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Bridge structures with complex geometry through facetted structural elements made of carbon reinforced ultra-high-performance concrete - Graph based decomposition and trajectory sensitive manufacturing

Applicants

Prof. Dr.-Ing. Dipl.-Wirt. Ing. Oliver Fischer Technische Universität München, Lehrstuhl für Massivbau 

Prof. Dr.-Ing. André Borrmann Technische Universität München, Lehrstuhl für Computergestützte Modellierung und Simulation

Scientific staff

Daniel Auer, M. Sc.Technische Universität München, Lehrstuhl für Massivbau

Lothar Kolbeck, M.Sc.Technische Universität München, Lehrstuhl für Computergestützte Modellierung und Simulation

Project describtion

The basic idea of the research project is to further develop the modularization principle by using faceted structural elements made of carbonreinforced ultra-high performance concrete [6] for concrete bridge construction. A conceptual sketch of the construction method is shown in Figure 1.  The approach, comparable to the geometric division of load-bearing structures into finite elements, is characterized by systematic decomposition of the overall structure into modules that can be easily manufactured. The boundary conditions to be complied with result from structural mechanical properties on the one hand, and from the requirements of manufacturing on the other hand. This complex optimization problem can only be solved by applying computer-aided methods which are informed by geometry, joining and fabrication techniques of the modules.

Figure 1: Conceptual sketch showing the adaptable modular construction method at the example of a downstand-beam girder of a beam bridge
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Figure 1: Conceptual sketch showing the adaptable modular construction method at the example of a downstand-beam girder of a beam bridge

The focus in the research project is on plate-shaped modules that can be applied to a wide range of potentially complex construction situations. Through graph-based data modeling in the background and procedural generation of the parametric geometry, these modules can be used as a powerful interface between design and manufacturing in an end-to-end digital process chain. The shape and adaptability of the module is shown in Figure 2.  

Figure 2: Highly adaptable module as an expressive digital interface between design and manufacturing
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Figure 2: Highly adaptable module as an expressive digital interface between design and manufacturing

Based on a trajectory-sensitive, iteratively optimized and homogenized determination of the printing paths, the additive manufacturing can be automated with the help of robotics and custom nozzle technology, see Figure 3: 

Figure 3: Trajectory-sensitive computation of the printing path (.li) and multi-layered extrusion printing with a Kuka-robot (ri.)
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Figure 3: Trajectory-sensitive computation of the printing path (.li) and multi-layered extrusion printing with a Kuka-robot (ri.)

The segmentation and production of the modules is always preceded by a bridge geometry specified by the engineer. The decomposition of the initial geometry into modules is done by applying a graph rewriting system. A graph rewriting system is a set of rules where each rule allows to recognize an occurring pattern in the product model structure of structures and to develop it automatically [2,4,7], for example a recursive subdivision of a girder up to segments suitable for manufacturing. Geometric and semantic-topological development go hand in hand, as exemplified by Figure 3. In addition to automating knowledge-intensive processes such as segmentation, the graph structures also enable a semantic-topologic structuring of the segmented girders.

Figure 4: Illustration of the recursive segmentation by splitting a girder both geometrically (le.) and a topologically (ri.)
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Figure 4: Illustration of the recursive segmentation by splitting a girder both geometrically (le.) and a topologically (ri.)

As a first validation of the project ideas, the Paulifurt Bridge and a planar projection of the Trumpfsteg have already been modeled, as shown in Figure 5. Further research includes a generalization for additional and more complex bridge structures.

Poster on project contents

Figure 5: Remodeling of the Paulifurtbrücke (le.) and the Trumpfsteg (ri.) based on the adaptable module.
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Figure 5: Remodeling of the Paulifurtbrücke (le.) and the Trumpfsteg (ri.) based on the adaptable module.

Research related to system construction development


The methodology presented in [7] was followed in the subproject on system design:  Based on design requirements (such as spans, number of lanes, etc.), suitable structural systems and cross-sections were explored. Mainly from structural-mechanical aspects (bearing conditions, coupling conditions), but finally also according to the intended flow manufacturing process and easy dry joinability, the system is finally divided into subsystems and these finally into standardized modules with standardized interfaces. Iteratively and in interdisciplinary exchange with other subprojects (on the subject of joining and dimensioning), two systems were modularized and elaborated in more detail in the subproject. As can be seen in Figure 1, the first is the substructure of an arch bridge and the second is a modular frame beam. During the system development, details of the dry connection technology and the matching of design and manufacturing possibilities proved to be the greatest challenges.

Figure 1: Two modular systems developed in the course of the project
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Figure 1: Two modular systems developed in the course of the project

Research related to design automation

Design automation in the sense of mass customization was explored divided into a parametric product modeling concept and the data and algorithm modeling for modularization and assembly. For the product modeling, object-oriented principles were consistently used. Specifically, the topological-semantic hierarchization was carried out in five levels, where the upper levels organizationally control the assembly with the help of auxiliary geometries and the lowest three levels contain modular assemblies, components and (interface-relevant) embedded elements. Algorithms were developed whose computational processes were semantically divided into auxiliary geometry processing, topology calculations, part manipulations and product model interaction. The algorithm thereby develops a graph model that stores the essential design entities and their relationships.

Figure 2: Illustration of the graph-based mass customization process
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Figure 2: Illustration of the graph-based mass customization process

Research related to additive manufacturing technology.


Based on a detailed, model-based 3D design, digital manufacturing methods were developed, in concrete based on additive manufacturing with carbon fiber reinforced UHPC. The structurally motivated idea for the printing path calculation was the trajectory-sensitive optimization for material savings for the given, anisotropic material.
The developed printing path planning algorithm includes a homogenization for nozzles without variable width and is based on NURBS curves and optimization calculation. First, an analysis domain with evaluation points of the main stress directions is formed. An initial set of control points of the initial curve is formed, offset curves are computed until the analysis domain is covered. In a narrow grid spacing the offset curves are discretized and the tangent of the curve is compared with the principal stress direction. The optimization algorithm varies the control points of the initial NURBS curve so that the sum of the deviations becomes minimal. Figure 3 illustrates the concept of the algorithmic printing path calculation and an associated print.

Figure 3: Illustration of printing path planning algorithm (top) and associated print (bottom)
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Figure 3: Illustration of printing path planning algorithm (top) and associated print (bottom)

Publications

[8] Kolbeck, L.; Vilgertshofer, S.; Borrmann, A.
Graph-based mass customization of modular precast bridges
Proceedings of 30th EG-ICE, London, 2023

[7] Kolbeck, L.; Vilgertshofer, S.; Abualdenien, S.; Borrmann, A.
Graph Rewriting Techniques for Engineering Design
Frontiers in Built Environment 7, Februar 2022, S. 1–19.

[6] Rutzen, M.; Lauff P., Niedermeier R., Fischer O., Raith M.; Grosse C.; Weiss U., Peter M.; Volkmer D.
Influence of fiber alignment on pseudoductility and microcracking in a cementitious carbon fiber composite material
Materials and Structures, 54:58, 2021. (doi:10.1617/s11527-021-01649-2)

[5] Borrmann, A.; Bruckmann, T.; Dörfler, K.; Hartmann, T.; Smarsly, K.
Towards realizing the information backbone of robotized construction – Computational Methods and cyber-physical architectures for collaborative robotic fleets
In: Proceedings of the CIB W78 Conference, Luxembourg, 2021

[4] Abualdenien, J.; Borrmann, A.
PBG: A parametric building graph capturing and transferring detailing patterns of building models
In: Proceedings of the CIB W78 Conference, Luxembourg, 2021

[3] Slepicka, M.; Vilgertshofer, S.; Borrmann, A.
Fabrication Information Modeling: Closing the gap between Building Information Modeling and Digital Fabrication
In: Proceedings of the 38th International Symposium on Automation and Robotics in Construction (ISARC), Dubai, UAE, 2021

[2] Kolbeck, L.; Auer, D.; Fischer, O.; Vilgertshofer, S.; Borrmann, A.
Modulare Brückenbauwerke aus carbonfaserbewehrtem Ultrahochleistungsbeton – Graph-basierter Entwurf und trajektoriensensitive Fertigung
Beton- und Stahlbetonbau 116, Sonderheft Schneller bauen S2, September 2021, S. 24–33.
(https://doi.org/10.1002/best.202100053)

[1] Fischer, O.; Auer, D.; Borrmann, A.; Afzal, M.:
Brückenbauwerke mit komplexer Geometrie durch facettierte Flächenelemente aus carbonbewehrtem Ultrahochleistungsbeton - Graphbasierte Zerlegung und trajektoriensensitive Fertigung.
In: BetonWerk International Nr. 5, 2020, S. 18
Link zum Artikel

Supervised theses

2023
[15] Liebl, F.
Konstruktive Entwicklung und Nachweiskonzept für einen modularen Rahmenriegel mit Trogquerschnitt
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Daniel Auer & Lothar Kolbeck

[14] Praveen, M.
Model-based structural proofing and analysis-informed design feedback for a modular bridge system
Master-Thesis, Technische Universität München, Lehrstuhl für Computergestützte Modellierung und Simulation, Lothar Kolbeck, M.Sc.

[13] Bader, A.
Parametrisches Modellierungskonzept für eine seriell vorfertigbaren Bogenbrücke
Bachelor Thesis, Technische Universität München, Lehrstuhl für Massivbau, Lothar Kolbeck

[12] Wohofsky, H.
Parametrische Detaillierung einer seriell vorfertigbaren Bogenbrücke in hohem Detaillierungsgrad
Bachelor Thesis, Technische Universität München, Lehrstuhl für Massivbau, Lothar Kolbeck

[11] Exner, C.,
Vergleich mehrerer Gestaltgrammatikimplementierungen bezüglich ihrer geometrischen und semantischen Expressivität
Bachelor Thesis, Technische Universität München, Lehrstuhl für Massivbau, Lothar Kolbeck

2022
[10] Mucheng, X.
Bottom-up design of modular concrete structures utilizing formal grammars
Master-Thesis, Technische Universität München, Lehrstuhl für Computergestützte Modellierung und Simulation, Lothar Kolbeck, M.Sc.

[9] Zhehong, Z.
Parametrische Entwurfsplanung von Brückenbauteilen in Modulbauweise mit statisch optimierter Segmentierung und einem Konzept der adaptiven Detaillierung
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Daniel Auer, M.Sc & Lothar Kolbeck, M.Sc.

2021
[8] Abaría, A.
Development and optimization of a nozzle system for the extrusion of ultra-high-strength concretes with carbon short fibers for use in the additive manufacturing process
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer, M. Sc.

[7] Fernández, B.
Optimization of the material composition of ultra-high-strength concrete formulations with carbon short fibers for application in the additive manufacturing process
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer M. Sc.

[6] Tappeiner, C.
Verbundverhalten der Zwischenschichten lagenweise extrudierter Betone
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer, M. Sc.

[5] Huber, S.
Entwicklung einer Formgrammatik für die statisch optimierte Segmentierung von Brückenbauteilen in Modulbauweise
Bachelor-Thesis, Technische Universität München, Lehrstuhl für Computergestützte Modellierung und Simulation, Lothar Kolbeck, M.Sc.

[4] Hammerschick, S.
Zum Tragverhalten von dehnungsverfestigenden zementgebundenen Hochleistungswerkstoffen
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer, M. Sc.

[3] Färber, A.
Numerische Simulation additiv gefertigter Bauteile aus Carbonkurzfaserbeton
Master-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer, M. Sc.

[2] Klöck, V.
Dokumentation des additiven Fertigungsprozesses hinsichtlich der Anwendung im Betonbau
Bachelor-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer, M. Sc.

[1] Vollherbst, A.
Pumpenförderung von Kurzfaserbetonen
Bachelor-Thesis, Technische Universität München, Lehrstuhl für Massivbau, Betreuer: Daniel Auer, M. Sc.