Title: Development of Precast High-Performance Fiber Reinforced Cement Composite Coupling Beams for Earthquake-Resistant Wall Systems

Author(s): G.J. Parra-Montesinos, J.K. Wight, and B.A. Canbolat

Publication: Symposium Paper

Volume: 228

Issue:

Appears on pages(s): 633-650

Keywords: displacement capacity; earthquake-resistant design; fiber reinforced concrete; load reversals; shear distortion; shear strength

DOI: 10.14359/14496

Date: 6/1/2005

Abstract:
Coupling beams in earthquake-resistant wall structures have long represented a design challenge due to the high shear stress and distortion demands imposed by strong earthquakes. Currently, the design of reinforced concrete coupling beams, particularly those with low span-to-depth ratios, involves substantial reinforcement detailing to ensure a stable behavior during earthquakes, leading to reinforcement congestion and construction difficulties. As a design alternative, the use of strain-hardening or high-performance fiber reinforced cement composites (HPFRCCs) in coupling beams was experimentally investigated. The use of composite materials with large strain capacity and damage tolerance was aimed at reducing transverse reinforcement requirements while maintaining adequate seismic behavior, making the construction of coupling beams more feasible. To validate this alternative, three HPFRCC coupling beam specimens and one control reinforced concrete coupling beam were tested. The main variables investigated were the type of material used in the coupling beams, fiber type, and reinforcement detailing. Test results indicate that in order to achieve large displacement capacity, diagonal reinforcement must be provided in the proposed HPFRCC coupling beams. However, the use of an advanced fiber cementitious material allowed the elimination of the transverse reinforcement required to provide confinement and diagonal bar support in RC coupling beams, thus, significantly simplifying the reinforcement details.