Algorithmic tool assess post seismic architectural stress
The only way to reduce the damages caused by an earthquake is to build structures that can support the seismic vibrations. Shaking table testing is so far one of the most widely used methods utlised in order to evaluate experimentally the behaviour of a structure under seismic conditions. During this testing, a scaled model is subjected to a prescribed base motion. Nevertheless, this method as well as other conventional methods used for the same purpose, introduce some uncertainty that can be reduced only by increasing the cost of testing. This consideration creates the need for a more economical alternative approach. The Mechanical Engineering Department of Bristol's University are one of the leading teams involved in the development of a new and perhaps the most promising approach called, real-time substructure (RTS) testing. According to this approach, a physical test is performed on a critical part of the structure while the remaining substructure is modelled numerically. Servo-hydraulic actuators are used to pass the results between the physical and the modelled substructure in real time. The numerical model outputs a set of interface displacements, which are then applied to the test specimen. The resulting resistance forces are measured and fed back to the numerical model. This step is repeated several times according to the test's protocol. In addition, an innovative algorithm called Minimal Control Synthesis (MCS) and a software tool have been developed in order to provide the required extremely rapid computation, communications and robust control, as well as to compensate for the time delay inherent in the actuators. Although the MCS algorithm can be used as a final product, it is in a continuous state of development and further research is being performed in collaboration with European and American research institutes. The fact that it has been mainly used in the context of earthquake engineering, should not hinder the potential applications of this approach in many other fields such as the car industry, aerospace and materials testing.
