Applications - Example 1
The MUST-SIM facility provides many essential features that aid in significantly advancing the state-of-the-art integrated seismic testing and analysis. The examples of application of the MUST-SIM Facility may be formulated from different angles. Three such examples are considered here: research needs in seismic risk mitigation, end-user industrial needs, and integration with existing NEES facilities.
Application 1: Testing and analysis of full-scale structures with Soil-Structure Interaction
Two story frame test with soil-structure interaction, soil response from analysis (far corner column attached through a 'dumb' connection and relative actions are imposed on the three others).
Through employing sub-structuring techniques while coupling the test specimen with analysis software to model the soil reliable, results will be obtained from the test to enable advancement of the understanding of the dynamic response of structures with their foundations and underlying soil. Construction of the large-scale model need not occupy the three LBCBs, since it can be constructed independently, then jacked up onto the loading platforms. Larger structures have been jacked up in this way in other laboratories. The conservatism built in design codes and assessment guidelines, which are there to bypass areas of lack of knowledge, would be reduced based on new knowledge. Since earthquake design is based on avoiding certain limit states of performance, these limit states have to be first evaluated accurately. Performance-based design utilizes more deformations than actions (not exclusively, since it is based on the performance objective which could be on occasion related more to forces). The effect of SSI on structural performance is traditionally thought to reduce forces, which is true in many cases. However, it increases displacements.
If the newly developed concepts of displacement-based design are invoked, the significance of the accurate assessment of the global secant stiffness of the structure-foundation system is seen to be critical to the choice of the displacement spectrum to be used in design. Results from such realistic tests will aid in further development and verification of displacement-based design, and more generally performance-based design as well as assessment techniques for existing systems.