scholarly journals Shell-supported footbridges

2020 ◽  
Vol 7 (1) ◽  
pp. 199-214
Author(s):  
Luigi Fenu ◽  
Eleonora Congiu ◽  
Giuseppe Carlo Marano ◽  
Bruno Briseghella
Keyword(s):  
Topology Optimization ◽  
High Efficiency ◽  
Shell Structures ◽  
Form Finding ◽  
Fundamental Research ◽  
Spring System ◽  
Earthquake Action ◽  
Concrete Shell ◽  
Concrete Shells ◽  
Thrust Network Analysis

AbstractArchitects and engineers have been always attracted by concrete shell structures due to their high efficiency and plastic shapes. In this paper the possibility to use concrete shells to support footbridges is explored. Starting from Musmeci’s fundamental research and work in shell bridge design, the use of numerical form-finding methods is analysed. The form-finding of a shell-supported footbridge shaped following Musmeci’s work is first introduced. Coupling Musmeci’s and Nervi’s experiences, an easy construction method using a stay-in-place ferrocement formwork is proposed. Moreover, the advantage of inserting holes in the shell through topology optimization to remove less exploited concrete has been considered. Curved shell-supported footbridges have been also studied, and the possibility of supporting the deck with the shell top edge, that is along a single curve only, has been investigated. The form-finding of curved shell-supported footbridges has been performed using a Particle-Spring System and Thrust Network Analysis. Finally, the form-finding of curved shell-supported footbridges subjected to both vertical and horizontal forces (i.e. earthquake action) has been implemented.

scholarly journals Form Finding of Shell Bridges Using the Pneumatic Forming of Hardened Concrete Construction Principle

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Benjamin Kromoser ◽  
Thomas Pachner ◽  
Chengcheng Tang ◽  
Johann Kollegger ◽  
Helmut Pottmann
Keyword(s):  
Fundamental Problem ◽  
Construction Method ◽  
Hardened Concrete ◽  
Membrane Action ◽  
Form Finding ◽  
Construction Principle ◽  
New Construction ◽  
Spring System ◽  
Concrete Shells ◽  
Curved Panels

Concrete shells are fascinating structures. Even thin shells can span over large areas without requiring any columns. If a form-defining load case exists, the shape of the shell can be designed to ensure that the forces in the structure are transferred primarily by the membrane action, which leads to an even distribution of the stresses across the shell surface. Concrete as a material, characterized by high compressive strength and low tensile strength, can be used with a very high degree of utilization. A fundamental problem with building concrete shells is the high effort required for the production of the complicated formwork. A new construction principle called Pneumatic Forming of Hardened Concrete (PFHC) was invented at TU Wien and requires no traditional formwork or falsework during the construction process. An air cushion is used to lift a flat hardened concrete plate, and at the same time, additional post-tensioning cables are tightened to support the transformation of the flat plate into a double-curved shell. One possible application of PFHC is the construction of shell bridges. Here, the shape of the shell has to be designed according to the acting loads and the boundary conditions of the construction method. This paper describes the partly conflicting factors involved in the form-finding process for practical application and the semiautomated workflow for optimizing the geometry of shell bridges. In the first optimization step, the final bridge shape is determined using a particle-spring system or alternatively a thrust-network approach. In the second optimization step, the shell is completed to form a full dome—this is called the reference geometry and is required for the new construction method. Finally, the reference geometry is discretized into single-curved panels by using a mesh-based optimization framework. To frame the presented work, an overview of different experimental and computer-aided form-finding methods is given.

scholarly journals The use of a particle method for the modelling of isotropic membrane stress for the form finding of shell structures

2015 ◽  
Vol 61 ◽  
pp. 24-31 ◽  
Author(s):  
Francis Aish ◽  
Sam Joyce ◽  
Samar Malek ◽  
Chris J.K. Williams
Keyword(s):  
Particle Method ◽  
Shell Structures ◽  
Membrane Stress ◽  
Form Finding

New solutions for constructing double-curved concrete shell structures

2010 ◽  
pp. 445-446
Author(s):  
M Johnson ◽  
P Kassabian ◽  
C Genter ◽  
M Love ◽  
T Love ◽  
...  
Keyword(s):  
Shell Structures ◽  
Concrete Shell

Form Finding of Shell Structures by Using Membrane Theory

2021 ◽  
pp. 213-237
Author(s):  
Francesco Marmo ◽  
Nicoló Vaiana
Keyword(s):  
Shell Structures ◽  
Membrane Theory ◽  
Form Finding

scholarly journals Substructure-Based Topology Optimization for Symmetric Hierarchical Lattice Structures

Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 678
Author(s):  
Zijun Wu ◽  
Renbin Xiao
Keyword(s):  
Topology Optimization ◽  
High Efficiency ◽  
Spline Interpolation ◽  
Optimization Method ◽  
Optimality Criteria ◽  
Lattice Structures ◽  
Hierarchical Lattice ◽  
B Spline ◽  
Design Variables ◽  
Optimality Criteria Method

This work presents a topology optimization method for symmetric hierarchical lattice structures with substructuring. In this method, we define two types of symmetric lattice substructures, each of which contains many finite elements. By controlling the materials distribution of these elements, the configuration of substructure can be changed. And then each substructure is condensed into a super-element. A surrogate model based on a series of super-elements can be built using the cubic B-spline interpolation. Here, the relative density of substructure is set as the design variable. The optimality criteria method is used for the updating of design variables on two scales. In the process of topology optimization, the symmetry of microstructure is determined by self-defined microstructure configuration, while the symmetry of macro structure is determined by boundary conditions. In this proposed method, because of the educing number of degree of freedoms on macrostructure, the proposed method has high efficiency in optimization. Numerical examples show that both the size and the number of substructures have essential influences on macro structure, indicating the effectiveness of the presented method.

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