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 cooling. Such a heat treatment process reduces the strength of steel... (more)

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 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. (hide)

Equipment	Component	Equipment Class	Facility
6 DOF Test System	6 DOF Controller	Other Utilities	University of Minnesota-Twin Cities
6 DOF Test System	Hydraulic Command and Control Computer	Other Utilities	University of Minnesota-Twin Cities
6 DOF Test System	Hydraulic Pump, 190 gpm	Hydraulic Power Infrastructure	University of Minnesota-Twin Cities
6 DOF Test System	North Strongwall, 7' x 35' x 35'	Reaction System	University of Minnesota-Twin Cities
6 DOF Test System	Strong Floor, 5.5	Reaction System	University of Minnesota-Twin Cities
6 DOF Test System	Threaded Adapters (x68)	Other Utilities	University of Minnesota-Twin Cities
6 DOF Test System	West Strong Wall, 7' x 35' x 35'	Reaction System	University of Minnesota-Twin Cities
Ancillary Actuator	220-Kip Ancillary Actuator Strong Wall/Strong Floor Attachment Bracket	Hydraulic Actuator	University of Minnesota-Twin Cities
Calibration Equipment	Invar Bars	Other Utilities	University of Minnesota-Twin Cities
Calibration Equipment	Mitutoyo Calipers	Other Utilities	University of Minnesota-Twin Cities
Calibration Equipment	Mitutoyo Gauge Blocks	Other Utilities	University of Minnesota-Twin Cities
Calibration Equipment	Trimos	Other Utilities	University of Minnesota-Twin Cities
Construction Equipment	25 ft Scissorslift	Other Utilities	University of Minnesota-Twin Cities
Construction Equipment	32 ft Scissorslift	Other Utilities	University of Minnesota-Twin Cities
Construction Equipment	EFCO Components	Other Utilities	University of Minnesota-Twin Cities
Construction Equipment	Supernuts	Other Utilities	University of Minnesota-Twin Cities
DAQ	Data Acquisition Computer	Other Utilities	University of Minnesota-Twin Cities
DAQ	NI Data Acquisition Board	DAQ Infrastructure	University of Minnesota-Twin Cities
DAQ	NI SCXI-1001	DAQ Infrastructure	University of Minnesota-Twin Cities
DAQ	NI SCXI-1102	DAQ Infrastructure	University of Minnesota-Twin Cities
DAQ	NI-SCXI-1520 8 channel universal strain bridge	DAQ Infrastructure	University of Minnesota-Twin Cities
DAQ	Sensor Connect Boxes	DAQ Infrastructure	University of Minnesota-Twin Cities
Krypton Measurement System	Calibration and Certification Documents	DAQ Infrastructure	University of Minnesota-Twin Cities
Krypton Measurement System	Krypton Calibration Bar	DAQ Infrastructure	University of Minnesota-Twin Cities
Krypton Measurement System	Krypton K600 Controller and Software	Other Utilities	University of Minnesota-Twin Cities
Krypton Measurement System	Metris (Krypton) K600 Camera	DAQ Infrastructure	University of Minnesota-Twin Cities
Krypton Measurement System	Metris (Krypton) LED Strober	DAQ Infrastructure	University of Minnesota-Twin Cities
Krypton Measurement System	Metris (Krypton) LEDs	DAQ Infrastructure	University of Minnesota-Twin Cities
Krypton Measurement System	Space Probe	DAQ Infrastructure	University of Minnesota-Twin Cities
Moving and Lifting Equipment	3 Ton Overhead Crane	Other Utilities	University of Minnesota-Twin Cities
Moving and Lifting Equipment	50 Ton Overhead Crane	Other Utilities	University of Minnesota-Twin Cities
Moving and Lifting Equipment	9000 lb capacity forklift	Other Utilities	University of Minnesota-Twin Cities
Networking	Cisco Catalyst	LAN Infrastructure	University of Minnesota-Twin Cities
Server	AXIS Q7900 Rack	Video Server	University of Minnesota-Twin Cities
Server	Backup Image Server	Computer System	University of Minnesota-Twin Cities
Server	Dell Poweredge 2950 Server	Computer System	University of Minnesota-Twin Cities
Server	HP LeftHand P4300 12TB SATA Starter SAN Solution	Computer System	University of Minnesota-Twin Cities
Server	Raritan Paragon II-UMT442 KVM Switch	Computer System	University of Minnesota-Twin Cities
Server	Tape Library	Computer System	University of Minnesota-Twin Cities
Telepresence	Audio Archiving and Streaming Computer	Other Utilities	University of Minnesota-Twin Cities
Telepresence	Central Control and Configuration Computer	Other Utilities	University of Minnesota-Twin Cities
Telepresence	Color Digital Still Image Camera	Camera	University of Minnesota-Twin Cities
Telepresence	Communication Color Video Camera	Camera	University of Minnesota-Twin Cities
Telepresence	Communication Color Video Camera	Camera	University of Minnesota-Twin Cities
Telepresence	Component Video Distributors	Other Utilities	University of Minnesota-Twin Cities
Telepresence	Computer Controlled Pan/Tilt Unit	Camera	University of Minnesota-Twin Cities
Telepresence	HD Color Video Cameras	Camera	University of Minnesota-Twin Cities
Telepresence	Microphone	Camera	University of Minnesota-Twin Cities
Telepresence	NEES Client Computer	Other Utilities	University of Minnesota-Twin Cities
Telepresence	NEES Client Laptop Computer	Other Utilities	University of Minnesota-Twin Cities
Telepresence	Robotic Towers	Camera	University of Minnesota-Twin Cities
Telepresence	Stereo Microphone Preamplifier	Camera	University of Minnesota-Twin Cities
Telepresence	Video Encoding Server	Other Utilities	University of Minnesota-Twin Cities
Telepresence	Video Internet Appliance	Other Utilities	University of Minnesota-Twin Cities

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