Soil challenges in the airport of the future (Mexico)

The airport of the future
Last year it was announced the construction of the Mexico city new international airport. Not only it will be one of the world's largest airports but it will also be the world's most sustainable airport and the first airport to be LEDD Platinun certified. As a matter of fact, it was called the "airport of the future" and "an inspiration for future airports".

The design of the airport was inspired by Mexican architecture and symbolism and was created to evoke a feeling of flight. The airport will honour the Mexican flag's coat of arms, which is a reference to Tenochtitlan, the pre-Columbian city on which the capital is built.

Image 1. Mexico City new international airport
Source: MexDF

The design and construction of this airport present special and unique challenges. The site for the new airport is located on the bed of the former Lake Texcoco. During the rainy season large sections of this area are inundated for several months and the soft soil conditions combined with ground water extraction result in large settlements. It is reported that some parts have already sunk some 5 meters since 1960. In order to deal with such challenges several engineering and technological innovations were required. In the present article we will discuss a little about the soil challenges (other features will be discussed in further articles).

Soil challenge
Mexico city and surrounding areas are located in what used to be a shallow lake (Texcoco lake). Thus, there is unstable soil with high water content and little capacity and the area is literally sinking. This poses extraordinary challenges for the design of structures. In the case of Mexico city new airport, this soil unstability posed two main problems: runways and terminals.

Six runways are planed for the new airport, each will be about 4 km long concrete topped embankments. In order to overcome sinking problems, each runway will be over a pile based deep foundation combined with polystyrene and other light materials.

The initial design was composed of two terminals connected by a railway. However, a railway was not a good alternative because in such unstable soil conditions tracks will bend or move. Thus, engineers decided to modify the initial idea by one spectacular six million square feet terminal (560 000 sqm). This will be the second biggest airport terminal in the world (Hong Kong terminal one 570 000 sqm). Besides, in order to ensure a very light building engineers decided that the whole terminal would be enclosed within a continuous, lightweight grid shell that embraces the inner layers of the building and seamlessly acts as both its walls and roof. Combining both skin and structure in a single system, the shell stretches from the fixed boarding bridges to the top of the roof. For better understanding, it as a series of interlocking shell structures that resist their loads through in-plane forces - rather than bending - and are, as a consequence, extremely lightweight. Moreover, such kind of structure does not require false work or scaffolding, it can be erected much faster and more economically with fewer materials and less energy than ordinary buildings.

Image 2. Inside of terminal

References and further reading
Airport of the future in Mexico.
Mexico City's new airport: an inspiration for future airports
NACO wins a multi-million euro tender to design the airside infrastructure for Mexico City's new airport

Forceeffect: A structural analysis Application

A structural analysis software

Usually engineers rely on structural analysis software for the analysis and design of any type of structural system. Nowadays there are several structural analysis software products. Among the most popular ones we can mention SAP2000, ETABS, RAM, STAAD pro or ROBOT. However, such softwares have a high computing cost (so do an economic cost) and need to be run on computers at the office. Thus, it is difficults for the field engineer to perform some fast calculations. In the last years smart phones and tables changed the ways we use computers. Everyday new smart phones and tablets application are available. Application with engineering application are not an exception. Some years ago popular enginnering software like AutoCAD and ESRI ArcGIS became available as online applications. Now structural software application joined the list. 

Figure 1. Sample bridge project.
Source: Forceeffect

Autodesk Forceeffect

Some time ago Autodesk released Forceeffect, a free application for structural analysis. Autodesk Forceeffect allows creating a structure with different types of support, different elements and subject to different forces. Then, it shows how the forces are distributed over the elements and the stresses the elements are subject to. Moreover, the user can easily modify the structure by just drag and drop the elements of the structure and the results are automatically updated. If this is not enough, the user is able to save and to generate html from the design. Moreover, in order to improve the presentation of the results Forceeffect also allows importing a background image to base the design. The following images show the application of Forceeffect for design of a bridge (Figure 1) and a backhoe (Figure 2). There are 16 sample projects and a users community. Forceeffect is free; the user only need to create an Autodesk account (in case is not a member yet) and sign in. The following video shows an introduction to Forceeffect.

Figure 2. Sample backhoe project
Source: Forceeffect

In this video you can see an introduction to Forceeffect

Further reading & references

The beauty of number π (PI)

&#960 (PI) approximation day

The following Wednesday 22 July the &#960 (PI) celebration day will be celebrated worldwide. The date was selected because 22 July also written as 22/7 is equivalent to 3.14285714286 which is very closest to the value of &#960 (3.14159265359); a difference of only 0.00126448926 or 0.04 % of the true &#960 value.
It is well known that &#960 is an irrational number (It can't be written exactly as a fraction or decimal number) that represents the ratio of a circle's circumference to its diameter. &#960 has several applications in our life. Some field where &#960 is commonly applied are:
  • Geometry: The simplest place &#960 is used is in finding the circumference or area of a circle. Of course, finding circumferences and areas can be useful in the real world. For instance, if you know the radius of a wheel and count the number of times the wheel turned, then it is possible to estimate the traveled distance and the speed (if you measure the time).
  • Signals: Sine waves have a fundamental period of 2*&#960, so &#960 becomes vital in signal processing, spectrum analysis. 
  • Probability: Everyone's favorite distribution (normal or Gaussian) has &#960 in the formula, and it is used in all areas of engineering to simulate unknown factors and loading conditions
  • Navigation: When planes fly great distances they are actually flying on a arc of a circle. The path must be calculated as such in order to accurately gauge fuel use, etc. Additionally, when locating yourself on a globe, &#960 comes into the calculation in most methods.
The beauty of PI as art
However, most of us did not realize that &#960 can be viasualized and it really is a very beautiful number.
Scientist Martin Krzywinski and artist Cristian Ilies Vasile published some visualizations of &#960. First, each digit of pi is represented by a dot of a different color and then these colored dots into a spiral. Then, series of circular representations of pi where the numbers are connected across the circle with a chord were created. New visualizations of &#960 were recently developed considering treemaps and paths.

The following images show some of the visualizations showing the beauty of &#960. The video has a more detailed explanation about the visualization process.

Image 1. Some &#960 visualizations made by Krzywinski and Vasile

In this video you can see an explanation of this visualization.

References & further reading
Visualizing PI
10 stunning images show the bauty hidden in pi
PI is beautiful

Happy 10th anniversary Google Earth

Google Earth 10th anniversary
Maybe when launching Google Earth you may have found a message abouth its 10th anniversaty. Indeed, last June 29, 2014 Google Earth celebrated its 10th anniversary. In order to celebrate its first decade Google Earth added two new features: Voyager and Earth View.
Image 1. Google Earth 10th anniversary message

Voyager shows the most recent imagery and data available. Voyager is divided in 4 categories: Street view highlights, 3D cities, Satellite - aerial imagery and highlight tour. The highlight tour flies around the planet highlighting samples from each of the new features.

Earth View
Although Earth View was already available, this new Earth View has been updated and now it offers 1500 new landscape images that allow us looking at the planet from above. Earth View shows landscapes from around the world as seen from space. The new landscapes are accessed through the Web gallery or using a Chrome extension.

The following video shows some features of the new layers and the tour.

Video 1. Google Earth Voyager tour

Nevertheless, it is important to remember that the celebration of this 10 anniversary began some months ago (January 2015) when Google Earth Pro became free. Until 2014 Google Earth Pro was available at 399 Us$ per year. Some of the most important features from GEP are the possibility to measure areas, 3D features and saving images.

The future
In a recent interview, Sean Askay (the new lead engineer overseeing future work on Google Earth) and Rebecca Moore (Google Earth Outreach manager) made some interesting comments about future plans for Google Earth which indicate a lot of thinking about leveraging the vast array of data Google has developed to create even more dynamic databases for new versions of Google Earth. Besides, there were some hints at uses of VR and AI technologies.

References & Further information
New Content for Google Earth’s 10th Anniversary
Google Earth Tenth Anniversary Brought New Features and Top Improvements