Reinforced Concrete Frames Project preparing for preliminary testing in NEES@Illinois small-scale facility

As part of the NEESR Project "Near Collapse Performance of Existing Reinforced Concrete Frame Buildings" (RC Frames), headed by PI Mehrdad Sasani (Northeastern University) and co-PI Xiaoyun Shao (Western Michigan), preparations are continuing for testing in the NEES@Illinois 1/5-Scale Laboratory in preparation for Large-Scale testing in the MUST-SIM facility.

Column shear-axial failure in existing vulnerable reinforced concrete (RC) frame buildings constructed before the mid 1970's is a major seismic risk. The challenges associated with spatial response and system load redistribution capability at the onset of collapse has not been resolved yet. The acceptance criteria in current seismic rehabilitation provisions are defined at the element level with no due consideration for the system robustness. Four sets of three-dimensional, geographically distributed hybrid simulations (HS) will be conducted using the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) facility at the University of Illinois at Urbana-Champaign to obtain the response up to collapse of a representative three-dimensional structural system subjected to one-directional and tri-axial seismic ground motions. This research will investigate, characterize, model, and derive practical procedures for the consequences of column shear-axial failure on the collapse of existing vulnerable RC structures. The project will develop system-level acceptance criteria and analytical tools for near collapse seismic performance of existing non-ductile RC frame structures. Data from this project will be archived and made available to the public through the NEES Project Warehouse/data repository at http://www.nees.org. This project is a collaborative effort between researchers from Northeastern University and Western Michigan University.

This project utilizes the unique hybrid simulation capability provided by NEES@Illinois to simulate near collapse response of existing vulnerable RC buildings through the integration of large-scale physical experiments and numerical models. If successful, this research project will shift the philosophy of structural assessment of vulnerable buildings from component-level to system-level evaluation. The application of system-level evaluation methods developed in this project can lead to more efficient and cost-effective rehabilitation methods for existing non-ductile RC buildings against collapse by identifying and prioritizing buildings susceptible to partial/total collapse. Thus, optimal use of limited resources can be made.

Testing of 1/10-scale models of the large-scale test specimens in the 1/5-Scale Laboratory is a critical step in the process to confirm that the complex hybrid simulation model and communications systems, including UI-SimCor, the simulation coordinator developed at the University of Illinois, will function as desired before moving on to the large-scale experiments.

This award is part of the National Earthquake Hazards Reduction Program (NEHRP).

You can watch activity in the MUST-SIM laboratory live by going to the Live Webcam on the NEES@Illinois homepage.

You can find more information regarding this project by going to the NEESR: Near Collapse Performance of Existing Reinforced Concrete Frame Buildings award announcement on the NSF website

September 6, 2013