal range allows thinking of power generation when water flowing in or out Lake Grevelingen. Generating tidal energy produces revenues and provides renewable energy. Therefore, the design of a Tidal Power Plant in the Brouwersdam has become the goal of this thesis.
Since caissons were used to close Lake Grevelingen off from the North Sea, as a starting point, it has been determined whether these caissons allow reusing with a new function; forming the powerhouse of a Tidal Power Plant. Mainly due to the concrete cover of the caisson, has shown to be inappropriate. Adapting the caissons becomes expensive and very time-consuming.
The starting point of the power plant construction was found in the turbine dimensions. In total six turbine types have been analyzed. Based on their efficiency, fish friendliness and ability to generate power in two directions, two optimal turbine types for low head power generation have been found: free-stream (Tocardo) and a modified bulb turbine (Pentair Fairbanks Nijhuis).
Due to the low head differences between lake Grevelingen and the North Sea, maximum energy generation will be required even for very low head differences. Hence, turbines able to generate energy at such low head differences will be required. In the Preliminary turbine design, two turbine types provided the most promising features: The Pentair Fairbanks modified Bulb turbine and the Tocardo free-stream turbine.
A total cross-sectional discharge area of 960 m2 would lead to a tidal range of 50 cm at Lake Grevelingen. Applying in total 18 turbines in a squared sluiceway with an inner space of 8.24 meter allows introducing a tidal range of 50 cm at the lake.
The free-stream turbine has already proven to generate power in low head environments in previous projects. The PFN modified bulb turbine has not yet been tested on such scale, but due to the expected higher efficiency rate, the energy generation of the PFN lies supposedly much higher than the Tocardo free-stream turbine. Therefore, it has been decided to temporarily apply the free-stream turbine until the PFN turbine has shown to meet the fish friendly requirements while ensuring high efficiencies. With current knowledge, the annual production of the Tocardo and PFN turbine has been estimated at 20 GWh and 80 GWh respectively. The energy production of the freestream turbine is based on the tidal data obtained from 2016. The same tidal data has been applied to the PFN turbine while accounting for the sea level rise as well. Since it is expected the PFN turbine will be in commission at 2030, an estimated sea level rise of 25 cm has been added to the 2016 tidal data.
The thickness of the concrete members in the preliminary design has been set at 500 mm. The conceptual design of structural elements has been dedicated to checking the assumption. In total four base cases have been studied, providing local and global forces emerged from uneven bedding of the rubble foundation layer. The rubble foundation layer functions as a bed protection foundation on which the Tidal Power Plant is located.
The influence of uneven bedding of the rubble foundation bed has been computed by considering the Tidal Power Plant as a beam on an elastic foundation. Due to an uneven bedding, one-dimensional base cases Hogging and Sagging are introduced. Sagging represents a beam on elastic foundation subject to a reduced foundation stiffness at the midsection of the beam. Hogging has been described as the opposite situation of sagging, a reduced bedding stiffness at the beam edges.
The structure’s strength has been determined while applying the hogging and sagging bases cases together with external and local forces. The external forces emerged from the hydraulic pressures in transverse direction and lateral earth pressures in longitudinal direction. The local forces concern the self-weight of an element or locally applied loads, such as the ballast load or road construction. The bending and shear resistance of the concrete members has been checked accordingly.
In addition to the forces obtained from hogging and sagging, a coupled 2-dimensional approach has been applied. Two base cases have been considered in the 2-dimensional plane. The uneven bedding induces the rise of torsional moments in the beam on an elastic foundation. The torsional resistance of the concrete members has been checked. Together with local and global one-dimensional forces, the governing reinforcement ratio has been determined for relevant concrete members. Combining the findings of the one-dimensional approach with the two-dimensional approach has resulted in reinforcement ratios exceeding 3%. Comparing this with the 1 % economical reinforcement ratio value, it has been concluded the 500 mm thickness of the concrete member is insufficient.
In further analyses, it is recommended to provide a cost estimation including revenues made from the energy production. The feasibility of the Tidal Power Plant will be determined by this cost estimation.

Soil-mix walls are subsoil walls, which are constructed by in situ mixing of soil
with cement and water. The technique was initially used as a ground improvement
technique and is now being developed as construction method for walls
with a structural purpose. Currently these walls are reinforced with large steel
profiles, which requires a large quantity of steel. Replacing the profiles with
bar reinforcement might lead to a decrease in required material quantity and
thus a reduction of material costs.
There are multiple aspects which influence the possibilities and limitations
of bar reinforced soil-mix walls. These include predictability of the material
quality, durability and cooperation between soil-mix and the reinforcement.
The aim of this project was to contribute to this research by analysing one
of the influential aspects. The specific goal of this research project was to
analyse the capacity of a reinforcement detail within a soil-mix wall and define
the governing failure mechanism. The research combined an experimental and
numerical approach to the subject.
The critical detail was chosen based on the Huybrechts et al. (2016), Ganne
et al. (2010), Dörendahl et al. (2004) and contact with soil-mix experts. To
model this detail in a finite element model, in 2D and 3D, material parameters
were derived from Denies et al. (2012a), Denies et al. (2014), Denies et al.
(2015a) and performed physical tests. The 2D models represented the most
critical sections of the detail based on the theoretical stress distribution. The
geometrical parameters of the reinforcement design were varified in the models
to provide insight in the influence of the design on the capacity.
The model results were used to define an preliminary set of design guidelines
for the reinforcement cage, related to the depth of the wall. Since only
the capacity of the detail is considered, these guidelines are not suficient for
a complete design of a bar reinforced soil-mix wall and can only serve as an
initial indication.
In conclusion, the reinforcement detail is most sensitive to failure due to vertical
splitting and has suficient capacity for acceptable wall depths. As stated
before there are multiple aspects relevant to the feasibility of bar reinforced
soil-mix walls. The predictability of the material quality, the bond with the
reinforcement and the durability of the soil-mix strongly influence the final
capacity and behaviour of the wall. Therefore it is important to perform further
research on these, and other, aspects to conclude on the total structural
integrity of an entire bar reinforced soil-mix wall.

The focus of this research is to provide solutions to the city of Campeche to decrease the
inundation risks generated by a hurricane with an occurrence of once in
fifty years. Campeche
is a city located at the Gulf of Mexico on the Yucatan Peninsula. The rapid growth of the
city is one of the reasons it is having troubles with the water and flood management of several
areas throughout the city. Although the municipality has already executed some improvements
to the drainage system during the last years, it is still lacking to cope with heavy rainfall and
storm surges due to hurricanes at several areas in the city.
In order to gain a better understanding of the location and the way it works in Campeche a
location, stakeholder and political analysis have been performed. Boundary conditions, program
requirements and preferences have been formulated based on this analysis. By examining
hurricanes over the last decades, a hurricane has been simulated with an occurrence of once in
the
fifty years. In the situation characterisation the city has been divided into several catchment
areas to determine their vulnerability (expressed in total amount of water accumulation), taking
into account the capacity of the current drainage system in the event of such a hurricane.
Four solutions have been chosen to elaborate. In this elaboration, calculations have been performed on the design and construction. For the implementation of the options suitable locations
have been determined and the possibilities and risks have been defi
ned.
In order to test the elaborated solutions on socioeconomic factors in combination with ecology,
safety and politics, a multi-criteria analysis has been performed. It can be concluded that all
options differ a lot from each other. Every option tackles another side of the problem and
therefore they score on totally different aspects. In the discussion, it is further elaborated what
the supplementary advantages and disadvantages of the proposed solutions are. Using this, the
integral system of water management measures is considered.
A few
fields can be found on which could be made an improvement in the future. Firstly,
the political system requires short term measures to count on enough support. Besides, citizens
should be kept informed and have to be made aware of the flooding problem. Drainage expansion
needs to take place in order to relief the most crucial parts in the city from their excess of water
during extreme weather conditions. Lastly, when expanding the city, the amount of green space
and inundation risks of the concerning area should be always kept in mind.

The out-of-plane behavior of unreinforced masonry walls subjected to lateral loading is a complex structural problem. This thesis focuses on the stability of URM walls in a building system under seismic loads that are comparable to those found in the Groningen scenario. The investigation is carried out by addressing both the physical and the geometrical nonlinear nature of the rocking mechanism.

The aim of this thesis is to investigate the behavioral differences of walls that have different load transfer mechanisms and identify a simple engi- neering model for a construction joint that connects these two different wall types.
Within the text; First, the problem description is provided among with a simple yet reliable soil modeling for finite element method, to illustrate the excavation work. Then, six engineering models have been constructed and analyzed and results are compared. Phased excavation in layered soil is performed by shell and interface elements provided by the FEM package Diana 10.1. In addition, the section forces are estimated for an upper and lower bound given for different wall mechanisms. To conclude, the criti- cal construction stage and the critical depths are reached. Expected section forces are computed and compared with the capacity of the critical con- struction joint.
This thesis highlights the reliable and simple modeling of a laterally supported phased excavation analysis. Furthermore, it outlines the factors effecting the resulting forces from different load transfer mechanisms and concludes that the critical section subject to this thesis is safe with the given conditions. . . .

Shells tend to be thin because their curvature enables them to carry distributed loads as membrane forces. The property of thinness stems from shells’ capacity to store membrane strain energy without much deformation. As a result, buckling failures often govern the design of shell structures. These buckling failures usually start locally, at a location where a combination of curvature and membrane forces is met. Moreover, shells tend to be imperfection-sensitive structures, that is, real-life shells (with initial geometric imperfections) usually cannot resist loads as high as the theoretically predicted critical buckling load. Advanced finite element analyses can accurately predict these so-called nonlinear buckling loads but require significant time and computation effort. On the other hand, current design equations are simple yet highly inaccurate and often penalize strength significantly. This treatise caters a Python script that executes nonlinear finite element analyses (using ANSYS Mechanical APDL) to generate a database of the nonlinear buckling loads of shell portions with varying membrane forces, curvatures and magnitudes of initial geometric imperfections. The aim, beyond the scope of this treatise, is to perform a parametric regression on said database to device design equation(s) that accurately predict the nonlinear buckling load of linear-elastic shell structures with initial geometric imperfections based merely on the linear elastic results of a geometrically perfect shell model.

In this study the cracking and debonding behaviour of cementitious screeds bonded to concrete bearing floors is
analysed. In order to obtain insight in this behaviour research is performed to the surface tensile strength of concrete,
the bond strength of screeds on concrete bearing floors, the behaviour of screeds during shrinkage and the methods to
determine the bond strength. This research is carried out by a theoretical study in which the screed shrinkage
behaviour as well as the screed / concrete behaviour during testing of the bond strength is analysed by means of
analytical and FEM studies. Besides this practical experiments are performed to obtain insight in the influence of
different parameters on the surface tensile strength of concrete / the bond strength of screeds on concrete bearing
floors. Furthermore practical experiments are executed to study the influence of different parameters on the outcome
of a preferred bond strength testing method.