Projects › Former

NEESR-II: Inelastic Web-Crushing Performance Limits of High-Strength-Concrete Structural Walls

Principal Investigators: Rigoberto Burgueno, Michigan State University; and Eric Hines, Tufts University.
This project will use the MAST 6-DOF Test System to investigate and establish rational performance levels for the development of seismic assessment and design approaches to high-strength-concrete (HSC) structural walls based on ductile shear failure mechanisms. The experimental component of the research is divided in two parts. Part I - Structural Wall Characterization: Investigation of the fundamental mechanisms and limits of dependable web crushing failures in HSC structural walls with confined boundaries for ductile shear response through pseudo-static tests on single walls with concrete strengths of 5, 10, 15, and 20 ksi. Part II - Wall Assemblies Characterization: Investigation of the three-dimensional behavioral mechanisms and the web-crushing performance limits of structural wall systems in the context of a hollow pier through multi-axial pseudo-static tests on two HSC wall-assembly test units with concrete strengths of 5 and 20 ksi.

NEESR-II: Highly Damage Tolerant and Intelligent Slab-Column Frame Systems Through Combination of Advanced Materials and Embedded Wireless Sensing

Principal Investigators: Gustavo Parra-Montesinos, University of Michigan; Carol Shield, University of Minnesota; Min-Yuan Cheng, University of Michigan.
Structural systems that combine reinforced concrete (RC) slab-column frames with moment resisting frames or shear walls find wide applications in zones of moderate and high seismicity. Due to combination of lateral displacements imposed during earthquakes with gravity loads, slab-column connections are prone to exhibit punching shear failures. Traditionally, the required shear strength of slab-column connections is achieved by the use of drop panels or shear stud rails. The work outlined in this proposal is to develop a highly damage tolerant and smart slab-column frame system through the use of high-performance fiber reinforced cement composites (HPFRCCs) and wireless sensing technology. The development of new materials (HPFRCC) and smart structure technologies (computationally rich wireless sensors) have previously occurred in isolated research communities – this proposal is a first of its kind to explore their combination so that an intelligent HPFRCC structure capable of sustaining large drift demands and self-performance monitoring can be derived. The revolutionary features of the NEES infrastructure offer exciting paths of exploration that will lead to a more profound investigation of intelligent HPFRCC slab-column systems. For more information about this project, please visit the project website.
Publications:
Cheng, M.-Y., Parra-Montesinos, G.J., and Shield, C.K. (2008). "Effectiveness of steel fibers versus shear stud reinforcement for punching shear resistance in slab-column connections subjected to bi-axial lateral displacements," 14th World Conference on Earthquake Engineering, Beijing, China, October 2008.
Parra-Montesinos, G.J., Cheng, M.-Y., and Shield, C.K. (2008). "Punching shear strength and deformation capacity of fiber reinforced concrete slab-column connections under earthquake-type loading," 7th RILEM International Symposium on Fibre Reinforced Concrete: Design and Applications (BEFIB 2008), Chennai, India, September 2008.

Pre-NEESR: Testing and Analyses of Nonrectangular Walls Under Multi-Directional Loads

Principal Investigators: Catherine French, University of Minnesota; Sri Sritharan, Iowa State University; Ricardo Lopez-Rodriguez, University of Puerto Rico, Mayaguez; Beth Brueggen, University of Minnesota; Jon Waugh, Iowa State University.
This project uses the 6-dof control capabilities of the MAST system to improve understanding of the behavior of T-shaped concrete shear walls. Nonrectangular shear walls are created by joining perpendicular shear walls to one another instead of leaving them separate. They are often placed around elevators and stairwells in building cores to provide lateral strength and stiffness. Because of limitations on testing equipment, previous research on nonrectangular walls has been limited to unidirectional loading or very simple bidirectional loading. Additionally, much of what is assumed about the behavior of these non-rectangular walls has been extrapolated from testing of simple rectangular walls. This research will help increase our understanding of these walls and may lead to specific design recommendations to assist engineers in the design of new structures. For more information about this project, please visit the project website.
Publications:
Brueggen, B., J. Waugh, S. Aaleti, B. Johnson, C. French, S. Sritharan, and S. Nakaki, (2007). "Tests of structural walls to determine deformation contributions of interest for performance-based design," Proceedings, 2007 Structures Congress, ASCE, Reston, VA.
French, C., Brueggen, B., Johnson, B., Sritharan, S., Waugh, J., Aaleti, S., Lopez-Rodriguez, R. R., Nakaki-Dow, S., (2008). "Collaborative Research: Testing and Analyses of Nonrectangular Walls under Multi-Directional Loads," NSF Engineering Research and Innovation Conference, Knoxville, TN.