Sunday, August 5, 2012

Shanghai World Financial Center Construction

Shanghai World Financial Center construction was one structure worth researching. As anyone could imagine, building such a structure as Shanghai World Financial Center requires knowledge that has not been know before-but with technology and testing the project was completed on August 28, 2008

The importance of developing building technologies to resists earth movement and high winds in high-rise construction holds an important value. Initially planned to be the world's tallest building, but because of economic situation, the Asian Financial Crises, and other delays, The Shanghai World Financial Center, located in Shanghai, China, is eye appealing. While it was in the building process, the building dimensions were increased for couple reasons that we know of. After a decision to increase gross area of the WFC in Shanghai by 15%, increase in overturning moment from wind forces of about 25% came as well. A diagonal bracing was also used. With the design changes, the service core shear wall was achieved and there came the decrease in the amount of steel needed for the robust structure.

The first structure was called the mega structure, which in reality consists of major structural columns, the major diagonals, and the belt trusses. The second one was a concrete walls of the service core I mentioned above. The third system was a relationship between concrete wall of the service core and the mega-columns, that were made by the outrigger trusses...

As the final design of LERA (Leslie E. Robertson Associates), Shanghai World Financial Center construction consisted of three relatively narrow columns, compared to seventeen wide columns. An important area to mention is how the stiffness of the perimeter and trusses has movement, as well as shears in the concrete walls of the service core, can be increased or decreased. The whole robust design is smiler that of the, previous, World Trade Center in NY. The wind engineering results were different compared to that of the World Trade Center in NY, based on extensive wind testing.

The earthquake engineering for the Shanghai World Financial Center construction was extensive. The design allows for a 200 year period for typhoon return and a 2000 year return on earthquake. In the process of its foundation construction, temporary support for both mat and below-grade concrete floors were made because of the use of top-down construction method, H-piles large steel sections extended from the piling to the ground surface...

Other issues that come with this high rise were the cost, as in any project. Because the pile cut-off was well below grade, it was costing too much to reinforce existing pile. LERA determined that the current pile foundation system they had in place could accept a larger expansion; they only had the issue of cutting the weight of the original building by 10% or more; the other aspect they had to do was to redistribute the loads to the pile so that increased lateral loads the come from wind and earthquake can be surpassed.

For Shanghai World Financial Center construction or other building areas where winds are a problem, the seismic effects typically include:

1. High base overturning moment and foundation design (wind, seismic)

2. High shear demand near base (seismic)

3. High gravity stresses in the vertical elements (and use of high-strength materials) to minimize structural sizes for
economic structural design and to maximize net floor area

4. Differential axial shortening under gravity forces, including effect on floor slope and outrigger force demands

5. Development of ductility in elements at the base of a structure under high compressive gravity stress (seismic)

6. Controlling lateral accelerations (wind)

7. Controlling story drift (wind, seismic)

8. Controlling damage so as to enable repair (seismic)

9. Ensuring ductile energy dissipation mechanisms and preventing brittle failures (seismic)

Each geographical location requires specific, special requirement, to be developed and tested, when the project is breaking new ground, like The Shanghai World Financial Center construction... Although other buildings were structured in that geographical location, but not with the same height and greatness...

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