A matter of format

The years were 1984 and 1985. SANEAGO had contracted the complete design of the water intake, storage and macro-distribution system for potable water in Goiânia, with a horizon for a population on the order of 2,750,000 inhabitants. Big thing.

SANEAGO asked that the design of the reservoirs be standardized and modularized to be adopted throughout the state. They were to be made of reinforced concrete (prestressed or not). Since there would be many large reservoirs throughout the state, it was decided to do it carefully and compare the costs of circular reservoirs (cylindrical) with rectangular reservoirs (parallelepipeds) and different area-in-plan x height (depth) ratios for the same volume, seeking an economical depth and standardizing the inlet-and-outlet through a single pipe close to the bottom using so-called “altitude” valves, which was an “audacity” in Brazil (a true doctoral thesis).

It is known that, for a fixed height and the same volume, the cylinder gives less area and therefore less concrete than the parallelepiped; however, besides the cost of the cylindrical “formwork” being higher than that of flat “formwork”, normally the arrangement on the site and the division into chambers (at least two) favors the parallelepiped solution. After many calculations and arguments, the conclusion was reached that the most economical and most practical solution, not only because of implementation cost but also because of maintenance and staged implementation, would be to use flat “formwork” with vertical walls braced by the bottom slab and by grid beams near the roof slab, without common walls or waiting walls for future expansions. That is, two separated parallelepipeds (to facilitate construction, maintenance and repairs, besides allowing one chamber to operate in case of problems in the other). It should be recorded that the number of concrete reservoirs built around there and that were never used because they presented leakage problems when filled is considerable, and these concerns are very valid.

The subject aroused great interest among those involved, both from the design team and from SANEAGO. At a certain point, the excellent architect Luiz Alberto C. C. Silva, who supported the team, suggested that the “elevated” reservoirs should be a “totem” that identified SANEAGO. I think that was the first time I heard that name with this application (obelisk, monument). He also suggested a prismatic shape with legs (hexagonal or octagonal section), inspired by an elevated reservoir then recently built in Rio by an industry, on Avenida Brasil around number 49,800 (it is still there). Luiz said he liked it because it gave “movement” to the structure as the observer moved while looking at it. An architect explaining reminds one of an oenologist describing wine...

It immediately occurred to us that the large “ground-level” reservoirs could also be hexagonal prisms, arranged like a beehive on the site. It was an intermediate situation between the rectangle and the circle, in a way unprecedented, and would serve as visual identity for SANEAGO.

Eureka! We got the support of SANEAGO (what an extraordinary group came together in that work: José Ubaldo, Manoel Inácio, Wilemy Paiva, Rivaldo Fleury, Francisco Humberto, Ricardo Correa, Nilo Nassar, Marcus Grael, Ibrahim Lasmar, M. Célia Moscoso, Affonso Accioly and others I no longer remember), and we went for that solution.

But what made me recall the subject and write these lines was the “public hearing” (at the time it had other names) for disclosure and approval by society.

SANEAGO summoned those interested: urban planners, structural designers, professors, builders, students and retirees, curious people, politicians, the press, radio, television, in short, a full auditorium.

We began to present the work developed over about 18 months: slides, overhead projector, blackboard, in short, the resources of the time. Urban spots, distribution of the consumption forecast for the next 20 to 30 years, sectorization, pressure zones (no one says it, but Goiânia and surroundings have about 300 meters of elevation difference between the lowest and the highest point and daily thermal amplitudes of up to 40°C), macro grid of pipes, pumping stations, telemetering, remote control and, finally, our pride: the hexagonal reservoirs in model and in pen-and-ink drawing.

Once the questions and comments were opened, after the usual praise, a colleague, I believe a professor of concrete at the Federal University of Goiás, pushy, with the voice projection of a “street vendor”, began to pick on the hexagonal reservoirs: where had we seen that? where else did they exist? _that it was a pointless invention, and so on.

I confess I became extremely irritated with the Tupiniquim argument: _so, if we had copied it from somewhere that the underdeveloped person judged to be inhabited by a superior race, then we could? National creativity of our own cannot?

The debate got messy. We became hostile and the professor had his “claque”; he was a good speaker, I had to contain myself because one does not fight with the audience. To the despair of the SANEAGO people and of our team, we were losing control of the auditorium and seeing that we would return to cylinders or parallelepipeds when an idea occurred to us:

_ Professor, we understand your concern with something unprecedented. But this is the land of Anhanguera, who set fire to the water and frightened the Indians so that they would show him where the emeralds and gold were. Everyone knows Goiás as the land of emeralds. Emerald is a beryl. Beryls are hexagonal crystals...

Total and long silence. We had gone too far in the argument to go back without hurting egos. But it became clear that, unexpectedly, the emerald argument, non-technical and unforeseen, had won. The chairman of the table took advantage of the moment of silence and said something like: _well, since there are no further comments, I declare the work approved.

No one protested.

Several reservoirs designed that way were built in Goiânia and have provided excellent service for more than 30 years. To this day. Let it be recorded.

Miguel Fernández y Fernández, engineer, chronicler and columnist, member of the National Academy of Engineering and of the Institute of Engineering # 2,362 characters.