What are the structural uses of SMAs in Constructions??

The concept of adaptive behavior has been an underlying theme of active control of structures which are subjected to earthquake and other environmental type of loads. The structure adapts its dynamic characteristics to meet the performance objectives at any instant. Recently companies used a thermo mechanical approach to develop a constitutive relation for bending of a composite beam with continuous SMA fibers embedded eccentric to neutral axis. So SMA’s can be successfully used for the active structural vibration control.

SMAs can be  used as self-stressing fibres and thus they can be applied for retrofitting. They are like self stressing fibres.  Self-stressing fibres are the ones in which reinforcement is placed into the composite in a non-stressed state. A prestressing force is introduced into the system without the use of large mechanical actuators, by providing SMAs. These materials do not need specialized electric equipments nor do they create safety problems in the field. Treatment can be applied at any time after hardening of the matrix instead of during its curing and hardening. Long or short term prestressing is introduced by triggering the change in SMAs shape using temperature or electricity.