Many existing SHM techniques, either on-line or off-line, use linear baseline models that do not provide enough information on a structure's dynamics. Therefore, more comprehensive nonlinear baseline models that offer further structural parameters to be monitored and consequently provide more useful information on safety and serviceability of structures during or after an event should be implemented in RTSHM algorithms. This research work proposes simpler, more suitable algorithms utilising a nonlinear Bouc-Wen hysteretic baseline model for RT-SHM of a large class of nonlinear hysteretic structures. The RT-SHM algorithms are devised so that they can accommodate different levels of the availability of design data or measured structural responses. The second focus of the project is on developing a high-speed, high-resolution seismic structural displacement measurement sensor to enable these methods by using line-scan cameras as a low-cost and powerful means of measuring structural displacements at high sampling rates and high resolution. Analytical studies and computer simulations are undertaken to develop novel RT-SHM algorithms, evaluate their robustness under different ground motions, and to investigate their sensitivity to small yet important amounts of damage.