Inst. Bauingenieurwesen

138 Items

Recent Submissions
Preparation and Characterization of Ultra-Lightweight Foamed Concrete Incorporating Lightweight Aggregates

Abd Elrahman, Mohamed ; El Madawy, Mohamed E. ; Chung, Sang-Yeop ; Sikora, Pawel ; Stephan, Dietmar (2019-04-06)

Increasing interest is nowadays being paid to improving the thermal insulation of buildings in order to save energy and reduce ecological problems. Foamed concrete has unique characteristics and considerable potential as a promising material in construction applications. It is produced with a wide range of dry densities, between 600 and 1600 kg/m3. However, at a low density below 500 kg/m3, it ...

Climate Change Demands Adaptive Management of Urban Lakes: Model-Based Assessment of Management Scenarios for Lake Tegel (Berlin, Germany)

Ladwig, Robert ; Furusato, Eiichi ; Kirillin, Georgiy ; Hinkelmann, Reinhard ; Hupfer, Michael (2018-02-10)

Lakes are known to be strongly affected by climate change as a result of their sensitivity to atmospheric forcing. The combined response of urban lakes to climatic changes and to urbanization of the catchment may be further altered by water quality management measures. We studied Lake Tegel in Berlin, Germany as a representative urban lake profoundly influenced by intense water management measu...

Modelling the Technical−Economic Relevance of the ETICS Construction Process

Sulakatko, Virgo (2018-11-09)

The increased number of energy efficiency requirements of the European Union has increased the renovation rate of apartment buildings. The external thermal insulation composite system (ETICS) is often used to upgrade the façade. However, the construction process shortcomings very often cause defects shortly after completion. This paper develops a technical–economic relevance assessment model of...

Pore Characteristics and Their Effects on the Material Properties of Foamed Concrete Evaluated Using Micro-CT Images and Numerical Approaches

Chung, Sang-Yeop ; Lehmann, Christian ; Abd Elrahman, Mohamed ; Stephan, Dietmar (2017-05-26)

Foamed concrete contains numerous pores inside the material, and these pores are a significant factor determining the material characteristics. In particular, the pore distribution characteristics of foamed concrete significantly affect its thermal and mechanical properties. Therefore, an appropriate investigation is necessary for a more detailed understanding of foamed concrete. Here, a set of...

Effect of Different Gradings of Lightweight Aggregates on the Properties of Concrete

Chung, Sang-Yeop ; Abd Elrahman, Mohamed ; Stephan, Dietmar (2017-06-07)

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Decision making in structural engineering problems under polymorphic uncertainty

Petryna, Yuri ; Drieschner, Martin (2019-02-22)

The treatment of diverse uncertainties is an important challenge in structural engineering problems, especially from the viewpoint of realistic analysis. Inaccuracy and variability are always present and have to be quantified by either probabilistic, possibilistic, polymorphic or other uncertainty approaches. Regardless to the applied uncertainty quantification method, the numerical predictions...

Adapting the water management to mitigate the impact of multiple stressors on an urban lake

Ladwig, Robert (2019)

Urban lakes are aquatic ecosystems that are influenced by a water management system and by a possibly strongly sealed urban catchment. The water management aims to fulfill multiple objectives: providing drinking water, sanitation and recreation for the people as well as keeping the ecosystem in a sustainable and resilient state. Urban lakes are facing several stressors. For instance, climate ch...

The assessment of hydrological impacts of climate change and their implications for water management across scales

Lobanova, Anastasia (2019)

The impacts of climate change can become a trigger for critical changes in the spatial and temporal distribution of water resources in many regions in Europe. This will lead from obviously negative effects in some regions to creation of opportunities in others. In the face of future changes: economic, social and environmental, both natural and triggered by anthropogenic activities, the effectiv...

A Novel Slope Failure Operator for a Non-Equilibrium Sediment Transport Model

Zhao, Jiaheng ; Özgen, Ilhan ; Liang, Dongfang ; Hinkelmann, Reinhard (2018)

Complex transport mechanism and interaction between fluid and sediment make the mathematical and numerical modeling of sediment transport very challenging. Different types of models can lead to different results. This paper investigates a non-equilibrium sediment transport model based on the total load. In this type of model, it is assumed that a bed slide will occur if the bed slope reaches a ...

A depth-averaged non-cohesive sediment transport model with improved discretization of flux and source terms

Zhao, Jiaheng ; Özgen-Xian, Ilhan ; Liang, Dongfang ; Wang, Tian ; Hinkelmann, Reinhard (2019)

This paper presents novel flux and source term treatments within a Godunov-type finite volume framework for predicting the depth-averaged shallow water flow and sediment transport with enhanced the accuracy and stability. The suspended load ratio is introduced to differentiate between the advection of the suspended load and the advection of water. A modified Harten, Lax and van Leer Riemann sol...

Comparison of depth-averaged concentration and bed load flux sediment transport models of dam-break flow

Zhao, Jiaheng ; Özgen, Ilhan ; Liang, Dongfang ; Hinkelmann, Reinhard (2017)

This paper presents numerical simulations of dam-break flow over a movable bed. Two different mathematical models were compared: a fully coupled formulation of shallow water equations with erosion and deposition terms (a depth-averaged concentration flux model), and shallow water equations with a fully coupled Exner equation (a bed load flux model). Both models were discretized using the cell-c...

An improved multislope MUSCL scheme for solving shallow water equations on unstructured grids

Zhao, Jiaheng ; Özgen-Xian, Ilhan ; Liang, Dongfang ; Wang, Tian ; Hinkelmann, Reinhard (2018-10-19)

This paper describes an improved vector manipulation multislope monotone upstream-centred scheme for conservation laws (MUSCL) reconstruction for solving the shallow water equations on unstructured grids. This improved MUSCL reconstruction method includes a bigger stencil for the interpolation and saves time for determining the geometric relations compared to the original vector manipulation me...

Improved multislope MUSCL reconstruction on unstructured grids for shallow water equations

Zhao, Jiaheng ; Özgen, Ilhan ; Liang, Dongfang ; Hinkelmann, Reinhard (2018)

In shallow water flow and transport modeling, the monotonic upstream‐centered scheme for conservation laws (MUSCL) is widely used to extend the original Godunov scheme to second‐order accuracy. The most important step in MUSCL‐type schemes is MUSCL reconstruction, which calculate‐extrapolates the values of independent variables from the cell center to the edge. The monotonicity of the scheme is...

Fully coupled robust shallow water flow and sediment transport model on unstructured grids

Zhao, Jiaheng (2019)

This Ph.D. thesis advances the fully coupling of robust shallow water flow and sediment transport modeling. The first part mainly focuses on the multislope MUSCL reconstruction for shallow water flow on unstructured grids. A limitation method for reconstruction of velocities avoids extremely high values for wet/dry fronts. The reconstruction methods are tested via analytical benchmarks and lab...

Modeling the impacts of climate extremes and multiple water uses to support water management in the Icó-Mandantes Bay, Northeast Brazil

Matta, Elena ; Koch, Hagen ; Selge, Florian ; Simshäuser, Max Nino ; Rossiter, Karina ; Silva, Gérsica Moraes Nogueira da ; Gunkel, Günter ; Hinkelmann, Reinhard (2018-07-25)

The hydropower production, water supply and aquaculture services of the Itaparica Reservoir are of immense importance for the Brazilian Northeast. Uncontrolled water resources consumption (e.g. irrigation, water supply), climate and land use change effects deteriorated the water quantity and quality in the reservoir, leading to socio-economic and environmental problems. In this work, a depth-av...

Decision making in structural engineering problems under polymorphic uncertainty

Petryna, Yuri ; Drieschner, Martin (2019-02-22)

The treatment of diverse uncertainties is an important challenge in structural engineering problems, especially from the viewpoint of realistic analysis. Inaccuracy and variability are always present and have to be quantified by either probabilistic, possibilistic, polymorphic or other uncertainty approaches. Regardless to the applied uncertainty quantification method, the numerical predictions...

Parameterization of arbitrary hole shapes using non-destructive testing and resulting stress concentration in a 2D plate with finite dimensions

Drieschner, Martin ; Petryna, Yuri ; Eichner, Lukas (2019-02-21)

Air void inclusions are mostly unavoidable in many different materials resulting from manufacturing processes or environmental conditions. In this contribution, non-destructive testing (NDT) like computer tomography (CT) is used for air void detection and quantification. The air voids lead to stress concentrations around them which influence significantly the structural integrity and at worst, ...

Acquisition of polymorphic uncertain data based on computer tomographic scans and integration in numerical models of adhesive bonds

Drieschner, Martin ; Petryna, Yuri (2019-02-21)

Since commercial wind turbines were introduced around 1980, the length of rotor blades has increased substantially up to 80m with consequently higher demands on availability and failure prevention. One of the typical failure mechanisms of rotor blades in operation are fatigue cracks in adhesive bonds often caused by air voids with a-priori unknown properties, which results from the manufacturi...

Electronic Supplementary to Doctoral Dissertation

Lobanova, Anastasia (2018)

This Electronic Supplementary contains the SWIM Model set up, calibrated and validated for all eight river basins, together with executables, used to perform modelling experiments for Doctoral Thesis "The assessment of hydrological impacts of climate change and their implications for water management across scales: from the local to European scale"

Full-scale performance of selected starch-based biodegradable polymers in sludge dewatering and recommendation for applications

Zhou, Kuangxin ; Stüber, Johan ; Schubert, Rabea-Luisa ; Kabbe, Christian ; Barjenbuch, Matthias (2017)

Agricultural reuse of dewatered sludge is a valid route for sludge valorization for small and mid-size wastewater treatment plants (WWTPs) due to the direct utilization of nutrients. A more stringent of German fertilizer ordinance requires the degradation of 20% of the synthetic additives like polymeric substance within two years, which came into force on 1 January 2017. This study assessed the...