Mohamed ElKafrawy

Shape memory alloy (SMA) is a material that can change shape in response to external stimuli such as temperature, stress, or magnetic fields. SMA types include nitinol (nickel-titanium), copper-aluminum-nickel, copper-zinc-aluminum, iron-manganese-silicon, and various nickel-titanium-X alloys, each exhibiting unique shape memory properties for different applications. Reinforced concrete (RC) T-beams strengthened and pre-stressed with Fe-SMA bars are numerically investigated for their flexural response under the influence of various parameters. The bars are embedded in a concrete layer attached to the beam’s soffit. Based on the numerical results, it was found that increasing the compression strength from 30 to 60 MPa slightly improves the beam’s strength (by 2%), but it significantly increases its ductility by approximately 45%. As opposed to this, the strength and ductility of the pre-stressed T-beam are considerably improved by using a larger diameter of Fe-SMA bars. Specifically, using 12 mm Fe-SMA bar over 6 mm resulted in 65% and 47% greater strength and ductility, respectively. Furthermore, this study examines the importance of considering the flange in the flexural design of pre-stressed beams. It is seen that considering a 500 mm flange width enhanced the ductility by 25% compared to the rectangular-section beam. The authors recommend further experimental work to validate and supplement the calculations and methodology used in the current numerical analysis.

In the wake of the 1994 Northridge and 1995 Kobe earthquakes, structural designers adopted performance-based engineering concepts instead of traditional deterministic design approaches. The primary change was to evaluate the design according to stakeholders’ interests instead of the engineering parameters. This evaluation process required a probabilistic estimation for the included variables at all design stages. The NHERI-SimCenter application framework provides generic solutions implemented in different hazard simulation problems. Seismic isolation is an efficient, proven technique for improving seismic performance by limiting drift ratios and reducing damage. During the design stage, seismic isolation-system parameters must be carefully calibrated to control different aspects of the response, and it is necessary to run multiple simulations and count for parameter uncertainties. This research introduced components for seismic isolation and incremental dynamic analysis procedures integrated with framework modules, such as uncertainty quantifications and damage and loss estimation. Furthermore, an illustrative case study was included to reflect the impacts of this development.