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MAST Laboratory
2525 4th St SE
Minneapolis, MN 55455

612-626-9561 main
612-624-5964 fax

Dept. of Civil Engineering
500 Pillsbury Drive SE
Minneapolis, MN 55455

612-625-5522 main
612-626-7750 fax
cive@umn.edu

Projects › Former

For a complete list of the University of Minnesota's current and former NEES experiments, see their activity page on the national NEES hub at nees.org/sitesactivities.

NEESR-CR: Multi-Scale, Mechanistic Fracture Prediction and Optimal Panel Zone Participation in Steel Moment Frame Buildings

Principal Investigators: Fry, Texas A&M
Steel moment frames are widely used for seismic-resistant building construction throughout the United States and in many other parts of the world. Although steel moment frames were studied extensively following the 1994 Northridge, California, earthquake, one critical technical issue remains unsolved: the role of the panel zone in steel moment frame joints (beam to column connections). Recent U.S. building codes have significantly increased the required strength of panel zones in steel moment frames. To satisfy these requirements, column sizes must be increased or doubler plates must be welded to the column, resulting in increased cost, sometimes substantially so. However, there is significant experimental evidence that moment frame joints with weak panel zones show highly ductile performance, and consistently achieve large interstory drift angles under cyclic loading without strength degradation. There is also analytical evidence suggesting excellent overall seismic performance can be achieved by moment frames with weak panel zones. This strongly suggests that current building codes have adopted an incorrect approach to panel zone design, needlessly increasing the cost of construction while potentially degrading seismic performance. The overall goal of this research is to resolve the question: how much panel zone participation should be permitted in evaluating the inelastic seismic response of a steel moment frame? Despite a number of past studies on this issue, there are sharply conflicting views of how panel zones should be treated in design, both within the research community as well as within the building regulatory community. At the crux of the disagreements are concerns regarding fracture induced by panel zone yielding. There appears to be broad agreement that panel zone yielding is a highly ductile process. However, there is broad disagreement on the role that panel zone yielding plays in joint fracture. To address these concerns will require the fundamental capability to predict fracture at joints with weak panel zones subject to seismic loading. Thus, the intellectual merit and a key objective of this research is to advance the state of the art in predicting cyclic rupture within critical ductile components of steel building structures, and to apply this knowledge to the problem of the panel zone in steel moment frames. To meet these goals, this research project will integrate (1) fundamental studies on cyclic rupture of steel components combined with high resolution finite element simulations of beam-column joints,(2) advanced frame simulation studies, (3) large-scale experimental studies conducted at the NEES equipment at the University of Minnesota, and (4) parametric computational studies on joint performance. With respect to broader impacts, the knowledge gained from this research is expected to impact design practice and building codes for seismic-resistant steel moment frames.

NEESR-CR Assessment of Punching Shear Vulnerability

Principal Investigators: G. Parra-Montesinos, University of Michigan; C.K. Shield, University of Minnesota
Slab-column (flat plate) frame systems are widely used in concrete construction because of their architectural appearance, functionality and economy. In regions of high seismic hazard, they have been used in structures of up to 60 stories, in combination with structural walls or moment resisting frames. Because of their potential for punching shear failures during earthquakes, shear reinforcement is often provided in the form of headed shear studs. Results from a test conducted as part of a NEESR project, however, have raised serious concerns about the effectiveness of this reinforcement for punching shear resistance. Given the large number of flat-plate structures with headed reinforcement built in the last decade, these test results could be an indication of a latent major problem that could surface in the next large earthquake on the west coast. It should be kept in mind that flat-plate connections with shear stud reinforcement have yet to be tested during a major earthquake. Thus, research is necessary to quantify the magnitude of the problem and develop retrofit strategies for preventing wide-spread failures during a large earthquake. If this is indeed as serious of a problem as the NEESR test results seem to indicate, the earthquake engineering community should act with diligence and prevent a situation similar to that observed with welded steel connections during the Northridge earthquake.

Publications also see project publications website:
Matzke, E. M. (2012), "Punching Shear Strength and Drift Capacity of Slab-Column Connections with Headed Shear Stud Reinforcement Subjected to Combined Gravity Load and Biaxial-Lateral Displacements," http://nees.org/resources/6762.

NEESR-CR: An Innovative Seismic Performance Enhancement Technique for Steel Building Beam-Column Connections

Principal Investigators: Hassan, NCSU
The proposed seismic enhancement technique involves heat treating sections of beam flanges by exposing these sections to a very high temperature for certain amount of time before slow air cooling. Such a heat treatment process reduces the strength of steel in the heat treated areas of the flange. Consequently, under seismic loading, a plastic hinge develops at the heat treated beam section (HBS). A connection enhanced by this technique will have the advantages of the popular reduced beam section (RBS) connection, but the HBS will have better energy dissipation than the RBS connection. In RBS connections, .weakening. of the beam flanges induces a plastic hinge away from the welds. In HBS connections, a plastic hinge develops at the heat treated section because of the reduced strength of steel. Moreover, as the beam flange remains intact and the inelastic modulus of steel is not altered at the HBS, the lateral and torsional buckling resistances of the HBS connection will be higher than those of the RBS connection. Consequently, the HBS connection will dissipate a larger amount of energy with a minimum loss of strength or stiffness compare to the RBS connection. Through a pilot study at NCSU, the seismic performance enhancement technique is validated analytically. This project will validate the technique by conducting full-scale connection experiments. Currently, RBS is the most popular connection design because of its seismic performance and cost effectiveness. The HBS connection is anticipated to be more seismically robust and economical than the RBS connection. The research will be performed through integrated experimental and analytical studies. Material experiments of heat treated and unconditioned coupons will be conducted and data will be analyzed to quantify the influence of heat treatment parameters (peak temperature and hold time) on the reduction of strength and to determine the constitutive model parameters. Detailed structural analyses of HBS connections will be performed to determine the optimum heat treatment parameters and geometry of HBS. Beam-column connections with and without HBS will be built and tested to demonstrate seismic performance enhancement of the modified connections. Detailed measurement of strains, displacements and rotations at various locations will be recorded for investigating both the local and global failure modes of HBS connections. Experimental and analytical results will be used to refine the technique and to develop a methodology for practical application of the technique.

NEESR-SG International Hybrid Simulation of Tomorrow's Braced Frame System

Principal Investigators: C. Roeder and D. Lehman, University of Washington; S. Mahin, University of California, Berkeley; T. Okazaki, C. Shield and K. Palmer, University of Minnesota; K.C. Tsai, National Center of Research in Earthquake Engineering, Taiwan; R. Tremblay, Ecole Polytechnique de Montreal, Canada; K. Kasai, Tokyo Institute of Technology, Japan;M. Nakashima, E-Defense, National Research Institute for Earth Science and Disaster Prevention, Japan.
Concentrically braced frames (CBFs) and buckling-restrained braced frames (BRBFs) are commonly used seismic-load resisting systems. A key design component in CBFs is the bracing connections which must develop the large strength of the brace in tension and accommodate the large rotation associated with brace buckling. Recent tests suggest that the interaction between framing action and brace connections can negatively affect the behavior of SCBFs. Additionally, recent tests indicate that the drift capacity of BRBFs can be rather small in cases when premature yielding of the beams and columns triggers instability of the system. In order to further examine the system behavior of CBFs and BRBFs, large-scale, three-dimensional tests will be conducted at the MAST laboratory at the University of Minnesota. These tests are a part of the NSF-NEES project entitled .International Hybrid Simulation of Tomorrow's Braced Frame Systems.. Two specimens will be tested in this program, a CBF specimen with HSS braces, and a BRBF specimen. The specimen design reflects the latest research findings from this ongoing project. Furthermore, the specimens include unique features such as: some braces framing into the column web; orthogonal brace bents sharing a corner column; a composite concrete slab; near-full scale; and braced bents loaded in the out-of-plane as well as in-plane direction. The 3D specimens will be tested under a bidirectional loading program based on a series of nonlinear time history analyses.

Publications also see project publications website:
Keith Palmer (2012), "Seismic Behavior, Performance and Design of Steel Concentrically Braced Frame Systems," http://nees.org/resources/5315.

Christopulos, A. S. (2005), "Improved Seismic Performance of Buckling Restrained Braced Frames," Department of Civil and Environmental Engineering, University of Washington.

Kotulka, B. A. (2007), "Analysis for a Design Guide on Gusset Plates used in Special Concentrically Braced Frames," Department of Civil and Environmental Engineering, University of Washington.

Herman, D. J. (2007), "Further Improvements on and Understanding of Special Concentrically Braced Frame Systems," Department of Civil and Environmental Engineering, University of Washington.

Lumpkin, E. J. (2009), "Enhanced Seismic Performance of Multi-Story Special Concentrically Brace Frames using a Balanced Design Procedure," Department of Civil and Environmental Engineering, University of Washington.

Powell, J. A. (2010), "Evaluation of Special Concentrically Braced Frames for Improved Seismic Performance and Constructability," Department of Civil and Environmental Engineering, University of Washington.

Clark, K. A. (2009), "Experimental Performance of Multi-Story X-Braced SCBF Systems," Department of Civil and Environmental Engineering, University of Washington.

Johnson, S. M. (2005), "Improved Seismic Performance of Special Concentrically Braced Frames," Department of Civil and Environmental Engineering, University of Washington.

NEES-II System Behavior Factors for Composite and Mixed Structural Systems

Principal Investigators: Roberto Leon, Georgia Institute of Technology; Jerome Hajjar, University of Illinois; Tiziano Perea, Georgia Institute of Technology; and Mark Denavit, University of Illinois.
This project is a NEESR-II award with the aim of developing system behavior factors for frames with composite beam-columns subjected to seismic loads. The system behavior factors to be developed in this research include the structural system (R) factor, lateral displacement amplification factor (Cd), and the system overstrength (Ω0) factor. In order to reach these goals, analytical and experimental studies will be conducted on both rectangular and circular concrete-filled tubes (RCFT and CCFT) and encased (SRC) shapes. The analytical studies will include parametric fiber and finite element analytical models. The experimental part to be conducted at MAST includes testing of 24 full-scale slender composite beam-columns (10 CFT, 8 RCFT and 6 SRC) to evaluate their strength, ductility and stiffness under large lateral displacements.

Publications also see project publications website:
Perea, T., Leon, R. T., Hajjar, J. F., and Denavit, M. D. (2012). "Full-Scale Tests of Slender Concrete-Filled Tubes: Axial Behavior," Journal of Structural Engineering, ASCE, (submitted for publication).

Denavit, M. D. and Hajjar, J. F. (2012). "Nonlinear Seismic Analysis of Circular Concrete-Filled Steel Tube Members and Frames," Journal of Structural Engineering, ASCE, (in press).

Denavit, M. D., Hajjar, J. F., and Leon, R. T. (2012). "Stability Analysis and Design of Steel-Concrete Composite Columns," Proceedings of the Annual Stability Conference, Grapevine, Texas, April 18-21, 2012, Structural Stability Research Council, Rolla, Missouri.

Hajjar, J. F., Denavit, M. D., Perea, T., and Leon, R. T. (2012). "Seismic Design and Stability Assessment of Composite Framing Systems," Proceedings of the 9th Conference or Urban Earthquake Engineering, Tokyo, Japan, March 6-8, 2012, Tokyo Institute of Technology, Tokyo, Japan.

Leon, R. T., Perea, T., Hajjar, J. F., and Denavit, M. D. (2011). "Concrete-filled Tubes Columns and Beam-Columns: A Database for the AISC 2005 and 2010 Specifications," Festschrift Gerhard Hanswille, Wuppertal, Germany, October 1-3, 2011, IKIB, Wuppertal, Germany, pp. 203-212.

Hajjar, J. F. and Denavit, M. D. (2011). "New Trends for Seismic Engineering of Steel and Composite Structures," Third International Symposium on Innovative Design of Steel Structures, Singapore and Hong Kong, June 28-30, 2011.

Denavit, M. D., Hajjar, J. F., and Leon, R. T. (2011). "Seismic Behavior of Steel Reinforced Concrete Beam-Columns and Frames," Proceedings of the ASCE/SEI Structures Congress 2011, Las Vegas, Nevada, April 14-16, 2011, ASCE, Reston, Virginia.

Perea, T., Leon, R. T., Denavit, M., and Hajjar, J. F. (2010). "Experimental Tests on Cyclic Beam-Column Interaction Strength of Concrete-Filled Steel Tubes," Proceedings of the 9th National Conference on Earthquake Engineering, Rathje, E. M. and Atkinson, G. A. (eds.), Toronto, Canada, July 12-14, 2010, Earthquake Engineering Research Institute, Oakland, California.

Denavit, M. D., Hajjar, J. F., Perea, T., and Leon, R. T. (2010). "Cyclic Evolution of Damage and Beam-column Interaction Strength of Concrete-Filled Steel Tube Beam-Columns," Proceedings of the 9th National Conference on Earthquake Engineering, Rathje, E. M. and Atkinson, G. A. (eds.), Toronto, Canada, July 12-14, 2010, Earthquake Engineering Research Institute, Oakland, California.

Leon, R. T., Perea, T., Hajjar, J. F., and Denavit, M. D. (2009). "Determination of Buckling Loads from Triaxial Load Tests of Slender Concrete-Filled Steel Tube Beam-Columns," Proceedings of the Third International Conference on Advances in Experimental Structural Engineering, San Francisco, California, October 15-16, 2009.

Denavit, M. D., Hajjar, J. F., Perea, T. and Leon, R. T. (2009). "Seismic Multi-Axial Behavior of Concrete-Filled Steel Tube Beam-Columns," Proceedings of the Asian-Pacific Network of Centers for Earthquake Engineering Research, Urbana, Illinois, August 13-14, 2009.

Perea, T. and Leon, R. T. (2008). "Behavior of Composite CFT Beam-Columns Based On Nonlinear Fiber Element Analysis," Proceedings of the 6th International Conference on Composite Construction in Steel and Concrete VI, Tabernash, Colorado, USA, July 20-24, 2008.

Reports and Theses (downloads available from project website):
Perea, T. (2010). "Analytical and Experimental Study on Slender Concrete-Filled Steel Tube Columns and Beam-Columns," Ph.D. dissertation, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, December.

Denavit, M. D. and Hajjar, J. F. (2010). "Nonlinear Seismic Analysis of Circular Concrete-Filled Steel Tube Members and Frames," Report No. NSEL-023, Newmark Structural Laboratory Report Series (ISSN 1940-9826), Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, March.

Gourley, B. C., Tort, C., Denavit, M. D., Schiller, P. H., and Hajjar, J. F. (2008). "A Synopsis of Studies of the Monotonic and Cyclic Behavior of Concrete-Filled Steel Tube Beam-Columns," Report No. NSEL-008, Newmark Structural Laboratory Report Series (ISSN 1940-9826), Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, April.

NEESR-GC: Mitigation of Collapse Risk in Vulnerable Concrete Buildings

Principal investigators: Jack Moehle, University of California at Berkeley; Adolfo Matamoros, University of Kansas; and Julio Ramirez, Purdue University.
The project will use the multi-directional loading capabilities of the MAST advanced 6-DOF control technology to study column behavior as it has not been done to date. The proposed experimental program will include 24 full-scale, rectangular cross-section columns. The specimens tentatively will have dimensions of 18x18 in. Specimens will have ~4,000-psi concrete with Gr. 60 deformed bars

Publications also see project publications website:

Kurt Henkhaus; Julio Ramirez; Santiago Pujol (2010), "Simultaneous Shear and Axial Failures of Reinforced Concrete Columns," http://nees.org/resources/747.

Adolfo Benjamin Matamoros; Lisa Matchulat (2010), "Axial Load Failure of Shear Critical Columns Subjected to High Levels of Axial Load," http://nees.org/resources/749.

Kurt Henkhaus (2012), "Axial Failure of Vulnerable Reinforced Concrete Columns Damaged by Shear Reversals," http://nees.org/resources/4980.

M.F. Riemer; Jack Moehle; Bozidar Stojadinovic; M.F. Riemer (2011), "Analytical and Experimental Assessment of Seismic Vulnerability of Beam-Column Joints without Transverse Reinforcement in Concrete Buildings," http://nees.org/resources/5607.

Sangjoon Park; Khalid Mosalam (2012), "Experimental and Analytical Studies on Reinforced Concrete Buildings with Seismically Vulnerable Beam- Column Joints," http://nees.org/resources/5609.

Sangjoon Park; Khalid Mosalam, "PEER_Report_about_Berkeley-C-series."

Michael James Givens, "Soil-Structure Interaction, Test Site No. 3, Experimental Setup Report."

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.

Publications also see project publications website:
(2009), "Final Research Report on HSC Wall Assemblies," http://nees.org/resources/4509.

(2009), "Final Research Report on HSC Cantilever Walls," http://nees.org/resources/4529.

(2010), "Final Research Report on Finite Element Analysis of HSC Structural Walls," http://nees.org/resources/4531.

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.

Publications also see project publications website:
Cheng, M.-Y., Parra-Montesinos, G.J. (2010), "UMCEE 09-01: Punching Shear Strength and Deformation Capacity of Fiber Reinforced Concrete Slab-Column Connections Under Earthquake-Type Loading," http://nees.org/resources/549.

Cheng, M.-Y., Parra-Montesinos, G.J. (2010), "Evaluation of Steel Fiber Reinforcement for Punching Shear Resistance in Slab-Column Connections-Part I: Monotonically Increased Load," http://nees.org/resources/830.

Cheng, M.-Y., Parra-Montesinos, G.J., and Shield, C.K. (2010), "Shear Strength and Drift Capacity of Fiber-Reinforced Concrete Slab-Column Connections Subjected to Biaxial Displacements," http://nees.org/resources/834.

Cheng, M.-Y., Parra-Montesinos, G.J. (2010), "Evaluation of Steel Fiber Reinforcement for Punching Shear Resistance in Slab-Column Connections-Part II: Lateral Displacement Reversals," http://nees.org/resources/832.

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.

Publications also see project publications website:
Johnson, B. (2010), "Anchorage Detailing Effects on Lateral Deformation Components of R/C Shear Walls," http://nees.org/resources/234.

Brueggen, B. (2010), "Performance of T-shaped Reinforced Concrete Structural Walls under Multi-Directional Loading," http://nees.org/resources/236.

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.