Building With Emotion

Our profession is engineering; our task is to build; our obligation is to do it right the first time, leaving a useful, beautiful, resistant, safe, practical, and perennial legacy for our society. We have always conceived these great missions as technical tasks that require preparation solidly based on the exact sciences and with very detailed planning. It has also required strict financial planning that allows us to execute and conclude them, also obtaining a benefit for construction companies. Without a doubt, all of this is a great truth; however, today, I want to invite you to analyze a different point of view.

As I mentioned above, the great projects, the most relevant that have been built, have been achieved by discipline in the tasks that we already mentioned. But after many years of dedication, I have discovered that the emotion with which they have been done, and not the sciences, is what achieves the greatest and most transcendent result. That is why in this article I want to take this opportunity to tell you about the emotions experienced by yours truly in some projects that I have carried out with prefabricated concrete structures.

Parque Delta Shopping Center

Mexico City, 2004

Danhos Group

The era of shopping centers was in full swing in the capital of Mexico. The owners knew the business, but as it was increasingly competitive, they explored more aggressive construction systems, which would add more value to the investment, achieving more profitable projects, with lower risks and capable of solving the ambitious architectural ideas they had. Parque Delta also combined for the first time a mix of commercial lines (a large self-service store with a department store, both leaders in their field, which would coexist in the same project). As if these challenges were not enough, the building is approximately 150,000m2. It was also built on terrain of high seismic activity, only 500m away from where, in the 1985 earthquakes, the structures of the old National Medical Center collapsed. So, the challenge was colossal, and we accepted it, fully trusting that prefabricated technology was enough to meet the demands.

The foundation design was concluded as a floating caisson, which implied one more challenge in that the assembly teams had to walk over the cover slab. The only way to do this was with prestressed slabs, like those that would be placed as a floor system and that could take the weight of cranes and trailers. It was a good result, but one that required enormous care to properly anchor the cranes in the appropriate places (exactly over the foundation beams), having previously drawn them, so that the operator and his supervisors could be clear about their positioning. It was like walking on a glass table, and when supporting the cranes we did not forget to do so exactly above the supports! As the work progressed, we had small and large setbacks, but we moved forward with critical thinking, discipline, and a great sense of teamwork. For example: the client demanded that the structure of the department store be closed with facades by Dec. 31, 2004, so we had to finish assembling the structure in November, so that they could assemble the facades in a month. However, it occurred to us that if we first assembled the structure adjacent to the three facades, forming a horseshoe, the facades could begin to be assembled even a month earlier and we would thus have until Dec. 31 to complete the structure. With this collaborative idea, thinking about the good of all, both tasks were completed on time. The store, as well as the entire shopping center, opened to the public in Oct. 2005 – only 18 months after starting the foundation.

Monterrey Bbva Soccer Stadium

Gpe. Monterrey, Nuevo Leon 2004

Femsa 

In the professional life of a civil engineer, it is not easy to have the opportunity to build a stadium of the magnitude of this project: 52,000 seats, making it one of the five largest in Mexico and, yes, the most modern. 

The owner had already wasted a lot of time on the issues of permits and official authorizations, and it was urgent for him to open the doors to a hobby that, being local, is one of the most important in the country. We were assigned to the project when those phases had already concluded, and time had to be made up. This is how we did it, manufacturing 98% of the elements that make up the stadium on site: Rakers or main beams, known as “alligators;” and stands for box seats, for the upper and lower bowls as well as other special precast elements. There were more than 2,000 pieces!  

It is a large, mixed structure, meaning the foundation and substructure of the basal levels and the famous tripod columns that support the upper stands were cast in-situ. The Rakers and all the stands were prefabricated; the façade and roof are metallic.

So, while the foundation and tripod columns were cast in-situ, the other elements were manufactured. It is incredible to think that a very ambitious architectural design (from the firm V&FO Mexico) in curved shapes was resolved with practically all prefabricated elements and a straight axis. Bravo to the architects!

There was a decision that from my point of view was crucial in the project: the metal structure that forms the facades and the roof, which extends in a cantilever around 50m over the stands, was supported in its entirety on only 73 x 2 = 146 ball joints or metal accessories, half of them located on the floor, in the foundation, and the other half directly in the Rakers, in their rear end, where the metal accessory drowned in the concrete that would serve to support the enormous monster (because of how big, not because of how ugly) that is the facade and roof of the stadium.

We made the owner and his supervisor see that although we could guarantee that said metal accessory would be properly drowned in the concrete of the Raker, it should not be us who manufactured it but the same company that was manufacturing the façade and the roof because they had the procedures and correct machinery; that it didn't matter if it had to be moved to the site, and it didn't matter if something that contractor 1 would build was placed by contractor 2 – that was just a matter of coordinating it – but the project deserved the best quality in each process. And so it was. The roof supplier delivered the 73 accessories to the foot of the mold and they were assembled on site – each weighing more than 3 tons!  This entailed a great deal of coordination but it is today we all sleep peacefully when a soccer match is being played in a full stadium – which is always the case! – because it is  a safe place!

Elevated Highways

Cdmx and Metropolitan Area

2002-2015

Living in a metropolis with 22 million people and that is only approximately 40 x 40km long (the same population as Shanghai, China, but with an area eight times smaller) is to live permanently in a chaotic state due to traffic, trucks, and public transportation services. The question is, What is the correct solution? Increase the public transportation system? Yeah! Improve roads? Yeah!  Implement a program called “Today, do not circulate?” Yes (although it was later counterproductive because the vehicle fleet grew). All the answers were “yes” because in truth, there was so much delay that any solution would help reduce the chaos. But it was not until the beginning of this century that the construction of the first elevated roads began, with the first elevated highways built over the main traffic arteries in the city.

There were several challenges that could not be avoided. Building only at night, it had to be a single-column structure, similar to a very slender, attractive, and durable inverted pendulum, with a minimum of work done on site and with the city alive and full. At that time, there were some examples in the world of these kinds of structures that could serve as a reference, as well as some others that collapsed due to earthquakes (Kobe, Japan). The challenge was colossal. But Mexican willpower, ingenuity, and technical knowledge could be added to the political will and the task was carried out. One of the most important viaducts in length and with a short construction time was the Viaducto Bicentenario del Estado de México, built in 2009-2010 precisely to celebrate the 200th anniversary of the beginning of Mexico's independence. It is an elevated highway structure that is over 25km long.

The secret for the solution was to make extremely sophisticated concrete pieces: a) footings-columns with integrated head and of the required total height, which sometimes led them to be the heaviest pieces of the viaducts, when they were more than 15m tall;   b) Support beams and central beams that were resolved with a single element spanning up to 45m in an ingenious Gerber system, which helped avoid having a continuous structure of the entire viaduct, like in Kobe – although rigid frames were formed, very long, not very desirable continuities were also broken by making isostatic supports from time to time. A very Mexican solution! On smaller scale viaducts  these had proven to work well in other past projects in the Mexico City area, such as for the metro.

Plant manufacturing broke all records in the country. For the first time, we were making pieces that had more than 100m3 of concrete each, more than 50 tons of rod each, and more than 10 tons of strand each. The companies obtained prestressing beds with a capacity of more than 5,000 tons, cranes of 200 and 300 tons for the yard, modular ones to move pieces of more than 450 tons, and cranes to assemble them, in some cases, with over 1,000 tons of capacity.

We rode in work windows that started at 11 at night; we had to complete several activities between 11 at night and 5 in the morning: move the equipment from where it was stored to the assembly point, assemble those enormous cranes, which took more than an hour and a half, erect the piece or parts for that day, only to dismantle the equipment again and return it to the shelter. If after 5 in the morning you did not allow the roads to reopen due to continuing in some of the processes, by 6 am the traffic was already chaotic, and you appeared on all the TV morning news shows – so we learned not to fail.

The “second-story structures,” as we called them, taught us that prefabrication must be a response that simplifies work on site, complicating work in the plant. Manufacturing with the best conditions and with the necessary number of molds and production lines, you can then break records and work again, making elevated viaducts of unprecedented lengths in a type A seismic zone worldwide, with the safety and functionality margins that are required.

I am infinitely grateful for your attention in allowing me to share the emotions of building with prefabricated concrete, which is without a doubt one of the greatest emotions in life!