Investigation of a Novel Pressurized Sand Damper for Sustainable Seismic and Wind Protection of Buildings

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Over the last 40 years, a variety of well-engineered structures, designed according to building codes that were valid at the time of their construction, experienced severe damage during earthquakes. Most of this damage was the result of excessive seismic displacements, and subsequent research has sought to enhance the seismic performance of civil structures through the development of various strategies to dampen structural displacements. Many existing technologies, however, are disruptive and costly. This research will perform laboratory testing and computer simulations for a newly developed damper, where the material enclosed within the damper is pressurized sand. This research will advance the state-of-the-art in high-performance structures by using a pressurized sand damper (PSD) device, which can perform well under a wide range of temperatures and is low-cost. Scientific understanding and advancement of the PSD will contribute to the welfare of society by mitigating human and economic losses caused by severe earthquake and prolonged wind loading, while meeting current requirements of longevity and sustainability of built infrastructure. Another advantage of the PSD is that it consists only of traditional materials (sand and steel) along with the established technology of post-tensioning, with which civil engineers are most familiar. Educational, outreach, and research activities will be created for middle and high school, undergraduate, and graduate students, including the university's Summer Camps for Girls. Experimental and simulation data generated by this project will be made available publicly in the NSF-supported Natural Hazards Engineering Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-CI.org). This award contributes to NSF's roles in the National Earthquake Hazards Reduction Program (NEHRP) and the National Windstorm Impact Reduction Program (NWIRP). The original contribution of this research is the development and the experimental and numerical validation of an innovative, low-cost, long-stroke, environmentally friendly, stable PSD that meets the criteria for sustainable engineering without suffering from the challenge of viscous heating. Energy dissipation in the PSD originates from the shearing action of the pressurized sand that exploits the pressure-dependent shear strength of the sand and its effect on increasing the dissipated energy during cyclic motion. The specific goals of this research are to (a) perform comprehensive testing on various configurations of the prototype damper to identify the physical similarities and scaling laws that govern the prototype design; (b) provide continuous, real-time monitoring and adjustment of the internal pressure of the sand damper; (c) conduct numerical modeling of the sand flow/behavior of the PSD using the discrete element method while utilizing crushable models of sand grains, which upon validation with the experimental data will allow for the design of sand dampers at various scales and configurations; and (d) refine a recently developed macroscopic, phenomenological model of the PSD that can be incorporated in open source codes such as OpenSees.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.