FIFTH Grade PBL

Hello Fifth graders! This the homework that each group must prepare. Read this article and answer the questions below. Each group will hand a paper in to the teacher with the answers and examples of earthquake resistant techniques (drawings).  It will be discussed on Friday, April 27,2018. Here also you can see examples that each group can use as a model of an earthquake resistant building, house or bridge.

Rubric:
Questions were answered out correctly   /5
The drawing resembles the correct model  /5
Houses, buildings and bridges are included   /5
Uses English to describe the drawing  /5
Uses creativity to share the drawing    /5
It is handed in to the teacher on time    /5

5: Proficient: A high degree of competence
4: Capable: An above average degree of competence
3: Satisfactory: A satisfactory degree of competence
2: Emerging: A limited degree of competence
1: Beginning: No key elements are adequately developed

How do they do it?

The Chile earthquake — at a magnitude of 8.8 — was much stronger than the one that hit Haiti, but casualties and damages appear to be far less. Why? (Shutterstock)

The opinion of the experts consulted by BBC Mundo is clear: the first secret behind the tough Chilean buildings is the structure of reinforced concrete and steel, sufficiently flexible and resistant to allow the building to move, wobble and not fall; insulators and seismic energy dissipating elements that allow the Earth’s movement to not be transferred to the building and, if transferred, that energy is absorbed.

Another crucial element is the use of soil study so that the foundations are appropriate.

This is a very specialized analysis that guarantees the stability of the building according very strict rules: “To each soil type corresponds a specific calculation for size, shape, depth and strength of the foundations,” explains the President of the Architects College of Chile, Sebastián Gray.

The second key factor is the awareness that auto-building without following these rules is harmful and a key element in the few landslides that have happened.

Experts agree that a key is in the structure of reinforced concrete and steel, sufficiently flexible and resistant to allow the building to move, wobble and not fall.

  Sebastian Gray, Architect talks about the real problem behind those buildings that did not resist an earthquake in Chile. Can you tell what that reason is?

Despite the code, some buildings did fall, most notably the one in Maipú and the other in Concepción. In your opinion, was this due to problems with the code, code enforcement, or something else?

Code enforcement, clearly. This appears to be a matter of  a relaxation in building procedures and hasty construction, which is the  responsibility of builders and developers, rather than a matter of structural design or the quality of materials, which are not an issue here. As part of the deregulation policies of the neoliberal economic model enacted in the 1980s, local authorities and professional associations were deprived of direct on-site supervision powers in the 1980s.

Structural design in Chile is reliable, based on state-of-the-art technologies, and has even developed innovations adopted in other regions around the world.

https://cachandochile.wordpress.com/2010/03/14/chiles-earthquake-an-arcitects-perspective/

After the Kobe earthquake, more buildings in Japan were constructed using base isolation, including apartments and condominiums, which are normally constructed using traditional methods. Today, about 100 base isolated buildings are built in Japan each year, not including single family homes.

Now, Japanese engineers are taking the concept of isolation a step further with “ground isolation.” In Sagamihara City outside Tokyo, they have built 21 separate buildings—six to 14 stories tall—on top of a three-acre concrete slab. The slab then sits on 150 isolation devices, including many very large rubber bearings, and all of the buildings move in sync. Ground isolation shows great promise and could bring base isolation to even more high-rise complexes.

Another idea we can get from Japan.

A closer look at the bearings that isolate the structure from the ground and the flexible utility hook-ups.

http://www.pbs.org/wgbh/nova/next/tech/rubber-bearings-seismic-protection/

What can be done to improve the earthquake resistance of a bridge?

Tuned mass dampers are used in tall buildings as well as in bridges to counteract the movement due to earthquakes as well as wind and other lateral loads. The Akashi Kaikyo bridge uses TMDs in the suspension towers for example.

Base isolation is one of the most common techniques used to resist earthquake movement. These are devices which essentially separate the horizontal movement of the foundation from the rest of the structure by using some form of sliding bearings. If designed properly this can drastically reduce earthquake damage.

Seismic Dampers are also common. These are a range of devices which act to remove seismic energy from the structure similar to how shock absorbers on a car remove the vibration energy of the car going over a rough road.

These technologies are well understood and are frequently used in bridges and buildings. There are more experimental techniques which are also possible such as: rocking isolation, or active damping systems (computer controlled dampers).

If desired these devices can also be used in combination in order to further enhance the earthquake response.

What are the most important elements in Chile's structures?

In accordance to Sebastian Gray, Which was the problem that caused some buildings to fall during the earthquake?

Who does Sebastian Gray blame for this?

What is Japan using to build new buildings?

Japan also uses TDM's. What is that?

You can use this pictures to prepare model of buildings, houses, and bridges which may be earthquake resistant . Be creative!