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Trench Drain in Brazil

Goodness Gracious! I just returned from a pleasure/business trip to Brazil.  Though the weather was good at times, the majority of my stay was overcast and rainy. I have no complaints on the +80 degree weather in January, however. I was given time to see some torrential rainfalls and a steady use of drainage systems in two distinctly different locations.

The first part of my trip was to a city called Belo Horizonte. This is a city of over 3.5 million people and with a population in the metropolitan area of well over 5 million. It is located just 5 hours north of Rio de Janerio. Belo is in the heart of the state of Minas Gerias, which is known for mining, iron production, cheese and a rum-like drink called Cachaca. The terrain is hilly. The infrastructure is old. Housing is made from concrete and ceramic tile. The streets are a mixture of stone and asphalt patchwork. When it rains here, you see lots of fast moving water on the streets.

The second part of my trip was to Rio de Janerio. While there, I stayed in the upscale area called Barra (pronounced ba ha).  In contrast to Belo, the Barra has newer housing, a lot of construction, a lot of commercial property, concrete and asphalt streets and flat terrain. It is know for the beaches, night life and carnivaal. When it rains in Rio, the water doesn’t flow as quickly as in Belo. Still, trench drain abounds here, as in Belo.

Trench Drain In Belo Horizonte

The trench drain I saw in Belo was all cast-in-place. That is to say, that the channels were formed of concrete, generally with a iron shoulder to support a grate of some sort. Four types of trench grate were identified; none of which were heavy duty. These are:

Sidewalk-Drain-No-GrateNo Grate

I was surprised how often grate-less trenches were used in sidewalks, streets, gas stations and parking lots to channel run-off water. If the channel is narrow or shallow, apparently it isn’t considered a pedestrian hazard.

Simple Iron Fabrication prIron Fabrication

Most grating I saw was formed from welded reinforcing bar or flat stock. The styles were rarely similar, indicating that they were fabricated with each construction effort. These were the most fun drains to find and were often on the hilliest slopes.

cast Iron prCast Iron

In some of the more commercial residential areas, I found cast iron grating. The sections were generally a meter in length and seemed to be able to handle the small automobile traffic common to Brazil (Class C at best). I found some of this grating at a local hardware store. No brand names are available. And apparently, there is no attention given to market standardization.

Concrete Grating prConcrete

I did locate concrete grating in a couple larger residential applications. I saw concrete used more in municipal drains systems. I was told that in larger cities, people steal cast iron grates to sell for scrap. In these areas, concrete trench grates are becoming more common.



Trench Drain In Rio De Janerio

In contrast to Belo, the majority of the trench drain I saw in Rio was associated with commercial property. But, as in Belo, I saw only cast-in-place systems. This time, however, the grates were wide and manufactured (rather than custom). I want to identify four types of grating that I saw:

Manufactured Bar Grating prBar grating (steel)

This seemed to be almost an H-20 loading grate. What I saw was manufactured from welded bar stock . One particular parking lot had over 100 LF of 2 foot wide trench using this grating.


Polymer Concrete Grating prBar Grating (polymer composite)

I’m still scratching my head on this one. I could swear I found grating made from polymer concrete. I would think that this grating would have to be wire or mesh reinforced. However, what I saw was cast and mineral based, and it seems to have a well thought out hold-down mechanism employed.

Standard Cast Iron Grate in Parking Garage prCast Iron

Simple cast iron grating was found in some of the ramps I saw in parking garages. Unlike those in Belo, these seemed to be a more durable design capable of class D loads. Again, all grating was in one meter section, no mater of the width. I saw no locking devices.

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Frame and Grate in Series for Trench Drain prFrame and Grate

I want to single out one type of cast iron grate that I feel is significant. At a grocery store parking lot, I found the use of a ½ meter square manhole frame and grates aligned in a series to make a trench drain. Though only 40 to 50 feet were found, it shows that excess money was spent to solve a drainage problem.

My observations of trench drain in the Brazilian cities of Belo and Rio are not exhaustive by any means. However, they are snapshots of what is being used in this country and have some value. Brazil currently has relatively cheap labor and “forgiving” building codes. The economy may not be ready for widespread use of the standardized trench drain materials currently used in Europe or North America. However, the infrastructure is ready.

Architects and engineers need to start incorporating standardized drainage systems into the designs of new construction projects. Simple former systems like EconoDrain would be a logical place for this country to begin. And, as Brazil is a county rich with iron casting production, it seems that this trench drain system is a natural fit.

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