new approach for designing rockfall galleries

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ROCKFALL GALLERIESA NEW APPROACH

rev. 1.1 - 26/05/2009 Piazza delle Erbe, 1 • I-38017 Mezzolombardo (TN) ItalyTel. +39 0461.60.55.28 • Fax +39 0461.18.60.182

web: www.rockfalldefence.com • email: info@rockfalldefence.com

Structural Engineering Department

Politecnico Milano

In collaboration with

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DEFENSIVE WORKS:A “passive” defensive infrastructure which solves, often once and for all, the problems related to falling rocks by diverting– and also stopping –

the boulder trajectory

ROCKFALL GALLERY

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ROCKFALL GALLERYFACTS: a concrete or steel structure + covering layer with a damping function (cushion layer)

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ROCKFALL GALLERYstandard project

• Problems during the design phase…– Empirical formulae (Kar-Montani)– Overestimation of the impact of forces on the

structure …lead to

Structures with a strong visual impactHeavy structures >>> global stability

Difficulties in setting up building yardsStructures with a limited architectural value

Long completion timeHigh costs

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ROCKFALL GALLERYNEW APPROACH

Real-size experiments (test scale 1:1)Numerical simulations with distinct elements

Decoupling of the impact phenomenon

INTERACTION

BETWEEN BLOCK AND CUSHION

TRANSMISSION

MATERIAL CUSHION

RESPONSE

STRESSSTRUCTURE

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ROCKFALL GALLERY NEW APPROACH- SOFTWARE

Software inputs• Block dimensions• Impact speed• Cushion thickness• Cushion typology* (material)

Outputs

Cushion stress data* The mixture of materials in the cushion has a considerable impact on the system performance rate

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ROCKFALL GALLERY NEW APPROACH - OPTIMIZATION

Results from the analysis of cushion stress:• Response of the slab• Reflected wave of the slab• 3D stress on the structure

Objectives• Optimized slab• Improved efficiency

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ROCKFALL GALLERY NEW APPROACH – NEW STRUCTURES

The propagation of the effort stands at the basis of the choice for the ideal type of gallery

– Arched gallery– Shelf tunnels– Polycentric galleries

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ROCKFALL GALLERY NEW APPROACH – NEW MATERIALS

• Materials for the cushion:• Multi-layer components• Damping 3D cells• High dissipation material• Integration with geosynthetic materials, metal grid

• Material for the structure:• Concrete• Steel• New dissipating elements• Bar tie rods/ strand tie rods / post tension cables

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ROCKFALL GALLERY NEW APPROACH – BENEFITS

• An overall efficient work

• Light structure

• Better environment integration

• An easy set up of building yards

• Aesthetically satisfying architecture

• Reduced completion time

• Reduced costs

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info@rockfalldefence.comwww.rockfalldefence.com

+39.0461.60.55.28

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