|Name of the client/building owner
||Desarrollos Comerciales y de Ocio Lorca
|Function of building
||Shops and stores
|Type of application of the membrane
|Primary function of the tensile structure
|Degree of enclosure
||Mediterranean - mild winters, dry hot summers
|Number of layers
|Short description of the project
||Lorca is one of the hottest places in Spain. In fact people from site say as a joke Lorca means “calor” (hot) upside down. There are more than 300 sunny days per year, and the average temperature is 20ºC.
So the goal of the open-air mall was to create shaded places with a significant decrease of temperature, to make it comfortable.
For the food court, three big conical roofs were planned in order to create vast shadows. At the lower points the membranes are anchored on the roof of the mall structure and the tops are supported by three main masts - one for each roof. The overlapping of the three membranes was designed to create a more dynamic visual result.
As an immediate outcome of these ideas and also due to the size of the roofs (each one of the two smaller structures is 800m2 Ferrari 1202 and the biggest is 2.000m2 Ferrari 1302) high loads appeared. This requires a high prestress (more than 2.000kN in some cases) and hence a strong primary structure and heavy duty cables. The final result still seems light within the large spans (in the central roof more than 60m).
All the masts and cables were placed exactly on the appropriate concrete pillar heads: some of the anchorage points on the slab were reinforced with additional steel frames and thicker slabs so that the load transmission was correct.
Steel plates for masts and cables were installed during the execution of the slabs, to assure a high quality load transmission. Some of these plates did weight over 800kg.
The prestress in the membranes and tie down cables was introduced in two ways. At the corner points special turnbuckles were used and at the top of the main masts the position of a floating ring connected to the top was adjusted by tensioning with hydraulic devices.
Each membrane was plotter cut and welded into one piece (even the 2.000 m2 one) in our factory, and crane folded in a precise way to allow an easy unfolding on site, at the right position.
Cable sizes did not allow using reasonable pocket borders, so a clamping system was designed to allow the installation of the clamps and the cables on the ground, and the uplifting roof by roof in only one operation.
Time needed for the installation of th food court roofs was one month, two weeks for the biggest and one week for each one of the smaller.
Ten more roofs were built for a specific restaurant. They were designed as inverted cones of about 80m2 each, with an eccentric mast, and were manufactured in the workshop and installed in a very fast way since all the system works as a modular kit construction.
Membranes were patterned, plotter cut and made in our factory in Ferrari 502 coloured fabric. Installation process on site took only one day per roof.
Finally a 600m2 roof was designed and built for the bowling terrace, following similar criteria than in the food court ones.
An articulated central arch created a significant shape in the middle, so it was easy to reduce loads on the membrane and the structures.
This roof was made in Ferrari 702, and its geometry and size allowed a common pocket border solution, so the complete roof was designed, engineered, built and installed in only 1 month.
Main dimensions and form
|Form of a single element