Transitioning towards a more circular construction industry is crucial for achieving climate-neutral and fully circular operations by 2030. One significant contribution to this goal is fully utilising the reuse potential of prefabricated inverted T-girders. The primary challenge lies in adapting the inverted T-girder system to enhance the circularity of the girders. To address this, a comprehensive literature review is conducted to understand the structural response and disassembly challenges associated with the system, providing valuable insights into potential improvements. This study employs a numerical model based on the Finite Element Method using DIANA FEA to assess the impact of various design adjustments, specifically the removal of end transverse diaphragms and increasing deck slab thickness. The numerical model uses horizontal and vertical curved shell elements and is subjected to several critical load cases to determine the maximum stresses for different design parameters. The results indicate that eliminating the end transverse diaphragms has minimal impact on the distribution of longitudinal bending moments and shear forces. However, it causes a localised increase in support forces by 17\%. Additionally, significant differences are observed in the deck slab, necessitating an additional capacity of 16\% for transverse bending moments and 17\% for twisting moments. The study also examines the effect of skew angles to evaluate the applicability of orthogonal system findings to skewed systems. As the skew angle decreases, a greater proportion of forces and moments is absorbed by the deck slab rather than the composite girders. However, the mutual differences between systems with and without end transverse diaphragms generally vary by up to 2.6\%, indicating that the findings for the orthogonal system are broadly applicable to skewed systems as well.

This thesis investigates the potential of Basalt Fibre-Reinforced Polymer (BFRP) as an alternative to traditional steel reinforcement in concrete structures, with a focus on enhancing shear capacity. BFRP offers advantages such as higher tensile strength, superior corrosion resistance, and environmental sustainability. The study compares two alternative BFRP stirrup designs—braided BFRP rods and laminated unidirectional (UD) BFRP strips—with traditional steel stirrups through uniaxial tensile testing and displacement-controlled three-point bending tests on reinforced concrete beams. The results show that while BFRP stirrups improve the shear capacity of concrete beams, they do not yet match the performance of steel stirrups due to issues like reduced stiffness and stress concentrations in corner sections. However, BFRP stirrups demonstrated potential advantages in terms of weight efficiency, suggesting a promising role in sustainable construction. The findings underscore the need for further refinement in BFRP production methods to achieve consistent quality and better performance in structural applications.

There are about 70 prestressed concrete T-beam girder bridges built between 1953 and 1970 in the Netherlands. Ensuring the safety of these existing bridges under current traffic conditions is
imperative. Upon initial assessment of these existing prestressed concrete T-girder bridges, half of them didn’t meet the safety requirement specified by the design code even though they didn’t show any sign of distress during inspection. This is because the system behaviour of the T-girder bridges (i.e.) load transfer mechanisms such as CMA (compressive Membrane Action) and load redistribution were not considered, which could potentially increase the calculated strength capacity of these existing bridges. Therefore, a computationally efficient method for evaluating these bridges is needed.
This research addresses the challenge of accurately predicting the strength capacity of prestressed concrete T-girder bridges using a computationally efficient approach. The study involves modelling the 2D bridge deck in the horizontal plane using orthotropic plate elements and 2D individual girders in the vertical plane with non-linear material properties. The 2D bridge model was compared with a 3D linear bridge deck model, showing a variation in bending moment between 10% to 13%, sufficient for studying load effects. The 2D individual girder model built was validated using experimental data of the disconnected T-beam test of the Vecht Bridge, incorporating a quasi-Newton solution method with the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. The predicted load versus deflection curve from the 2D non-linear individual girder model closely followed the load versus deflection curve obtained from the experimental test results. To combine the 2D bridge deck model with the 2D non-linear individual girder model, an equivalent loading technique was developed by numerically solving the shear force distribution of the critical girder in the 2D bridge deck model. The staggered 2D Non-Linear Finite Element Approach developed utilising the equivalent loading technique accurately predicted the ultimate failure load of the connected T-beams (system behavior) within 10% of experimental values, despite neglecting the effect of end crossbeams. The 2D bridge deck model without considering crossbeam effects showed conservative stiffness estimates. Crossbeam inclusion in the model indicated significant improvements in stiffness, load distribution and redistribution. The 3D non-linear finite element model predicted 87% to 95% of the failure load of the connected T-beam tests [10]. The 2D non-linear individual girder model using the staggered non-linear approach predicted up to 96.5% of the ultimate failure load of the connected T-beam test, achieving this with a run time of approximately 18 to 21 minutes. Overall, the staggered 2D Non-Linear Finite Element Approach developed shows promise for preliminary bridge safety assessments offering a balance between computational efficiency and accurate prediction of strength capacity.

In the Netherlands, numerous bridges face reassessment. During this assessment, it is observed that in some cases, the applied shear reinforcement (stirrups) does not meet the detailing requirement given in the national annex of the NEN-EN 1992-2. This requirement, which states that the stirrups must enclose the longitudinal reinforcement to ensure adequate anchorage, is referred by the RBK. This guideline calculates the shear capacity by combining the concrete and the stirrup contribution. However, the contribution of the stirrups can only be included when the detailing requirement is satisfied. In this research, a case study is used in which stirrups are applied that do not meet this requirement. These stirrups are expected to still contribute to the total shear capacity. Therefore, the main aim of this research is to develop a model that can predict the shear capacity by including the anchorage influence of these non conforming stirrups.

In this research, a layered approach is modeled to determine the shear capacity. This approach divides the cross section into several layers, and each of these layers is individually analyzed with the Modified Compression Field Theory (MCFT). The next step in the development of the model is to implement the anchorage behavior. There are two rebar anchorages included in this research; the straight and hooked rebar anchorage. Separate approaches are used to determine the anchorage capacities, which are based on existing experimental research. In both approaches, the axial stress in the applied shear reinforcement could be limited to these anchorage capacities.

Due to the limited availability of experimental research on reinforced concrete beams with non conforming stirrups, this research includes a constrained validation of the model. Subsequently, the shear capacity of the bridge within the case study is predicted. The first cross section in the span region, where the hooked rebar anchorage is governing. As a result of the high anchorage capacity, little influence is observed in the shear capacity of this cross section. The straight rebar anchorage of the stirrup is governing in the support region. This type of anchorage has a greater influence due to the lower anchorage capacity compared to the anchorage capacity of the hooked rebar. However, in both cases, the predicted shear capacity of the model exceeds the concrete shear capacity based on the RBK. Therefore, based on these results, it can be concluded that there is still a contribution of the non conforming stirrups to the total shear capacity.

The proposed model within this research could be used to predict the shear capacity of reinforced concrete beams with non-conforming stirrups. However, for more accurate results, it is recommended to further develop this model to overcome its current limitations. Additionally, it is recommended to conduct more experimental research on these types of beams, due to the limited amount found in literature. Finally, it should be taken into account that the model in this research uses a conservative assumption that the crack is perfectly aligned with the non-conforming stirrup.

In the more than sixty years of experience in forensic structural engineering of Adviesbureau Hageman, damages in underground concrete parking structures repeatedly passed by. In a master study, mainly based on the comprehensive archive of Adviesbureau Hageman, an overview of the various damages that can be distinguished, is made and causes for the occurrence and measures to prevent them, are addressed. Furthermore, one category of damages, that is not limited to only parking structures, but generally occurring in concrete structures, is damage to concrete corbels. In order to investigate the behaviour of such corbels, finite element analyses are performed with the FE Code ATENA. Its behaviour in case of a corbel and support according to the Codes is investigated, but also in case of a support close to the edge and applied horizontal loading due to imposed deformations in the elements that are supported by the corbel. In the thesis the overview of damages in concrete parking structures and the study into the behaviour of corbels will be presented.

Concrete is widely used in civil engineering and despite its long history, accurate prediction of the hardening process, particularly in partially restrained conditions, remains a challenge. During the hardening of partially restrained concrete, residual stresses occur due to restrained deformations caused by factors such as heating/cooling and shrinkage of the concrete. Accurately predicting the development of these residual stresses during restrained hardening is critical for proper design calculations, as cracking must be controlled by reinforcement. However, predicting the development of these design stresses is complex and depends on a number of processes and parameters, including temperature development, development of mechanical properties and the degree of restraint. These stresses also decrease with time due to creep and relaxation, which further complicates predictions, especially when dealing with restrained concrete combined with shrinkage.

In addition, hardening concrete will eventually be subjected to external loads, resulting in additional stresses that may require additional reinforcement. However, when it is difficult to accurately predict the development of design stresses, approximations must be made. These approximations may either take full account of the stresses from both hardening and external loading, or reduce the residual stresses by some factor. Such factors may be based on design codes or rough estimates. Consequently, these approximations can lead to either over- or underestimation of the reinforcement required in the design, mainly due to a lack of understanding of the actual design stresses. Therefore, the research question investigated in this thesis is as follows:

What is the effect of applying time-dependent finite element analysis, including the combination of hardening processes and external loads, on improving the prediction of the development of design stresses for partially restrained concrete?

The research starts with a comprehensive literature review covering the stress development during hardening of restrained concrete, the current calculation methods and models and a validation experiment. The validation experiment, a Temperature-Stress Testing Machine (TSTM) found in literature, is modelled and the analysis results are compared with the experimental results to validate the accuracy of modelling the hardening of partially restrained concrete. A method is developed to accurately predict the hardening of restrained concrete using a combination of transient heat transfer analysis and structural non-linear analysis. This non-linear analysis uses a combination of time and load steps to apply the required degree of restraint. The finite element analysis, using measured thermal and material properties from the literature, shows good agreement with the TSTM experimental results.

In order to verify the accuracy of commonly used material models, the Eurocode and fib Model Code material models within DIANA FEA are compared with the results of the TSTM experiment. However, it was found that these material models have inaccuracies due to the use of large step sizes for the Kelvin chains that define the creep and Young’s modulus developments. Therefore, a viscoelastic material model based on the fib Model Code was developed and found to be more accurate. This material model was validated against the TSTM experiment and hand calculations. Although differences were found in the development of design stresses between the experimental results and the prescribed standards, these were mainly due to the difference in autogenous shrinkage and coefficient of thermal expansion.

Using the knowledge gained from the modelling of the TSTM experiment and the validated viscoelastic material model, a case study of the railway underpass in Leiden is performed. The chosen modelling approach is a time-dependent non-linear finite element analysis that includes all construction phases, hardening processes, and external loads within a 3D model of solid 3D elements. The model excludes concrete cracking, reinforcement and prestressing of the deck to limit complexity. This calculation method is expected to provide a more detailed insight into the development of design stresses and ensures high calculation accuracy and completeness compared to other methods. The use of a full 3D model was necessary to accurately model the temperature development in the hardening concrete, which has a significant effect on the design stresses…

Traditional approaches to noise barrier design often rely on outdated techniques and resource-intensive materials like concrete and steel. However, with sustainability gaining prominence, aligning noise barrier design with green construction principles becomes crucial. Structural optimization, aimed at minimizing material usage, emerges as a promising strategy to mitigate environmental impact. This study focuses on determining the optimal geometry of a noise barrier composed of low-tensile strength material, under the influence of self-weight and uniformly distributed lateral load.

The methodology employed addresses this question through a series of key steps. Beginning with a two-dimensional analytical form-finding process, optimal cross-sections are derived for the noise barrier. The application of uniform strength theory, known for its efficiency in generating material-effective structures, results in constant stress shapes. These solutions are validated using Finite Element Analysis (FEA) to ensure conformity with predefined stress criteria. Subsequently, numerical structural optimization is conducted to achieve minimum weight geometries that adhere to stress constraints, utilizing a penalty function. The validation process involves comparing numerically optimized geometries with analytical solutions, confirming their reliability and mutual consistency. This validated optimization approach is then extended to three dimensions, exploring the optimal combination of longitudinal profiles and varying cross-sections along the barrier.

Analytical solutions for 2D uniform strength cross-sections of the noise barrier differ based on load conditions. For self-weight, an exponential function describes constant stress, ensuring uniform compressive stress across the structure. Conversely, under uniformly distributed lateral load, a linear function depicts constant maximum bending stress along the height. The interaction between self-weight and lateral load results in symmetric geometries defined by specified constant tensile stress. A square root geometry guarantees constant zero tensile stress, offering advantages like reduced need for additional structural elements and practicality in real-world scenarios.

A significant distinction arises between 2D cross-section and 3D structural optimization regarding bending capacity. In three dimensions, the entire structure contributes to bending resistance by shaping itself. Releasing the rotational degree of freedom at the bottom support enables the generation of a corrugated longitudinal profile, enhancing bending stiffness. This corrugation distributes bending moments over longer spans, reducing stress and material requirements. Notably, the optimized corrugated profile exhibits enhanced bending stiffness, minimizing the impact of practical constraints.

In summary, this research provides insights into optimal geometries for free-standing structures, highlighting the efficiency of analytical and numerical approaches. The numerical optimization framework proves highly effective and efficient, contributing valuable insights to noise barrier design within a sustainable framework.

Previous earthquake reports have highlighted the high vulnerability of masonry walls to failure when subjected to the out-of-plane (OOP) loading. Particularly, this OOP failure is a significant cause of collapse in unreinforced masonry (URM) buildings, especially those with slender walls and large openings. Moreover, in the past they were designed with minor regard to seismic design concepts. In Groningen, the Netherlands, where the majority of houses are constructed using unreinforced masonry, there have been frequent occurrences of low-intensity seismic activity, causing pre-damage to the walls. Typically, the walls get pre-damaged in the in-plane (IP) direction due to low-intensity shakes and settlements, since the box-like behaviour is established when the forces are low. Box-behaviour refers to the case where there is a strong connection between orthogonal walls and a stiff rigid floor diaphragm. As a consequence, the walls experience the desired IP shear failure during seismic loading. However, research regarding the OOP performance of pre-damaged URM walls is limited, and existing studies have shown that IP pre-damage decreases the ultimate OOP load-bearing capacity of the walls. To address this gap, this report aims to conduct a preliminary investigation on the OOP strength of pre-damaged URM walls, considering both walls without and with openings. Notably, there is no existing evidence in the literature regarding walls with openings on this specific topic. The primary research question can be stated as follows:
How does the in-plane pre-damage affect the out-of-plane load-bearing strength of URM walls?

This thesis employs a numerical modelling approach to address the research question. The software package DIANA 10.5 is used, adopting a simplified micro modelling method with shell elements to simulate the behaviour of masonry. Bricks are modelled with continuum shell elements, while the mortar joints are modelled using zero-thickness interface elements. Also, the potential vertical crack in the bricks is considered using the interface elements. The validation of the numerical modelling approach is performed in two steps. Firstly, the mechanical properties of the numerical model are calibrated using small-scale material tests. In the second step, the calibrated parameters are directly applied to the numerical monotonic analyses of full-scale walls, and the results are then compared to experimental test results. The calcium silicate (CS) brick masonry tests, from material to structural levels, conducted at the Delft University of Technology are selected as benchmarks for the calibration and validation of the numerical model. A good agreement is observed between the numerical and experimental results for the IP walls in terms of initial stiffness, peak shear force, and crack patterns. However, the results for the OOP walls are significantly overestimated, with an average overestimation of 35% for the peak force. This is attributed to the differences in boundary conditions (full or partial rotation restriction), type of tests (cyclic or monotonic) and loading conditions (displacement control or load control) between the numerical simulation and experimental tests. Nevertheless, the crack patterns are in good agreement with the experiments.

The validated model is used to investigate the OOP performance of pre-damaged walls, including both solid wall (without opening) and wall with an asymmetric opening. Two distinct approaches are considered to simulate the response of the pre-damaged walls. In the first approach, known as the reduced-parameters approach, a model is created with varying properties: reduced stiffness and strengths are assigned to locations where cracks were observed during the IP tests, while regular properties are maintained in other locations. Subsequently, the model is subjected to OOP analyses. In the second approach, known as the sequential loading approach, the wall is initially monotonically loaded in the IP direction that represents the pre-damage of the wall. Then, the OOP load is applied while maintaining the IP pre-deformation until the wall experiences failure. The study considers four different states of pre-damage, ranging from minor to extensive damage. For the solid wall, the damage levels are based on the observed damage during the IP tests up to the maximum drift of 0.2%. On the other hand, the damage levels for the wall with opening are derived from the damage observed during the IP monotonic pushover numerical simulation up to the maximum drift of 0.14%.

For the solid wall, it is found that both approaches give same results for low pre-applied IP damages, up to 0.06% drift. The reduction of the OOP peak strength is almost negligible until this drift level. As the damage increases, the reduction of the strength also sharply increases. At the maximum of 0.2% IP-drift, 40% reduction of the OOP peak strength of the wall is observed in the reduced-parameters approach, while in sequential loading approach, the wall immediately failed resulting in negligible OOP strength because of the severe IP damage. For the wall with opening, similar to the solid wall, no measurable influence of the OOP strength due to minor IP damages, up to 0.06% drift, could be observed in both approaches. The maximum reduction that could be observed is approximately 15% at maximum of 0.14% pre-applied IP drift. In the sequential loading approach, as the level of pre-damage is increased, the pre-peak stiffness of the force-displacement curve decreases, as expected for a pre-damaged wall. However, the reduced-parameters approach does not show this reduction, which could be attributed to the pre-damage applied only at specific locations. For both types of walls, there is no significant difference in the crack pattern of the undamaged and pre-damaged wall. The well-known envelope crack pattern is obtained in both cases.

To conclude, the out-of-plane load-bearing strength of URM walls is significantly affected by the presence of in-plane damages. The impact is minimal under minor in-plane damages but increases rapidly as the damage becomes more severe.

This thesis limits the numerical analyses to monotonic loading. However, for future research, it would be beneficial to extend the analyses to include cyclic or dynamic loads, as they provide a more realistic representation of seismic loading conditions. Moreover, it is recommended to incorporate various boundary conditions for the OOP loading. For instance, the research could be expanded to include a C-shaped wall configuration, where the lateral edges are supported by return walls, a scenario commonly encountered in practice.

To stop the depletion of natural resources, reduce climate change and fight biodiversity loss a circular economy in 2050 is pursued. In the upcoming years a challenging opportunity arises. Many existing bridges and viaducts with bridge decks consisting of prefabricated concrete girders have to be replaced. These girders although not designed according to circularity concepts have potential to be reused in a new structure, which is in line with the highest achievable level of circularity. However, the construction market is not ready for this innovation. So, while current research still aims at the feasibility and suitability of the girders for reuse in new structures, this research aims at the next step of preparing the construction market. This is of high relevance because it speeds up the introduction process of the innovation and thereby safes girders from demolition.

In this research the focus is on the adaptions and modifications needed in the traditional design process to ensure a more frequent implementation of reuse of existing bridge girders in new designs. After a literature review into the type of bridge girders in the Netherlands, the structural feasibility, obstacles for reuse identified by the industry, the design process and environmental impacts a design approach is developed. Simultaneously to the development of this design approach a case study is performed to give a more practical view to design aspects. In this way the approach could be verified, adapted and modified.

The design approach consists of roadmaps, possible procedures and recommendations that guides project teams through each step of the system and preliminary design. In the case study a bridge deck for a 107 [m] long bridge, divided over 5 spans with reuse of existing girders is designed. The design approach is suspectable to changes due to experiences, gained knowledge and developments in the construction industry. Therefore, it needs review over time. The design approach concentrates on inverted T-girders but can be extended and applied to other girder types as well.

In conclusion, this research provides the foundations for a changed design approach that is needed to prepare the construction market for reusing existing girders. By giving guidance to project teams, the view shifts from using new girders to reusing existing girders. This is valuable to reach the environmental objective of a circular economy in 2050.

The development of an efficient and sustainable transportation system is crucial for the effective functioning of economies. Concrete, a widely used material for road construction, poses significant environmental challenges. A sustainable alternative is to use alkali-activated concrete (AAC) for road construction. However, the aggregates used in AAC are generally mined, contributing to the negative environmental impact. To address this concern, municipal solid waste incineration (MSWI) ashes, specifically MSWI bottom ash (BA), can be utilised to replace natural aggregates. Thus the construction of pavements using sustainable concrete facilitates its growing demand without burdening the environment.

This research focuses on the utilisation of municipal solid waste incineration bottom ash (MSWI BA) aggregates in AAC for potential application in pavements. The study was divided into five phases: aggregate characterisation, mechanical performance evaluation, long-term performance study, microstructure analysis, and life cycle assessment (LCA) analysis. The physical properties of MSWI BA aggregates indicated that the aggregates are porous and weak. Nonetheless, these aggregates showed comparable properties to natural aggregates and can still be used for pavement application. However, the metallic aluminium in the MSWI BA aggregates releases hydrogen gas leading to concrete cracking and swelling, thus, hindering its use in various applications. To address this concern, alkaline pre-treatment using sodium hydroxide solution was employed in this research. An optimal replacement level of 30% was chosen based on the effectiveness of the pre-treatment in removing metallic aluminium and the compressive strength of AAC containing MSWI BA aggregates.

In the next phase of the research, the mechanical and long-term performance of AAC with optimum replacement level was evaluated. The results demonstrated that the concrete satisfied the mechanical performance requirements for pavements. However, the freeze-thaw resistance of the AAC was below the norm requirement due to the air voids and associated cracking, which was confirmed through scanning electron microscopy (SEM) and X-ray computed tomography analysis.

SEM analysis revealed reactive phases in the MSWI BA aggregates and poor aggregate-matrix bonding for the coarser fraction compared to the finer aggregate fraction, leading to decreased mechanical performance. Despite these findings, the AAC containing MSWI BA aggregates satisfied the majority of the norm requirements, indicating its potential for road pavement application. However, evaluating the environmental impact of adding MSWI BA aggregates in concrete is essential. The life cycle assessment analysis demonstrated that the optimal MSWI BA sample exhibited better environmental effects, indicated by a lower environmental cost indicator value compared to AAC and ordinary Portland cement concrete samples with similar performance.

In conclusion, the pre-treatment method utilised in this research is optimal for a replacement level of 30% of gravel with MSWI BA aggregates. The AAC with 30% replacement level meets all the mechanical property requirements stipulated by the norm for pavement application, exhibits good air void distribution, and has limited environmental impact owing to the lower ECI value. This study evaluated the feasibility of applying MSWI BA aggregates in AAC for pavement application and showed promising results.

On the 17th of October 2021, a concrete grandstand element collapsed at the Goffert stadium in the Netherlands after a crowd jumped on it for 8 seconds. An investigation by an engineering consultancy firm concluded that the design loads in the building code are too low, raising questions about the safety of grandstand elements. Currently, no method to assess the reliability of grandstand elements exists.

This thesis presents a state-of-the-art method to determine the reliability of concrete grandstand elements. The reliability is assessed by performing a non-linear dynamical analysis. The element is modelled as a non-linear single-degree-of-freedom system. Excitation signals are synthetically generated by consulting the literature and by analyzing a data set of jumping crowds. A bi-linear force- displacement relationship based on technical drawings of the collapsed grandstand element is adopted and extended by a model uncertainty parameter which accounts for both the non-linearity of the analysis and the uncertainty related to the dynamical basis of the analysis. The reliability is determined through a Monte Carlo simulation: almost 100,000 simulations can be performed per assessment.

Out of the 100,000 simulations, 0 failed. This result is not in line with what happened; one failed out of only a few elements. This gives rise to two different investigations. On the one hand, the failure of the Goffert stadium grandstand elements has to be explained. On the other hand, the lifetime reliability of a grandstand element has to be determined.

The first assessment indicated that if the element’s resistance conforms to the technical drawings, there is no cause for concern regarding its reliability. Measurements on 23 other grandstand elements in the same stadium showed a high variation in the concrete cover. The collapsed element was, therefore, also likely subjected to a high variation in the concrete cover. To understand the influence of an increased concrete cover on the reliability, two additional analyses were performed, where the post-yielding resistance of the structure was slightly reduced. This resulted in an increase in the probability of failure, which indicates that this parameter plays a crucial role in determining the reliability of grandstand elements. These points combined make it more plausible that the element failed because the concrete cover was larger than intended rather than the design loads being too low, as concluded by the engineering firm.

When investigating the lifetime reliability of grandstand elements in general, no collapse is expected after 8 seconds but rather after 30 seconds or even longer durations. Therefore, two additional analyses were performed where signals of longer durations (120 seconds and 300 seconds) excited the system. In these analyses, it is assumed that the resistance of the grandstand element conforms to the technical drawings. Signs of a converged reliability were perceived as 120- and 300-second excitation signals led to a probability of failure of the same order of magnitude, indicating that a steady-state solution is obtained after 120 seconds of jumping. In that case, the lifetime reliability of a grandstand element would be equal to the 120-second reliability. The corresponding reliability passes the lifetime reliability requirements for existing structures in consequence class 2 (for a reference period of 15 years).

While the results presented are estimations, and a larger sample size is needed for a converged probability of failure, the proposed method provides a valuable framework for assessing the reliability of grandstand elements. This method can easily be extended to any grandstand element by changing the model parameters, and the true reliability of grandstand elements can be assessed by performing more (1-10 million) simulations.

Crownwalls are often placed on top of vertical composite breakwaters to reduce overtopping. Adding a seawards facing overhang at the top of crownwalls has successfully reduced overtopping even further without increasing the freeboard of the crownwall. Crownwalls with a fully curved (FC) face are most often used in seawalls where they are subjected to wave load by breaking waves. However, it has recently become of interest to explore the possibility of using the fully curved shape for vertical breakwater crownwalls instead of a crownwall with a recurve (R). This thesis aimed to investigate further the wave loading by non-breaking waves and the dynamic response of a FC crownwall on a vertical breakwater through an offline one-way coupling of a CFD-generated pressure-time series and a FEM model in Diana FEA. The results were then compared to those of other studies on the wave load and dynamic response of a R crownwall. Pressure-time series from CFD numerical simulations of three wave states (W5, W6 and W7) were analysed to determine how the structure was loaded. The analysis of the pressure-time series showed that for the smallest wave state, W5, the pressure distribution at the moment of maximum total force was trapezoidal. However, for the larger wave states, W6 and W7, there was a pressure peak at the top of the curve of the crownwall due to the C-CI phenomenon. Waves with impulsive pressure and force impacts were found in all wave states, and the pressure and force impulses were much less variable than the maximum pressure and force values. Dynamic nonlinear analysis showed the fully curved crownwall cracks under wave load by wave states 6 and 7. Cracking occurs at the centre of the curve, where the largest tensile stresses are located. Comparing the results to those of the recurved crownwall, it was concluded that the fully curved crownwall was less favourable than the recurved crownwall. For the same wave states, the FC crownwall was subjected to larger wave forces than the R crownwall, which led to a larger bending moment exerted on the structure. The FC crownwall is also larger than the R crownwall, with the same freeboard, and therefore requires more use of concrete. Due to the shape of the FC crownwall, the maximum tensile stresses are 2.5-3 times higher than those in the R crownwall. More use of steel reinforcement bars is therefore also needed. It would, however, be interesting to investigate further FC crownwalls on vertical breakwaters with different geometries, e.g. radius of the curve, to see if their design can be improved. The applicability of the extended Goda method for calculating static wave load on recurved crownwalls was also investigated for the FC crownwall. It was found that for waves with wave steepness less than 6% and vertical wave velocity less than 2.4 m/s, the calculation method could be used for a preliminary design. However, the dynamic response of the structure must be addressed in the final design, e.g. with a dynamic analysis or the DAF method.

With the continuous increase in transportation volume, bridges face the challenge of carrying higher traffic loads. As a result, bridges undergo fatigue due to repeated and increasing loads, leading to progressive deterioration of their structural reliability. While existing codes already account for several variables affecting the concrete's ability to withstand compression fatigue, some critical factors are still not considered. Furthermore, the modelling aspects of Finite Element Analysis (FEA) are often simplified or disregarded in practical applications, leading to an inaccurate estimation of fatigue life for concrete. As a result, a considerable number of bridges may be rejected for fatigue despite the possibility that they are not susceptible to this issue.
To address these issues, this thesis presents a parametric study that explores and quantifies the influence of various parameters on the fatigue life of inverted T-girder bridges, focusing on modelling aspects and material degradation. For this reason, a special case study was specifically designed to fail in fatigue within its lifespan. The fatigue analysis process employed both analytical and numerical methods, with the fatigue failure of the beams determined based on the bending failure at the beam's midspan criterion. A basic case was established as a basis for analysis, and the effect of each parameter was evaluated by incorporating it into the basic case and calculating the fatigue life of the bridge.
The analysis results demonstrate that stress distribution affecting parameters are significantly important in determining the fatigue performance of a bridge. The analysis identified that accounting for the gradual development of prestress losses, rather than instantaneous losses, and utilising area loads for vehicle modelling are critical aspects that substantially prolong the bridge's fatigue life. Furthermore, performing a historical lane configuration analysis is crucial for accurately assessing fatigue, as it significantly impacts the fatigue life of the bridge and identifies its critical components. The inclusion of material degradation caused by cyclic loading in the fatigue analysis is highly advantageous. It can even result in the bridge no longer being susceptible to fatigue. It is worth noting that accounting for the cracking of the slab in the lateral has a major negative effect on the fatigue life of the bridge. However, it is necessary to include it in the analysis to avoid an inaccurate and overly optimistic fatigue assessment. The study also provides specific equations to calculate the effect of time-dependent traffic volume on fatigue life. Lastly, the research investigated other parameters, such as the composite action of the structural components, which had a minor effect on the fatigue life of the bridge.
It is important to note that the influence percentage of most parameters cannot be generalised to all bridges, as they are contingent on specific factors unique to each case. Nevertheless, this research provides insights into the magnitude and contribution of the investigated parameters' effect on the fatigue life of concrete bridges, outlining those that must be necessarily included in the fatigue assessment.

With the rise of hydrogen as a green alternative for fossil fuels, the demand for storage capacity of hydrogen increases significantly. Due to the high risk of explosions in urban environments it brings along, the blast analysis of buildings within in range of the explosions becomes more relevant.

The goal of this research is to develop a quick method to analyse the roof of a building subjected to blast load. This is done by first clarifying the blast load definition on a reinforced concrete (RC) structural element through existing design standards and literature. Next, the material behaviour of the concrete and the reinforcement steel is scrutinised by an extensive literature study. Materials behave differently under dynamic loads. The dynamic material properties are increased by the strength increase factor (SIF) and the dynamic increase factor (DIF).

In blast analysis, most energy is dissipated though plastic deformation. Therefore, it is of great importance to accurately describe the nonlinear behaviour of RC elements. The nonlinear behaviour of RC elements is translated in the moment-curvature relationship. This relationship is calculated on cross-sectional level and serves as input for the global beam or slab model. The global structural behaviour of the beam or the slab is calculated using the finite difference method (FDM). The FDM model generates a force-deflection (F-u) relationship which can be used in the single degree of freedom (SDOF) mass-spring system. The SDOF mass-spring system is used in this research to predict the dynamic behaviour of RC elements.

The research method is validated by published experiments and finite element analysis. Three experiments are reported, where the following results are obtained:
• Flexural stiffness may be assumed when the scaled distance is above 1.2 m/kg1/3. This is labelled as the ‘far field design range’.
• When choosing the DIFs carefully, the dynamic behaviour of RC elements can be predicted well.
• The FDM model can provide a good estimation of the nonlinear F-u relationship. The method of incorporating cracks in the FDM model is not previously presented in published literature.
• The unloading stiffness requires additional care. This research briefly covers the unloading stiffness.
• According to the UFC 3-340-02 (Department of Defence, US, 2008), RC elements without shear reinforcement and without the possibility of membrane action, fail at a support rotation of 2 degrees. This is where crushing is supposed to happen. This research shows that this is rather conservative and that the support rotation can go up to 6 degrees before failure.

Finally, the validated research method is applied on a case study. The case study contains a slab supported on two stiff beams on opposing sides. This results in a main span (weak direction) and a secondary span (stiff direction) due to the flexural stiffness of the supporting beams. In most cases, the slab supported by beams can be approached as a SDOF mass-spring system. After occurrence of cracks, the slab reinforcement in the main span direction will absorb most of the energy and is therefore the dominating member in the two degrees of freedom (2DOF) mass-spring system.

Sustained economic growth based on a linear production model is not feasible on a planet with finite resources and a limited capacity to absorb wastes. By 2050, the world's population has grown exponentially to 9.7 billion and a tripling of the global use of materials can be realistically expected. Therefore, the transition towards a circular economy has become one of the top priorities of the European Union and its national governments. The Dutch government has stated the ambition to achieve a fully circular economy by 2050 at the latest.

Worldwide, the construction sector contributes to approximately 13\% of the global economy and employment of over 110 million workers. However, the construction sector is also responsible for 50\% of the total raw material consumption, 40\% of the energy usage and for 39\% of all carbon dioxide emissions. The construction sector therefore shows excellent potential for the transition to a more circular production model. One of the initiatives in the Netherlands to accelerate this transition is called 'het betonakkoord'. This initiative aims to make the concrete supply chain more sustainable by focusing on high quality application of recycled or reused building materials and on circular design.

Another interesting development is ongoing in the Netherlands. Since 2019, the housing shortage is 300.000 units and is continuously increasing to approximately 400.000 units by 2025. Combined with the economic growth of the past decade has resulted in skyrocketing house prices. One of the most effective solutions to overcome this problem is to simply built new houses. However, taken into consideration the transition towards a circular economy, raises a fundamental question of how to design sustainable residential buildings with regard to circular principles. This question is quite extensive and consists of a variety of both structural and non-structural aspects. This thesis project focuses on the circular design of a load-bearing floor system for utilisation as a storey floor.

First, extensive literature review is performed in order to identify circular principles and strategies in the design phase of buildings. This thesis project adopted the framework of Cheshire. The framework consist of six nested circles which represent the hierarchy of the framework. Within the framework, Cheshire proposes five design principles in his book: building in layers, designing-out waste, design for adaptability, design for disassembly and material selection. This thesis project expanded the design principles of Cheshire, by defining and providing hands-on strategies or criteria for each design principle. In total, 42 criteria are proposed for transposition into a comprehensive framework for application in practice.

Next, several recent residential and utility building projects are reviewed to determine the state-of-the-art regarding the implementation of circular design principles in practice. The general tendency is that these projects take the deconstructability and, to a limited extent, the selection of materials of the buildings into account. The common denominator in all recent projects, and especially for residential buildings, is the reduction of environmental impact through the realisation of net zero energy buildings.

Concrete floor systems are still widely used in newly built residential and utility buildings, due to their favourable characteristics. Therefore, the four most commonly used concrete floor systems are reviewed and discussed, These four floor systems are primarily designed in accordance with the demands of users and contractors. As a result of this thesis project, a newly designed floor system is proposed which is fundamentally based on the theoretical design framework developed in this report. Implementation of all five design principles was not considered feasible given the current state-of-the-art and regulatory barriers. Therefore, the newly proposed floor system is based on strategies and criteria related to the design principles of adaptability and disassembly. These design principles form the starting point of the multi-criteria analysis conducted in this report. The multi-criteria analysis is conducted in the first place to evaluate the performances of the four most commonly used concrete floor systems in the context of the considered circular design principles and secondly to compare the newly proposed floor system with the four most commonly used concrete floor systems. Based on the weighted rating scale, a maximum score of one hundred can be obtained. Results from the multi-criteria analysis reveal that three out of four commonly used concrete floor systems score well (scoring between 60 and 80) regarding the circular design principles. The newly proposed floor system scores excellent (scoring between 80 and 100).

The structural resistance of the newly proposed floor system is verified in accordance with codes of practice and state-of-the-art research under normal loading conditions. Horizontal wind loading is taken into consideration as well with respect to the stability of floor systems. Moreover, several stakeholder prerequisites are included in the design. Possibilities for recesses, staircases or vertical shafts for example, and building services are provided and suggested. Buildability aspects, such as the fabrication and assembly process are discussed in the report as well.

Structural health monitoring of buildings is useful for a few reasons. It provides information on the usage and cause of damage to a building. This can result in targeted maintenance or allow for potential improvements.

Traditionally, a building can be monitored by installing sensors during construction or maintenance work. These can be strain gauges, inertial measurement units or surveying equipment. However, not all buildings have such sensors installed due to lack of space or the cost of the equipment. To overcome this, a spaceborne technique shows potential, namely multi-temporal interferometric synthetic aperture radar (MT-InSAR). This technique has already been applied to monitor damage to sections of buildings or large structures, for instance facades or deformations of bridges. In the context of entire buildings, the result of an MT-InSAR analysis has not yet been paired with a computational model. This is mainly due to the relatively small scale of a building and low spatial density of the displacement data.

This thesis integrates remote sensing data, acquiring displacements due to mining, with a computational structural finite element model of a church structure. The displacements have been interpolated using MT-InSAR data, which contains projections of nonlinear displacements in vertical and West-East directions. The interpolation has been performed using two techniques. The first is Ordinary Kriging, which is used to obtain a general insight into the deformations and the shape of the deformed region near the church. The second uses the least squares method to fit polynomial shape functions. The resulting displacements of the least squares analysis have been integrated into a nonlinear structural finite element model. The structural model consists of a soil-structure interaction model and nonlinear material properties, and is used to assess crack propagation.

Integrating remote sensing with computational modelling, shows potential in providing a monitoring technique for buildings. The interpolation method can be used to obtain displacements at a building, even when the spatial density of the InSAR analysis is limited. The main limitation is the information on the horizontal displacements obtained by the InSAR technique, where the displacement along the North-South is unknown. Furthermore, the structure and integration can then be performed using a finite element model, which can follow crack propagation and account for soil-structure interaction.

To calculate the flexural-shear resistance of prestressed concrete members without shear reinforcement, a method based on Critical Shear Crack Theory (CSCT) has been presented for the new Eurocode (prEN1992). Two alternatives provided in draft 7/2020 (prEN1, prEN2) are the starting point given, and two other alternatives are proposed for analysis by this thesis (prEN3, prEN4). These alternatives and other design codes were evaluated based on the concepts involved, assumptions made, and the results obtained compared with experimental results.

The research started by compiling basic concepts handled by empirical (ACI318-19 or EC2), MCFT-based (AASHTO-LRFD), and CSCT-based (prEN1992) approaches for the calculation of the flexural-shear resistance of members without shear reinforcement. Experimental results of slender prestressed concrete beams without shear reinforcement were collected from the ACI-DAfStb-PC/2015 database, and these tests were classified into subsets according to the relevant criteria used in the different design codes such as type of shear failure or cross-section shape. Subset 1 groups rectangular and I/T shaped beams with flexural-shear failure. Subset 2 retains the rectangular beams from subset 1, and subset 3 filters the tests from subset 2, applying conditions checking for anchorage or flexural failures. In addition, different critical locations were assumed, some according to design code suggestions (x_r=d or x_r=a-d), and others according to an assumption based on test results (x_r=0.65a).

The comparative evaluation results of the flexural-shear strength estimated by the different design codes with the experimental results were made for the 3 subsets and 3 critical locations defined. From this data set, the critical location x_r=a-d was chosen as the appropriate based on a general evaluation of the precision acquired by the approaches and the higher flexural stresses present. Then the data for the 3 subsets at this location are captured and presented in a range from lowest to highest from here on.

Based on the results, it was concluded that AASHTO-LRFD and prEN1 are the most precise approaches with COV less than 0.25. However, AASHTO-LRFD tends to obtain very conservative results. ACI318-19M has the worst performance in terms of precision with COV in the range of 0.29 to 0.45, its approximate method tends to get results below the desired level of safety, and its detailed method tends to be more conservative. EC2 achieves a regular precision with COV between 0.28 and 0.31, the linearized alternative for the new Eurocode (prEN2) obtains similar COV values ending up with a regular precision as well, and both approaches have a good level of safety.

To improve prEN2, new alternatives (prEN3 and prEN4) were derived based on the linearization of the main failure criterion of the CSCT. Of the alternatives, prEN4 was the most precise (COV=0.25-0.26) with a good level of safety, recognizing that this alternative correctly applies the concept of prestressing as preload and incorporates the effect of the normal loads on the shear strength with a direct relationship dependent on the ratio d/a_cs, where a_cs=|M_Ed/V_Ed |. Finally, all approaches were tested in terms of usability in design cases for simply supported and continuous slab decks, concluding that prEN4 has a significant advantage in usability since it is an expression similar to the one used in the current EC2, and also obtains results that are on the safe side compared with a more precise approach like prEN1.
Alternative 4 (prEN4) is an approach with good accuracy and safety level, and can incorporate the effect of prestress on shear resistance straightforwardly and consistently, complying with the main assumptions of the CSCT and the assumption of prestressing as a preload indicated for the Eurocodes, thus incorporating only the influence of normal loads applied to the neutral axis to contribute to the shear resistance. prEN4 is also an approach that has been shown to capture the influence of all parameters considered to obtain a reliable estimation of the flexural-shear resistance; therefore, it is recommended to consider it as a potential alternative for a handy and reliable calculation of the flexural-shear resistance of beams without shear reinforcement.

An experimental research into the use of basalt as reinforcement in concrete to reduce the ECI value of a concrete quay wall apron. In this research experiments with basalt minibars and basalt reinforced polymer rebars are performed to compare directly to steel fibres and steel rebars. With the test results 4 designs are produced resulting in material requirements per type of reinforcement. By using these amounts of material an ECI value is determined showing that in this research basalt is an option to reduce the environmental impact. The ECI value presented in this research are in euros/year lifespan, meaning that for a different lifespan the material shows different values. Here the pros of basalt come out as the material is resistant to corrosion as it is a stone like material. Therefore in this research with a product that is placed in water, the lifespan of a steel reinforced apron could only reach 50 years where the apron with basalt reinforcement reached 100 years.

A parking garage of Eindhoven airport partially collapsed in 2017. It was caused by failure of the longitudinal joint (long-side) of the composite plank floor or breedplaatvloer on the roof level. Experimental and numerical research showed that the joint suffered high positive bending moment in its transverse direction. However, from the investigation results, there was not enough resistance at the concrete-to-concrete interface around the joint to transfer the tensile force from the precast to the cast-in-situ section, which led to delamination of the two layers of concrete and resulting in failure when the delamination crack reaches the end of the coupling reinforcements. As happened in that case, the concrete-to-concrete interface usually is the weakest link and has a critical role on behaviour of a composite concrete system, especially the one which has unreinforced interface (no stirrup near joint). Further studies have been conducted to understand the influence of various details around the joint on the interface behaviour. In this thesis, details in spacing between lap splices (coupling reinforcements in cast-in-situ layer and bottom reinforcements in precast layer), spacing between connecting reinforcements (stirrups crossing the interface near the joint), the role of connecting reinforcement, and the sensitivity of interface parameters were studied numerically using DIANA finite element analysis software. Since the spacings are in direction of the specimen’s width, interface behaviour was analysed in both longitudinal and transverse directions. An additional study about compressive membrane action or arching was also conducted to understand the influence of lateral restraint, which usually occurs in composite plank floor systems used in buildings, including the one used in Eindhoven parking garage, to the capacity of the structure. This action was suspected of providing additional strength to the existing composite plank floor

Two composite SHCC-concrete beam specimens from the experimental research by Harrass [1] were used in this numerical study since the experiment had both unreinforced and reinforced interface specimens which were important for this study. The unreinforced interface beam (Sample 1) was suitable for the study of lap splice spacing and lateral restraint without any influence from reinforcement crossing the interface, while the reinforced interface beam (Sample 7) was suitable for the study of stirrups spacing. The specimens are solid beams (without weight-saving element) consisting of a SHCC (Strain Hardening Cementitious Concrete) precast layer with a joint in the mid-span, and a regular concrete cast-in-situ layer. By using DIANA 10.4 finite element analysis software, this study is able to simulate both specimens in 2D and 3D numerical models. The models represented Sample 1 failed with a horizontal crack along the interface and a flexural crack at the end of coupling reinforcement reaches the top of the cast-in-situ layer, while the models represented Sample 7 failed with a horizontal crack along the interface, a flexural crack at the end of coupling reinforcement, and a crack at the stirrup location in precast layer. From the verification study, the reinforcement bond-slip function (CEB-FIB 2010) was chosen not to be used for the rest of the study since it did not affect much the load capacity and the failure mechanism of the specimens. Consequently, pull-out failure of the stirrup is excluded for the rest of this study.

Prior to the main study, the influence of each interface parameter was studied in both unreinforced and reinforced interface models by varying the interface parameters. It was observed that interface tensile strength and stiffness are governing in the unreinforced interface model. Within the range of those parameters, the load capacity was increased and decreased by more than 50% in compared to the reference model verified by Sample 1. By adding a rectangular stirrup near the joint of unreinforced interface model, the model with reinforced interface has a different governing parameter, the cohesion, and the variability of the results decrease. Within the range of the cohesion, the load capacity was increased and decreased up to 30% in compared to the reference model verified by Sample 7. Since the interface parameters influence the capacity of both unreinforced and reinforced interface beams, two different interface types are used for the whole of the study. They are known as “smooth interface” which uses the parameters obtained from the verification with the experimental specimen, and “perfect bonded interface” which use rigid connection between the elements of the two concrete layers.

To study the influence of lap splices spacing, models with three lap splices setup from Harrass’ experiment (three coupling reinforcements and three bottom reinforcements) were compared to models with a single lap splice (one coupling reinforcement and one bottom reinforcement) with the same total reinforcement area. As a result, with perfect bonded interface, model with single lap splice has higher load capacity by more than 10% in compared to model with three lap splices though both models failed with the same failure mechanism which was the horizontal crack along coupling reinforcement and a flexural crack at the end of coupling reinforcement reaches the top of the cast-in-situ layer. Stress concentration around coupling reinforcements were observed in all models, especially in model with single coupling reinforcement. However, different horizontal crack propagation occurred in each models. Uniform horizontal crack propagation along the interface were observed in models with smooth interface, while more concentrated crack propagation around the coupling reinforcements were observed in models with perfect bonded interface, especially in model with single lap splice. This different crack propagation in models with perfect bonded interface could be the cause of different load capacity since more uncracked elements could provide more tensile force transfer from precast layer to cast-in-situ layer.

In the study of the influence of stirrups spacing, models with rectangular stirrup (two legs) setup were compared to models with a single leg vertical stirrup setup with the same total reinforcement area. In both cases the presence of the stirrup near the joint stopped the propagation of the horizontal crack. As a result, all models could reach yielding of the coupling reinforcement for both interface types although different structural stiffness is observed. The plausible cause for this difference in structural stiffness was the higher tensile stress in stirrups of model with two legs stirrups compared to model with single leg stirrup. This higher tensile stress might be resulted by the more distributed stirrups across the width of the beam.

In the additional study, models with full height lateral restraint at the support were compared with models with simple support. As a result, with perfect bonded interface, model with lateral restraint has higher load and displacement capacity by more than 14 and 2.5 times consecutively compared to the model without lateral restraint. In compared to the collapse load, the numerical result of model with lateral restraint has higher load capacity by almost 4 times. With smooth interface, model with lateral restraint has higher load and displacement capacity by more than 10 and 5.5 times consecutively compared to the model without lateral restraint. In compared to the collapse load, the numerical result of model with lateral restraint has higher load capacity by more than 2 times. These increases are in accordance with a research by Ockleston [2] which found a considerable increase of load capacity on concrete slab with lateral restraint compared to the yield line theory. Part of the increase of capacity was resulted by the fix boundary action due to bending moment at support. However, it was observed that compressive membrane action started to develop after the first flexural crack as the horizontal force at support rapidly increased after that crack. Although the models with lateral restraint of both interface types had a different failure mechanism compared to the models without lateral restraint, they have a similar final stage of the failure mechanism, which is the flexural crack at the end of coupling reinforcement. This flexural crack propagation can be prevented from occurring earlier due to the high compressive stress at the top part of the cast-in-situ layer. When the concrete crushed at the support due to limited rotation capacity of the concrete, the compressive stress dropped causing the flexural crack at the end of coupling reinforcement to develop.

In conclusion, there was an influence of the interface behaviour to the failure and the capacity of composite SHCC-concrete beam. However, the influence was varied, depending on the coupling reinforcement spacing, presence of stirrup crossing the interface near the joint, spacing of stirrup, and interface type. It is also concluded that compressive membrane action in addition to fix bending action, which occurred due to the lateral restraint, increased the capacity of the structure. This increase depended on the interface type and rotation capacity of the concrete. A wider range of the influencing parameters are needed in future studies to get a more robust results which are beneficial for a more general conclusions. However, the series of experimental research based on this study are essential to provide a verification on the results of this numerical study.

In concrete structures, shear failure is one of the failure mechanisms that should be estimated carefully due to its brittle nature. As the technology advances, the capacity of shear in concrete structures can be calculated with the analytical formulation in codes and standards and simulated with NLFEA. The shear capacity is affected by the size which is a phenomenon observed from experiments where the change in the structure size does not have a linear relation to the structural strength. This can be referred to as the experimental size effect. When estimating the shear capacity with NLFEA, this effect must be included in order to avoid over-estimation of capacity. However, another size effect can be found from the result of NLFEA. The change in structural size has an influence on the global response of concrete structures with different numerical configurations in a simulation with NLFEA. A numerical configuration consists of several numerical parameters. This effect is referred to as the numerical size effect. Therefore, it is necessary to incorporate the experimental size effect and reduce the influence of the numerical size effect in a numerical model in order to increase the accuracy and precision of the simulation with NLFEA. The aim of this study is to investigate how the numerical size effect influences the NLFEA results, which will help understand how to improve the accuracy of the simulation. The investigation is done by studying numerical models with a variation on several numerical parameters, such as load increment, error tolerance, the maximum number of iterations and mesh size. The study is focused on identifying the influence of these numerical parameters for cases with different structural sizes and comparable shear slenderness. This is done by observing the global behaviour of the structure and comparing NLFEA results to their respective experimental results. Any difference in the simulated global response is analysed by observing the difference between the experimental and the simulated crack pattern and the convergence state of the respective step. The study is done in three stages. The study is initiated by investigating how the flexural shear failure mode can be obtained with NLFEA. Two specimens with comparable shear slenderness (a/d), 3.70 and 3.91 for beam A123A1 and H123A respectively, are used as a reference for the simulation model. It was found that bad convergence was achieved at the later stage of the analysis and by not accepting non-converged steps, the results became dependent on the convergence state of the analysis where different peak loads were achieved in different numerical configurations for the same case study. The study continues by identifying the correlation of numerical parameters with the results of NLFEA by creating simulation models with different iterative incremental solutions, load increment, error tolerance, and the maximum number of iterations. All load steps are accepted in this stage, regardless of their convergence state, and the rotating crack model is used in these numerical models. The NLFEA results are post-processed by setting up an upper limit in the error tolerance in order to minimize the variation of the peak load and attain a higher consistency of the results. At the last stage, another study is performed to identify the correlation between mesh sizes with the results of NLFEA by simulating several models with different mesh sizes. All load steps are also accepted in this stage, regardless of their convergence state, and the rotating crack model is used in these numerical models The NLFEA results are also post-processed with the same criteria attained in the previous stage. It is concluded that the results of NLFEA are dependent on the following numerical parameters, the load increment, error tolerance, and the maximum number of iterations, due to different initiations and propagation of dowel crack in the non-converged steps, which influences the convergence condition in the later stage of the NLFEA. The formation and rapid propagation of the dowel crack results in the excessive change in the principal strain direction and magnitude, which induces high relative energy variation and out-of-balance force. These numerical parameters indirectly contribute to the error found in each step in the analysis. An additional study is done by replacing the crack model with a fixed crack model with a damage-based shear retention model, but it was found that this did not solve the problem due to the excessive change in the shear retention factor on the elements that lead to premature failure of the beam. The observation related to the numerical size effect reveals that the mesh size controls the propagation rate of the dowel crack. The use of a smaller mesh size will reduce the propagation rate of the dowel crack after its initiation due to a smaller increment of the crack width between each load step. As a result, the increment of the crack width becomes smaller as the mesh size decrease. This becomes more pronounced due to the effect of excessive change of the principal stress-strain direction and magnitude. Full Newton-Raphson method has been proven to give the smallest variation of the peak load ratio (Pnorm), ranging from 0.887-1.140 for specimen A123A1 and 1.055-1.246 for specimen H123A, compared to the other iterative-incremental method with the use of load increment ratio (load increment/experimental peak load) within 0.03-0.006 in combination with evaluation of acceptable analysis step with error tolerance, where the predefined error tolerance must be set to Gerr = 0.0001 and Ferr = 0.01, and non-converged steps can still be accepted if the relative energy variation and out-of-balance force of the corresponding step are below 0.03 and 0.58 respectively. An additional criterion related to the shear displacement on the major flexural shear crack (Δ) should be added to the evaluation of the acceptable analysis step in order to prevent an excessive crack opening on the major flexural shear crack at the peak load. The analysis step can still be considered valid if the respective step satisfies the criterion of the error tolerance and the vertical crack opening on the major flexural crack on the respective step is below the ultimate tensile crack width (CWt,u), which can be calculated from the Guidelines for Nonlinear Finite Element Analysis of Concrete Structures (Hendriks & Roosen, 2020). A mesh size ratio which larger than h/15 is required to have the correct simulated failure.