Editing Concrete (section)

===Earthquake safety===
As discussed above, concrete is very strong in compression, but weak in tension. Larger earthquakes can generate very large shear loads on structures. These shear loads subject the structure to both tensile and compressional loads. Concrete structures without reinforcement, like other unreinforced masonry structures, can fail during severe earthquake shaking. Unreinforced masonry structures constitute one of the largest earthquake risks globally.<ref>{{cite web|url=http://www.fema.gov/library/viewRecord.do?id=4067 |title=Unreinforced Masonry Buildings and Earthquakes: Developing Successful Risk Reduction Programs FEMA P-774 |archive-url=https://web.archive.org/web/20110912163041/http://www.fema.gov/library/viewRecord.do?id=4067|archive-date=12 September 2011 }}</ref> These risks can be reduced through seismic retrofitting of at-risk buildings, (e.g. school buildings in Istanbul, Turkey).<ref>{{cite conference|url=http://www.curee.org/architecture/docs/S08-034.pdf |title=Seismic Retrofit Design Of Historic Century-Old School Buildings In Istanbul, Turkey |archive-url=https://web.archive.org/web/20120111151034/http://www.curee.org/architecture/docs/S08-034.pdf|archive-date=11 January 2012|first1=C.C. |last1=Simsir |first2=A. |last2=Jain |first3=G.C. |last3=Hart |first4=M.P. |last4=Levy |conference=14th World Conference on Earthquake Engineering|date=12–17 October 2008}}</ref>