Title: Behavior of Steel Fiber-Reinforced Concrete Deep Beams with Large Opening

Author(s): Dipti R. Sahoo, Carlos A. Flores, and Shih-Ho Chao

Publication: Structural Journal

Volume: 109

Issue: 2

Appears on pages(s): 193-204

Keywords: deep beam; fiber-reinforced concrete; opening; structural concrete; strut-and-tie model

DOI: 10.14359/51683630

Date: 3/1/2012

Abstract:
Large openings in reinforced concrete (RC) deep beams generally interrupt the load transfer by concrete struts and cause a sharp decrease in strength and serviceability. The reinforcement detailing of these deep beams based on strut-and-tie models (STMs) can be complex and, very often, these models may not predict the failure mechanism of deep beams due to localized damages. This study investigates the performance of two RC and two steel fiber-reinforced concrete (SFRC) deep beams with large openings under monotonically increased concentrated loads. The boundary regions near the supports of two specimens were strengthened with steel cages formed by steel reinforcement bars. The RC specimen with strengthened boundaries exhibited a ductile mode of failure and had significantly higher ultimate strength than predicted by STMs. Although the complex reinforcement detailing as per STMs was not used, the SFRC specimens with 1.5% volume fraction of fibers reached much higher strength than the design load and exhibited significant postpeak residual strength and a ductile mode of failure.