The Performance-based Engineering Research for Multi-hazards (PERFORM) Structural Testbed will enable large-scale research on the performance of structures under extreme winds, earthquakes, and disproportionate collapse, as well as the influence of material degradation. This project will be responsible for oversight of the PERFORM Structural Testbed and will address the facility’s upcoming needs in the areas of safety, metrology, and sustainable operation. An initial planning phase of the project will develop a roadmap that articulates the unique role of NIST in measurement of structural performance and establishes an administrative plan for sustained operation of the testbed. A second commissioning phase will bring the testbed to full operation by (a) outfitting the facility with a modular set of reaction blocks to enable the application of lateral loads in structural testing and (b) equipping the facility with instrumentation and data acquisition systems for measurement of structural deformations, strains, and forces with quantified uncertainty. A third phase of the project will focus on metrology and operations, with responsibility for scheduling maintenance of equipment, maintaining safety records, coordinating research activities, and pursuing innovative sensor technologies to further enhance the facility’s measurement capabilities.
Objective - To establish, maintain, and continually enhance the support infrastructure required to safely conduct measurements on the performance of structures under multiple hazards with quantified uncertainty.
What is the new technical idea? The modular, reconfigurable PERFORM Structural Testbed will enable full-scale experimental evaluation of structural performance under multiple hazards, using state-of-the-art metrology with quantified uncertainty, to promote innovation in the design of robust structural systems by advancing the development of performance-based standards. A roadmap for the structural testbed, to be developed in the initial planning phase of the project, will further articulate the following aspects of NIST’s unique role in measurement of structural performance and will establish an administrative plan to maintain and continually enhance this facility.
What is the research plan? This research project will be conducted in three phases. In the initial planning phase, a roadmap will be developed to establish a technical and administrative plan for operation of the structural testbed. A commissioning phase will focus on delivering a fully operational facility that is capable of characterizing structural performance under multiple hazards, including both vertical and lateral loading representative of extreme winds and earthquakes. After commissioning is completed, a third phase of the project will focus on metrology and sustainable operation. Throughout the duration of the project a sustained focus on safety will be maintained. The following paragraphs provide further discussion on each of these aspects of the project.
Roadmap: Full-scale structural testing is a vital, yet resource-intensive activity that requires careful planning to ensure that adequate programmatic resources will be available for years to come. A roadmap will be developed to articulate NIST’s unique role in state-of-the art measurements of structural performance and to establish administrative plans to ensure that adequate resources are available for sustained operation and continued enhancement of the structural testbed.
Safety: Safety considerations in structural testing must be given high priority and require focused and sustained attention. This project will be responsible for coordinating the development of safety documentation and for maintaining records of authorized users of equipment in the PERFORM Structural Testbed. By integrating those key personnel in the division with prior experience in testing of large-scale structures, this project will provide a holistic perspective on safety to help ensure safe execution of structural testing activities.
Commissioning: The PERFORM Structural Testbed currently incorporates a reinforced concrete strong floor, a state-of-the-art hydraulic power distribution and control system with an integrated 220 kip capacity servohydraulic load frame, and multiple servohydraulic actuators for application of structural loads. This project will identify and prioritize the investments required to bring the structural testbed to full-operation, taking proactive steps toward realizing a fully-functioning facility. Commissioning tests, which will be staggered as new equipment becomes operational, will verify the performance of newly added experimental capabilities to ensure safe and effective execution of tests and other laboratory activities. A key product of the commissioning phase will be a modular system of structural reaction blocks that will be integrated with the existing strong floor using post-tensioning rods. These reaction blocks, together with the strong floor, provide a reconfigurable reaction system for application of vertical and horizontal loads, as well as for bracing of test specimens. Commissioning tests of the reaction system will be planned to characterize the stiffness of the system for loads applied at different heights and along different axes of the blocks. A second key product of the commissioning phase will be an instrumentation and data acquisition system with state-of-the-art sensors for measurement of structural deformations and strains associated with nonlinear structural and material performance.
Operations: Following the successful completion of the commissioning phase, this project will continually maintain the support infrastructure required to conduct large-scale structural testing and ancillary testing of materials and structural components. Sustainable operation of the PERFORM Structural Testbed, including the hydraulic power distribution and control system and the integrated servohydraulic load frame, will require long-term coordinated planning and investment. Budgeting for costs associated with procurement and maintenance of equipment will be coordinated with current and future users of the equipment. An up-to-date equipment inventory will be maintained, and regular maintenance will be scheduled to ensure uninterrupted operation of the equipment and quality of the experimental measurements. This project will facilitate the scheduling and planning of testing activities, equipment usage, and space usage in the structural testbed and will maintain authorization records for the facility’s personnel.
Metrology: Project staff will continue to pursue the identification and development of innovative sensor technologies in an effort to further enhance the measurement capabilities of the facility and provide opportunities to develop richer, more meaningful datasets. As the project transitions beyond the commissioning phase, increased consideration will be given to quantification and reduction of uncertainty in measurements taken in the PERFORM Structural Testbed during structural testing. Specific attention will be given to acquiring precision laboratory standards (e.g., gold or platinum standard load cell, high-accuracy displacement calibrator) for calibration of ancillary sensors, and to establishing rigorous and repeatable calibration procedures. Innovative sensor technologies with potential applications in the field are of particular interest (e.g., for condition assessment of deteriorating infrastructure or for post-disaster evaluation of structures). A specific measurement challenge that this project will address is the quantification of concrete cracking and damage progression in the nonlinear performance of reinforced concrete structures. Measurement approaches to be considered for this purpose include techniques currently being explored based on fiber-optic sensors and ultrasound measurements, as well as techniques based on image processing and electrical resistivity.
NIST (2014a). Measurement Science R&D Roadmap for Windstorm and Coastal Inundation Impact Reduction, NIST GCR - 14-973-13, prepared by the NEHRP Consultants Joint Venture for the National Institute of Standards and Technology, Gaithersburg, MD.
NIST (2014b). Development of NIST Measurement Science R&D Roadmap: Earthquake Risk Reduction in Buildings, NIST GCR - 13-917-3, prepared by the National Institute of Building Sciences for the National Institute of Standards and Technology, Gaithersburg, MD.
Kuligowski, E., Lombardo, F., Phan, L. and Levitan, M. (2013). Technical Investigation of the May 22, 2011, Tornado in Joplin, Missouri, NIST NCSTAR 3, National Institute of Standards and Technology, Gaithersburg, MD.