Behavior of Diagonally-Reinforced Concrete Coupling Beams With High-Strength Steel Bars


Abstract eng:
Coupling beams reinforced with Grade 60 (420 MPa) steel and with a clear span-to-depth ratio less than 2.0 often require heavily congested diagonal reinforcement to ensure adequate strength, stiffness, and deformation capacity. The constructability of these members would be markedly improved if the diagonal reinforcement were replaced with a smaller quantity of high-strength steel reinforcement. The aim of this study is to determine whether coupling beam performance is compromised when high-strength (Grade 120, or 830 MPa) steel is used in place of conventional reinforcement. Tests have been designed to investigate the behavior of diagonally reinforced coupling beams constructed with Grade 120 (830 MPa) steel reinforcement under reversed cyclic loading. Three beams have been designed and constructed; one with Grade 60 (420 MPa) reinforcement and two with Grade 120 (830 MPa) reinforcement. One of the specimens with Grade 120 reinforcement was designed based on a shear stress of 15√f’c, psi (1.25√f’c, MPa), where f’c is the specified concrete compressive strength. The other specimens were designed for a shear stress of 10√f’c, psi (0.83√f’c, MPa), the upper limit permitted by the ACI Building Code. High target shear stresses are feasible, from a constructability standpoint, because of the significant reduction in reinforcement volume associated with the use of high-strength reinforcement. The specimens have dimensions of 10 by 18 in. (25.4 by 45.7 cm) and a length of 34 in. (86.4 cm), which results in an aspect ratio of 1.9. The beams were cast monolithically with larger concrete sections at each end to simulate interfaces with wall boundary elements. A summary of the experimental program is presented with details on test setup, loading protocol, and specimen design. Preliminary test results are reported for the specimen with Grade 120 (830 MPa) reinforcement with a target shear stress of 10√f’c, psi (0.83√f’c, MPa).

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 2497.:
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