Publications

Adaptive bone re-modelling for optimization of porous structural components

Year: 2022
Author(s): Jens Olsson, Mats Ander, Christopher John Kenneth Williams
Publication Type: Paper in proceeding

This paper presents a speculative application of adaptive bone-remodelling to generate porous structures for building components using a numerical meshless method. We hypothesize that such porous structures could then be 3d printed to achieve light weight and material efficient
building components. The meshless model is built up of particles that are connected by arms to their neighbours within a distance called a horizon. The re-modelling adaption is then based on the ratio of arms strain over average arm strain which is mapped to a third-order polynomial function and used to scale the arm stiffness in a way that mimics the resorption and densification of bone tissue. The method is shown to work rather well in the recreation of the structural patterns found in cross section of a femur bone. The translation to a geometry which can be manufactured with additive techniques is not tackled specifically and suggest a direction for further work.


Combining Open Source and Commercial Tools in Digital Twin for Cities Generation

Year: 2022
Author(s): Vasilis Naserentin, Sanjay Somanath, Orfeas Eleftheriou, Anders Logg
Publication Type: Paper in proceeding

Evidently, Smart Cities are on the rise and there is an increasing need for digital twins of these complex environments and their corresponding 3D models. The creation and maintenance of such twins is a time consuming task, since cities are living evolving organisms. In this paper we are presenting work done within the Digital Twin Cities Centre (DTCC) in Sweden in the field of automated 3D city model generation. We showcase a novel method of combining open source and commercial software for creating digital twins of any urban context in a procedural way from raw input data and using Unreal Engine as a visualization front-end. We combine two different workflows, one based on the commercial software suite Feature Manipulation Engine and in parallel we utilize the open source code developed within the Centre, dubbed DTCC Builder. The assets created can be used in urban planning, multi-physics continuum mechanics simulations and for visualization and illustration on a 3D scale. By using, in a complementary way, established commercial software and state of the art open source C++ code we manage to utilize the quality of life features the first provides, while assigning the demanding tasks of comforming mesh generation to the former. The longer term goal is (nearly) real-time mesh digital twinning of any city and user interaction with the 3D assets provided.


Evaluation of social facilities coverage: A case study of Sofia city

Year: 2022
Author(s): Stoyan Boyukliyski, Dessislava Petrova-Antonova, Sanjay Somanath
Publication Type: Paper in proceeding

In order to aid the decision making process related to the provision of public services as to maximize the benefits for society, it is crucial to evaluate the current social facilities demand in terms of spatial distribution and access. The paper aims to solve this problem by proposing a method for automated assessment of the coverage of public services within an urban region using a capacitated graph. The methodology abstracts residential buildings into demand nodes and public service buildings into supply nodes within a graph and then uses shortest distance calculations in order to balance the two, while prioritizing residential buildings based on distance. The paper is focused on creating a general pipeline that can be used on any type of public services, as long as a certain geospatial and demographic data are available. The method is described without referencing specific tools, but focusing on the general procedure. The procedure is then applied to the whole city of Sofa, focusing on assessing the coverage of kindergartens using the 15 minutes walking distance, followed by a brief discussion of results.


Pathways towards carbon neutrality: A participatory analysis of the Gothenburg’s energy plan

Year: 2022
Author(s): Daniela Maiullari, Alvar Palm, Holger Wallbaum, Liane Thuvander
Publication Type: Journal article

Among International Energy Agency members, Sweden is one of the upfront countries in implementing energy policies to achieve zero net emissions. Despite having the lowest share of fossil sources in its primary energy supply, becoming carbon neutral by 2045 is a challenging target. To meet the national goal, cities’ roadmaps and strategic plans have a leading role in facilitating the implementation of energy efficiency measures and renewable production systems. However, succeeding in city energy transitions requires envisioning and understanding of risk and vulnerability levels of the new socio-technical energy system. This study presents a review of the City of Gothenburg’s Energy Plan 2022-2030 and discusses potential challenges
for its implementation. Based on a document study, stakeholder workshop, and interviews the research identifies four key aspects: i) the coordination between energy and urban planning, ii) the future stability of district heating and cooling, iii) the balance in electrification of the buildings and transport, iv) communication and tools in decision-making processes. Finally, the study suggests new measures that should be allocated in the plan to guarantee the development of instruments and analysis for addressing the identified challenges.


Modelling the construction and long-term response of Göta Tunnel

Year: 2021
Author(s): Johannes Tornborg, Mats Karlsson, Anders Kullingsjö, Minna Karstunen
Publication Type: Journal article

This paper presents a benchmark of a rate-dependent constitutive model for soft soils, implemented in a 2D finite element code, against the response of an instrumented excavation in sensitive clay: Göta Tunnel in Gothenburg. The monitoring data, which comprise time-series of pore water pressures, displacements, earth pressures and strut forces, provide valuable insights of the time-dependent response during the construction period. The long-term response, in terms of the ongoing settlement rates, is assessed using remote sensing data. The results of the numerical simulations demonstrate that the constitutive model, Creep-SCLAY1S, is capable of capturing the observed response. The trends of vertical and horizontal displacements are captured well until the stage of dewatering, and the evolution of pore pressures and earth pressures is computed with high accuracy, excluding peaks in the measurement values arising from pile and rock anchor installation. Most importantly, the results demonstrate that the rate-dependent model enables to model the complete service life of the tunnel, from construction of the excavation to the tunnel operation, with one unified model parameter set. Furthermore, the comparisons highlight the importance of assessing installation effects both in the choice of construction methods and modelling.


An entity-relationship model of the flow of waste and resources in city-regions: Improving knowledge management for the circular economy

Year: 2021
Author(s): Jonathan Edgardo Cohen, Jorge Gil
Publication Type: Journal article

Waste and resources management is one of the domains where urban and regional planning can transition towards a Circular Economy, thus slowing environmental degradation. Improving waste and resources management in cities requires an adequate understanding of multiple systems and how they interact. New technologies contribute to improve waste management and resource efficiency, but knowledge silos hinder the possibility of delivering sound holistic solutions. Furthermore, lack of compatibility between data formats and diverse definitions of the same concept reduces information exchange across different urban domains. This paper addresses the challenge of organising and standardising information about waste and resources management in city regions. Given the amount and variety of data constantly captured, data models and standards are a crucial element of Industry 4.0. The paper proposes an Entity-Relationship Model to harmonise definitions and integrate information on waste and resources management. Furthermore, it helps to formalise the components of the system and their relationships. Semi-structured interviews with government officials, mobile app developers and academics provided insights into the specific system and endorsed the model. Finally, the paper illustrates the translation of the ERM into a relational database schema and instantiates Waste Management and industrial Symbiosis cases in Buenos Aires (ARG) and Helsingborg (SWE) to validate its general applicability. The data model for the Circular Flow of Waste and Resources presented here enhances traditional waste management perspectives by introducing Circular Economy strategies and spatial variables in the model. Thus, this research represents a step towards unlocking the true potential of Industry 4.0.


From soft soil modelling to engineering application

Year: 2021
Author(s): Minna Karstunen
Publication Type: Paper in proceeding

Soft soil engineering is still a challenge, in particular when we increasingly need to construct on densely populated urban areas next to existing structures, and need to deal with the effects of climate change. The paper discusses the systematic research by the author and her co-workers in the last 20 years that has resulted in the development and validation of advanced soil models, specifically geared for Scandinavian soft soil conditions. The culmination of this research is Creep-SCLAY1S, a rate dependent anisotropic model, which is backed by hierarchical development and systematic validation. Some recent examples of engineering applications where the model was used are are highlighted, in addition to the parameter determination and calibration.


Experience from short-and long-term performance of deep excavations in soft sensitive clays

Year: 2021
Author(s): Johannes Tornborg, Mats Karlsson, Anders Kullingsjö, Minna Karstunen
Publication Type: Paper in proceeding

Design of excavations and permanent underground structures requires accurate predictions of e.g. deformations and earth pressures for both the short-and long-term. As excavation depths increase and/or the proximity to adjacent infrastructure decreases, there is a need to improve and develop existing design methods and validate numerical models. The first part of this paper revisits the measurement data from a previous excavation, the Göta Tunnel in Gothenburg, Sweden, in order to benchmark a contemporary constitutive soil model, called Creep-SCLAY1S. This study looks into time series including e.g. final dewatering of the excavation, followed by the development of pore water pressures, earth pressures and deformations over time (until 2 years after excavation). The model predictions are in general in good agreement with the measurement data up to final dewatering. However, installation effects due to drilling are believed to have caused continued deformations which are difficult to capture in the numerical model. Part two of the paper presents details of a recently instrumented excavation in soft clay in Central Gothenburg. The measurement data comprises e.g. pore water pressures, deformations as well as vertical and horizontal earth pressures at three locations under the permanent structure. Continued long-term measurements are planned and the existing and future data are believed to provide valuable insights on the development of the stress state and earth pressures under permanent structures in soft clay.


City Information Modelling: Digital Planning for Sustainable Cities

Year: 2020
Author(s): Jorge Gil
Publication Type: Other text in scientific journal

No abstact available


Towards spatial integration of qualitative data for urban transformation – challenges with automated geovisualization of perception of urban places

Year: 2020
Author(s): Liane Thuvander, Fabio Latino, Christoforos Zangelidis, Marco Adelfio, Vasilis Naserentin, Anders Logg
Publication Type: Paper in proceeding

Urban planning needs to face and integrate ecological, social, and economic aspects of city living. So far, attempts to integrate different urban simulation models into one technical platform have focused on quantitative data. The aim of this paper is to present the preparation for an automated method to spatially integrate and visualize interview-based qualitative data on the perception of urban places into a virtual platform. The Gothenburg suburb of Hammarkullen is used as a case study. Two CAQDAS software, NVivo and Atlas.ti, were tested. In both
software, locations and urban qualities were coded and clustered. Visualization strategies such as information tree structures, geo-coded quotations, spatial word clouds, linked to 2D maps and 3D environments were developed. Results identify the challenges to overcome and show limitations of the software in terms of creating graphs and relationships as well as automated geocoding of data to maps. The project offers a step towards the integration of qualitative (social)
data into digital environments that can be scaled up. By that, it contributes with a new dimension of analysis of urban environments which is necessary for sustainable transformation of cities.


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