AT WORK: BUILDING GREEN SKYSCRAPERS
When Yoram and Sholem Cimet set off to build a major tower in Mexico City’s Glorieta Insurgentes area, they knew they had an exceptional project on their hands.
“This area has four of the most important neighborhoods in the city coming together. The Glorieta is a very important icon in the city. When we found this plot, with all of this going on around it, it became a very important jobsite. We had to have a building that had a lot of quality and a lot of personality to equal the importance of the avenues and the site itself in the city. It’s a building of very important design and very important structure,” says Yoram.
Sholem and Yoram, both trained architects, are a father and son team. Yoram joined his father on the skyscraper project called Torre Glorieta, where the two of them have led almost the entire design, construction, and development process
up on the project was necessary not only because of the volume of work to be done, but the type of work—the project is uniquely challenging, even for Sholem’s 35 years of experience with his company, Constructora Cimet, specializing in office buildings. The two handled the land acquisition, completed the architectural plans, and managed the building work.
An Important Location
“The rotunda here of the Glorieta los Insurgentes has some of the main avenues of the city going through it. The main avenue would be the Avenida Insurgentes, which is the longest avenue in America. And the other one is Avenida Chapultepec, that leads to the main park and forest with the castle from when Mexico used to be a monarchy,” explains Yoram. “Those are very important avenues in Mexico City that go North and South, East and West. When the city was building the subway station they made a very large rotunda here at the conjunction of these two avenues and that changed the complexion of this area of the city. It’s the central part of Mexico City and it’s the main transport hub of the city: the first subway line and the first metro bus line run through here.” Indeed, Yoram estimates that with the bus and train circulation combined with automobile, foot, and bicycle traffic, more than 500,000 people move through the rotunda adjacent to the building each day.
Covering 60,000 square feet of floor space, the building is 25 levels high, not including the three-floor underground parkade. The building will feature a heliport, a rooftop garden, and—beneath the basement levels—fully operational water and sewage treatment plants.Including these facilities mean that, with the uptake of rainwater during Mexico City’s four or five month rainy season, the building will be 100% water self-sufficient. This feature of the building is part of a larger initiative for Torre Glorieta: achieving LEED status, the world’s premier benchmark for high-performance green buildings.
Developed by the United States Green Building Council, Leadership in Energy and Environmental Design (or LEED) is a building certification process meant to promote the design and construction of energy-efficient buildings that use sustainable resources and materials. LEED uses a point system to evaluate the environmental merits of a project, with categories like energy and atmosphere, innovation in design, and sustainable sites. “When we designed and started construction of the building we knew we had to comply with the highest standards internationally,” explains Yoram, “we were building in a very important jobsite with a very important design. We knew we needed to comply with LEED, and to be sustainable”. For Torre Glorieta, the building’s self-recycling water system combined with other design elements like hyper-efficient air conditioning, plumbing, and lighting to not only warrant LEED certification, but Gold status—the second highest rating possible.
Beyond environmental concerns, Yoram and Sholem had some other pescado to fry before construction on the building could begin. The largest and most complicated of all? Concrete. The finished Torre Glorieta has over 25,000 m³ of concrete, and a vast majority of it required specialized problem solving to pour. “No aspect of this project is standard,” explains Yoram, “not the plot of land, not the architectural design, and especially not the concrete design.” The two biggest obstacles affecting the Cimet’s project: swampy ground and high seismic activity.
Mexico City is built on a drained lake. In order to stabilize the building in such squelchy soil, massive underground pilings and walls had to be poured, some as voluminous as 380 m³ at a time—a major risk in a labyrinthine city with unpredictable traffic delays and a project where one late load would be disastrous. Another geographical obstacle working against the Constructora Cimet team is the fact that metropolitan Mexico City stands in a notable earthquake zone, where seismic activity is frequent and occasionally heavy. As such, the Torre Glorieta’s columns needed to be flexural and possess a certifiable degree of elasticity, characteristics that had to be implemented into the concrete design. For Yoram, this was a major challenge. It was such a challenge, he says, that “no concrete company in Mexico would guarantee that the elastic module of the concrete would be met”. So, not only was excellent quality concrete utterly critical to the project, but the concrete designs were unique and varied, ranging from 55 MPA all the way down to 30 MPA—and suppliers were unable to meet the requirements. The Cimets had no choice but to produce their own concrete, on site. Enter the ProAll Reimer Mixer, stage left.
Using a mobile mixer meant the concrete was mixed immediately, producing the freshest possible concrete for the building’s columns and guaranteeing the elastic modulus of the concrete design would be met. Since a Reimer Mixer can be loaded as it pours, it also meant that the building’s gigantic monolithic foundation pours could be achieved, even if it meant pouring for more than 24 hours continuously. So, the Cimets had the control they were looking for, but the quality was another question; with stakes high, they needed to ensure standards were being met. Their solution: on–site lab certification, with curing and compression tests done right there, on demand. Yoram explains: “We had an external lab working with us. We gave them an area on site where they could do all their testing and they worked from there. They’d take batches from every single pour we had, and we’ve worked very close with them with the concrete formulas, hitting the sweet spots with them on the concrete with the different resistances that we’ve needed and of course, since they are on-site, in the pour itself; we can manage the concrete if we need. We were able to comply with all the testing that is done and needed for the concrete of the building, so the security complies with the highest standards of construction and concrete design and concrete building.” So, with over 25,000 m3 of concrete and each pour tested by an external lab, how did the volumetric mixer’s concrete perform? “We had no failures on test results,” explains Yoram. None? “Not one”.
A Greener Mixer
With such lofty environmental objectives, how would this non-traditional approach to concrete affect the project’s status as a Gold LEED building? Using a ProAll Reimer Mixer not only left the LEED certification intact, it was enhanced. “When we chose to produce our concrete on site we talked a lot with the LEED professionals and the people who are advising us in the LEED certification, and for them it was a total new thing. When we did a lot of formulas we started to realize that we were saving a lot of energy in the production of the concrete since it’s a very simple production which we do with a ProAll Reimer Mixer, instead of having all that concrete come from a plant that is very far away. So there’s a lot of savings in transport and there’s a lot of savings in the production itself in the machinery that’s needed to produce the concrete. Here it’s very simple. And of course, there’s no waste. We use all the concrete we produce, so all those were very important for the LEED people as well. They’ve actually been trying to make this kind of concrete production as something maybe not mandatory, but as something that does give you extra credits on your certification. That’s an ongoing thing that we’re trying right now. But it’s been a very big innovation in the construction of the building. And for LEED, it is an innovation and they have to start having a whole big study internationally at concrete production on site versus off site concrete production, and all the benefits that we can have from this. And probably in a few years to come we will see some of those credits being given to the people that take this kind of construction and production of concrete to the site, because of all the abilities it brings to the building.”
The concrete for Torre Glorieta is now completely in place, with the project scheduled for completion this year (the Cimets are in talks to sell the building or rent it to a major tenant). For their troubles, the Constructora Cimet concrete team were finalist for World of Concrete’s Crews That Rock award for both 2014 and 2015.
For Sholem and Yoram Cimet, choosing a volumetric mixer meant a solution to several significant problems, and was a vital component of the project’s success. However, as Yoram describes, the ramifications for this project may stretch much farther: “Having the construction of the concrete on site makes a huge difference for building construction. It’s very cost-effective. It’s very good on timing. It helps us a lot. I’m pretty sure a lot of other construction companies will start looking at this method and start adopting it since its worked wonders for us and I’m sure it would for anyone else. I’d like to say that I think that the way this building has been built and the way it was designed architecturally, structurally, and the way we have built it will change the way of construction in Mexico City, and maybe worldwide”.