The BBVA Tower

Hi, my name is Leonardo Da Vinci... Don't you believe me? Well, you do right! I am Rodolfo, the searcher of materials and construction systems of most fame of today. I have always believed that my ancestor Leonardo should live in our time, a mind privileged like yours should have had that prerogative, or you have not thought about the wonders that he could have created at this time, who once was the greatest scientific genius and artistic of the 15th and 16th centuries? I yes, of course.

I think much about it when I travel to Mexico, that country so cheerful, so incredible, so full of sweet and sour surprises and unique in the world (although this is a no-brainer). From the year 2010 I have been visiting regularly the capital to see how it develops one of my favorite projects: The Tower BBVA Bancomer.

Fourth Stop: The Metal Tower.

BBVA Bancomer opted for the city of Mexico to celebrate the merger of the largest bank in the country (Bancomer) and one of the most important financial institutions of the world (BBVA), The project was chosen by contest between two architectural firms who were responsible of the design of the Tower BBVA Bancomer, these firms are "Legorreta + Legorreta" (father and son) and "Rogers Stirk Harbour + Partners" (I also miss the companies of a single name). The bet was risky because of the different architectural languages used by the two companies, but I had supported them from the beginning in its decision: without risk there is not victory and it is clear that the result is magnificent!

After the construction is complete, the Tower will be 235 meters of height and consists of 50 apartments that will provide approximately 78,000 square meters of space for offices, which will be filled by 4,500 employees. The design evokes a texture of traditional lattice of Mexican architecture. I would also like to highlight the gardens every nine plants that will delight of workers (vertical villages), the Coffee Shop will be on a terrace over the Park located in the “Paseo de la Reforma” with spectacular views and an auditorium to promote a greater interaction among employees.

It is important to note here that the building has a clear will of energy efficiency and of commitment to the environment, this is designed and built thinking to be certified LEED (leader in energy and environmental design), which is the American standard which recognizes structures committed to the environment. The construction will have energy savings of 25%, maximum use of natural light, generous green spaces, a saving of between 30 and 50% of water and 75% recycling of construction products.

Why Metal?

The metals are so important in the history that you would not understand the evolution of humanity without them. They are can molded in hot and/or in cold and they can adopt the most incredible shapes, are rigid when is required and are flexible when you need. The profits include the entire imaginable spectrum: tools, weapons, cooking utensils, jewellery, decorations, surgical material, vehicles... and how not, the construction.

The metal more used in construction is the steel and its most assiduous form are the metal profiles (T, double T, IPN, IPE, etc.). With these profiles you can build in height because they lighten the weight of the building (it come in handy for the foundations), they allow a few more lights (distance between pillars), and they also allow free passage for installations (a big plus) and, above all, greatly reduced the time of execution of the work and the need for space to deposit the work material given that being made of prefabricated parts and we not require a place to store it until use.

There is another reason to use the steel as structure in our buildings: it have a great tenacity (energy that the material absorbs before the crack) with it which resists any effort, especially to traction. There are three forms of structural unions: using rivets, unions bolted and unions welded; these last two are those that are used more often due to the advantages that represent. The screws allow permanent joints and mounting and dismounting of the structure and the welds ensuring the continuity of efforts between the different pieces of the same material. However, the welds must be carried out by professionals in the field and we must corroborate its state with some method non-invasive (liquids penetrant, ultrasonic, x-ray, etc.)

 

Coffee to 150 meters

The last time I was in the building, I carried a few litres of Balché, it is a drink used by the ancient Maya as liquor ceremonial, I searched for the drink in the State of Tabasco, where not added alcohol, all with the idea of making a gift to the workers because they have very well behaved with me during my visits. But the Manager not allowed which I handed the drink to the workers, "is their duty to treat you well," he said aloud, after he whisper to me that he divided the drink it later with them, he imposed his authority... that things have the works!

Yet, he forced that they carried two coffees for us to 150 meters to height. I assure you that to drink a very hot coffee at that height while it watches huge metal beams that it is hoisting with the Paseo de la Reforma below... is one of the best experiences of my life!

I hope to see the finish of the construction of the Torre BBVA Bancomer and, if we are in his inauguration, perhaps I can invite you to Balche in the coffee shop, only perhaps, clear. Good bye.

The Reinforced Concrete: Bombay Arts Society

Hi, it is not easy to be always traveling but that it doesn´t mean that it is bad or unbearable, I, Rodolfo, usually I spend my time reading a book in the airports (nothing of thrillers, of course) or I watch some classic in my Tablet (a Nexus 9... Is it not on the market yet? Is that you have already forgotten who I am?), the last movie was Ben-Hur the film is known for its horse racing and because it has many differences with the novel but it is worth see Charlton Heston in his 200 minutes of filming.

Well, the case is that I love the films, I cannot remedy it, and therefore I travel a lot to Mumbai to see with it surprise us in Bollywood (Mumbai was formerly Bombay). I have a few friends working in the art society of Bombay (it situated there) and thanks to them I found out that they were doing a building whose main singularity is the form of the exterior... completely curvilinear! It would be impossible to achieve if it we do not use the reinforced concrete...

The Third Stop: The Reinforced Concrete.

If the previous article was based on the Ecological Concrete, this it is based on the Reinforced Concrete. The concrete is the most widely used material in construction but has a characteristic "uncomfortable": it works very well to compression (it supports loads directly on it) but it not works very well to flexion (it not support attempting to fold) so it has many limitations in structural systems. In the middle of the 19th century emerged the reinforced concrete, which it consists basically to be included one or more steel reinforcing rods within the concrete mass, this contributing to withstand the loads to flexion of the constructive element.

Today, it is very difficult to find a construction that it did not made with reinforced concrete: bridges, buildings, pipelines or installations of certain scale... Even the urban furniture is usually made of this material!!

The two materials is complement perfectly because they have virtually the same coefficient of expansion, because when the concrete is solidified it shrinks around the steel and they have to cooperate closely: the concrete protects the steel from corrosion (as a father to a son) because the alkaline PH is acting and passive the steel (it covering it with a film that prevents that external agents to attack it).

Bombay Arts Society

But I'm going around the bush very fast: as I had said I'm in Bandra, Mumbai, India, and although you may not believe it I have not come here to drink the Bombay Sapphire, I have come to see this spectacular and unusual building: the Bombay Arts Society created by Sanjay Puri Architects in a display of architectural pleasure rarely seen...

The building is public and it intends to serve the community of artists, its owners are the institution called Society arts of Bombay, which it is a society of art with centuries of antiquity. It contains art galleries, a small auditorium, a coffee shop (a public building without coffee shop would be horrible!), and offices for the artists. The parcel where it is located has 1,300 square meters of surface and the construction of building has 1,000 square meters.

Some persons liken the building with the cubist sculptures of Henry Moore, clear that I won't do it among other things because it is an absurd comparison. The characteristic shape is achieved making the outside structure with concrete reinforced, with this it is shaping to the material and it is make that the transmission of stress get to the foundations, so we avoid the construction of pillars and corners on the inside; this create spaces curved in both sides of the skin by setting some really special stays.

Steel mesh in curved wall

Construction

This type of building is the nightmare of the formwork workers and, at the same time, it is a challenge that will appeal to the most professional. The first thing that we must do is to identify well the singular points and repetitive elements. Why? Because we have to make unique formworks in the singular points and in the repetitive elements we can establish a pattern and make molds which help us in our work.

We have to take into account: the steel bars are elastics, this implies that if we bend it will tend to return to the position initial, in the parts where this phenomenon exists we will have to tie them very well to bars that maintain a position less stressed. So we avoid that in the future it can break the outer layer of concrete that covers them.

It is also good that we can guarantee the continuity of the concrete in the meeting point between ceilings and external walls, in other words: we do not fill the walls of concrete below the base of the ceiling into twenty or thirty centimetres; this will ensure a proper transmission of stress at that point.

I shiver of excitement thinking about beautiful forms that I can create with this material in my future construction! Bye bye!

The Ecological Concrete

Hi, I stand before you today, readers, overwhelmed and embarrassed because I'm going to skip a written rule that I expressed in my last article: "My name is Rodolfo and I have the intention of creating a building with different materials and building systems, but all of them have to have been already used in some construction, if not, How will I know that it really works?"... Do you remember? I regretted to have written it, because I had discovered a very special place with a very special material... that you don't want to miss!

A childhood friend is the guilty for all this, I not, of course, she is like Mafalda in various senses, as you know, Mafalda is a famous character of an Argentine cartoonist... is he called Quino? Anyway, the fact is that over the years she became an architect of weapons take and totally identifiable with the character of character... I do not recommend that you face it! Her name is Cristina and once took me to a place impressive where in addition to studying, they want to improve the world, this site is the M.I.T. (Massachusetts Institute of Technology) and there is where I discovered recently that they try to vary the concrete to a... Ecological concrete.

• Third Stop: The Ecological Concrete.

The concrete has very bad reputation, especially among the environmentalists, but it is not quite true that it is so bad. I do not defend what is, but i defend what it does. It is, without doubt, the material most used in the world. So much, that the Greeks already knew their existence in the year 500 BC (you did not know, huh?). The building of today is not understand structurally and aesthetically without it.

With the mixture of water, sand, gravel and cement is obtained concrete, it can add additives and different elements to vary its features and it make more durable, lighter, heavier... A fundamental quality is the solidification of the material: its components are mixed with the required dosage and after a few minutes starts to solidify, finally it takes the form with which we mold it and one strength and durability that will not make more than increase.

The main problem is that the concrete produces a tenth of the greenhouse gases generated by the industry and that, of course, this contributes to global warming, but we have to "the guys from the M.I.T." as I affectionately call them. Recently I was invited to his laboratory and they taught me some tests and theories with which they are intend to manufacture a ecological concrete which will reduce the carbon footprint, it is fantastic!

• Pellenq and the “magic ratio”

The cement, a key element of the concrete, it is make by cooking to 1500 degrees centigrade of the limestone (rich in calcium) and the clay (rich in silica). These materials vary but the proportions of calcium and silica is must keep, this produces a paste that it is called Clinker. The most of the greenhouse gases produced by the material are responsability of the descarbonization of the calcium and the silica.

Well, Rolan Pellenq (MIT researcher) and the professors Krystyn Van Bliet, Franz-Josef Ulm, Sidney Yip and Markus Buehler is describe in the journal Nature Communications a new analysis that suggests that the reduction in the proportion of silica and calcium would lower CO2 emissions and they would also produce a better and stronger concrete.

Pellenq and his boys discovered that the ratio between the calcium and the silica could be reduced from the 1´7, which it is the accepted standard, to 1´5 and it achieve the twice of the resistance of normal cement. With this low ratio, the crystalline structure well ordered progresses into a disordered structure vitreous, this produces that the material improve their mechanical strength and eliminate the residual stresses, with this it is make more resistant to fracture. This ratio, the 1´5, it is called "the magic ratio" for Pelleq.

• Example

We imagine now that in the tallest building in the world, the Burj Khalifa, which it is located in Burj Dubai, (if you have not gone yet, I recommend) it would have used this new "concrete ecological", as it did used 330,000 cubic metres of concrete which equals to 792,000 tons (around of nine million of people: I know cities more small) this would mean that instead of expell 316.800 tons of CO2 only would be expelled 158,000 tons.

In short, already I have ordered the staff of M.I.T. that they have to finish their experiments, because I want to use this concrete in my future construction. Bye bye.

The Bridge of Wood

Hi, you know that my name is Rodolfo and I have the intention of creating a building with different materials and building systems, but all of them have to have been already used in some construction, if not, How will I know that it really works?

What is difficult is deliver me from the newspapers, they follow me wherever I want to go, sometimes it is a problem being so well known... I feel like a character of Agatha Christie´s books being aware of the possibility that it is caught, and when they do … It cannot believe!! At last, to get to the point. that I have other things to do.

Second stop: the pedestrian bridge of wood

They say that it is the highest pedestrian bridge in the world, which I put in doubt, but I am sure that is highest in Singapure... I was already invited to the inauguration in 2008, but I was being to do and could not attend, so that the Prime Minister was angry... I speak, of course, of the Henderson wave pedestrian bridge, linking the hills of Mount Faber, Telok Blangah Hill and Kent Ridge Park, which are the three beautiful parks.

The most showy thing, beside the gardens before mentioned, of the highway Henderson Road (below the bridge) and the sights of the city, I mean, they are seven wavinesses that form the bridge and that simulate the waves of the sea for the most romantics and the silhouette of a serpent for the others (here I am). The design was gained by IJP Corporation and RSP Architects, Planners and Engineers in an international contest summoned by the Authority of Urban Development (URA).

Here are the dates. The materials used in construction were three: reinforced concrete pillars that sustain the catwalk, Steel as structure for support and acting as catenary (giving the characteristic shape of the bridge) and the wood that covers the entire walkable surface and that rises in the upward sections; the bridge has a length of 274 metres and a width of eight meters; in total there are more than 1,500 square meters of wood surface and there are areas where it appears doubly curved; the highest tower reaches a height of 38 metres.

Well, I have come here only to see the wood, which is unique in the world since it only found in the South-East Asia, called yellow Balau.

Characteristics and uses of Balau wood

The Balau wood is a tropical high density fiberboard, compact and with a high content of oils and tropical resins, it belongs to the Dipterocarpaceae family (award to who memorize it). It is appreciated for its robustness and resistance, and for his behavior with the water, which mades it very popular in shipbuilding and (guess) bridges, also it has excellent mechanical properties.

Currently the yellow or red Balau wood (the two existing varieties) is used in the construction of outdoor furniture, pergolas and parquet flooring. We must make sure that the wood comes from a provider of trust, since if the drying of wood is done incorrectly if not it can crack and warp; It is important to buy sealed wood: wich will avoid to lose its natural oils. Still I have not decided where I will use it in my future construction, but I am sure of one thing: it will be innovative.

Association between wood and steel

A critical point in this type of structure is the bond between the steel and the wood. It is not easy because of the large differences between the two materials, especially when they act outdoor and in what corresponds to the differences in dilation. Never forget that wood is an anisotropic material (different mechanical properties in different directions) and steel a homogeneous material (same properties in different directions).

The union will be made with self-drilling screws to transfer both materials. As you can see in the Henderson Wave bridge, very clearly, the different wooden slats are less separated lengthways (lengthwise) that in the transverse (to wide), this is because the wood fibers dilate more on its thickness than in its long, therefore "they are stretched" more in width than length..

As a last note, if you have the temerity to cross this bridge, remember that you can not smoke in it, for people who smoke. Good bye.