Self-Centering Beams for Resilient Earthquake Resistance
A self-contained self-centering beam (SCB) has been developed that provides self-centering seismic behavior with enhanced constructability (Darling 2012). The SCB consists of a beam with concentric tubes connected to the bottom flange. The tubes at the bottom flange are precompressed using post-tensioning strands and connected to the beam and columns in such a way as to produce restoring forces regardless of whether the SCB is racked to the right or left.
Preliminary design, computational analyses, and large-scale experiments show that this system offers several advantages as compared to some currently available self-centering seismic systems. The SCB can be shop fabricated and allows erection with conventional field construction techniques. There is no post-tensioning in the field or fit-up of bearing surfaces. Preliminary SCB designs required approximately the same amount of steel as the comparison SMRF suggesting a relatively competitive cost compared with conventional moment frames, although some cost premium is possible associated with fabrication (Darling and Eatherton 2012). Furthermore, the SCB behavior characteristics, such as strength, stiffness, and ductility can be independently tuned. Unlike conventional moment frames, this system will not require the lateral strength to be overdesigned relative to demands. Also, frame layout in a floor plan is not constrained by special detailing as required for currently available SC moment frames which experience floor expansion.
Research is being conducted to develop this system for use in practice. Component tests were conducted on post-tensioning assemblies and energy dissipating elements. Large-scale testing is be conducted, accompanied by significant computational modeling.
Schematic Drawing of the Frame Analyzed in Darling and Eatherton 2012
Research Supported by: National Science Foundation and Virginia Tech
For a video of the test, click here: Testing Video
Eatherton, M.R. and Maurya, A. (2020) “Experimental Investigation of a Self-Centering Beam Moment Frame”, AISC Engineering Journal, Vol. 57, pp. 221-241.
Maurya, A., Eatherton, M.R., Matsui, R., and Florig, S.H. (2016) “Experimental Investigation of Miniature Buckling Restrained Braces for Use as Structural Fuses” Journal of Constructional Steel Research, Vol. 127, pp. 54-65.
Maurya, A., and Eatherton, M.R. (2016) “Experimental Study of the Restoring Force Mechanism in the Self-Centering Beam (SCB)” Frontiers of Structural and Civil Engineering, Vol. 10, No. 3, pp. 272-282.
Darling, S. (2012) Seismic Response of Short Period Structures and the Development of a Self-Centering Truss Moment Frame with Energy-Dissipating Elements for Improved Performance, M.S. Thesis, Virginia Tech
Maurya, A., (2016) Experimental and Computational Investigation of a Self-Centering Beam Moment Frame (SCB-MF), Ph.D. Dissertation, Virginia Tech
- Buckling Restrained Brace Subassemblage Testing
- Testing of Steel Crates
- Development of a Spectral Matching Algorithm
- End-Plate Moment Connections
- Ring-Shaped Steel Plate Shear Walls
- Super High Tension Bolts
- Effect of Fasteners and Defects in the Protected Zone on the Performance of Moment Frames
- Controlled Rocking of Steel Braced Frames with Replaceable Energy Dissipating Fuses
- Development of a Self-Centering Buckling Restrained Brace
- Understanding Structural Response During Earthquakes Using Wavelet Transforms
- Characterizing Hysteretic Behavior of Cold-Formed Steel Members and Connections