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06.05: Wind and Earthquake Damping System for the Isozaki/Allianz Tower in Milan, Italy
Author(s) -
Castellano M. Gabriella,
Borella Rudy,
Pigouni Aikaterini E.,
Infanti Samuele
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.187
Subject(s) - tower , damper , structural engineering , induced seismicity , displacement (psychology) , engineering , wind speed , geotechnical engineering , geology , civil engineering , psychology , oceanography , psychotherapist
The Isozaki or Allianz Tower in Milan, designed by Arata Isozaki and Andrea Maffei, is one of the three office towers of the CityLife, redevelopment project in the area of the historic exhibition area of Milan. It's a mixed reinforced concrete and steel structure of 202 m height (207 m considering the city ground level) and 247 m including the television antenna. It has 50 storeys above ground, and is the tallest Italian building according to the criteria of highest occupied floor and height to tip. Due to the height and the slender shape (24 m × 60 m in plan) of the tower, the wind and seismic protection system comprises 8 special fluid viscous dampers (FVDs) connected to the base of the building by means of 4 long struts (two for each strut). Each FVDs is characterized by 1304 kN maximum force and ±150 mm maximum displacement capacity. They manage to mitigate the wind effects by suppressing the anticipated wind‐induced accelerations and improving the comfort inside the building. Although Milan is a low seismicity area, the dampers were also designed to sustain also earthquake effects. Therefore, due to the completely different dynamic behaviour of wind and earthquake, the dampers were designed to change behaviour passively, i.e. activated only by the different velocity of the relative displacement between the two ends of the damper. Thus, the velocity exponent α of the typical force vs. velocity constitutive law of the fluid viscous dampers is 1 (linear behaviour) under wind input while is lower than 0.1 (strongly non‐linear behaviour) under earthquake input. Two of the 8 FVDs were subjected to a complete test protocol required by European Standard “Anti‐seismic devices” EN15129:2009 in FIP Industriale Laboratories. This paper describes the FVDs and reports the most important test results, confirming the required behaviour of the devices both under service wind and ULS wind or earthquake.