Year: 2024
Author(s): Emil Adiels, Mats Ander, Christopher John Kenneth Williams
Publication Type: Journal article
Surface geometry plays a central role in the design of bridges, vaults and shells, using various techniques for generating a geometry which aims to balance structural, spatial, aesthetic and construction requirements.
In this paper we propose the use of surfaces defined such that given closed curves subtend a constant solid angle at all points on the surface and form its boundary. Constant solid angle surfaces enable one to control the boundary slope and hence achieve an approximately constant span-to-height ratio as the span varies, making them structurally viable for shell structures. In addition, when the entire surface boundary is in the same plane, the slope of the surface around the boundary is constant and thus follows a principal curvature direction. Such surfaces are suitable for surface grids where planar quadrilaterals meet the surface boundaries. They can also be used as the Airy stress function in the form finding of shells having forces concentrated at the corners.
Our technique employs the Gauss-Bonnet theorem to calculate the solid angle of a point in space and Newton's method to move the point onto the constant solid angle surface. We use the Biot-Savart law to find the gradient of the solid angle. The technique can be applied in parallel to each surface point without an initial mesh, opening up for future studies and other applications when boundary curves are known but the initial topology is unknown.
We show the geometrical properties, possibilities and limitations of surfaces of constant solid angle using examples in three dimensions.
Year: 2024
Author(s): Oliver Disney
Publication Type: Licentiate thesis
Building Information Modeling (BIM) was expected to rapidly transform the construction industry, but its uptake has been unexpectedly slow. Furthermore, even state-of-the-art BIM projects have been challenged by hardware and software issues, limiting BIM’s implementation in the construction phase. This research explores an emerging approach to construction: Total BIM. Total BIM embraces BIM in its totality in that BIM is actively used in the construction phase by implementing model-based construction processes. It replaces 2D drawings as the legally binding source of information, enabling site workers to interact with modern cloud-based BIM software to create and extract necessary and relevant information.
Until recently, there has been a lack of real-world cases successfully implementing BIM as the single source of information for construction workers, which has hindered the possibility for researchers to explore the use of Total BIM in practice. However, this is beginning to change in Sweden and Norway, with the emergence of pioneering Total BIM projects. The purpose of this study has been to explore how Total BIM can be implemented as a single source of information across the design and construction phases of real-world projects. To achieve this, three in-depth case studies were conducted, collecting qualitative data from semi-structured interviews, observations, workshops, and more.
The findings, presented in four appended papers, demonstrate that implementing Total BIM in construction projects is possible and may even be preferred compared with traditional ways of working. Total BIM could serve as the missing link for advancing digitalization in the construction industry. Construction workers become an important part of structured data creation, through integrated processes such as requests for information (RFIs), controls, checklists and photos. This structured data enables new opportunities for informed, data-driven decision-making and site monitoring.
This research contributes rich empirical data from real-world case studies of Total BIM projects, illustrating how Total BIM overcomes limitations observed in previous state-of-the-art BIM projects. Additionally, it questions whether Total BIM could represent the digital disruption that the construction industry has been missing. For practitioners, this research provides real-world examples from Total BIM projects, demonstrating Total BIM implementation and highlighting key processes, while highlighting how Total BIM can create value.
Year: 2024
Author(s): Jens Forssén
Publication Type: Journal article
Randomness in the medium of propagation affects the signal received at a distance from a source resulting in amplitude and phase fluctuations as well as reduced coherence between different paths of propagation. A method is described and validated for incorporating such fluctuations and decorrelations in sound signals in a single approach. Here, simplified conditions are used of open space, with or without a single reflecting surface, assuming fluctuations as for plane waves in homogeneous and isotropic temperature turbulence. Validating results are shown for Gaussian and von Karman turbulence models and exemplifying sound clips are provided as supplementary material.
Year: 2023
Author(s): Vasilis Naserentin, Georgios Spaias, Anestis Kaimakamidis, Nikos Pitsianis, Anders Logg
Publication Type: Paper in proceeding
The growing interest in creating digital twins of cities has sparked a surge in the development of detailed 3D models. In this paper we examine the current state-of-the-art in generating high-resolution 3D models of cities using neural network techniques. Additionally, we showcase the outcomes of two case studies that demonstrate the practical applications of these techniques in 3D city model generation. The first case study focuses on rooftop segmentation using publicly available Swedish cadastral data, while the second case study explores façade feature extraction using Google Street View data.
Year: 2023
Author(s): Pierre Wikby, Ayman Abed, Mats Karlsson, Jonas Sundell, Minna Karstunen
Publication Type: Paper in proceeding
Leakage into rock tunnels covered by thick soft clay deposits may cause a pore water pressure drop over large areas through underdrainage, resulting in settlement problems and potential damage to structures. In urban areas, heterogeneity in soil properties can be substantial. In this paper, a case study with a systematic sensitivity analysis combined with coupled hydro-mechanical finite element analyses was performed for three key parameters (overconsolidation ratio, vertical hydraulic conductivity and hydraulic anisotropy) considering one scenario of underdrainage. The results show that both the magnitude and uncertainty of settlements are strongly stratigraphy-dependent. The overconsolidation ratio contributed the most to the settlement uncertainty and the effect of vertical hydraulic conductivity was also found to be significant, while the changes in hydraulic anisotropy had negligible influence.
Year: 2023
Author(s): Mattia Mangia, Carla Di Biccari, Mattias Roupé
Publication Type: Paper in proceeding
Complex infrastructures such as railway networks face increasing challenges related to resource allocation, external events, constraints, and demands. Therefore, it is crucial to optimize the Asset Management (AM) phase to ensure the value and functionality of the assets. The integration of Building Information Modelling (BIM) and Geographic Information Systems (GIS) can support this phase, but it can only yield benefits with a comprehensive approach that considers and addresses the specific needs and resources of the assets and their AM organization. The main benefits include improved data management, manipulation, information visualization and optimized resource allocation. This study describes an intermediate step towards developing a BIM/GIS integration framework for AM that can guide both researchers and practitioners. The framework aims to bridge theory and practice by incorporating insights from literature reviews and case studies. Its main objectives are to provide a comprehensive multi-stakeholder view and methods for effectively integrating BIM and GIS in this context. To develop the framework, the study employed focus groups, interviews, and practical BIM/GIS tests, which provided insights reported in this article. Furthermore, the study provides research directions for effective BIM/GIS integration in infrastructure AM.
Year: 2023
Author(s): Mikael Johansson, Mattias Roupé, Mikael Viklund Tallgren
Publication Type: Paper in proceeding
Building Information Modeling (BIM) is changing the way architects and engineers produce and deliver design results, and object-oriented 3D models are now starting to replace traditional 2D drawings during the construction phase. This allows for a number of applications to increase efficiency, such as quantity take-off, cost-estimation, and planning, but it also supports better communication and increased understanding at the construction site by means of detailed 3D models together with various visualization techniques. However, even in projects with a fully BIM-based design, there is one remaining part that is still done primarily using 2D drawings and sketches – the construction site layout plan. In addition to not take advantage of the benefits offered by 3D, it also makes it difficult to integrate site layout planning within the openBIM ecosystem. In this paper we present the design and evaluation of a user-friendly, IFC-compatible software system that supports collaborative, multi-user creation of construction site layout plans using both multi-touch table and immersive VR. By allowing temporary structures, machines, and other components to be easily added and updated it is possible to continuously produce and communicate 3D site layout plans that are aligned with the schedule and supports integration with other BIM-tools.
Year: 2020
Author(s): Alexander Gösta, André Agi, Jacob Flårback, Jesper Karlsson, Ellen Simonsson
Publication Type: Journal article
This article aims to map how different digital tools can be useful for architects and how they might affect their work processes. Researchers and professionals were interviewed to investigate what they found valuable to measure, which methods they used within their analyses, as well
as the opportunities and risks they see for the future of the field with regards to digital tools. As part of the survey, a workshop was held with architects and project managers examining the possibilities of connecting existing methods and tools to the sustainability certification system,
City Lab Action Guide, and through that, to achieve a more ambitious set of sustainability goals for the projects. Findings from the study indicate that there are risks associated with giving data an increasingly important role in the design work. A working model never provides the full truth
but is inherently limited by its constraints. It is important to acknowledge that all angles and aspects of a problem can never be represented in a model. Another possible risk identified lies in the quality of, and access to, data. In a scenario where data plays an increasingly important
role, it is not only the quality of the datasets that is of utmost importance, but it is equally important that the urban planners who request the analyses ask the questions first, and then collect the necessary data, instead of vice versa.
Year: 2020
Author(s): Beata Stahre Wästberg, Jens Forssén, Liane Thuvander, Monica Billger, Anders Logg, Fabio Latino
Publication Type: Magazine article
Inom dagens stadsplanering används oftast 2D-kartor för att visa beräknade värden för framtida bullernivåer. Dessa kartor kan ibland vara svåra att tolka. För att öka förståelsen och underlätta kommunikationen mellan olika aktörer inom planeringsprocessen, har vi inom forskningsprojektet DemoVirPEN på Chalmers och Göteborgs universitet utvecklat en prototyp av ett verktyg för visualisering och auralisering (ljudsimulering) av buller från vägtrafik i en stadsmodell.
Year: 2020
Author(s): Bernd Ketzler, Vasilis Naserentin, Fabio Latino, Christoforos Zangelidis, Liane Thuvander, Anders Logg
Publication Type: Journal article
During the last decades, a variety of digital tools have been developed to support both the planning and management of cities, as well as the inclusion of civic society. Here, the concept of a Digital Twin – which is rapidly emerging throughout many disciplines due to advances in technology, computational capacities and availability of large amounts of data – plays an important role. In short, a digital twin is a living virtual model, a connected digital representation of a physical system and has been a central concept in the manufacturing industry for the past decades. In this article, we review the terminology of digital twins for cities and identify commonalities and relations to the more established term 3D city models. Our fi ndings indicate an increasing use of the term digital twin in academic literature, both in general and in the context of cities and the built environment. We fi nd that while there is as yet no consensus on the exact defi nition of what constitutes a digital twin, it is increasingly being used to describe something that is more than a 3D city model (including, e.g. semantic data, real-time sensor data, physical models, and simulations). At the same time, the term has not yet replaced the term 3D city model as the most dominant term in the 3D GIS domain. By looking at grey literature we discuss how digital twins for cities are implemented in practice and present examples of digital twins in a global perspective. Further, we discuss some of the application areas and potential challenges for future development and implementation of digital twins for cities. We conclude that there are signifi cant opportunities for up-scaling digital twins, with the potential to bring benefi ts to the city and its citizens and clients.
