Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior. Once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface.
This Earthquake resistance design be a good task for an adult. Your "shake table" is now ready to shake some towers!
Use the same base size and shape for each tower, so that the size of the towers' footprints are the same, and only their heights vary. What are the heights of the different towers? To test each structure, create a lateral shaking movement using the same distance of displacement you previously measured.
Did all, none or some of the towers fall? If some fell and others did not, what were the differences in height between these towers? In general, did the taller towers fall more frequently than the shorter ones?
In this activity, you kept the footprint of each tower the same and only changed the height. Try testing LEGO towers with different-size bases. Do you think that by changing the footprint you could make taller buildings more stable?
You could also calculate the area of the base by multiplying its length times its width in centimeters and divide this by the height for each tower to get the ratio of base to height.
How do the towers' base-to-height ratios compare with how they perform on your shake table? Try building towers out of a different material that allows you to test different structural designs. Good materials are straws, popsicle sticks or toothpicks and marshmallows.
Try comparing square designs to triangular or hexagonal designs. Try adding extra structural elements to your designs. Can you design a stabler tower? How tall can you build it before it loses stability?
Observations and results In general, did the taller towers fall whereas the shorter towers remained standing? If you varied the footprint of the towers, were the ones with larger footprints generally more stable than the ones with smaller footprints? Structures that are tall or skinny are generally less stable, making them more likely to fall when exposed to lateral forces, whereas ones that are shorter or wider at the base are generally more steadfast.
Architects and engineers use all kinds of innovative techniques along with these basic principles to build amazing skyscrapers.
Building heights keep creeping upward as technology allows engineers to safely build higher. One major technological breakthrough that allowed for the creation of skyscrapers in the late s was the development of a material that was lighter and stronger than previously used materials: Before this, buildings were mostly made of brick and stone.
Architects and engineers designed skyscrapers with a steel framework that supported the building's weight, which meant that the walls no longer had to be load-bearing as they had previously been. This development, along with other innovative ideas and materials, allowed for the creation of skyscrapers—and as our technologies continue to improve we are be able to reach ever closer to the sky.Reclamation Library Glossary.
Listed alphabetically below are definitions for terms commonly used by the Bureau of Reclamation. Clickable alphabet links have been provided at the beginning and end of the glossary to aid in searches. ENDS Note Set 22 Fabn 1 Steel– AISC Load and Resistance Factor Design Load and Resistance Factor Design The Manual of Steel Construction LRFD, 3rd ed.
by the American Institute of Steel Construction requires that all steel structures and . Earthquake Resistant Design According To UBC Major Changes from UBC (1) Soil Profile Types: The four Site Coefficients S1 to S4 of the UBC , which are independent of the level of ground shaking, were expanded to six.
Earthquake-Resistant Design Concepts. An Introduction to the NEHRP Recommended Seismic Provisions for New Buildings and Other Structures. FEMA P / December Eurocode 8: Seismic Design of Buildings Worked examples Worked examples presented at the Workshop “EC 8: Seismic Design of Buildings”, Lisbon, Feb.
Support to the implementation, harmonization and further development of the Eurocodes. Eurocode 8 EN Design of Structures for Earthquake Resistance Summary: European standard for the design of structures for earthquake resistance. Modern design methods include ductile behaviour, capacity design, seismic isolation.