Madagascar: a hotel designed to resist cyclones

Optimized scale model of the bungalow, to analyse ventilation comfort

The hotel to be built on Sainte-Marie Island a few hundred meters from the east coast of Madagascar is exemplary in many respects.  Firstly, following the principle of fair trade tourism, some of the profits generated by visitor stays will be assigned to financing of a clinic that the 18 000 inhabitants of the island need.  Two associations have been created for this purpose.  The "Andzaha  Ecolodge" is exclusively aimed at the hotel structure, and "Andzaha Health" is dedicated to management of the clinic.

The second advantage is that construction of the buildings will respect a particularly strict process.  “The operation initiator, Gérard Hoareau, wanted the twenty bungalows in this hotel complex to be sustainable, says Fabrice de Oliveira.  This is why he called us in to carry out a wind study.”  An essential precaution before starting to break the ground in 2010, because the island is right on the path of cyclones that regularly cross the Indian Ocean.


Resisting cyclones

The work done by CSTB included three aspects.  The first step dealt with optimising the shape of bungalows to resist cyclone stresses.  The triangular-shaped buildings have a central chimney, which has the advantage of resisting a large proportion of tear off forces applied to the roof by creating a negative pressure inside the constructed volume.  “Secondly, we created models of the bungalows and the hotel restaurant at 1:25 scale continues Fabrice de Oliveira.  We used them in the wind tunnel to analyse loads applied to the different structures for winds up to 200 km/h at a height of 10 m.  It was found that the proposed "cyclone" design reduces vertical load due to wind on buildings and on the restaurant roof by up to 50%.”  Finally, since the wind direction is known, CSTB recommended optimum relative positioning of the bungalows, to improve natural ventilation inside the buildings.  All of which aims at improving tourist comfort.

Optimized scale model of the bungalow, to analyse wind load
Scale model of the restaurant, to analyse wind load

A special design for bungalows on piles

The Andzaha Ecolodge is located on a three-hectare private site and in particular comprises about twenty bungalows, ten of which are located with their "feet in the water" and 10 are located along the beach.  They were designed by the architect Claudia Rubio.  A special design was made for the structures supported on piles, particularly dealing with air passageways between the sea and the floors.