MRI: Acquisition of an Infrastructure for Real-Time Testing of Wind Effects on Structures

Colorado State University, Fort Collins CO

Investigators

Abstract

ABSTRACT Mitigation of natural and human-induced hazards will play a fundamental role in defining what society demands of engineers in the U.S. and worldwide. In the past, designing to a minimum standard was believed by many to provide adequate performance. A new developing paradigm, shared by several engineering fields, is performance based engineering (PBE), which seeks to measure design adequacy based on multi-objective system performance rather than the traditional component strength approach. To date, this paradigm has only received attention by earthquake engineering researchers. This MRI award will enable researchers at Colorado State University to take a step toward establishing a design philosophy for performance-based wind engineering (PBWE) by utilizing what has been learned by earthquake engineering researchers (i.e. utilizing the NEES IT infrastructure for test equipment linkage). In order to do this, an infrastructure improvement to enable hybrid spatiotemporal testing of wind effects on structures will be acquired. This will make it possible to (1) apply realistic wind loads on structures, and (2) couple the left and right sides of the equation of motion during simulated wind loading in the presence of nonlinearities. Both these capabilities are essential for this next generation of design philosophies. Specifically, performance-based wind engineering (PBWE) is to be a new paradigm that will focus on damage-limiting design and construction of new as well as renovation of existing structures subjected to wind load. This design philosophy is barely at the conceptual stage and research on its merits and possibilities has just begun. At the current time the laboratory infrastructure necessary to begin the development of such a philosophy is deficient in several major areas: (1) laboratory tests must be able to model material and geometric nonlinearities, for example deformation dependent structural damping and aeroelastic effects associated with large aerodynamic response of wind-sensitive structures; (2) within the development of PBWE, new technologies such as active control and supplemental damping systems, must be able to be modeled in the laboratory; and (3) a significant number of tests will need to be conducted to allow researchers to formalize a proposal for development of a PBWE philosophy to the U.S. and world-wide communities. Economic (and sometimes laboratory) constraints make this number of tests impractical. However, if hybrid testing and analysis is enabled, testing costs would be reduced to a fraction of their current cost. These testing and analysis deficiencies will be mitigated through the acquisition of an infrastructure that will link Colorado State University's Wind Engineering and Fluids Laboratory and Structural Engineering Laboratory, thus enabling the research and education tools to solve combined wind/structural engineering problems. In order to do this five instrumentation components: A wind pressure measurement system, high performance DAQ/IO Interface, actuator suite, actuator control system, and a computer network system to integrate these components will be purchased. The broader impact of this MRI award is the ability to (1) systematically address existing structural design code deficiencies, and (2) provide the technological experimental infrastructure for the emergence of performance-based wind engineering. Both these broader impacts will lead to safer and more affordable structures, including single and multi-family dwellings, and mid and high-rise buildings. The still broader impact is the technological crossover of information between a system that was developed for the linkage of an earthquake network (NEES) to other strains of engineering such as structural wind engineering. The intellectual merit of this MRI award includes (1) the ability to experimentally solve the equation of motion in the presence of geometric and/or material nonlinearities and (2) the ability to perform spatio-temporal hybrid tests. Neither of these have been accomplished for wind loading of structures, hindering new concepts and methodologies worldwide.