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Ergebnisse nach Hochschule und Institut
Publikation Areal rainfall estimation using moving cars. Computer experiments including hydrological modeling(Copernicus, 26.09.2016) Rabiei, Ehsan; Haberlandt, Uwe; Sester, Monika; Fitzner, Daniel; Wallner, MarkusThe need for high temporal and spatial resolution precipitation data for hydrological analyses has been discussed in several studies. Although rain gauges provide valuable information, a very dense rain gauge network is costly. As a result, several new ideas have emerged to help estimating areal rainfall with higher temporal and spatial resolution. Rabiei et al. (2013) observed that moving cars, called RainCars (RCs), can potentially be a new source of data for measuring rain rate. The optical sensors used in that study are designed for operating the windscreen wipers and showed promising results for rainfall measurement purposes. Their measurement accuracy has been quantified in laboratory experiments. Considering explicitly those errors, the main objective of this study is to investigate the benefit of using RCs for estimating areal rainfall. For that, computer experiments are carried out, where radar rainfall is considered as the reference and the other sources of data, i.e., RCs and rain gauges, are extracted from radar data. Comparing the quality of areal rainfall estimation by RCs with rain gauges and reference data helps to investigate the benefit of the RCs. The value of this additional source of data is not only assessed for areal rainfall estimation performance but also for use in hydrological modeling. Considering measurement errors derived from laboratory experiments, the result shows that the RCs provide useful additional information for areal rainfall estimation as well as for hydrological modeling. Moreover, by testing larger uncertainties for RCs, they observed to be useful up to a certain level for areal rainfall estimation and discharge simulation.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Pedestrian and transit accessibility on a micro level. Results and challenges(University of Minnesota, 2016) van Eggermond, Michael; Erath, AlexanderIn thispaper, we connect two notions of accessibility that are more often than not considered separately: pedestrian accessibility and transit accessibility. We move away from the notion of zonal accessibility and measure fine-grained accessibility using door-to-door travel times. Two pedestrian networks are compared to a baseline scenario considering Euclidean distances for a large metropolitan area in which each individual building is considered as an activity opportunity. It is shown that pedestrian accessibility to jobs differs when pedestrian distances are approximated with different networks that are more representative of reality. Stop-to-stop public transport travel times are extracted from an agent-based simulation of public transport smart card data. The effect of less-than-optimal connections from transit to the pedestrian network, a local measurement, can be seen when calculating the accessibility to all destinations in the city. We suggest moving away from Euclidean-based distance analyses. Limitations can be found in the data available; the connection of buildings to the network becomes important, as does the inclusion of pedestrian crossings. For an inclusive accessibility measure, it will be necessary to calculate generalized costs for pedestrians and generate different pedestrian networks that reflect the limitations of different user groups.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation The role of location in residential location choice models. A review of literature(University of Minnesota, 2014) Schirmer, Patrick M.; van Eggermond, Michael; Axhausen, Kay W.Geospatial data available to researchers has increased tremendously over the last several decades, opening up opportunities to define residential location in multiple ways. This has led to a myriad of variables to define "location'' in residential location choice models. In this paper, we propose a common classification for location variables and categorize findings from a wide range of studies. We find similar preferences but different measurement methods and market segments for locations across different study regions. Recent studies consider the residential unit as choice alternative, making it possible to include a detailed description of the built environment. However, these studies are still limited in number and the inclusion of socioeconomic environment is more common. Transport land-use models can benefit from the inclusion of points of interest, such as schools, network distances, and the distance to previous locations. For the results of location choice models to be transferable to different disciplines, and avoid multi-collinearity, it is necessary to present different model specifications, including variables of interest in different disciplines.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Parameter estimation: drivers of extreme discharge in the Northwestern Switzerland(17.11.2017) Pavia Santolamazza, Daniela; Lebrenz, Henning; Bárdossy, András06 - PräsentationPublikation Interaction of Sliding, Shear, and Flexure for Earthquake Design of Reinforced Concrete Shear Walls(17.10.2017) Trost, Burkhart; Schuler, Harald; Stojadinovic, Bozidar06 - PräsentationPublikation Sliding Deformation Model for Reinforced Concrete Shear Walls under Seismic Loading(01/2017) Trost, Burkhart; Schuler, Harald; Stojadinovic, BozidarAccounting 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.04B - Beitrag KonferenzschriftPublikation A new approach for the description of discharge extremes in small catchments(26.04.2017) Pavia Santolamazza, Daniela; Lebrenz, Henning; Bárdossy, András06 - PräsentationPublikation Evaluation of an experimental Method via numerical Simulations(CRC Press, 2007) Schuler, Harald; Carpinteri, Alberto; Gambarova, Pietro G.; Ferro, Giuseppe; Plizzari, Giovanni04B - Beitrag KonferenzschriftPublikation Sliding resistance at the joint between a structural wall and the basement ceiling: a mechanical model(24.08.2014) Schuler, Harald; Trost, BurkhartThis 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.04B - Beitrag KonferenzschriftPublikation Experimental Investigation of Sliding on Compact Sliding Specimens under Cyclic Loads(08/2014) Trost, Burkhart; Schuler, Harald; Stojadinovic, BozidarThis 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.04B - Beitrag Konferenzschrift