A transition towards a circular economy is proposed by initiators like the Ellen MacArthur Foundation and architect Thomas Rau, in order to preserve and enhance natural capital, optimise resource yields, and minimise system risks. A circular economy seeks to ultimately decouple global economic development from the consumption of non-renewable resources, and will eventually result in an economy of services. In this transition, the construction sector plays a major role because it is responsible for 50% of the total resource use, 40% of demolition waste and 35% of CO2 emissions.
The design of the façade system of a building which is offered as a service is essential. Assembly and disassembly of components of such a building occurs more often compared to traditional buildings, so the components and elements have to be designed so that they can facilitate this. This is especially true for the components of the façade which, due to the relatively short lifespan of a façade have to be flexible. To help incorporate circular principles in the design, a new method or tool is needed to help making design decisions and compare different alternatives. The main objective of this master thesis is to investigate the suitability of cold-formed steel components for circular façade design and to develop an assessment method to measure the degree of circularity of façades. Current assessment methods for determining the circularity of products either focus on the environmental impact or the flow of materials and protecting existing value, and not on the degree of circularity related to certain design options. Also, there is no method which focusses specifically on façades.
A circular economy is restorative and regenerative, and aims to keep products, components, and materials at their highest utility and value at all times. This is achieved by controlling finite stocks and balancing renewable resource flows, circulating products, components, and materials, and designing out negative externalities. Circular design criteria are derived from the design strategies Design for Disassembly, Design for Adaptability and Modular Design. Currently used façade systems do have the potential to be used in a circular economy, provided that the design criteria for circular use are met.
During the Case Study two designs are proposed: a traditional façade system which uses sandwich panels, and a façade system which uses façade panels designed based on a concept for roof panels developed by CFP Engineering (two alternatives). The aim of this case study is to investigate the suitability of the newly developed façade element for circular façade design. Additionally, it will serve as input for the assessment method which is illustrated later in this thesis, and set boundary conditions for the comparison of the life cycle costs and level of circularity.
The most important design parameters to determine the circularity of a façade system are: the amount of materials used, the possibility for reassembly, the environmental impact of the system, the amount of reused and renewable materials, the availability of information and the amount of toxic materials. These parameters can be measured by calculating the Façade Circularity Indicator which, as the name suggests, cannot be considered an exact value. The Façade Circularity Indicator originates by combining an existing method (Material Circularity Indicator, developed by the Ellen MacArthur Foundation) with research on Design for Disassembly (Durmisevic, 2016). A prerequisite of this method is a Life Cycle Assessment calculation. The method can be used during the design phase to help making design decisions. Based on the Life Cycle Assessment, the environmental costs of the traditional façade system are 22% higher than the environmental costs of the case study alternatives, which makes the traditional façade system less suitable for use in a circular economy. When the mass of the components is used as a weight variable, the Façade Circularity Indicator of the traditional façade system is 9 to 12% lower than that of the case study alternatives. When environmental costs are used as a weight variable, the Façade Circularity Indicator of the traditional façade system is 54 to 60% lower than that of the case study alternatives. This also indicates that the traditional façade system less suitable for use in a circular economy.
As an overall conclusion, it can be stated that cold-formed components are suitable for use in circular façade design because of their relatively low weight, low life cycle costs and the possibility to (dis)assemble them with relative ease. Furthermore, an indication of level of circularity of façades can be given based on a combination of the Material Circularity Indicator and Design for Disassembly factors.
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For the design of a steel sheet pile, verification checks should be done on multiple failure mechanisms. One of the failure mechanisms which should be checked is the check on global buckling. This is a mechanism in which the deformation of the pile is enlarged due to the normal or vertical force. With the enlargement of the sheet pile, the soil must be displaced as well, which results in extra resistance against global buckling. However, the check to this mechanism stated by the Eurocode is based on the so called critical global buckling load, which is currently based on the stiffness of the sheet pile. The resistance delivered by the soil is fully neglected in the check on global buckling, which gives that it is thought that this check is too conservative. It is studied how the influence of the soil can be taken into account to the global buckling mechanism. This is done by describing the background of the current check, followed by stating possible methods to determine the influence of the soil. By the use of calculation program’s D-sheet pilling and Plaxis 2D, some examples are calculated in which the proposed methods are compared with the current method. From those examples, it was found that the check on global buckling might be significant lower if the influence of the soil is taken into account. ... Read more

The weirs in the river Meuse reach their theoretical lifespan. The weirs were built in the early 1930s and now one is faced with a replacement task. Various studies have been carried out in recent years on the future of the weirs in the river Meuse. This concerns research into the entire weir system, different types of weirs and the way in which the current weirs should be replaced. This study does not focus on one specific task, but focuses on various aspects that are important for the replacement task, both “soft” and “hard” technical aspects. The first aspect is to find a suitable assessment framework that a new weir must meet. This assessment framework has been developed by means of literature research and interviews with specialists from Rijkswaterstaat, resulting in a risk and opportunity plan especially for weir structures. The assessment framework thus forms the basis for finding both a suitable weir type and a suitable solution for construction. A variant study has been carried out into different weir types. The considered weir types are delineated into a conventional variant, the flap weir, and three innovative variants, namely variants with inflatable technology. The steel-rubber gate, also known as the Obermeyer weir, scores best. This weir type consists of air-filled bellows that inflates and deflates the flaps. It is distinctive in terms of discharge capacity, nuisance and ease of maintenance.
The next phase is to make a conceptual design. A new weir regime has been developed on the basis of several considered weir configurations. A weir configuration with two weir spans of 50 m weir, each with 5 separate flap-bellow components has been designed. Furthermore, the weir sill has been designed with a length of 34 m. Based on the design loads on the bottom, a soil protection has been designed. A block mattress with a geotextile as a filter proves to be a suitable soil protection. The downstream length of the bottom protection is designed as a total of 50 m. Thereafter the forces in the membrane are determined, after which a suitable type of membrane is designed.
The last phase of this research focuses on finding a suitable solution for construction for the new weir in Linne. Three different construction methods have been developed, in-situ, side channel and prefab. For each method, the (global) weir dimensions are verified for the governing load situations. Ultimately, a suitable construction method is selected on the basis of an overall cost indication and assessment criteria, derived from the assessment framework that has been compiled in the first phase. Construction variant C, the prefab solution, scores best. It is an innovative solution in which the entire weir, including flap and bellow elements, is built in a construction dock upstream of the current weir and then transported using pontoons with winches. The major challenges of this construction method are the floating transport where the enormous weir construction must not be damaged, the coupling of the air supply pipes to the compressors in the abutment underwater by divers and the guarantee of a good transfer of forces from the weir sill to the bottom. On the other hand, there is considered to be a great advantage over the other variants in terms of, among other things, costs and construction time. The solution is therefore proposed as the implementation solution for the Obermeyer weir to replace the current weir in Linne.
In addition to this study, a strategy has been developed to deal with uncertainty in design as a depth study. The case of the bottom protection for the new weir has been used to apply this strategy. Different stability relations have been compared that come to the required nominal stone diameter. Based on a consideration of the impact in costs, impact on failure and risk mitigation measures included in this strategy, a broadly-based choice can be made for the design of the soil protection. ... Read more

For calculation of the resistance of a composite slab against the transverse shear force, the Eurocode 4 (composite structures) simply refers to the calculation procedures of the Eurocode 2 (concrete structures). It is assumed that the composite slab consists out of a consecutive range of concrete ribs in its width direction, which are solely responsible for resisting the transverse shear force. To calculate the transverse shear capacity of these concrete ribs, an empirical formula is used that was originally derived for regular reinforced concrete beams (without stirrups). However, the concrete ribs of the composite slab are created by the profile of the steel deck, making that each concrete rib is accompanied by two steel webs on the sides. According to the Eurocode 3 (steel structures), these webs of the steel deck have their own transverse shear capacity, which is neglected by the current design approach defined in the Eurocode 4. Besides, the interaction between the steel deck and the concrete may lead to an even higher transverse shear capacity of the composite slab. In this thesis, the aforementioned two aspects, which are currently overlooked by the design principle of the Eurocode 4, are further studied by means of non-linear finite element modelling.

The validation of this empirical formula of the Eurocode 2 for calculating the transverse shear capacity of the concrete ribs is the first point of interest. From the finite element analysis (FEA) of the concrete section of ComFlor 210, it is concluded that the prediction of the transverse shear capacity by the Eurocode 2 is unnecessarily conservative. The study suggests to use the mean width of the concrete rib (b0) in calculation, instead of the minimum width in the tensile area of the concrete rib (bw), as an improvement to the method of the Eurocode 2.

In the next stage, the contribution of the steel deck to the transverse shear capacity of the composite slab is studied. The exact bonding properties between the steel deck and the concrete (at the interface) were not clear when the finite element model was developed, so some assumptions had to be made. When assuming that the steel deck can’t separate from the concrete and the relative slip is restrained in longitudinal direction by the embossments, an increase of 131.6% in transverse shear capacity is found. Because of the assumed interface properties, the steel deck contributes to the total transverse shear capacity in the following ways: it resists a part of the transverse shear force in its webs; it acts as reinforcement to the concrete like a longitudinal rebar; it acts as reinforcement to the concrete like stirrups. However, whether this stirrup-functioning of the steel deck’s webs is representative for the actual transverse shear behaviour of deep composite slabs is being questioned, because it relies on the assumption of no separation at the interface. Therefore, a second FEA of ComFlor 210 is executed in which the interaction between the steel deck and the concrete is neglectable. Still, an increase of 51.4% in transverse shear capacity is found, which can be considered as a lower bound value.

At last, from the FEA results of this thesis, it can indeed be concluded that the current Eurocode 4 provides a unnecessarily conservative calculation method for the transverse shear capacity of ComFlor 210. However, using a simple engineering model that adds up the partial resistances of the concrete ribs and the steel deck’s webs, gives a better prediction while still being safe. For the partial resistance of the concrete ribs, the empirical formula of the Eurocode 2 is used, but this parameter bw is substituted by b0 as already mentioned in the foregoing. For the partial resistance of the steel deck’s webs, the procedures of the Eurocode 3 are followed. ... Read more

At this moment hydraulic structures are designed based on a simple method: the Dynamic Amplification Factor (DAF) method. This method does not consider the full dynamic interaction between the wave impacts, structure and water. The research project DynaHicS focusses on the dynamic behaviour of hydraulic structures, taking into account fluid-structure interaction (FSI). The main goal of the DynaHicS project is to develop new design guidelines to identify dynamic behaviour of hydraulic structures, so that more economical designs can be made in the future. The master thesis focusses on improving the current design method, which can contribute to the development of a new design method for hydraulic structures in the future. The present design method, the DAF method, is extended in time and space. This is done by developing a method to determine the force-time signal of multiple wave impacts, whereby the results from scale model tests are no longer required. In this method the spatial variation (height and width) of the wave impact force over the structure surface is taken into account. ... Read more

The building and construction sector play a key role in achieving a sustainable development. In European countries, buildings are responsible for 40-45% of energy consumption, leading to significant amounts of CO2 emissions. The implementation of reusable structures lead to less waste and harmful emissions to the environment. The main purpose of this thesis is to analyse and evaluate the use of a new type of demountable shear connectors, resin injected bolts, in steel-concrete composite structures through push-out tests. Steel-concrete composite structures are commonly used in flooring systems of offices, car parks and bridge decks throughout the world. The most widely used shear connectors are welded headed studs. Even though they are inexpensive and extended research has been conducted about their application, welded headed studs do not allow for the demountability and reusability of the structural components. An innovative type of shear connector consists of a coupler and a bolt which are embedded in the prefabricated concrete deck. The assembly of the concrete deck with the flange of the steel section which has oversized holes is achieved through resin injected bolts. Resin injected bolts are bolts in which the cavity formed by the clearance between the bolt and the hole is filled up with resin. Large hole clearances allow for fabrication tolerances and lead to a faster execution. Push-out tests were conducted in the laboratory in order to examine resin injected bolts in terms of shear capacity, stiffness and ductility. Two different test configurations were created, one with resin injected bolts and the other one with reinforced resin injected bolts. For each configuration three specimens were tested which were nominally identical, one was loaded until failure using displacement control and the other two were loaded initially in force-controlled load cycles and then until failure. The results obtained from the experiments are compared with the results from researches conducted on other types of demountable shear connectors. FEA models were developed with the same geometry, materials and loading as in experiments using the ABAQUS software and push-out test were performed in order to check the validity of the experimental work. In addition, a parametric study was conducted using FEA in order to evaluate the influence of certain parameters on shear resistance and stiffness. The parameters considered are: the concrete strength class, the bolt diameter, the bolt strength class, the embedded bolt height, the hole diameter of the steel section, the effect of the L-angle profile and the injection material. ... Read more

The increasing number of vehicles does not stop, axle loads get higher and wheel contact surfaces have decreased causing bridges to show significant fatigue damage. Demolishing and building a new bridge is out of the picture due to the current ideas on sustainability and environmental impact. Therefore renovation is necessary, as much of the existing structures should be reused in the design of a new structure. This results in massive challenges especially in the design of new movable bridge leaves which should reuse the pillars and foundation of the current bridge. The weight of the new movable bridge is limited to the same or even less than the old one, but should outperform it by many years. Parametric models have been created for both bridge types, orthotropic and hybrid, using finite element software RFEM to quantify this added. Both bridge models have been exposed to the same load cases stated in the Eurocode for traffic loads and fatigue loads. Maximum deflection and stresses have been verified in the steel of both bridges for the traffic loads. The sandwich panel has been verified for buckling and fatigue using a local model. The fatigue load cases have been used to verify the bridges steel frame. Global fatigue details in the connection between main girder and crossbeams have been investigated. Results showed a clear favour towards the hybrid bridge for all of the spans and widths investigated. The difference in weight of the hybrid bridges showed a decrease of 15 to 30% as opposed to the orthotropic steel bridge. This decrease in weight was mainly caused by the difference in deck structure. The sandwich panel, with a weight of 85 kilograms per square meter, shows far less weight contribution in the hybrid bridge than the stiffeners and deck plate, with a combined weight of 256 kilograms per square meter, have in the steel orthotropic bridge. A cost comparison showed that the OSD bridge and hybrid bridge are competitive in pricing in an early design stage. However there are many uncertainties that could result in one of the bridge types being significantly more expensive than the other. More experience with FRP and the hybrid interaction is needed to create better cost indications in such an early design stage. The environmental impact showed a difference ranging from 10% to 30% in favour of the hybrid bridge for both the CO2 impact analysis and the life cycle analysis by GWW. This difference was obtained when considering the production of the movable bridge including the counterweight and span. The difference is mainly due to the large amount of steel needed for the bridge leaf of the steel orthotropic bridge which also means that more material is needed for the counterweight. Although further research is necessary, this report shows the added value of hybrid bridges with full hybrid interaction and creates a step towards more use of hybrid steel and fibre reinforced polymer structures.
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When designing a construction pit adjacent to a navigation channel, the event of a ship colliding with the structure is something to take into account in the design of the pit. However, several aspects regarding ship collisions, i.e. the probability of occurrence of a collision, the magnitude of the collision force and the influence on the safety of the pit, are uncertain. The goal of this research is to develop a method to determine the safety of a temporary construction pit. The Blankenburg Connection, which is being built by BAAK, is used as a case study in this thesis. The construction pit in this project is located in the Scheur and has to deal with a busy navigation channel. The end-wall of the pit is a temporary wall, as it has to be removed in order to to be able to float a tunnel element to the middle of the channel.A Bayesian Network is used as a method to take into account all the different parameters influencing the probability of collision. When comparing the outcome of the model with values based on historical data for the Scheur, it can be concluded that the model predicts the probability quite well. A small difference can be noticed, which is probably explained by the fact of under-reporting. To determine the magnitude of the force, a Monte Carlo simulation is used. In this way a probability density function of the magnitude of the force is generated, giving insight in the occurrence of forces on the structure. The resistance of the structure is determined and mitigation measures to increase the safety of the construction pit are examined. ... Read more

Overheight vehicle impact is the impact of a heavy dump truck with a rigid raised trailer on the beam of a light-weighted and flexible temporary overhead sign structure. The structure is initially not designed to resist overheight vehicle impacts and the impacts occurring during construction works with impact velocities up to 40 km/h result in total collapse of the structure and, consequently, high risks with respect to road users’ safety. These serious consequences in combination with the need for revised design specifications and calculations have led to the following main research question:

“Is it feasible to create a design for the temporary overhead sign structure which is able to resist the overheight vehicle impact of raised trailers of dump trucks in work zones?”

In this research study, a load analysis is performed in order to approximate the impact load for the impact problem analysed assuming viscoelastic behaviour. The analysis demonstrated that the impact response is barely influenced by the dynamic effects in the structure. The mass of the vehicle and the global stiffness of the structure dominate the impact response. The impact load can be approximated based on the quasi-static approximation.

The current temporary overhead sign structure is not able to resist overheight vehicle impacts since the tensile resistance of the bolts of the column base plate connection is much smaller than the internal tensile forces it is subjected to as a result of the large overturning moment and the small internal lever arm in the connection. The behaviour of the structure could be improved by redesigning the column structure while focussing on increasing the internal lever arm and simultaneously limiting the transverse stiffness of the column structure and with that limiting the magnitude of the impact load.

Some design considerations are analysed demonstrating that it is a challenging task to develop a design for the demountable temporary overhead sign structure which is able to resist the overheight vehicle impact with a mass of 20,000 kg while limiting the structural mass based on the design requirements as provided by Rijkswaterstaat. The possibilities are limited up to an impact velocity of 7.4 km/h after replacing the original column with a lattice column structure.

The study is based on viscoelastic behaviour of the structure neglecting the influence of plastic deforming of the structure and vehicle during impact which may be of significance. Moreover, the actions of the driver during impact are not taken into account. Including the influence of these aspects and developing an optimized design for the structure might somewhat increase the currently approximated critical impact velocity of 7.4 km/h.

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The standard NEN 3215 contains a certain rain intensity for the rainwater drainage from roofs. By making use of the rainfall predictions for 2050, the consequences of this new intensity for the standard are analysed. Based on this analysis, a change of this rain intensity in NEN 3215 is recommended. ... Read more

A composite slab consisting of in-situ casted reinforced concrete on profiled sheeting, which is connected to steel beams by shear connectors, is a common structural flooring system in office and multi-storey car park buildings. The headed welded studs, which are most widely used shear connectors, are inexpensive and easy to install because they can be welded to the steel beam through the profiled sheeting. A permanent link is created between the composite slab and steel beams leading to a time-consuming and expensive deconstruction process.

Various types of bolted shear connections, recently investigated by various researchers in Europe, Australia, and the USA, provide a demountable alternative for the flooring system. A part of this thesis describes the experimental study using a bolted shear connector consisting of an embedded bolt/coupler and external bolt, originally developed for a prefabricated solid concrete deck.

A full-scale composite beam was tested in two life cycles under total working loads up to $200kN$ in a 4-point bending set-up. In addition to bolted shear connectors, a timber joist was embedded in the composite slab over the web of the steel beam. After the first life cycle, the timber joist provides the cut edge of the slab. The experiment is used to model behavior of the composite beam in the first life cycle. The slab is then cut, demounted, re-assembled and tested again in the second life cycle. The load was applied up to $200kN$ and finally to failure. Multiple arrangements of shear connectors were investigated in second life cycle to analyze the performance of a prefabricated composite beam

Experience gained by the experiments on the composite beam in the first and the second life cycles is accompanied by FE analysis. Recommendations for practical use of the demountable composite floor system are proposed based on the experimental and numerical findings.

In addition, an investigation in the field of BIM (Building Information Modeling) functionality in the context of demountable structures was conducted. In order to identify the potential benefits of the BIM a case study of an in-situ casted car park was conducted. A number of software packages were used to conduct structural analysis, modeling and visualization of the construction sequence. As a result of this case study, valuable experience was gained on an application of BIM technologies for a design of demountable and reusable structures. ... Read more

Nowadays football stadium encounter a lot of problems. Often services are outdated and the capacity is often too large or too small. These capacity problems especially occur in stadium that are built for major tournaments. When the tournament is finished, no appropriate tenants can be found and the stadium often remains empty. Another problem for a football stadium is the infrequent use. Most stadiums are in use only 20-25 times a year. Because these times are spread relatively even throughout the year, there are no large periods in which construction or refurbishment can happen. Besides all this, football stadium are unique structures, which require a large investment. Football clubs are often not capable of making such an investment.
A lot of possible solutions are researched in the past, such as a demountable stadium or a modular, that can easily be enlarged or reduced by adding or removing extra modules.
In this research another possible solution to these problems is drafted. By structurally uncoupling the grandstand structures and the roof structure, a lot of possibilities arise for the stadium. Grandstand structures can easily be enlarged or reduced, services can be refurbished without extensive construction and even movable grandstands can be designed. By moving the grandstand, the stadium can become suitable for other sports or events.
Besides the extra possibilities that arise, uncoupling the two structures also causes the opportunity to design both structures in a structurally efficient way. Bendingmoments can be prevented as much as possible,which makes the structure much more efficient. A lot of material can be saved, making the total stadium much cheaper.
In this research the roof structure is designed. The starting point in this design was that the structure should be optimal with regards to material usage. Different shapes are designed, which are compared by both structural and functional aspects. A few systems are selected that will be used for the preliminary calculations. In the preliminary calculations each of the different systems is calculated and optimised with Karamba and Galapagos. The total self-weights of the systems are compared and the best scoring system is analyzed further.
This final system is then modeled parametrically. Multiple parameters, like the height, centre-to-centre distances and the different cross-sections, are optimised to determine the optimal design with regards to material usage. After all parameters are optimised, the final design is calculated thoroughly. The results of these calculations are compared to similar structures to check if it really is an optimal design. From the results it follows that similar structures have a larger self-weight. This shows that the design in this research is indeed an appropriate alternative compared to more traditional stadium designs.
Besides the final design, also some design options are researched to see their influence on the structural behaviour of the roof structure. These design options are, for instance, a slightly different shape or a roof with a hole in it. These options can be seen as extras for the design. The determination of the structural consequences of these extras show how much they influence the total price of the system. ... Read more