Impact studies are becoming widespread for high-rise buildings
The observation made during the past few months by CSTB teams shows a turning point in the construction of high-rise buildings. Or rather in the approach used by owners and architects in how they carry out such projects. "At the moment, we are systematically called in during the tall building design phase, says Sophie Moreau from CSTB. These recurrent requests all have the same purpose, to carry out studies on the impact of these buildings with regard to the environment in which they will be located." There is no doubt that mentalities have changed. Nowadays, concerns about the ambiance created around the future building are fully taken into account. This is applicable to all real estate programmes initiated around the perimeter of the Paris West business district. In the future, the EPAD (the La Défense Public Development Office) obliges every promoter to demonstrate that the environment will not be degraded.
Wind, noise, sunshine….: a targeted service
CSTB provides a targeted service in response to the queries of professionals involved in the many projects currently under progress, both in La Défense with the Gan, Air2, Phare, Majunga and AVA towers, and in other districts (Nœud Papillon in Nanterre, the large philharmonic hall in Paris la Villette, etc.). "We are working to modify aerodynamic conditions related to building a given tower building, to change its geometry, size, etc, continues Sophie Moreau. Everything must be done as early as possible to reduce negative phenomena (wind, draughts and gusts that could make the building surroundings unpleasant in any way." The wind analysis is only one aspect of CSTB’s work: evaluation of additional loads, if any, on nearby buildings, changes to sunshine, simulation of acoustic effects (input and output, etc.). All these parameters are carefully examined before the building permit is even deposited.
Explanation of phenomena, numbers and suggestions
"For each ordered study, we deliver a complete document containing the detailed explanation of the phenomena considered, says Sophie Moreau. We also give an estimated order of magnitude (as a percentage) of potential degradation and information about the dynamic behaviour of the structure. Finally, we provide a few qualitative illustrations and lines for reflection in carrying out the project." The suggestions made are intended to be very specific about improvement of the site considered: places to be avoided when making a children’s playground, installation of specific urban furniture, installation of a pergola, plantations, etc. These are all "preliminaries" that in many cases can be considered in more detail during a second series of analyses carried out in CSTB’s Jules Verne wind tunnel.