Experimental & numerical structural analyses

Experimental assessment will be conducted to examine the response of green facades under wind and earthquake loading, comprising two separate test campaigns for wind load and seismic load assessments. Prior to these tests, a numerical modelling approach will be employed to anticipate their behaviour. Additionally, a parametric study will be carried out to apply the findings to real buildings, considering various installation and usage scenarios.

Task 3.1 – Cladding aerodynamics: Wind tunnel tests
Wind tunnel tests will be carried out on different configurations of green wall, first at full scale with real vegetation, then at a reduced scale, but considering a whole building in order to assess the response of the green walls under wind blowing in both normal and parallel directions. This will allow to determine the aerodynamic properties of the green wall based on the overall building shape, the gap between the wall and the building, and the type of greenery.

Task 3.2 – Numerical modelling of the wind response
Based on the testing and the indications for the load bearing behaviour of the greeneries, numerical analyses will be carried out on different combinations of plantings and substructure. The variations will cover combinations which are highly in a range of membrane-like load bearing behaviour to those, which are mainly in bending. These analyses include a Newmark time-step analysis to capture dynamic responses to gusty wind loads.

Task 3.3 – Numerical modelling of the seismic response
Numerical models will be developed to simulate the response of the green wall and underlying structure under earthquake loads, allowing a prediction of the experimental behaviour of the test set-ups. Once terminated the testing campaign (T3.4), these models will be calibrated on the test results. Finally, a case study will be examined numerically based on an existing structure using these models to verify the design process.

Task 3.4 – Shake-table tests
This task involves investigating the seismic response of a full-scale one-story steel frame supporting green walls in two directions. Different variables will be considered, such as distances between the wall and facade, types of building materials, and various structural solutions. Shake-table tests will focus on the wall + panel configuration at building corners, considering actions applied in both orthogonal and parallel directions. Steel green façade prototypes are to be fabricated by ItalMesh srl and AM Legutio.

Task 3.5 – Parametric study
A parametric study of the structural behaviour will be performed by means of models calibrated on the experimental results. These numerical analyses will be aimed at the definition of the behaviour of real scale vertical walls, as well as at the assessment of possible scale effects that could not be identified in the scaled specimens used for wind tunnel as well as shake table tests.