Institut Bauingenieurwesen

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Spall experiments for the measurement of the tensile strength and fracture energy of concrete at high strain rates, International Journal of Impact Engineering 32
(Elsevier, 2006) Schuler, Harald; Mayrhofer, Christoph; Thoma, Klaus [in: International Journal of Impact Engineering]
01A - Beitrag in wissenschaftlicher Zeitschrift
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
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
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
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
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
Sliding resistance at the joint between a structural wall and the basement ceiling: a mechanical model
(24.08.2014) Schuler, Harald; Trost, Burkhart [in: Second European Conference on Earthquake Engineering and Seismology, Istanbul, August 2014]
This paper presents a mechanical model which is used to analyse the sliding resistance at the cold joint of nearly quadratic basement walls. The analysis is done on a building with a height of 40m and a basement wall size of 4m x 4m. In the parameter study the axial force and the reinforcement ratios, at the boundary and in the web, are varied. Analysed are the resistances of aggregate interlock, dowel action and the shear resistance of the reinforcement which is under compression. The study shows that for a quadratic wall in most cases, failure due to sliding occurs before the maximum flexural deformation is reached. Thus the flexural ductility, e.g. in pushover analysis, is overestimated when the anchorage lengths of the structural wall is short. Therefore it is recommended for squat walls to take a previous sliding failure into account in a performance-based earthquake analysis.
04 - Beitrag Sammelband oder Konferenzschrift
Sliding Deformation Model for Reinforced Concrete Shear Walls under Seismic Loading
(01/2017) Trost, Burkhart; Schuler, Harald; Stojadinovic, Bozidar [in: 16th World Conference on Earthquake, Santiago Chile, January 2017]
Accounting for all possible failure modes in seismic design and construction of reinforced concrete shear walls is important to ensure that the expected seismic performance of the building structures is attained. Sliding is a shear wall failure mode that can occur at flexural cracks or at cold joints. For example, significant sliding was observed at a four-story reinforced concrete building tested on the E-Defense shaking table. Whyte, Synge and Luna observed and examined sliding failure in their squat shear wall tests. In earthquake engineering, the sliding resistance on a crack in a reinforced concrete structural element is defined by simple equations in nearly all modern codes (EC8, ACI 318-1, fib-Model Code 2010). These equations have been developed for crack sizes occurring at serviceability performance levels and modified for use in seismic design. Large crack widths, which are common under earthquake loads, are not explicitly considered. This article presents a sliding resistance and deformation model for reinforced concrete shear walls. This model includes the interaction between the concrete and the reinforcement and complies with the equilibrium of forces and the compatibility of deformations at each point in the sliding process. At the core of the model is a plastic micro-model that characterises the interlocking process of the aggregate on an existing crack. Depending on the concrete strength, the compression stress, and the roughness of the crack surface, the force transferred across the crack is determined for any displacement and any crack width. The model is validated against a seriesof sliding tests on compact sliding specimens.
04 - Beitrag Sammelband oder Konferenzschrift
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
A new approach for the description of discharge extremes in small catchments
(26.04.2017) Pavia Santolamazza, Daniela; Lebrenz, Henning; Bárdossy, András
06 - Präsentation
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
Parameter estimation: drivers of extreme discharge in the Northwestern Switzerland
(17.11.2017) Pavia Santolamazza, Daniela; Lebrenz, Henning; Bárdossy, András
06 - Präsentation
Using backcasting to support corporate mobility management
(2021) van Eggermond, Michael; Erath, Alexander
The paper at hand describes a research project conducted in collaboration with a major employer based in Basel, Switzerland. The company employs innovative mobility policies, such as a strict parking regime, with lots only available to employees who have to travel more than 45 minutes by public transport, offers bike sharing and public transport bonuses, but would like to further reduce parking lots and desires to reduce greenhouse emissions resulting from commuting while remaining an attractive employer. The aim of the project was the to better understand the impact of exogenous developments (e.g. new train lines, road pricing, infrastructure improvements, safer cycling routes) and endogenous mobility policies (e.g. bike sharing, parking fees, charging stations). These developments and policies were identified in a series of workshops with stakeholders. At the same, key performance indicators were formulated. Instead of forecasting the impact of these policy measures, the project set out to describe a desirable future (e.g., less emissions, attractive employer), reason backwards from the desired situation and formulate a package of policy measures that could in this future, whilst taking into account exogenous developments. This process is also known as backcasting and has been applied in several studies (e.g. Banister et al., 2000; Barandier 2015) To quantify the impact of the policy measures several data sets were available and newly collected. Travel times and distances for motorized private transport, walking and cycling were calculated using the Google travel time API for all employees. As Google’s API only offers limited coverage for public transport in Germany and France, use was made of publicly available public transport schedules and the open-source routing engine R5. A survey was conducted among employees, resulting in over 6000 responses. Based on the survey data, choice models were estimated and applied. Exogenous and endogenous developments for over 10 policy measures were quantified using simplified assumptions, whilst taking into account the spatial differences, and used to forecast the impact of each individual measure and combinations of measures. Measures include the impact of e-bike provision, the impact of improved cycling infrastructure, new train stations and the differentiated parking fees. The project resulted in a set of mobility policies and recommendations to monitor these mobility policies, and the methodology has been applied at other stakeholders to support sustainable mobility policies.
06 - Präsentation
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
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
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
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
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
Sicher und kompetent unterwegs. Eine Analyse zu Velofahrkompetenzen und Unfallprävention
(VSS, 2023) van Eggermond, Michael; Schaffner, Dorothea; Studer, Nora [in: Strasse & Verkehr]
Die Förderung des Velofahrens ist zentral für ein nachhaltiges Mobilitätssystem. Dabei kommt der Verkehrssicherheit eine bedeutende Rolle zu. Die Sicherheit kann durch verschiedene Massnahmen erhöht werden: Unabdingbar ist die Verbesserung der Veloinfrastruktur. Für eine sichere Navigation im Mischverkehr in Städten kann zusätzlich die Förderung von Velofahrkompetenzen einen entscheidenden Beitrag zur Vermeidung von Unfällen leisten. Auf Basis von vier Studien legt dieser Beitrag dar, welche Velofahrkompetenzen unfallvermeidend sind und bei welchen Velofahrkompetenzen sich bei der Schweizer Bevölkerung ein Entwicklungspotenzial zeigt sowie wie Velofahrkompetenzen mit einem digitalen Training gefördert werden können.
01B - Beitrag in Magazin oder Zeitung
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

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