Earthquake engineering structures
From Wikipedia, the free encyclopedia
Earthquake engineering structures are designed and constructed to withstand various types of hazardous earthquake exposures at the sites of their particular location.
Earthquake engineering is treating its subject structures like defensive fortifications in military engineering but for the warfare on earthquakes. Both earthquake and military general design principles are similar: be ready to slow down or mitigate the advance of a possible attacker.
According to building codes, earthquake engineering structures are meant to "withstand" the largest earthquake of a certain probability that is likely to occur at their location. This means the loss of life should be minimized by preventing collapse of the buildings [1].
Ancient architects believed that devastating earthquakes were a result of wrath of Gods and, therefore, could not be resisted by humans. Nowadays, the people's attitude has changed dramatically though the term earthquake engineering structure does not necessarily mean it is extremely strong and/or expensive one like the El Castillo pyramid at Chichen Itza shown above.
Currently, the most powerful and cost-effective tool of the earthquake engineering structures is base isolation which makes use of passive structural vibration control technologies; see, e.g., the Cathedral structure to the left.
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[edit] Trends and projects
Some of the new state-of-the-art trends and/or projects in the field of earthquake engineering structures are presented below.
[edit] Earthquake Shelter
One of the Japanese construction company has developed a revolutionary quake-proofed method for Japanese home owners. Instead of rather expensive quake-proofing of the whole home, it proposed a budget-friendly 6 x 6 x 6 ft shelter that could easily fit any small room which is, apparently, a fast and attractive solution.
Japan is one of the world most earthquake-prone countries: one tremor occurs there almost every five minutes. Therefore, the tenant of the homes like one depicted to the right will have now some peace of mind. See, also, [3].
[edit] Concurrent shake-table testing
Concurrent shake-table testing of two or more building models is a vivid, persuasive and effective way to validate earthquake engineering solutions experimentally.
Thus, two wooden houses built before adoption of the 1981 Japanese Building Code were moved to E-Defense [4] for testing (see both pictures aside). The left house was reinforced to enhance its seismic resistance, while the other one was not. These two models were set on E-Defense platform and tested simultaneously [5].
[edit] Combined vibration control solution
Designed by architect Merrill W. Baird of Glendale, working in collaboration with A. C. Martin Architects of Los Angeles, the Municipal Services Building at 633 East Broadway, Glendale was completed in 1966 [6]. Prominently sited at the corner of East Broadway and Glendale Avenue, this civic building serves as a heraldic element of Glendale’s civic center.
In October 2004 Architectural Resources Group (ARG) was contracted by Nabih Youssef & Associates, Structural Engineers, to provide services regarding a historic resource assessment of the building due to a proposed seismic retrofit.
In 2008, the Municipal Services Building of the City of Glendale, California was seismically retrofitted using an innovative combined vibration control solution: the existing elevated building foundation of the building was put on high damping rubber bearings.
[edit] Steel plate shear walls system
A steel plate shear wall (SPSW) consists of steel infill plates bounded by a column-beam system. When such infill plates occupy each level within a framed bay of a structure, they constitute a SPSW system [2].
SPSW behavior is analogous to a vertical plate girder cantilevered from its base. Similar to plate girders, the SPSW system optimizes component performance by taking advantage of the post-buckling behavior of the steel infill panels.
The Ritz-Carlton/JW Marriott hotel building, a part of the LA Live development in Los Angeles, California, is the first building in Los Angeles that uses an advanced steel plate shear wall system to resist the lateral loads of strong earthquakes and winds.
[edit] Kashiwazaki-Kariwa Nuclear Power Plant is partially upgraded
The Kashiwazaki-Kariwa Nuclear Power Plant, the largest nuclear generating station in the world by net electrical power rating, happened to be near the epicenter of the strongest Mw 6.6 July 2007 Chūetsu offshore earthquake [3]. This initiated an extended shutdown for structural inspection which indicated that a greater earthquake-proofing was needed before operation could be resumed [4].
On May 9, 2009, one unit (Unit 7) was restarted, after the seismic upgrades. The test run had to continue for 50 days. The plant had been completely shut down for almost 22 months following the earthquake.
[edit] See also
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Wikimedia Commons has media related to: Earthquake engineering structures |
[edit] References
- ^ Seismology Committee (1999). Recommended Lateral Force Requirements and Commentary. Structural Engineers Association of California.
- ^ Kharrazi, M.H.K., 2005, “Rational Method for Analysis and Design of Steel Plate Walls,” Ph.D. Dissertation, University of British Columbia, Vancouver, Canada,
- ^ ""Profits shaken at Tepco"". World Nuclear News. 31 July 2007. http://www.world-nuclear-news.org/corporate/Profits_shaken_at_Tepco_310707.shtml. Retrieved on 2007-08-01.
- ^ Asahi.com. Quake exposes nuke-plant danger. July 18, 2007.
