Purpose Rubber-based isolation systems produce enormous isolator displacement, requiring large seismic gap and causing excessive residual displacement, which can damage the isolator and it has lack of energy dissipation capability. These can be overcome by incorporating shape memory alloy (SMA) with rubber bearing (SMARB). However, studies were conducted ignoring the effect of soil structure interaction (SSI), which significantly alters seismic responses of isolated buildings due to soil flexibility effect. Methods This study aims to assess the optimal seismic performance of a multistoreyed building isolated with SMARB device subjected to recorded earthquakes using particle swarm optimization algorithm to minimize top storey acceleration of building considering the effect of different types of soil, which is modelled using direct method and the soil is considered linear, elastic, massless and homogeneous. The numerical modelling of SMA is done using Graesser-Cozzarelli model and the responses are evaluated by solving dynamic equation of motion of the combined system, which comprises the superstructure, isolator and soil. Results The effect of SSI reduces top storey acceleration and isolator displacement of the isolated building. The top storey acceleration is reduced by 3.1%, 27.8% and 35.8% and isolator displacement is reduced by 15.2%, 24.9% and 32.0% for hard, medium and soft soil, respectively. Negligible residual displacement is obtained for SMARB system considering SSI effects. Conclusion Among the various isolation devices (rubber bearing, lead rubber bearing and SMARB), SMARB performs significantly better and ignoring the effects of soil typology leads to a severe underestimation of the performance of the isolated building.

Reinforced concrete frame buildings are at risk of earthquake. Improving their response by adequate strengthening provision is an issue of major importance. Among the recent techniques introduced to increase the seismic resistance of this type of structure, shape memory alloy materials were found to bepromising. They have largedamping properties and significant re-centering capacity that reduce seismic efforts and limit damage. This work was dedicated to assessing the enhancement of building seismic capacity based on shape memory alloys of different sorts. Reinforcement consists of using rebars made from this material to replace longitudinal steel rebars in the critical zones of beams. A comparison of seismic performance induced by this technique with that associated with the conventional option relying entirely on steel as reinforcement was conducted. This was performed in the case of a medium-rise regular building subjected to medium and strong earthquakes when strengthened using four different shape memory materials including nickel titanium and ferrous-based alloys. SeismoStruct software was used to simulate the building through the static pushover analysis and the nonlinear time-history dynamic analysis. The building was anchored in the soil assumed to be rigid and the inelastic displacement-based beam element was used to discretize the structural members by setting up five integration sections and 150 fibers. In comparison with the steel-based option, it was found in both sites of construction that the use of shape memory yields an improvement in seismic resistance and re-centering performance. By using these smart reinforcements, the residual maximum inter-story displacement was reduced to less than a quarter of its value associated with the steel-based reinforcement. Furthermore, ferrous-based shape memory alloys were identified to yield a cost-effective strengthening alternative with regards to the common nickel titanium option and less than 10% of relative variation was observed in comparison with this latter.