Institut Bauingenieurwesen

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A new approach for the description of discharge extremes in small catchments
(26.04.2017) Pavia Santolamazza, Daniela; Lebrenz, Henning; Bárdossy, András
06 - Präsentation
A Virtual reality experiment to study citizen perception of future street scenarios
(SSRN, 31.03.2023) Sánchez-Vaquerizo, Javier Argota; Hausladen, Carina Ines; Mahajan, Sachit; Matter, Marc; Siebermann, Michael; van Eggermond, Michael; Helbing, Dirk
The current allocation of street space is based on expected vehicular peak-hour flows. Flexible and adaptive use of this space can respond to changing needs. To evaluate the acceptance of flexible street layouts, several urban environments were designed and implemented in virtual reality. Participants explored these designs in immersive virtual reality in a 2x3 mixed factorial experiment, in which we analysed self-reported, behavioural and physiological responses from participants. Distinct communication strategies were varied between subjects. Participants' responses reveal a preference for familiar solutions. Unconventional street layouts are less preferred, perceived as unsafe and cause a measurably greater stress response. Furthermore, information provision focusing on comparisons led participants to focus primarily on the drawbacks, instead of the advantages, of novel scenarios. When being able to freely express thoughts and opinions, participants were focused more on the impact of the space on behaviour rather than the objective physical features themselves. Especially, this last finding suggests that it is vital to develop new street scenarios in an inclusive and democratic way: the success of innovating urban spaces depends on how well the vast diversity of citizens' needs is considered and met.
05 - Forschungs- oder Arbeitsbericht
Aktivitätenbasierte Verkehrsmodelle: Methoden, Anwendungen, Vor- und Nachteile
(Schweizerischer Verband der Strassen- und Verkehrsfachleute, 2022) Erath, Alexander; Vitins, Basil; Fellendorf, Martin; Arendt, Michael [in: Strasse und Verkehr]
Aktivitätenbasierte Verkehrsmodelle (ABM) sind ein vielversprechender Ansatz der Verkehrsmodellierung. Gegenüber den in der Praxis mehrheitlich eingesetzten aggregierten Modellansätzen bieten ABM verschiedene Vorteile. ABM erlauben vielseitigere Auswertungsmöglichkeiten und flexiblere, methodisch konsistentere Abbildungen von intermodalen Wegeketten – zum Beispiel für ÖV- oder Langsamverkehrsstudien – und zeitlich dynamischen Massnahmen, zum Beispiel Mobility Pricing. Gleichzeitig sind ABM in der Praxis bisher noch weniger etabliert und stellen höhere Anforderungen bei der Modellierung. Im Rahmen eines SVI-Forschungsprojekts wurden Voraussetzungen sowie Vor- und Nachteile des Einsatzes von ABM untersucht, um Modellbetreibern eine Entscheidungshilfe zu bieten.
01B - Beitrag in Magazin oder Zeitung
Analyse der Relevanz von weg- und tourenbasierten Verkehrsmittelwahlansätzen am Beispiel eines aggregierten und eines aktivitätenbasierten Verkehrsmodells der Stadt Halle
(Hochschule für Architektur, Bau und Geomatik FHNW, 03.03.2023) Cachaco, Fabio; Erath, Alexander
Die Masterarbeit untersucht die Relevanz und Auswirkung von weg- und tourenbasierten Verkehrsmittelwahlansätzen. Hierzu erfolgt zunächst eine qualitative Beschreibung der Wirkungsweise verschiedener Ansätze zur Modellierung der Verkehrsmittelwahl. Der Schwerpunkt wird insbesondere auf den Aggregation Bias und die Nutzenfunktion gelegt. Im Rahmen von Fallstudien mit synthetischen Daten und einem Verkehrsmodell erfolgt eine quantitative Abschätzung der Relevanz des Aggregation Bias.
11 - Studentische Arbeit
Assessing cycling skills in Switzerland
(11/2022) van Eggermond, Michael; Schaffner, Dorothea; Studer, Nora
For many people, safety concerns are a major barrier to ride a bicycle. Indeed, cyclists bear a higher risk than most other types of road users. Improving cycling infrastructure is the most obvious and effective way to increase cycling safety. This paper sets out to identify skills required by cyclists to navigate safely through an urban environment in Switzerland. We set out to identify situations that might result in accidents and require specific competences. This research has shown that there is potential to further develop cyclists’ skills. Rather than focusing on motoric skills or presenting simple situations, we advise that skills should be trained based on more complex situations. These situations include turning, branching, maintaining distance from parked cars and recognising right of way in residential areas.
04B - Beitrag Konferenzschrift
Begleitstudie zum Tier-Pilotprojekt in Riehen
(Hochschule für Architektur, Bau und Geomatik, Institut Bauingenieurwesen, 16.01.2023) Erath, Alexander; van Eggermond, Michael
05 - Forschungs- oder Arbeitsbericht
Calibration of a regional agent-based travel demand model to simulate the spread of COVID-19
(2021) Mesaric, Raphael; Erath, Alexander
The recent COVID-19 pandemic has shown the need of readily available tools to simulate the spreading of infectious diseases and assess the potential impact of policy measures aimed at the containment of the disease. The most common approach in epidemiology is to use compartmental models which model disease spreading as a series of stocks (compartments) and flows. The most basic version considers three compartments: susceptible, infectious and recovered. One of the core assumptions of these models, however, is a homogeneous population which is a serious limitation when it comes to clustered outbreaks. The research at hand uses an agent-based travel demand model (MATSim) coupled with a recently developed extension (EpiSim) to simulate the spread of the pandemic by tracking the interactions of agents und subsequently identifying infections by following their contact network. This overcomes the compartmental assumption of the previous models. In this presentation, we summarize the calibration results of the EpiSim model which is based on the regional activity- and agent-based travel demand model of the trinational region around Basel. The calibration procedure is based on data on case numbers and hospitalisations from three countries (Switzerland, Germany and France) at different spatial resolution. The underlying models account for the effect of border closures and spatially varying restrictions to limit the spread of COVID-19. In contrast to existing studies, this model pays particular attention to disease import through external traffic from outside the model area as well as cross-border travel demand.
06 - Präsentation
Destination choice modeling with spatially distributed constraints
(University of Minnesota, 03.07.2023) Vitins, Basil; Erath, Alexander [in: Journal of Transport and Land Use]
01A - Beitrag in wissenschaftlicher Zeitschrift
Elemente der Werkstoffformulierung für Beton und deren Verwendung in der Kurzzeitdynamik
(Ernst & Sohn, 2007) Schuler, Harald [in: Beton- und Stahlbetonbau]
01B - Beitrag in Magazin oder Zeitung
Estimation of the Variogram Using Kendall's Tau for a Robust Geostatistical Interpolation
(14.01.2017) Lebrenz, Henning; Bárdossy, András [in: Journal of Hydrologic Engineering]
The estimation of an appropriate variogram is a crucial step toward the description of spatial dependence, the geostatistical interpolation of environmental variables, and the subsequent hydrological engineering. The classical variogram in the literature ideally necessitates a normal distribution of the variable and is not robust against outliers within the data. These presumptions are hardly given under empirical conditions and, therefore, a new estimation method is proposed for the variogram. The new method is based on the description of spatial dependence by the robust rank coefficient τ and generalizes the method from the Gaussian to the general case of empirical distributions. The conversion of the robust estimate using a Monte-Carlo simulation and subsequent quantile-quantile transformation with the empirical marginal distribution performs the generalization. Monthly precipitation data from South Africa serve as the variable and were artificially contaminated with outliers. The effects on the variogram and subsequent geostatistical interpolation were investigated for the proposed, classical, and four existing robust variogram models in this comparative study. The investigation revealed that the proposed variogram describes a distinct spatial dependence structure under empirical conditions, which is robust against outliers. The cross validation of the linear estimator demonstrates that the proposed variogram tends to improve the bias and spread of the resulting error distribution, and hence the quality of the geostatistical interpolation.
01A - Beitrag in wissenschaftlicher Zeitschrift
Evaluation and acceptance of an online cycling training for adults to master complex traffic situations
(16.11.2023) van Eggermond, Michael
06 - Präsentation
Evaluation of an experimental Method via numerical Simulations
(CRC Press, 2007) Schuler, Harald; Carpinteri, Alberto; Gambarova, Pietro G.; Ferro, Giuseppe; Plizzari, Giovanni [in: Fracture Mechanics of Concrete and Concrete Structures. Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures, Catania, Italy, 17-22 June 2007]
04B - Beitrag Konferenzschrift
Experimental Investigation of Sliding on Compact Sliding Specimens under Cyclic Loads
(08/2014) Trost, Burkhart; Schuler, Harald; Stojadinovic, Bozidar [in: Second European Conference on Earthquake Engineering and Seismology, Istanbul, August 2014]
This experimental investigation addresses the sliding behaviour found to occur in reinforced concrete shear walls under earthquake loads. This investigation compromises a series of 13 compact specimens. The tests were conducted in a biaxial test setup. The test sequences were designed to mimic the load and displacement history of a portion of the squat wall under horizontal cyclic loading. The specimens were pre-cracked up to a defined crack width. Next, diagonal compression was applied. Through the variation of the reinforcement ratio, the initial crack width, the number of cycles and the amplitudes, the effects of aggregate interlock, dowel action and shear friction in the crack were quantified. In this paper we will present the observations and the results of the cyclic tests on the core specimen group and on the monotonically tested specimens.
04 - Beitrag Sammelband oder Konferenzschrift
Faserbeton unter hochdynamischer Einwirkung
(Ernst & Sohn, 2007) Fuchs, Maximilian; Keuser, Manfred; Schuler, Harald; Thoma, Klaus [in: Beton- und Stahlbetonbau]
01B - Beitrag in Magazin oder Zeitung
Forecasting district-wide pedestrian volumes in multi-level networks in high-density mixed-use areas
(Western Norway University of Applied Sciences (HVL), 06/2022) Mavros, Panos; van Eggermond, Michael; Erath, Alexander; Helle, Veera; Acebillo, Pablo; Xu, Shuchen; van Nees, Akkelies; de Koning, Remco Elric; Jacobsen Åsli, Thale [in: 13th International Space Syntax Symposium]
This paper is concerned with improvements in the forecasting of pedestrian flows in multilevel pedestrian networks in high-density urban environments. 3D network topology measures are combined with land-use data, and validated against extensive pedestrian counts, to provide both evidence for the applicability of network analysis in tropical metropolises, as well as a calibrated tool for urban planners. The research focuses on four area in Singapore. These areas have in common that they all are prominent transport hubs, but differ in surrounding land-use types and dominant network topology (e.g. indoor, outdoor, above ground, below ground, at grade). Multi-level pedestrian networks were drawn based on OpenStreetMap, include sidewalks on both sides of major roads for a radius up to 2 kilometres from the site centroids. Spatial network analysis was performed using sDNA which allows vertical networks to generate measures describing the spatial configuration of the network. Subsequently, pedestrian counts were conducted during three consecutive days. In total, counts were conducted at more than 250 locations in 2018 and 2019, well before the global COVID19 pandemic. Pedestrian flows are set against a series of variables, including pedestrian attractors and generators (e.g. shops, offices, hotels, dwellings), and variables describing the spatial configuration of the network, using advanced regression models. Our results show that betweenness metrics (i.e. space syntax choice) combined with land-use yield high predictive power. Dependent on the study site, network metrics based on angular distance outperform those based on metric distance or perceived link distance. This research demonstrates that is necessary to account for the multi-level nature of networks, and that indoor flows through private developments cannot be neglected, in particular when planning for integrated transport developments. The paper concludes with recommendations and implications for practice.
04B - Beitrag Konferenzschrift
Fracture Behaviour of High Performance Concrete (HPC) infestigated with a Hopkinson-Bar
(EDP Sciences, 2006) Schuler, Harald; Hanson, Hakan [in: Journal de Physique IV]
01A - Beitrag in wissenschaftlicher Zeitschrift
How relevant is the aggregation bias with regards to mode choice in aggregated transport demand models?
(12.05.2023) Erath, Alexander; Cachaco, Fabio
06 - Präsentation
How relevant is the aggregation bias with regards to mode choice?
(Swiss Transport Research Conference, 12.05.2023) Erath, Alexander; Cachaco, Fabio; Alahi, Alexandre [in: Conference Proceedings of the 23rd Swiss Transport Research Conference]
Most travel demand models used in practice still apply a four-step approach which describes travel demand in an aggregated manner. Aggregation bias refers to the assumption that group characteristics are shared by all the individuals who are members of that group as compared to an approach that evaluates travel behaviour on the level of individuals. The use of average values applied to aggregated populations across spatial zones and time periods distorts a model’s sensitivity to investment and policy alternatives (Castiglione u. a. 2015). Our paper examines the relevance and impact of aggregation bias with regards to trip- and tour-based mode choice. The paper starts with a short literature review and a theoretical description of the problem. The main part of the paper consists of two case studies which we have developed to quantitatively assess the relevance of the aggregation bias. The first case study is based on synthetic data that reflects typical rates of mobility tool ownership and travel times by different modes for a given travel relation in an urban, agglomeration and rural context in Switzerland. The relevance of the aggregation bias is assessed by different ways to consider mobility tool ownership and systematic adaptations of the considered travel times. The second case study is based on the implementation of an activity-based and disaggregated demand model for the German city of Halle based on which an aggregated model is derived that shared exact same transport network and overall travel demand. We use the two models to assess the relevance of the aggregation bias based on three scenarios with different transport planning measures.
04B - Beitrag Konferenzschrift
Human navigation in a multilevel travelling salesperson problem
(PsyArXiv, 22.01.2022) Mavros, Panagiotis; van Eggermond, Michael; Hölscher, Christoph
Finding the optimal tour that visits a series of locations sequentially, such as going for errands, is an everyday task formally known as the travelling salesperson problem (TSP). In this article we focus on the understudied type of multilevel or M-TSP, which take place in a multilevel environment, like a building. In a TSP, the number of alternative tours the decision-maker needs to consider is given by the factorial of the locations to visit; hence a 3-target TSP has 6 alternatives and a 12- target TSP has 479 million. Considerable research has focused on combinatorial optimisation algorithms for TSPs, and in the cognitive sciences there has equally been a sustained interest on how various foraging species and humans achieve remarkably optimal performance. However, research has primarily studied planar environments, and it is unclear how people will combine horizontal and vertical spatial information to make navigational decisions in a multilevel TSP. In this study, we asked 41 participants to first learn the locations of 12 shops (targets) in a multilevel building, and then complete a structure mapping task and two open 8-target M-TSP tasks (more than 40.000 alternatives). Using bayesian methods for mixed effects modelling, we show that human performance in navigational M-TSPs is lower than this of Euclidean TSPs, and we differentiate between the choice of tour (visit sequence) and transitions (local wayfinding). Our results show an effect of horizontal versus vertical learning. We also found that performance in navigational TSP are a composite of global and local decision making, and the people adaptively employ a path-based, rather than euclidean, measure of distance when this is ecologically relevant. Overall we provide multiple sources of evidence for the horizontal bias theory both in mental representations and wayfinding behaviour. This study contributes to current knowledge of mental representations 3D space and is the first huto provide human data on an multilevel TSP. More generally, these findings have implications for our understanding of wayfinding and navigational behaviour in multilevel environments.
05 - Forschungs- oder Arbeitsbericht
Interaction of Sliding, Shear, and Flexure for Earthquake Design of Reinforced Concrete Shear Walls
(17.10.2017) Trost, Burkhart; Schuler, Harald; Stojadinovic, Bozidar
06 - Präsentation

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