Material Behavior

Seismic Behavior of Ultra-High-Performance Fiber-Reinforced Concrete Moment Frame Members

---

Abstract

Ultra-high-performance fiber-reinforced concrete (UHP-FRC) has superior material properties with high compressive strength (> 22 ksi [150 MPa]) and shear strength, improved tensile and compressive ductility, and excellent bond and confinement characteristics. All of these features provide an improved and innovative way to design earthquake-resistant moment frame members. In order to maintain adequate ductility, high-strength concrete (HSC) requires a large amount of transverse reinforcement, which has traditionally added to the complexity of the process. In UHP-FRC, the addition of high-strength steel microfibers into high-strength concrete can resolve such congestion issues and still allow the concrete to remain self-consolidating. The use of UHP-FRC completely changes the typical failure modes of flexural concrete members of moment frames as it improves confinement and prevents premature concrete distress and bar buckling, which provides increased resistance to strong seismic forces. Current ACI 318 provisions limit the longitudinal reinforcement ratio in beams of special moment frames to prevent undesirable shear damage. On the other hand, using UHP-FRC can also result in reduced cross sections or an increased number of longitudinal bars because of its high shear resistance capacity. Since the compressive and post-cracking tensile behavior of UHP-FRC is different from that of conventional concrete, new design criteria need to be developed for UHP-FRC flexural members of special moment frames. This paper presents the authors’ research on the novel design aspects of UHP-FRC and their experimental results after testing full- and large-scale UHP-FRC moment frame columns and beams.

Keywords: beam, moment frame, seismic, confinement, earthquake, UHP-FRC, column

How to Cite:

Chao, S., Kaka, V., Palacios, G., Kim, J., Choi, Y., Aghdasi, P., Nojavan, A. & Schultz, A., (2016) “Seismic Behavior of Ultra-High-Performance Fiber-Reinforced Concrete Moment Frame Members”, International Interactive Symposium on Ultra-High Performance Concrete 1(1). doi: https://doi.org/10.21838/uhpc.2016.44