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2019
Journal article
Open Access
Dynamics of a new seismic isolation device based on tribological smooth rocking (TROCKSISD)
Froli M., Giresini L., Laccone F.
A novel isolation device is introduced to seismically protect slender structures or historic assets within the philosophy of Damage Avoidance Design (DAD). This device is conceived to allow smooth, controlled and damped rocking thanks to spherical contact surfaces, elastic springs which ensure re-centering, frictional layers and viscous elastic dampers able to dissipate energy during motion. The conceptual framework of the device is analyzed, and corresponding equations of motions obtained for the equivalent two degrees-of-freedom system. The proposed Performance Based Approach allows identifying geometric and mechanical features of the system. Extensive dynamic analyses with spectra-compatible ground motions are performed and the primary contribution of friction, developed by the relative slip of the two spherical surfaces, is discussed. Finally, the dynamic response under selected earthquakes is evaluated by comparing the isolated and the corresponding not isolated response, to highlight the beneficial effects produced by the proposed isolation technique.Source: Engineering structures 193 (2019): 154–169. doi:10.1016/j.engstruct.2019.05.014
DOI: 10.1016/j.engstruct.2019.05.014
Metrics:
Froli M., Giresini L., Laccone F.
A novel isolation device is introduced to seismically protect slender structures or historic assets within the philosophy of Damage Avoidance Design (DAD). This device is conceived to allow smooth, controlled and damped rocking thanks to spherical contact surfaces, elastic springs which ensure re-centering, frictional layers and viscous elastic dampers able to dissipate energy during motion. The conceptual framework of the device is analyzed, and corresponding equations of motions obtained for the equivalent two degrees-of-freedom system. The proposed Performance Based Approach allows identifying geometric and mechanical features of the system. Extensive dynamic analyses with spectra-compatible ground motions are performed and the primary contribution of friction, developed by the relative slip of the two spherical surfaces, is discussed. Finally, the dynamic response under selected earthquakes is evaluated by comparing the isolated and the corresponding not isolated response, to highlight the beneficial effects produced by the proposed isolation technique.Source: Engineering structures 193 (2019): 154–169. doi:10.1016/j.engstruct.2019.05.014
DOI: 10.1016/j.engstruct.2019.05.014
Metrics:
See at:
Engineering Structures 
| ISTI Repository | Engineering Structures 
| www.sciencedirect.com | CNR ExploRA
2019
Conference article
Open Access
A new seismic isolation device based on tribological smooth rocking (TROCKSISD)
Froli M., Giresini L., Laccone F.
In the field of seismic risk mitigation of art objects, an innovative isolation device is here il-lustrated. The device, called TROCKSISD (Tribological ROCKing Seismic ISolation Device), couples multiple components to dissipate energy and control smooth rocking: spherical con-tact surfaces with frictional layers, elastic springs ensuring re-centering and viscous elastic dampers. The conceptual idea is described and the equations of motions of the two degrees of freedom system presented, discussing the performance-based structural behaviour and the mechanical/geometric parameters involved. Moreover, dynamic analyses are performed to understand the role of the frictional layers with respect to the peripheral dampers in the miti-gation of motion under spectrum compatible seismic records. The results in terms of rocking spectra are presented and comparisons with the equivalent single degree of freedom system without the isolation device are made.Source: COMPDYN 2019 - 7th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, pp. 750–760, Crete, Greece, 24-26 June 2019
DOI: 10.7712/120119.6954.19893
Metrics:
Froli M., Giresini L., Laccone F.
In the field of seismic risk mitigation of art objects, an innovative isolation device is here il-lustrated. The device, called TROCKSISD (Tribological ROCKing Seismic ISolation Device), couples multiple components to dissipate energy and control smooth rocking: spherical con-tact surfaces with frictional layers, elastic springs ensuring re-centering and viscous elastic dampers. The conceptual idea is described and the equations of motions of the two degrees of freedom system presented, discussing the performance-based structural behaviour and the mechanical/geometric parameters involved. Moreover, dynamic analyses are performed to understand the role of the frictional layers with respect to the peripheral dampers in the miti-gation of motion under spectrum compatible seismic records. The results in terms of rocking spectra are presented and comparisons with the equivalent single degree of freedom system without the isolation device are made.Source: COMPDYN 2019 - 7th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, pp. 750–760, Crete, Greece, 24-26 June 2019
DOI: 10.7712/120119.6954.19893
Metrics:
See at:
arpi.unipi.it | ISTI Repository | www.eccomasproceedia.org | doi.org | CNR ExploRA
2020
Journal article
Open Access
TVT(delta) concept for long-span glass-steel footbridges
Froli M., Laccone F., Natali A.
Transparency and structural lightness are inspiring ideas in the design of footbridges. Glass is the most performing transparent material to be used for structural purposes because of its high compressive strength, chemical stability, and absence of fatigue and viscosity phenomena at room temperature. However, its fragility constitutes a challenging limit in structural applications. This research provides and discusses a specific concept named TVT? (Travi Vitree Tensegrity) for lightweight long-span beam-like footbridges made of structural glass. Hence, two design approaches of fail-safe design (FSD) and damage avoidance design (DAD) are applied to guarantee adequate safety levels and postcracking serviceability, respectively, with low damages on the main components. FSD provides the adoption of structural collaboration between glass and steel. Following DAD, glass is segmented into triangular panels, and reciprocal diffuse prestress is performed by steel tendons. This strategy assures low rehabilitation costs because only collapsed elements should be replaced once failed. At ultimate limit state (ULS), the TVT? footbridge attains a global ductile behavior in which the yielding of steel tendons occurs before any fragile failure. Such result is achieved through a hierarchic calibration of the chain of failures. In glass panels, which are mostly precompressed, the buckling failure, representing the main risk, is delayed by the mutual stabilization of the panels' compressed edges with steel clamping. However, because an accidental event may cause a localized or diffuse brittle failure of glass components, the system is designed to maintain a residual load bearing capacity in this scenario. At the serviceability limit state (SLS), the TVT? footbridge is highly stiffened by the presence of glass panes, partially encased in metallic frames. Crack initiation is delayed by precompression.Source: Journal of bridge engineering (Online) 25 (2020). doi:10.1061/(ASCE)BE.1943-5592.0001514
DOI: 10.1061/(asce)be.1943-5592.0001514
Metrics:
Froli M., Laccone F., Natali A.
Transparency and structural lightness are inspiring ideas in the design of footbridges. Glass is the most performing transparent material to be used for structural purposes because of its high compressive strength, chemical stability, and absence of fatigue and viscosity phenomena at room temperature. However, its fragility constitutes a challenging limit in structural applications. This research provides and discusses a specific concept named TVT? (Travi Vitree Tensegrity) for lightweight long-span beam-like footbridges made of structural glass. Hence, two design approaches of fail-safe design (FSD) and damage avoidance design (DAD) are applied to guarantee adequate safety levels and postcracking serviceability, respectively, with low damages on the main components. FSD provides the adoption of structural collaboration between glass and steel. Following DAD, glass is segmented into triangular panels, and reciprocal diffuse prestress is performed by steel tendons. This strategy assures low rehabilitation costs because only collapsed elements should be replaced once failed. At ultimate limit state (ULS), the TVT? footbridge attains a global ductile behavior in which the yielding of steel tendons occurs before any fragile failure. Such result is achieved through a hierarchic calibration of the chain of failures. In glass panels, which are mostly precompressed, the buckling failure, representing the main risk, is delayed by the mutual stabilization of the panels' compressed edges with steel clamping. However, because an accidental event may cause a localized or diffuse brittle failure of glass components, the system is designed to maintain a residual load bearing capacity in this scenario. At the serviceability limit state (SLS), the TVT? footbridge is highly stiffened by the presence of glass panes, partially encased in metallic frames. Crack initiation is delayed by precompression.Source: Journal of bridge engineering (Online) 25 (2020). doi:10.1061/(ASCE)BE.1943-5592.0001514
DOI: 10.1061/(asce)be.1943-5592.0001514
Metrics:
See at:
ascelibrary.org | ISTI Repository | Journal of Bridge Engineering | CNR ExploRA
2020
Journal article
Restricted
Glass-steel triangulated structures: parametric nonlinear finite-element analysis of in-plane and out-of-plane structural response of triangular laminated glass panels
Laccone F., Louter C., Froli M.
Glass exhibits brittle failure behavior. Therefore, redundancy is a fundamental design requirement when using glass as a main structural material. On this basis, a novel structural concept has been developed for hybrid glass-steel posttensioned triangulated structures, where the two materials collaborate. In forming such lattice structure, local fracture must be avoided. This paper presents a parametric study that highlights the influences of mechanical and geometrical parameters on the in-plane and out-of-plane static behaviour of laminated triangular glass panels. The resulting data set constitutes a useful source for the designer to select the most appropriate component. The main sensitivity parameters are panel length, laminate thickness, and interlayer stiffness.Source: Journal of architectural engineering (2020). doi:10.1061/(ASCE)AE.1943-5568.0000374
DOI: 10.1061/(asce)ae.1943-5568.0000374
Metrics:
Laccone F., Louter C., Froli M.
Glass exhibits brittle failure behavior. Therefore, redundancy is a fundamental design requirement when using glass as a main structural material. On this basis, a novel structural concept has been developed for hybrid glass-steel posttensioned triangulated structures, where the two materials collaborate. In forming such lattice structure, local fracture must be avoided. This paper presents a parametric study that highlights the influences of mechanical and geometrical parameters on the in-plane and out-of-plane static behaviour of laminated triangular glass panels. The resulting data set constitutes a useful source for the designer to select the most appropriate component. The main sensitivity parameters are panel length, laminate thickness, and interlayer stiffness.Source: Journal of architectural engineering (2020). doi:10.1061/(ASCE)AE.1943-5568.0000374
DOI: 10.1061/(asce)ae.1943-5568.0000374
Metrics:
See at:
ascelibrary.org | Journal of Architectural Engineering | CNR ExploRA
2019
Doctoral thesis
Open Access
Reinforced and post-tensioned structural glass shells: Concept, morphogenesis and analysis
Laccone F.
The relationship between architecture and structure is a key point in the conceptual phase of a building or one of its components. Glass structures can be considered optimal from the material usage viewpoint because they simultaneously offer transparency, an idea always pursued by architects, and good structural performances. Transparent and free-form glass shells are fascinating objects from both the aesthetic and structural engineering point of view, but are practically difficult to realize, apart from limited favourable cases, and have a low safety level. This work explores a new structural concept for triangulated glass shells, in which the glass panels are both reinforced and post-tensioned. Hence, the net formed by the reinforcements constitutes a redundancy barrier to avoid global collapse in case of glass cracking. In order to ensure an adequate safety level, glass should be prevented from carrying tensile stresses. To this aim, a novel algorithm is developed for the automatic design of the piecewise geometry of the shell and the derivation of the optimal cables distribution with respective preloads. Global nonlinear analyses have been performed to prove the feasibility of the concept and to highlight the advantages that these structures offer with respect to the grid shells competitors. At the local level, the main components of these systems are investigated: the node is tested experimentally and its behaviour is successively described numerically, and the triangular laminated panels are explored with parametric nonlinear models. The thesis is written as a monograph. Some papers prepared during the study are included as part of the work.
Laccone F.
The relationship between architecture and structure is a key point in the conceptual phase of a building or one of its components. Glass structures can be considered optimal from the material usage viewpoint because they simultaneously offer transparency, an idea always pursued by architects, and good structural performances. Transparent and free-form glass shells are fascinating objects from both the aesthetic and structural engineering point of view, but are practically difficult to realize, apart from limited favourable cases, and have a low safety level. This work explores a new structural concept for triangulated glass shells, in which the glass panels are both reinforced and post-tensioned. Hence, the net formed by the reinforcements constitutes a redundancy barrier to avoid global collapse in case of glass cracking. In order to ensure an adequate safety level, glass should be prevented from carrying tensile stresses. To this aim, a novel algorithm is developed for the automatic design of the piecewise geometry of the shell and the derivation of the optimal cables distribution with respective preloads. Global nonlinear analyses have been performed to prove the feasibility of the concept and to highlight the advantages that these structures offer with respect to the grid shells competitors. At the local level, the main components of these systems are investigated: the node is tested experimentally and its behaviour is successively described numerically, and the triangular laminated panels are explored with parametric nonlinear models. The thesis is written as a monograph. Some papers prepared during the study are included as part of the work.
See at:
etd.adm.unipi.it | ISTI Repository | CNR ExploRA
2020
Journal article
Open Access
Conceptual design and FEM structural response of a suspended glass sphere made of reinforced curved polygonal panels
Froli M, Laccone F.
The paper introduces a novel concept for structural glass shells that is based on the mechanical coupling of double curved heat-bent glass panels and a wire frame mesh, which constitutes a grid of unbonded edge-reinforcement. Additionally, this grid has the purpose of providing redundancy. The panels have load-bearing function, they are clamped at the vertices and dry-assembled. The main novelty lies in the use of polygonal curved panelswith a nodal force transfer mechanism. This concept has been validated on an illustrative design case of a 6 m-diameter suspended glass sphere, in which regular pentagonal and hexagonal spherical panels are employed. The good strength and stiffness achieved for this structure is demonstrated by means of local and global FE models. Another fundamental feature of the concept is that the reinforcement grid provides residual strength in the extreme scenarios in which all panels are completely failed. A quantitative measure of redundancy is obtained by comparing this scenario with the ULS.Source: Glass Structures & Engineering 6 (2020): 287–308. doi:10.1007/s40940-020-00130-w
DOI: 10.1007/s40940-020-00130-w
Metrics:
Froli M, Laccone F.
The paper introduces a novel concept for structural glass shells that is based on the mechanical coupling of double curved heat-bent glass panels and a wire frame mesh, which constitutes a grid of unbonded edge-reinforcement. Additionally, this grid has the purpose of providing redundancy. The panels have load-bearing function, they are clamped at the vertices and dry-assembled. The main novelty lies in the use of polygonal curved panelswith a nodal force transfer mechanism. This concept has been validated on an illustrative design case of a 6 m-diameter suspended glass sphere, in which regular pentagonal and hexagonal spherical panels are employed. The good strength and stiffness achieved for this structure is demonstrated by means of local and global FE models. Another fundamental feature of the concept is that the reinforcement grid provides residual strength in the extreme scenarios in which all panels are completely failed. A quantitative measure of redundancy is obtained by comparing this scenario with the ULS.Source: Glass Structures & Engineering 6 (2020): 287–308. doi:10.1007/s40940-020-00130-w
DOI: 10.1007/s40940-020-00130-w
Metrics:
See at:
ISTI Repository | Glass Structures & Engineering | link.springer.com | CNR ExploRA
2021
Journal article
Open Access
Morphogenesis of a bundled tall building: biomimetic, structural, and wind-energy design of a multi-core-outrigger system combined with diagrid
Laccone F., Casali A., Sodano M., Froli M.
Skyscrapers are among the most distinctive building types of the modern age. Since many resources are attributed to these buildings, their design should consider a proper performance-based construction economy and environmental sustainable development. This research introduces a new concept for a bundled tall building founded on the use of a multi-core-outrigger system, which is additionally enriched with diagrid structures. The concept is inspired by the bamboo plant and follows the biomimetic design principles for the structural organization and performance-based criteria for optimizing the lateral stiffness and for shaping the cross section. Particularly, the incident wind speed is maximized to exploit Vertical Axis Wind Turbines (VAWTs), which are located along the whole building height at the center of the bundled towers. The building morphogenesis is accomplished by a multistep methodology that is fully developed in a parametric environment and includes structural and computational fluid dynamic analyses. With the aim of validating the proposed concept, a case study of a 320-m-tall three-core building has been designed for the city of Pisa, Italy. The use of VAWTs results in an annual emissions reduction of about 10 kgCO(2)/m(2).Source: The structural design of tall and special buildings 30 (2021). doi:10.1002/tal.1839
DOI: 10.1002/tal.1839
Metrics:
Laccone F., Casali A., Sodano M., Froli M.
Skyscrapers are among the most distinctive building types of the modern age. Since many resources are attributed to these buildings, their design should consider a proper performance-based construction economy and environmental sustainable development. This research introduces a new concept for a bundled tall building founded on the use of a multi-core-outrigger system, which is additionally enriched with diagrid structures. The concept is inspired by the bamboo plant and follows the biomimetic design principles for the structural organization and performance-based criteria for optimizing the lateral stiffness and for shaping the cross section. Particularly, the incident wind speed is maximized to exploit Vertical Axis Wind Turbines (VAWTs), which are located along the whole building height at the center of the bundled towers. The building morphogenesis is accomplished by a multistep methodology that is fully developed in a parametric environment and includes structural and computational fluid dynamic analyses. With the aim of validating the proposed concept, a case study of a 320-m-tall three-core building has been designed for the city of Pisa, Italy. The use of VAWTs results in an annual emissions reduction of about 10 kgCO(2)/m(2).Source: The structural design of tall and special buildings 30 (2021). doi:10.1002/tal.1839
DOI: 10.1002/tal.1839
Metrics:
See at:
ISTI Repository | The Structural Design of Tall and Special Buildings | onlinelibrary.wiley.com | CNR ExploRA
2021
Journal article
Open Access
Experimental and numerical investigation on a passive control system for the mitigation of vibrations on SDOF and MDOF structures: mini Tribological ROCKing Seismic Isolation Device (miniTROCKSISD)
Giresini L., Puppio M. L., Laccone F., Froli M.
This paper illustrates the results of an experimental campaign performed on a scale prototype of a base dissipator called Mini Tribological ROCKing Seismic Isolation Device. This device allows a smooth, controlled and damped rocking by means of frictional layers and viscous elastic springs, which aim at decoupling the frequencies of the superstructure, at dissipating energy during motion and at re-centering the system once the external action vanishes. Four superstructures are tested - a shear type frame, braced and unbraced, a multi-story frame and a SDOF oscillator - with 96 ambient vibration and impulsive tests. An analytical model is illustrated and validated by the experimental tests. The reduction of relative displacement demand is analyzed for all the cases together with the reduction of the acceleration demand, showing positive effects of the base dissipator on the dynamic behavior of all the superstructures.Source: Journal of earthquake engineering (2021). doi:10.1080/13632469.2021.1964646
DOI: 10.1080/13632469.2021.1964646
Metrics:
Giresini L., Puppio M. L., Laccone F., Froli M.
This paper illustrates the results of an experimental campaign performed on a scale prototype of a base dissipator called Mini Tribological ROCKing Seismic Isolation Device. This device allows a smooth, controlled and damped rocking by means of frictional layers and viscous elastic springs, which aim at decoupling the frequencies of the superstructure, at dissipating energy during motion and at re-centering the system once the external action vanishes. Four superstructures are tested - a shear type frame, braced and unbraced, a multi-story frame and a SDOF oscillator - with 96 ambient vibration and impulsive tests. An analytical model is illustrated and validated by the experimental tests. The reduction of relative displacement demand is analyzed for all the cases together with the reduction of the acceleration demand, showing positive effects of the base dissipator on the dynamic behavior of all the superstructures.Source: Journal of earthquake engineering (2021). doi:10.1080/13632469.2021.1964646
DOI: 10.1080/13632469.2021.1964646
Metrics:
See at:
ISTI Repository | www.tandfonline.com | CNR ExploRA
2023
Contribution to conference
Unknown
Static- and fabrication-aware concrete shells segmented into flat tiles
Laccone F., Menicagli S.
The design of freeform concrete shells has gained popularity recently, pushed by computational tools that allow manipulating and exploring complex shapes interactively. However, their actual fabrication, even on a small scale, still poses challenges of feasibility and cost. Continuous shells require accurate and dense formworks, while segmented shells offer a low prefabrication rate, especially in the case of variable curvature. We propose a novel structural concept for freeform shells, in which the shape is decomposed into flat tiles, touching each other at the midpoint of the edges. Once assembled, the tiles are post-tensioned to minimize the resulting tension on the structure under service load. The outer surface is finally completed with an in situ cast that fills the gaps and activates the entire shell behavior. The bottom surface presents a jagged aesthetic due to gaps and misalignments at the seams. We developed an automatic pipeline to manage the design process from a general input shape to fabrication. The input shape is segmented based on a field-aligned quad mesh computed from the principal stress of the thin shell. The flat tiles are obtained by extruding each face along the normal of the associated checkerboard mesh, i.e., a mesh whose 'solid' parts are the planar rhomboids with vertices on each quad edge's midpoint. The contact between adjacent tiles is ensured only at their edge midpoints so that forces can flow along the cross directions, namely the principal directions. Candidate post-tensioning paths are found by clustering the segments linking pairs of opposite midpoints of the tiles' edges. We discard paths that do not terminate on the boundary, closed loops, or paths with significant kinks, to avoid localized shear on the surface.Source: fib International Symposium on Conceptual Design of Concrete Structures, pp. 175–175, Oslo, Norway, 29/06/2023 - 01/07/2023
Laccone F., Menicagli S.
The design of freeform concrete shells has gained popularity recently, pushed by computational tools that allow manipulating and exploring complex shapes interactively. However, their actual fabrication, even on a small scale, still poses challenges of feasibility and cost. Continuous shells require accurate and dense formworks, while segmented shells offer a low prefabrication rate, especially in the case of variable curvature. We propose a novel structural concept for freeform shells, in which the shape is decomposed into flat tiles, touching each other at the midpoint of the edges. Once assembled, the tiles are post-tensioned to minimize the resulting tension on the structure under service load. The outer surface is finally completed with an in situ cast that fills the gaps and activates the entire shell behavior. The bottom surface presents a jagged aesthetic due to gaps and misalignments at the seams. We developed an automatic pipeline to manage the design process from a general input shape to fabrication. The input shape is segmented based on a field-aligned quad mesh computed from the principal stress of the thin shell. The flat tiles are obtained by extruding each face along the normal of the associated checkerboard mesh, i.e., a mesh whose 'solid' parts are the planar rhomboids with vertices on each quad edge's midpoint. The contact between adjacent tiles is ensured only at their edge midpoints so that forces can flow along the cross directions, namely the principal directions. Candidate post-tensioning paths are found by clustering the segments linking pairs of opposite midpoints of the tiles' edges. We discard paths that do not terminate on the boundary, closed loops, or paths with significant kinks, to avoid localized shear on the surface.Source: fib International Symposium on Conceptual Design of Concrete Structures, pp. 175–175, Oslo, Norway, 29/06/2023 - 01/07/2023
See at: CNR ExploRA
2023
Journal article
Open Access
Exploring new frontiers in gridshell design: the FreeGrid benchmark
Bruno L., Gabriele S., Grande E., Imbimbo M., Laccone F., Marmo F., Mele E., Raffaele L., Tomei V., Venuti F.
Gridshell structures require an intricate design activity that shall comply with several design goals of diverse nature. This design phase can be approached with different methods and strategies and usually requires multiple competencies from different scientific fields. In this context, a common benchmark, called FreeGrid, is proposed to the scientific and practitioners' communities in order to test and compare different approaches to the design and optimization of steel gridshells on the bases of ad-hoc defined performance metrics. FreeGrid sets three design baseline problems: a barrel vault, a parabolic dome, and a hyperbolic paraboloid, having their spring line partially not constrained (free-edge) and subjected to uniform and piecewise uniform load conditions. Participants are called to modify the baseline gridshell(s), observing a limited number of design constraints (related to geometry, external constraints and material), in order to improve their structural, buildability, and sustainability performances through the maximization of a bulk quantitative performance metric. Specifically, the structural performance metric accounts for both ultimate and serviceability behavior, through the calculation of the critical Load Factor and maximum vertical displacement; the buildability performance metric includes the evaluation of face planarity, uniformity of structural joints and members; the sustainability performance metric is based on the structure embodied carbon. This paper describes the baseline gridshells setups, the proposed performance metrics and the recommended method for performance assessment. The complete data of the baseline structures are made available according to an Open Data policy, together with postprocessing utilities intended to align the procedure to obtain the performance metrics.Source: Structures (Oxford) 58 (2023). doi:10.1016/j.istruc.2023.105678
DOI: 10.1016/j.istruc.2023.105678
Metrics:
Bruno L., Gabriele S., Grande E., Imbimbo M., Laccone F., Marmo F., Mele E., Raffaele L., Tomei V., Venuti F.
Gridshell structures require an intricate design activity that shall comply with several design goals of diverse nature. This design phase can be approached with different methods and strategies and usually requires multiple competencies from different scientific fields. In this context, a common benchmark, called FreeGrid, is proposed to the scientific and practitioners' communities in order to test and compare different approaches to the design and optimization of steel gridshells on the bases of ad-hoc defined performance metrics. FreeGrid sets three design baseline problems: a barrel vault, a parabolic dome, and a hyperbolic paraboloid, having their spring line partially not constrained (free-edge) and subjected to uniform and piecewise uniform load conditions. Participants are called to modify the baseline gridshell(s), observing a limited number of design constraints (related to geometry, external constraints and material), in order to improve their structural, buildability, and sustainability performances through the maximization of a bulk quantitative performance metric. Specifically, the structural performance metric accounts for both ultimate and serviceability behavior, through the calculation of the critical Load Factor and maximum vertical displacement; the buildability performance metric includes the evaluation of face planarity, uniformity of structural joints and members; the sustainability performance metric is based on the structure embodied carbon. This paper describes the baseline gridshells setups, the proposed performance metrics and the recommended method for performance assessment. The complete data of the baseline structures are made available according to an Open Data policy, together with postprocessing utilities intended to align the procedure to obtain the performance metrics.Source: Structures (Oxford) 58 (2023). doi:10.1016/j.istruc.2023.105678
DOI: 10.1016/j.istruc.2023.105678
Metrics:
See at:
ISTI Repository | www.sciencedirect.com | CNR ExploRA
2023
Conference article
Open Access
FreeGrid: a benchmark on design and optimisation of free-edge gridshells
Bruno L, Cignoni P., Gabriele S., Grande E., Imbimbo M., Laccone F., Marmo F., Mele E., Raffaele L., Tomei V., Venuti F.
FreeGrid is meant to offer a common benchmark to test and compare different approaches to the design and optimization of steel gridshells, from man-based heuristic design to AI-based one. FreeGrid sets three design baseline problems: a barrel vault, a paraboloidal dome, and a hyperbolic paraboloid, having their spring line partially not constrained (free-edge) and subjected to symmetric and asymmetric load conditions. Participants are called to modify the baseline gridshell(s) in order to improve their structural performances, buildability, and sustainability, all three of them weighted in a single, bulk quantitative performance metric. Participants shall comply with a limited number of design constraints, while any other design solution is allowed. Baseline setups, performance metrics and design constraints will be fully detailed in technical specifications made publicly available. The full data of the baseline structures will be offered to participants according to an Open Data policy, together with postprocessing utilities intended to align the procedure to obtain the performance metrics. The FreeGrid benchmark will be launched within the IASS Symposium 2023 in Melbourne.Source: IASS 2023 -International Association for Shell and Spatial Structure Annual Symposium, pp. 1047–1057, Melbourne, Australia, 10-14/07/2023
Bruno L, Cignoni P., Gabriele S., Grande E., Imbimbo M., Laccone F., Marmo F., Mele E., Raffaele L., Tomei V., Venuti F.
FreeGrid is meant to offer a common benchmark to test and compare different approaches to the design and optimization of steel gridshells, from man-based heuristic design to AI-based one. FreeGrid sets three design baseline problems: a barrel vault, a paraboloidal dome, and a hyperbolic paraboloid, having their spring line partially not constrained (free-edge) and subjected to symmetric and asymmetric load conditions. Participants are called to modify the baseline gridshell(s) in order to improve their structural performances, buildability, and sustainability, all three of them weighted in a single, bulk quantitative performance metric. Participants shall comply with a limited number of design constraints, while any other design solution is allowed. Baseline setups, performance metrics and design constraints will be fully detailed in technical specifications made publicly available. The full data of the baseline structures will be offered to participants according to an Open Data policy, together with postprocessing utilities intended to align the procedure to obtain the performance metrics. The FreeGrid benchmark will be launched within the IASS Symposium 2023 in Melbourne.Source: IASS 2023 -International Association for Shell and Spatial Structure Annual Symposium, pp. 1047–1057, Melbourne, Australia, 10-14/07/2023
See at:
iass2023.org.au | CNR ExploRA
2019
Journal article
Open Access
Automatic design of cable-tensioned glass shells
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
We propose an optimization algorithm for the design of post-tensioned architectural shell structures, composed of triangular glass panels, in which glass has a load-bearing function. Due to its brittle nature, glass can fail when it is subject to tensile forces. Hence, we enrich the structure with a cable net, which is specifically designed to post-tension the shell, relieving the underlying glass structure from tension. We automatically derive an optimized cable layout, together with the appropriate pre-load of each cable. The method is driven by a physically based static analysis of the shell subject to its service load. We assess our approach by applying non-linear finite element analysis to several real-scale application scenarios. Such a method of cable tensioning produces glass shells that are optimized from the material usage viewpoint since they exploit the high compression strength of glass. As a result, they are lightweight and robust. Both aesthetic and static qualities are improved with respect to grid shell competitors.Source: Computer graphics forum (Online) 39 (2019): 260–273. doi:10.1111/cgf.13801
DOI: 10.1111/cgf.13801
Metrics:
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
We propose an optimization algorithm for the design of post-tensioned architectural shell structures, composed of triangular glass panels, in which glass has a load-bearing function. Due to its brittle nature, glass can fail when it is subject to tensile forces. Hence, we enrich the structure with a cable net, which is specifically designed to post-tension the shell, relieving the underlying glass structure from tension. We automatically derive an optimized cable layout, together with the appropriate pre-load of each cable. The method is driven by a physically based static analysis of the shell subject to its service load. We assess our approach by applying non-linear finite element analysis to several real-scale application scenarios. Such a method of cable tensioning produces glass shells that are optimized from the material usage viewpoint since they exploit the high compression strength of glass. As a result, they are lightweight and robust. Both aesthetic and static qualities are improved with respect to grid shell competitors.Source: Computer graphics forum (Online) 39 (2019): 260–273. doi:10.1111/cgf.13801
DOI: 10.1111/cgf.13801
Metrics:
See at:
ISTI Repository | Computer Graphics Forum | onlinelibrary.wiley.com | CNR ExploRA
2019
Conference article
Open Access
Concept and cable-tensioning optimization of post-tensioned shells made of structural glass
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
Shells made of structural glass are charming objects from both the aesthetics and the engineering point of view. However, they pose two signicant challenges: the rst one is to assure adequate safety and redundancy concerning possible global collapse; the second one is to guarantee the economy for replacing collapsed components. To address both requirements, this research explores a novel concept where triangular panels of structural glass are both post-tensioned and reinforced to create 3D free-form systems. Hence, the ligree steel truss, made of edges reinforcements, is sized in performance-based perspective to bear at least the weight of all panels in the occurrence of simultaneous cracks (worst-case scenario). The panels are post-tensioned using a set of edge-aligned cables that add benecial compressive stress on the surface. The cable placement and pre-loads are optimized to minimize the tensile stress acting on the shell and match the manufacturing constraints. These shells optimize material usage by providing not only a transparent and fascinating building separation but also load-bearing capabilities. Visual and structural lightness are improved to grid shell competitors.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 2133–2140, Barcelona, 7-10/10/2019
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
Shells made of structural glass are charming objects from both the aesthetics and the engineering point of view. However, they pose two signicant challenges: the rst one is to assure adequate safety and redundancy concerning possible global collapse; the second one is to guarantee the economy for replacing collapsed components. To address both requirements, this research explores a novel concept where triangular panels of structural glass are both post-tensioned and reinforced to create 3D free-form systems. Hence, the ligree steel truss, made of edges reinforcements, is sized in performance-based perspective to bear at least the weight of all panels in the occurrence of simultaneous cracks (worst-case scenario). The panels are post-tensioned using a set of edge-aligned cables that add benecial compressive stress on the surface. The cable placement and pre-loads are optimized to minimize the tensile stress acting on the shell and match the manufacturing constraints. These shells optimize material usage by providing not only a transparent and fascinating building separation but also load-bearing capabilities. Visual and structural lightness are improved to grid shell competitors.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 2133–2140, Barcelona, 7-10/10/2019
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ISTI Repository | CNR ExploRA
2020
Conference article
Open Access
Automated Design and Analysis of Reinforced and Post-Tensioned Glass Shells
Laccone F., Malomo L., Pietroni N., Froli M., Cignoni P.
Shells made of structural glass are beautiful objects from both the aesthetics and the engineering point of view. However, they pose two significant challenges. The first one is to assure adequate safety and redundancy concerning possible global collapse. Being single-layered, in a shell made of structural glass, the brittle cracking of a single pane can lead to a sudden propagation of failure, up to instability. The second one is to guarantee cheap replacing possibilities for potentially collapsed components. This research explores a novel concept to address both requirements, where glass is both post-tensioned and reinforced and develops the research on TVT post-tensioned glass beams. Following the Fail-Safe Design (FSD) principles, a steel reinforcement relieves glass deficiencies (i.e. brittleness and low tensile strength). Following the Damage Avoidance Design (DAD) principles, glass segmentation and post-tensioning avoid the propagation of cracks. Up to now, glass-steel systems were limited to mono-dimensional elements (such as beams and columns) or simple bi-dimensional elements (arches, domes, barrel vaults). Instead, massive structures are usually realized as grid shells, where glass is used as simple cladding. This research investigates piecewise triangulated glass shells to enable the creation of 3D free-form glass-steel systems, where glass is load-bearing material. Hence, laminated glass panels are mechanically coupled with a filigree steel truss, whose elements are placed at the edges of the panel and act as an unbonded reinforcement. In a performance-based perspective, these steel trusses can be sized to bear at least the weight of all panels in the occurrence of simultaneous cracks (worst-case scenario). The panels are post-tensioned using a set of edge-aligned cables that add beneficial compressive stress on glass to prevent crack initiation. The cable placement and accompanying pre-loads are derived with an optimization strategy that minimizes the tensile stress acting on the shell. This optimization procedure also considers the practical constraints involved in the process. The results obtained through this automated procedure are later investigated using nonlinear FE analyses. The resulting structures optimize the total material usage providing contemporarily both transparency and load-bearing capabilities. Posttensioned shells excel in static performances, achieving high stiffness and good redundancy for the worst-case scenario, and improve the structural lightness and the visual impact with respect to state-of-the-art competitors.Source: Challenging Glass 7 Conference on Architectural and Structural Applications of Glass, Ghent University, September 2020
Laccone F., Malomo L., Pietroni N., Froli M., Cignoni P.
Shells made of structural glass are beautiful objects from both the aesthetics and the engineering point of view. However, they pose two significant challenges. The first one is to assure adequate safety and redundancy concerning possible global collapse. Being single-layered, in a shell made of structural glass, the brittle cracking of a single pane can lead to a sudden propagation of failure, up to instability. The second one is to guarantee cheap replacing possibilities for potentially collapsed components. This research explores a novel concept to address both requirements, where glass is both post-tensioned and reinforced and develops the research on TVT post-tensioned glass beams. Following the Fail-Safe Design (FSD) principles, a steel reinforcement relieves glass deficiencies (i.e. brittleness and low tensile strength). Following the Damage Avoidance Design (DAD) principles, glass segmentation and post-tensioning avoid the propagation of cracks. Up to now, glass-steel systems were limited to mono-dimensional elements (such as beams and columns) or simple bi-dimensional elements (arches, domes, barrel vaults). Instead, massive structures are usually realized as grid shells, where glass is used as simple cladding. This research investigates piecewise triangulated glass shells to enable the creation of 3D free-form glass-steel systems, where glass is load-bearing material. Hence, laminated glass panels are mechanically coupled with a filigree steel truss, whose elements are placed at the edges of the panel and act as an unbonded reinforcement. In a performance-based perspective, these steel trusses can be sized to bear at least the weight of all panels in the occurrence of simultaneous cracks (worst-case scenario). The panels are post-tensioned using a set of edge-aligned cables that add beneficial compressive stress on glass to prevent crack initiation. The cable placement and accompanying pre-loads are derived with an optimization strategy that minimizes the tensile stress acting on the shell. This optimization procedure also considers the practical constraints involved in the process. The results obtained through this automated procedure are later investigated using nonlinear FE analyses. The resulting structures optimize the total material usage providing contemporarily both transparency and load-bearing capabilities. Posttensioned shells excel in static performances, achieving high stiffness and good redundancy for the worst-case scenario, and improve the structural lightness and the visual impact with respect to state-of-the-art competitors.Source: Challenging Glass 7 Conference on Architectural and Structural Applications of Glass, Ghent University, September 2020
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journals.open.tudelft.nl | ISTI Repository | CNR ExploRA
2021
Journal article
Open Access
Integrated computational framework for the design and fabrication of bending-active structures made from flat sheet material
Laccone F., Malomo L., Pietroni N., Cignoni P., Schork T.
This paper introduces an integrated computational design framework for the design and realization of arbitrarily-curved bending-active architectural structures. The developed framework consists of a series of methods that enable the production of a complex 3D structures composed of a set of flat 2D panels whose mechanical properties are locally tuned by varying the shape of embedded spiraling patterns. The resulting panels perform as variable stiffness elements, and they are optimized to match a desired target shape once assembled together. The presented framework includes all the steps for the physical delivery of architectural objects, including conception, static assessment, and digital fabrication. The developed framework has been applied to an architectural scale prototype, which demonstrates the potential of integrating architectural design, computational simulation, structural engineering, and digital fabrication, opening up several possible novel applications in the building sector.Source: Structures (Oxford) 34 (2021): 979–994. doi:10.1016/j.istruc.2021.08.004
DOI: 10.1016/j.istruc.2021.08.004
Metrics:
Laccone F., Malomo L., Pietroni N., Cignoni P., Schork T.
This paper introduces an integrated computational design framework for the design and realization of arbitrarily-curved bending-active architectural structures. The developed framework consists of a series of methods that enable the production of a complex 3D structures composed of a set of flat 2D panels whose mechanical properties are locally tuned by varying the shape of embedded spiraling patterns. The resulting panels perform as variable stiffness elements, and they are optimized to match a desired target shape once assembled together. The presented framework includes all the steps for the physical delivery of architectural objects, including conception, static assessment, and digital fabrication. The developed framework has been applied to an architectural scale prototype, which demonstrates the potential of integrating architectural design, computational simulation, structural engineering, and digital fabrication, opening up several possible novel applications in the building sector.Source: Structures (Oxford) 34 (2021): 979–994. doi:10.1016/j.istruc.2021.08.004
DOI: 10.1016/j.istruc.2021.08.004
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ISTI Repository | ISTI Repository | www.sciencedirect.com | CNR ExploRA
2022
Conference article
Open Access
Exploratory study on a segmented shell made of recycled-HDPE plastic
Laccone F., Manolas I., Malomo L., Cignoni P.
Recycled HDPE plastic can be obtained from up to 100% waste material and can be produced in the shape of panels and rods. The aim of this work is to explore the possibility to employ this material for structural purposes. The proposed concept for segmented shells is based on the cassette system, namely a spatial waffle structure clamped by inner and outer plates, and a shaping strategy of the shell cross section targeted on bending. The concept is applied on translational surfaces, in which the transverse cross section serves as the shaping objective. A digital workflow is implemented to explore the possible solutions and to evaluate the shells' feasibility from both a fabrication and a structural point of view. A case study of 5.2 meters is further explored with nonlinear analysis.Source: IASS 2020/21 - Inspiring the Next Generation. The 7th International Conference on Spatial Structures and the Annual Symposium of the IASS, pp. 1859–1870, University of Surrey, UK, 23-27/08/2021
DOI: 10.15126/900337
Project(s): EVOCATION
Metrics:
Laccone F., Manolas I., Malomo L., Cignoni P.
Recycled HDPE plastic can be obtained from up to 100% waste material and can be produced in the shape of panels and rods. The aim of this work is to explore the possibility to employ this material for structural purposes. The proposed concept for segmented shells is based on the cassette system, namely a spatial waffle structure clamped by inner and outer plates, and a shaping strategy of the shell cross section targeted on bending. The concept is applied on translational surfaces, in which the transverse cross section serves as the shaping objective. A digital workflow is implemented to explore the possible solutions and to evaluate the shells' feasibility from both a fabrication and a structural point of view. A case study of 5.2 meters is further explored with nonlinear analysis.Source: IASS 2020/21 - Inspiring the Next Generation. The 7th International Conference on Spatial Structures and the Annual Symposium of the IASS, pp. 1859–1870, University of Surrey, UK, 23-27/08/2021
DOI: 10.15126/900337
Project(s): EVOCATION
Metrics:
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ISTI Repository | openresearch.surrey.ac.uk | CNR ExploRA
2022
Journal article
Open Access
Automated generation of flat tileable patterns and 3D reduced model simulation
Manolas I., Laccone F., Cherchi G., Malomo L., Cignoni P.
The computational fabrication community is developing an increasing interest in the use of patterned surfaces, which can be designed to show ornamental and unconventional aesthetics or to perform as a proper structural material with a wide range of features. Geometrically designing and controlling the deformation capabilities of these patterns in response to external stimuli is a complex task due to the large number of variables involved. This paper introduces a method for generating sets of tileable and exchangeable flat patterns as well as a model-reduction strategy that enables their mechanical simulation at interactive rates. This method is included in a design pipeline that aims to turn any general flat surface into a pattern tessellation, which is able to deform under a given loading scenario. To validate our approach, we apply it to different contexts, including real-scale 3D printed specimens, for which we compare our results with the ones provided by a ground-truth solver.Source: Computers & graphics 106 (2022): 141–151. doi:10.1016/j.cag.2022.05.020
DOI: 10.1016/j.cag.2022.05.020
Project(s): EVOCATION
Metrics:
Manolas I., Laccone F., Cherchi G., Malomo L., Cignoni P.
The computational fabrication community is developing an increasing interest in the use of patterned surfaces, which can be designed to show ornamental and unconventional aesthetics or to perform as a proper structural material with a wide range of features. Geometrically designing and controlling the deformation capabilities of these patterns in response to external stimuli is a complex task due to the large number of variables involved. This paper introduces a method for generating sets of tileable and exchangeable flat patterns as well as a model-reduction strategy that enables their mechanical simulation at interactive rates. This method is included in a design pipeline that aims to turn any general flat surface into a pattern tessellation, which is able to deform under a given loading scenario. To validate our approach, we apply it to different contexts, including real-scale 3D printed specimens, for which we compare our results with the ones provided by a ground-truth solver.Source: Computers & graphics 106 (2022): 141–151. doi:10.1016/j.cag.2022.05.020
DOI: 10.1016/j.cag.2022.05.020
Project(s): EVOCATION
Metrics:
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ISTI Repository | www.sciencedirect.com | CNR ExploRA
2022
Journal article
Restricted
Vorogrid: a static-aware variable-density Voronoi mesh to design the tube structure tessellation of tall buildings
Laccone F., Gaudioso D., Malomo L., Cignoni P., Froli M.
In the context of tall building design, the tube concept represents one of the most performing systems. The diagrid is the widespread type of tube system and consists of a diagonal grid of beams that wraps the building, forming a diamond pattern. It performs as lateral bracing and is additionally able to sustain vertical loading through axial forces. Despite its efficiency, a growing interest is recently observed in alternative geometries to replace the diagrid pattern and improve the architectural impact conferred by the building skin aesthetics on the urban environment. The paper pursues the use of a Voronoimesh, in which the geometry of the cells is steered to known schemes for the structural design of a cantilever tube structure. The objective is to mimic a macroscopic structural behavior through a topology and sizemodification of the Voronoimesh that increases the density for creating resisting paths with higher stiffness. The paper proposes a novel method Vorogrid for designing a new class of tall buildings equipped with an organic-looking and mechanically sound tube structure, which makes them a valuable alternative to competitors (diagrid, hexagrid, random Voronoi). Diagrids and hexagrids still remain more efficient in terms of forces and displacements but are characterized by a more usual appearance, instead Vorogrid offers more design control and better performances on average with respect to random Voronoi structures. This method is streamed into a pipeline that includes grid initialization strategies, geometric and structural optimization to mitigate the effects of the grid randomness, and structural sizing.Source: Computer-aided civil and infrastructure engineering (Online) (2022): 1–19. doi:10.1111/mice.12912
DOI: 10.1111/mice.12912
Metrics:
Laccone F., Gaudioso D., Malomo L., Cignoni P., Froli M.
In the context of tall building design, the tube concept represents one of the most performing systems. The diagrid is the widespread type of tube system and consists of a diagonal grid of beams that wraps the building, forming a diamond pattern. It performs as lateral bracing and is additionally able to sustain vertical loading through axial forces. Despite its efficiency, a growing interest is recently observed in alternative geometries to replace the diagrid pattern and improve the architectural impact conferred by the building skin aesthetics on the urban environment. The paper pursues the use of a Voronoimesh, in which the geometry of the cells is steered to known schemes for the structural design of a cantilever tube structure. The objective is to mimic a macroscopic structural behavior through a topology and sizemodification of the Voronoimesh that increases the density for creating resisting paths with higher stiffness. The paper proposes a novel method Vorogrid for designing a new class of tall buildings equipped with an organic-looking and mechanically sound tube structure, which makes them a valuable alternative to competitors (diagrid, hexagrid, random Voronoi). Diagrids and hexagrids still remain more efficient in terms of forces and displacements but are characterized by a more usual appearance, instead Vorogrid offers more design control and better performances on average with respect to random Voronoi structures. This method is streamed into a pipeline that includes grid initialization strategies, geometric and structural optimization to mitigate the effects of the grid randomness, and structural sizing.Source: Computer-aided civil and infrastructure engineering (Online) (2022): 1–19. doi:10.1111/mice.12912
DOI: 10.1111/mice.12912
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onlinelibrary.wiley.com | CNR ExploRA
2022
Conference article
Open Access
A computational tool for the analysis of 3D bending-active structures based on the dynamic relaxation method
Manolas I., Laccone F., Cherchi G., Malomo L., Cignoni P.
The use of elastic deformation of straight or flat structural components for achieving complex 3D shapes has acquired attention from recent computational design works, particularly in architectural geometry. The so-called bending-active structures are built by deforming and restraining the components mutually to form a stable configuration. While the manufacturing of components from flat raw material and their assembly are simple and inexpensive, the complexity lies in the design phase, in which computational tools are required to predict the deformation and forces under a prescribed form-finding load or displacement. Currently, there is a scarcity of open and efficient tools that hinder the design of bending-active structures. This paper proposes and validates an open-source computational tool for predicting the static equilibrium of general bending-active structures in the form of a network of elements using the dynamic relaxation method. We apply our tool to various real-world examples and compare the results to a commercial FEM solver. The proposed tool shows accuracy and good time performance, making it a significant addition to the available open-source structural engineering toolkit.Source: Smart Tools and Applications in Graphics - Eurographics Italian Chapter Conference, Cagliari, Italy, 17-18/11/2022
DOI: 10.2312/stag.20221250
Project(s): EVOCATION
Metrics:
Manolas I., Laccone F., Cherchi G., Malomo L., Cignoni P.
The use of elastic deformation of straight or flat structural components for achieving complex 3D shapes has acquired attention from recent computational design works, particularly in architectural geometry. The so-called bending-active structures are built by deforming and restraining the components mutually to form a stable configuration. While the manufacturing of components from flat raw material and their assembly are simple and inexpensive, the complexity lies in the design phase, in which computational tools are required to predict the deformation and forces under a prescribed form-finding load or displacement. Currently, there is a scarcity of open and efficient tools that hinder the design of bending-active structures. This paper proposes and validates an open-source computational tool for predicting the static equilibrium of general bending-active structures in the form of a network of elements using the dynamic relaxation method. We apply our tool to various real-world examples and compare the results to a commercial FEM solver. The proposed tool shows accuracy and good time performance, making it a significant addition to the available open-source structural engineering toolkit.Source: Smart Tools and Applications in Graphics - Eurographics Italian Chapter Conference, Cagliari, Italy, 17-18/11/2022
DOI: 10.2312/stag.20221250
Project(s): EVOCATION
Metrics:
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diglib.eg.org | ISTI Repository | CNR ExploRA
2023
Conference article
Open Access
Static- and fabrication-aware segmented concrete shells made of post-tensioned precast flat tiles
Laccone F., Menicagli S., Cignoni P., Malomo L.
This paper introduces a novel structural concept for freeform shells, in which the shape is decomposed into flat tiles to be assembled sequentially with the help of falseworks. Once the structure is completed, the tiles are post-tensioned to minimize the tension forces and avoid detachment. The entire design process, from an input shape to fabrication, is managed by an automatic pipeline. The input shape is segmented into a field-aligned quad mesh, computed from the principal stress of the thin shell. The flat tiles are obtained by extruding each face along the normal of the best-fitting plane per face. The contact between adjacent tiles is ensured only at their edge midpoints so the forces can mainly flow along the cross directions. The best configuration of cable paths and pre-loads is found by solving a constrained optimization problem exploiting a reduced beam model of the shell. All tiles can be prefabricated in the shop with an adaptable and reusable molding system. Once the structure is completed, the top surface is finally completed with an in situ cast that fills the gaps and activates the entire shell behavior. In contrast, the bottom surface maintains its jagged aesthetics.Source: IWSS 2023 - Italian Workshop on Shell and Spatial Structures, pp. 1–10, Turin, Italy, 26-28/06/2023
DOI: 10.1007/978-3-031-44328-2_1
Metrics:
Laccone F., Menicagli S., Cignoni P., Malomo L.
This paper introduces a novel structural concept for freeform shells, in which the shape is decomposed into flat tiles to be assembled sequentially with the help of falseworks. Once the structure is completed, the tiles are post-tensioned to minimize the tension forces and avoid detachment. The entire design process, from an input shape to fabrication, is managed by an automatic pipeline. The input shape is segmented into a field-aligned quad mesh, computed from the principal stress of the thin shell. The flat tiles are obtained by extruding each face along the normal of the best-fitting plane per face. The contact between adjacent tiles is ensured only at their edge midpoints so the forces can mainly flow along the cross directions. The best configuration of cable paths and pre-loads is found by solving a constrained optimization problem exploiting a reduced beam model of the shell. All tiles can be prefabricated in the shop with an adaptable and reusable molding system. Once the structure is completed, the top surface is finally completed with an in situ cast that fills the gaps and activates the entire shell behavior. In contrast, the bottom surface maintains its jagged aesthetics.Source: IWSS 2023 - Italian Workshop on Shell and Spatial Structures, pp. 1–10, Turin, Italy, 26-28/06/2023
DOI: 10.1007/978-3-031-44328-2_1
Metrics:
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ISTI Repository | link.springer.com | CNR ExploRA