Rotation capacity and stress redistribution ability of R-UHPFRC–RC composite continuous beams: an experimental investigation

Abstract

The results of tests on two continuous composite beams combining a reinforced concrete (RC) beam with a layer of reinforced ultra-high performance fiber reinforced concrete (R-UHPFRC) are presented. The R-UHPFRC element acts both as a tensile membrane and a flexural element. The tests show the element's contribution to the member capacity by allowing the redistribution of the internal forces. The continuous beams are placed on two intermediate supports; the shear span-depth ratios and stirrup content are chosen to provoke two successive formations of local flexure-shear collapse mechanisms, forming a plastic hinge at each support. With the formation of the first support hinge, the stresses redistribute. As the applied actuator displacement increases, the member continues to resist the increasing force up to the formation of a second support hinge that causes the member to collapse. The member deflection and resistance at collapse were respectively 4.5 and 1.3 times greater than the corresponding values at the formation of the first hinge. The response demonstrates the redundancy in RC beams with additional R-UHPFRC reinforcement, which can be used for designing structures against progressive collapse.

Tailoring Confining Jacket for Concrete Column Using Ultra High Performance-Fiber Reinforced Cementitious Composites (UHP-FRCC) with High Volume Fly Ash (HVFA)

“…One of the most well-known and relevant applications of UHP-FRCC is the retrofitting of existing structures, especially the jacketing of concrete columns and beams, due to these mechanical properties. The aim is to harden those parts of the existing structures that are exposed to high environmental and mechanical actions, especially in the most highly stressed cross-sections and in the structural joints [8,9,10].…”

Ultra-High-Performance Fibre-Reinforced Concrete for Rehabilitation and Strengthening of Concrete Structures: A Suitability Assessment

“…Shear strengthening can be carried out to avoid these brittle shear failures which violate the limit state design concept. Noshiravani and Brühwiler [100] presented the results of an experimental programme for strengthening RC beams with UHPFRC. A cantilever beam test set-up was used to test beams with a span of 1600 mm and a lever-arm length of 800 mm.…”

“Structural UHPFRC”: Welcome to the post-concrete era !

“…With an appropriate design of the rebars in the UHPFRC layer, the reduction of plastic rotation capacity can be controlled. Smooth high yield strength reinforcing bars in the UHPFRC layer offer a large increase in resistance while the post-peak rotation capacity remains high [7,15]. The structural behavior in terms of moment -curvature relation of composite sections subjected to bending as well as the ultimate bending moment are calculated using the conventional sectional model for RC with the extension to account for the R-UHPFRC layer in the monolithic section (Fig.…”