2001-2 the versatile canopies

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THE VERSATILE CANOPIES

By Sanchez, J. 1) and Escrig, F. 2)

1)2)Professor of the School of Architecture of Sevilla. Spain.

SUMMARYThe use of canopies for industrial or engineering purposes are discussed in this paper were we describethe use made in two different sewage disposal plants. The characteristics of these projects is that is notpossible to use mast inside of the space. Other is that the volume must be completely closed. And theother that not always the area is circular.

1. GENERAL SURVEY.Canopies are surfaces with an internal high point hanged from a internal mast or external supports thatpermits the use inside without obstacles.They are a lot of solutions used to cover public spaces, sports and commercial areas many of them verypublished. La Verne of Berger (Figure 1) or The Glass Pavilion in Riadh of Otto (Figure 2) are examplesof the masted internally. The Haj Terminal of Geiger (Figure 3) or The Palenque in the Expo 92 of Prada (Figure 4) are examples of the externally masted.

Fig. 1. La Verne College.

Fig. 2. The Glass Pavilion in Riadh.

Fig. 3. The Haj Terminal in Riadh.

Fig. 4. Palenque for the Expo’92.



In general this kind of solution has not been used for other purposes. We have designed several canopies

to cover residual water tanks based in the same ideas.

2. LA CHINA TANKS FOR DEPURATION OF RESIDUAL WATER IN MADRID.

It was necessary to cover near of 10.000 sqm. without interrupt the use of the plant and taking in

account the complex surface were to work, the poor state of conservation and the need of use thepath existent at the moment. Additionally we had a very limited budged and were forced to work

in the limit of 60 US$ sqm. in plant. Otherwise the aggressive atmosphere recommended not using use

steel in contact with the air of the enclosure.

We decided to use canopies as an appropriate solution to avoid these problems. The Figure 5 shows

the area where to act and the Figure 6 a general aspect of the plant.

Fig. 5. General Plan of the plant.

Fig. 6. Several view previous to the works.



For the squared tanks we decided to use three mast like shown in the Figure 7 supporting each one two

canopies (Figure 8).

For the circular tank we used a tripod as shown in the Figure 9.

Fig. 9. Perspective of the roofs.

Fig. 7.General view of the roofs.

Fig. 8. Lateral elevation of the squared roofs.



3. ANALYSIS AND DIMENSIONING,

To analyse this structure we have been used the programme CABLE, developed by our team and

based in the Reference 3.

We have use loads as pretensing, wind loads and snow loads. Global wind is considered as 30 Kp/

sqm. 60 Kp/sqm. for snow and prestressing as required.

The Figure 10 shows the stresses for the worst combination of loads for square canopies. Wile theFigure 11 shows it for circular one.

As the results we show in the Figure 12 the cables to stabilise the masts and the tripode while the

Figure 13 shows the cables stabilising the canopies.

Fig. 10. Stresses in the cables of the squared tanks. Fig. 11. Stresses in the cables of circular tanks.



Fig. 12. Cables to stabilise the masts.

Fig. 13. Cables of the squared tanks.

Fig. 14. Principal masts. Fig. 15. Anchoring of the perimeter.



Fig. 18. The roofs completely finished.

Fig. 16. Tripode of the circular canopies. Fig. 17. Internal view.

4. CONSTRUCTION.

In the Figure 14 we show the principal masts with a length of 25 m. In the Figures 15 and 16 we can see

the tripod and the lateral anchorage. The Figure 17 shows an internal view and the Figure 18 a generalview of the works completely finished.

Along a year the complex has been in use without problems in spite of sever winds and rain that,

combined, could produce ponds because the low profile of the canopies.

At this moment we can resume that the construction of canopies with a fixed top point is very easy while

if this point is movable, as happens in the squared canopies, it presents more difficulty.

Then in the next construction we have used exclusively the tripod supporting.



5. OTHER CANOPIES.

In the same way we have built other canopies for the same use as Butarque in Madrid (Figure 19)

hanged also from a tripod (Figure 20). The Figure 21 shows the process of erecting and the Figure 22

some general aspects.

Fig. 19. Elevation of circular canopies for Butarque.

Fig. 20. Previous design of the Butarque canopies. Fig. 21. Process of erecting the canopies.



Fig. 22. Finished canopies.

5. REFERENCES.

1. Escrig, F., Sanchez, J. “ Estructuras en tracción de cables.(Tension structures of cables)” STAR.

Structural Architecture, nº 5. Escuela de Arquitectura de Sevilla) 2000 pp.100.

2. Ishii, Kazuo. “Membrane Designs and Structures in the world” Shinkenchikn-Sah Co ltd. 1999.

3. Krishna, Prew. “Cable Suspended Roofs” McGraw 1978.

4. Otto, Frei, “Tensile Structures” MIT Press 1962-66.

2001-2 the versatile canopies

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