SHAPE MEMORY ALLOY Shape Memory Alloys (SMAs) are inter metallic alloys that can regain their original shape even after being subjected to intense heat and deformations. When used in building construction, it can endure heavy strains and still revert back to its original shape. Some examples include Ni-Ti, or nitinol, Cu-Al-Ni, Fe-Mn-Si, and Cu-Zn-Al systems, Ni-Mn-Ga, etc. SMAs are very elastic due to two unique metallic phases called Austenite(low temperature phase), Martensite(high temperature phase)
Nitinol
Among all the SMAs, Nitinol is super elastic, which means that it can absorb the stress imposed by an earthquake and return back to its original shape(the super elasticity of nickel titanium is between 10 to 30 times the elasticity of normal metals like steel.) Improving the Seismic Performance of Buildings SMAs have also been used to create devices similar to those described above to protect buildings from earthquakes. Currently, this kind of technology cannot be used to prevent the development of cracks occurring during an earthquake, however, they can prevent excessive deformation and collapse during the aftershocks. Conclusion Shape-memory alloys are a rapidly developing material that will become a good option for tackling the challenges that society is now facing, such as natural disaster resilience and demand for high performance. SMAs can also be used to reinforce bridges (highway bridge in Michigan) and effectively repair heritage structures(the bell tower of San Giorgio church at Trignano in Italy) It is essential that engineers and researchers work together to popularize this innovative material’s use in building structures and facades as well as in infrastructure.
Innovative Construction Materials & Techniques - Earthquake
Hima Karthik. S 1190100870